1
|
Stellato C, Matsukura S, Fal A, White J, Beck LA, Proud D, Schleimer RP. Differential Regulation of Epithelial-Derived C-C Chemokine Expression by IL-4 and the Glucocorticoid Budesonide. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.10.5624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Airway epithelial cells are a rich source of eosinophil-selective C-C chemokines. We investigated whether cytokines and the topical glucocorticoid budesonide differentially regulate RANTES, monocyte chemoattractant protein-4 (MCP-4), and eotaxin mRNA and protein expression in the human bronchial epithelial cell line BEAS-2B and in primary human bronchial epithelial cells by Northern blot analysis and ELISAs. Eotaxin and MCP-4 mRNA expression induced by TNF-α alone or in combination with IFN-γ was near-maximal after 1 h, peaked at 4 and 8 h, respectively, remained unchanged up to 24 h, and was protein synthesis independent. In contrast, RANTES mRNA was detectable only after 2 h and slowly increased to a peak at 24 h, and was protein synthesis dependent. Induction of eotaxin and MCP-4 mRNA showed a 10- to 100-fold greater sensitivity to TNF-α compared with RANTES mRNA. IL-4 and IFN-γ had selective effects on chemokine expression; IL-4 selectively up-regulated the expression of eotaxin and MCP-4 and potentiated TNF-α-induced eotaxin, while IFN-γ markedly potentiated only the TNF-α-induced expression of RANTES. Although budesonide inhibited the expression of chemokine mRNA to a variable extent, it effectively inhibited production of eotaxin and RANTES protein. Budesonide inhibited both RANTES- and eotaxin promoter-driven reporter gene activity. Budesonide also selectively accelerated the decay of eotaxin and MCP-4 mRNA. These results point to IL-4 as a possible mediator by which Th2 cells may induce selective production of C-C chemokines from epithelium and indicate that glucocorticoid inhibit chemokine expression through multiple mechanisms of action.
Collapse
Affiliation(s)
- Cristiana Stellato
- *Division of Clinical Immunology and Allergy, Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224; and
| | - Satoshi Matsukura
- *Division of Clinical Immunology and Allergy, Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224; and
| | - Andrzej Fal
- *Division of Clinical Immunology and Allergy, Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224; and
| | - John White
- †Department of Pharmacology, SmithKline Beecham, King of Prussia, PA 19406
| | - Lisa A. Beck
- *Division of Clinical Immunology and Allergy, Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224; and
| | - David Proud
- *Division of Clinical Immunology and Allergy, Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224; and
| | - Robert P. Schleimer
- *Division of Clinical Immunology and Allergy, Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224; and
| |
Collapse
|
2
|
Liu L, Ridefelt P, Håkansson L, Venge P. Regulation of Human Eosinophil Migration Across Lung Epithelial Monolayers by Distinct Calcium Signaling Mechanisms in the Two Cell Types. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.10.5649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
In asthmatic patients, eosinophils massively infiltrate the lung tissues and migrate through lung epithelium into the airways. The regulatory mechanisms involved are obscure. We studied the role of calcium in the migration of human eosinophils across monolayers of human lung epithelial H292 cell line cells induced by combined chemotactic solutions of platelet-activating factor and C5a. The transepithelial migration of eosinophils was attenuated by depletion of the external Ca2+ in the migration system, whereas the eosinophil migration itself was unaffected as evidenced by measuring eosinophil chemotaxis in the Boyden chamber in the absence of epithelial cells. Buffering of intracellular Ca2+ in eosinophils with 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetra(acetoxymethyl) ester (BAPTA/AM) inhibited both eosinophil transepithelial migration and eosinophil chemotaxis in the Boyden chamber, suggesting the importance of intracellular Ca2+ in eosinophil transmigration. Although loading of BAPTA/AM or addition of thapsigargin to the epithelial cells effectively changed their cytoplasmic free Ca2+ concentrations, neither of these treatments affected transepithelial migration of eosinophils. Interestingly, addition of La3+ (0.2 mM) to epithelial cells suppressed eosinophil transmigration whereas addition of La3+ to eosinophils did not. Taken together, these results show the importance of Ca2+ in eosinophil migration across lung epithelium and support a distinctive regulatory role of intracellular and extracellular Ca2+ for the two cell types involved in this process; i.e., the transmigration of human eosinophils across a monolayer of lung epithelial cells is regulated by the intracellular Ca2+ in eosinophils, whereas the ability of the lung epithelial cell monolayer to allow eosinophil passage is dependent on the extracellular Ca2+.
Collapse
Affiliation(s)
- Lixin Liu
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Peter Ridefelt
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Lena Håkansson
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Per Venge
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| |
Collapse
|
3
|
Wickremasinghe MI, Thomas LH, Friedland JS. Pulmonary Epithelial Cells are a Source of IL-8 in the Response to Mycobacterium tuberculosis: Essential Role of IL-1 from Infected Monocytes in a NF-κB-Dependent Network. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.7.3936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Abstract
Pulmonary epithelial cells, covering a 70-m2 surface area, have not previously been considered an important source of chemokines in pulmonary tuberculosis. We analyzed IL-8 secretion from A549 cells and primary normal human bronchial epithelial cells (NHBE) infected by Mycobacterium tuberculosis. Direct infection of A549 cells by M. tuberculosis caused IL-8 secretion of 7720 ± 1610 pg/106 cells, but no IL-8 secretion from NHBE after 24 h. In contrast, conditioned media from M. tuberculosis-infected human monocytes (CoMTB) induced a much greater IL-8 secretion of 92,635 ± 13,180 pg/106 A549 cells and 13,416 ± 3,529 pg/106 NHBE after 24 h. CoMTB induced rapid IL-8 mRNA accumulation, which was stable over 24 h, compared with TNF-α-induced transcripts. CoMTB stimulated nuclear binding of p65, p50, and c-Rel subunits of NF-κB to IL-8 promoter sequences. Transient transfections with IL-8 promoter reporter constructs showed NF-κB binding-site mutations abolished IL-8 promoter activity while NF-IL-6 binding-site mutations decreased promoter activity to 50.2 ± 6.3% of wild-type activity. IL-1R antagonist but not neutralizing anti-TNF-α inhibited epithelial cell IL-8 secretion, mRNA accumulation, and NF-κB binding. Recombinant IL-1β (2 ng/ml) induced similar levels of IL-8 secretion to CoMTB in both A549 cells and NHBE. Pulmonary epithelial cells are a major source of IL-8 in the initial host response to pulmonary tuberculosis. Such IL-8 secretion is NF-κB dependent, NF-IL-6 requiring, and activated by an IL-1-mediated pathway as a consequence of phagocytosis of M. tuberculosis by monocytes.
Collapse
Affiliation(s)
- Melissa I. Wickremasinghe
- Department of Infectious Diseases, Imperial College of Science Technology and Medicine, Hammersmith Campus, London, United Kingdom
| | - Lynette H. Thomas
- Department of Infectious Diseases, Imperial College of Science Technology and Medicine, Hammersmith Campus, London, United Kingdom
| | - Jon S. Friedland
- Department of Infectious Diseases, Imperial College of Science Technology and Medicine, Hammersmith Campus, London, United Kingdom
| |
Collapse
|
4
|
Jahnsen FL, Haye R, Gran E, Brandtzaeg P, Johansen FE. Glucocorticosteroids Inhibit mRNA Expression for Eotaxin, Eotaxin-2, and Monocyte-Chemotactic Protein-4 in Human Airway Inflammation with Eosinophilia. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.3.1545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
How eosinophils are preferentially recruited to inflammatory sites remains elusive, but increasing evidence suggests that chemokines that bind to the CCR3 participate in this process. In this study, we investigated the transcript levels and chemotactic activity of CCR3-binding chemokines in nasal polyps, a disorder often showing prominent eosinophilia. We found that mRNA expression for eotaxin, eotaxin-2, and monocyte-chemotactic protein-4 was significantly increased in nasal polyps compared with turbinate mucosa from the same patients, or histologically normal nasal mucosa from control subjects. Interestingly, the novel CCR3-specific chemokine, eotaxin-2, showed the highest transcript levels. Consistent with these mRNA data, polyp tissue fluid exhibited strong chemotactic activity for eosinophils that was significantly inhibited by a blocking Ab against CCR3. When patients were treated systemically with glucocorticosteroids, the mRNA levels in the polyps were reduced to that found in turbinate mucosa for all chemokines. Together, these findings suggested an important role for CCR3-binding chemokines in eosinophil recruitment to nasal polyps. Such chemokines, therefore, most likely contribute significantly in the pathogenesis of eosinophil-related disorders; and the reduced chemokine expression observed after steroid treatment might reflect, at least in part, how steroids inhibit tissue accumulation of eosinophils.
Collapse
Affiliation(s)
- Frode L. Jahnsen
- *Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), Institute of Pathology, and
| | - Rolf Haye
- †Department of Ear, Nose, and Throat, University of Oslo, The National Hospital, Rikshospitalet, Oslo, Norway
| | - Einar Gran
- †Department of Ear, Nose, and Throat, University of Oslo, The National Hospital, Rikshospitalet, Oslo, Norway
| | - Per Brandtzaeg
- *Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), Institute of Pathology, and
| | - Finn-Eirik Johansen
- *Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), Institute of Pathology, and
| |
Collapse
|
5
|
Sauty A, Dziejman M, Taha RA, Iarossi AS, Neote K, Garcia-Zepeda EA, Hamid Q, Luster AD. The T Cell-Specific CXC Chemokines IP-10, Mig, and I-TAC Are Expressed by Activated Human Bronchial Epithelial Cells. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.6.3549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Recruitment of activated T cells to mucosal surfaces, such as the airway epithelium, is important in host defense and for the development of inflammatory diseases at these sites. We therefore asked whether the CXC chemokines IFN-induced protein of 10 kDa (IP-10), monokine induced by IFN-γ (Mig), and IFN-inducible T-cell α-chemoattractant (I-TAC), which specifically chemoattract activated T cells by signaling through the chemokine receptor CXCR3, were inducible in respiratory epithelial cells. The effects of proinflammatory cytokines, including IFN-γ (Th1-type cytokine), Th2-type cytokines (IL-4, IL-10, and IL-13), and dexamethasone were studied in normal human bronchial epithelial cells (NHBEC) and in two human respiratory epithelial cell lines, A549 and BEAS-2B. We found that IFN-γ, but not TNF-α or IL-1β, strongly induced IP-10, Mig, and I-TAC mRNA accumulation mainly in NHBEC and that TNF-α and IL-1β synergized with IFN-γ induction in all three cell types. High levels of IP-10 protein (>800 ng/ml) were detected in supernatants of IFN-γ/TNF-α-stimulated NHBEC. Neither dexamethasone nor Th2 cytokines modulated IP-10, Mig, or I-TAC expression. Since IFN-γ is up-regulated in tuberculosis (TB), using in situ hybridization we studied the expression of IP-10 in the airways of TB patients and found that IP-10 mRNA was expressed in the bronchial epithelium. In addition, IP-10-positive cells obtained by bronchoalveolar lavage were significantly increased in TB patients compared with normal controls. These results show that activated bronchial epithelium is an important source of IP-10, Mig, and I-TAC, which may, in pulmonary diseases such as TB (in which IFN-γ is highly expressed) play an important role in the recruitment of activated T cells.
Collapse
Affiliation(s)
- Alain Sauty
- *Infectious Disease Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129
| | - Michelle Dziejman
- *Infectious Disease Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129
| | - Rame A. Taha
- †Meakins Christie Laboratories, Montreal Chest Institute Research Centre, McGill University, Montreal, Quebec, Canada; and
| | - Albert S. Iarossi
- *Infectious Disease Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129
| | - Kuldeep Neote
- ‡Department of Molecular Sciences, Pfizer Inc., Groton, CT 06340
| | - Eduardo A. Garcia-Zepeda
- *Infectious Disease Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129
| | - Qutayba Hamid
- †Meakins Christie Laboratories, Montreal Chest Institute Research Centre, McGill University, Montreal, Quebec, Canada; and
| | - Andrew D. Luster
- *Infectious Disease Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129
| |
Collapse
|
6
|
Selvan RS, Kapadia HB, Platt JL. Complement-Induced Expression of Chemokine Genes in Endothelium: Regulation by IL-1-Dependent and -Independent Mechanisms. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.8.4388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Activation of complement in the vicinity of endothelium is thought to contribute to the tissue manifestations of inflammatory and immune responses. Endothelial cells contribute to these processes in part by the elaboration of chemokines that activate various leukocytes and direct their migration into tissues. We investigated the mechanisms by which activation of complement on endothelial cell surfaces might influence the expression of chemokine genes in endothelial cells. In a model for the immune reaction occurring in a xenograft, human serum, as a source of xenoreactive anti-endothelial Abs and complement, induced expression of the monocyte chemotactic protein-1 (MCP-1), IL-8, and RANTES genes. The MCP-1 and IL-8 genes were expressed within 3 h as a first phase and at >12 h as a second phase. The RANTES gene was expressed in porcine endothelial cells only 12 h after exposure to human serum. The expression of these genes required activation of complement and assembly of membrane attack complex, as it was inhibited by soluble CR1 and did not occur in the absence of C8. The early phase of MCP-1 and IL-8 gene expression did not require de novo protein synthesis. The late phase of MCP-1, IL-8, and RANTES gene expression predominantly required the production of IL-1α as an intermediate step. The results indicate that the expression of chemokine genes in endothelial cells occurs as a function of differential responses to complement and may in part be conditioned by the availability of IL-1α.
Collapse
|
7
|
Liu L, Zuurbier AEM, Mul FPJ, Verhoeven AJ, Lutter R, Knol EF, Roos D. Triple Role of Platelet-Activating Factor in Eosinophil Migration Across Monolayers of Lung Epithelial Cells: Eosinophil Chemoattractant and Priming Agent and Epithelial Cell Activator. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.6.3064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Infiltration of eosinophils into the lung lumen is a hallmark of allergic asthmatic inflammation. To reach the lung lumen, eosinophils must migrate across the vascular endothelium, through the interstitial matrix, and across the lung epithelium. The regulation of this process is obscure. In this study, we investigated the migration of human eosinophils across confluent monolayers of either human lung H292 epithelial cells or primary human bronchial epithelial cells. Established eosinophil chemoattractants (IL-8, RANTES, platelet-activating factor (PAF), leukotriene B4, and complement fragment 5a (C5a)) or activation of the epithelial cells with IL-1β induced little eosinophil transmigration (<7% in 2 h). In contrast, addition of PAF in combination with C5a induced extensive (>20%) transepithelial migration of unprimed and IL-5-primed eosinophils. Eosinophil migration assessed in a Boyden chamber assay, i.e., without an epithelial monolayer, was only slightly increased upon addition of PAF and C5a. Preincubation of eosinophils with the PAF receptor antagonist WEB 2086 only inhibited migration of unprimed eosinophils toward PAF and C5a, whereas preincubation of epithelial cells with WEB 2086 abolished migration of both IL-5-primed and unprimed eosinophils. This latter result indicated the presence of PAF receptors on epithelial cells. Indeed, addition of PAF to epithelial cells induced an increase in cytosolic free Ca2+, which was blocked by the PAF receptor antagonists WEB 2086 and TCV-309. Our results show that PAF induces permissive changes in epithelial cells, and that PAF acts as a chemoattractant and priming agent for the eosinophils.
Collapse
Affiliation(s)
- Lixin Liu
- *Central Laboratory of The Netherlands Red Cross Blood Transfusion Service and Laboratory of Experimental and Clinical Immunology, and
| | - Astrid E. M. Zuurbier
- *Central Laboratory of The Netherlands Red Cross Blood Transfusion Service and Laboratory of Experimental and Clinical Immunology, and
| | - Frederik P. J. Mul
- *Central Laboratory of The Netherlands Red Cross Blood Transfusion Service and Laboratory of Experimental and Clinical Immunology, and
| | - Arthur J. Verhoeven
- *Central Laboratory of The Netherlands Red Cross Blood Transfusion Service and Laboratory of Experimental and Clinical Immunology, and
| | - René Lutter
- †Department of Pulmonology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Edward F. Knol
- *Central Laboratory of The Netherlands Red Cross Blood Transfusion Service and Laboratory of Experimental and Clinical Immunology, and
| | - Dirk Roos
- *Central Laboratory of The Netherlands Red Cross Blood Transfusion Service and Laboratory of Experimental and Clinical Immunology, and
| |
Collapse
|
8
|
Ayad O, Stark JM, Fiedler MM, Menendez IY, Ryan MA, Wong HR. The Heat Shock Response Inhibits RANTES Gene Expression in Cultured Human Lung Epithelium. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.5.2594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The chemokine RANTES is thought to be involved in the pathophysiology of inflammation-associated acute lung injury. Although much is known regarding signals that induce RANTES gene expression, relatively few data exist regarding signals that inhibit RANTES gene expression. The heat shock response, a highly conserved cellular defense mechanism, has been demonstrated to inhibit a variety of lung proinflammatory responses. We tested the hypothesis that induction of the heat shock response inhibits RANTES gene expression. Treatment of A549 cells with TNF-α induced RANTES gene expression in a concentration-dependent manner. Induction of the heat shock response inhibited subsequent TNF-α-mediated RANTES mRNA expression and secretion of immunoreactive RANTES. Transient transfection assays involving a RANTES promoter-luciferase reporter plasmid demonstrated that the heat shock response inhibited TNF-α-mediated activation of the RANTES promoter. Inhibition of NF-κB nuclear translocation with isohelenin inhibited TNF-α-mediated RANTES mRNA expression, indicating that RANTES gene expression is NF-κB dependent in A549 cells. Induction of the heat shock response inhibited degradation of the NF-κB inhibitory protein, I-κBα but did not significantly inhibit phosphorylation of I-κBα. We conclude that the heat shock response inhibits RANTES gene expression by a mechanism involving inhibition of NF-κB nuclear translocation and subsequent inhibition of RANTES promoter activation. The mechanism by which the heat shock response inhibits NF-κB nuclear translocation involves stabilization of I-κBα, without significantly affecting phosphorylation of I-κBα.
Collapse
Affiliation(s)
- Onsy Ayad
- *Division of Critical Care Medicine and
| | - James M. Stark
- †Division of Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Michael M. Fiedler
- †Division of Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH 45229
| | | | | | | |
Collapse
|
9
|
Tamada K, Harada M, Abe K, Li T, Nomoto K. IL-4-Producing NK1.1+ T Cells Are Resistant to Glucocorticoid-Induced Apoptosis: Implications for the Th1/Th2 Balance. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.3.1239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
To elucidate the mechanisms by which glucocorticoids promote Th2-type responses, we investigated the influence of dexamethasone (DEX) on both cytokine production and viability of NK1.1+ T cells. The in vivo administration of DEX enhanced the IL-4 production of spleen cells and liver mononuclear cells in wild-type mice, but not in β2m-deficient mice. DEX reduced the cellularity of conventional T cells, but not that of NK1.1+ T cells, in both spleen and liver, suggesting an increased proportion of NK1.1+ T cells. Moreover, the proportion of IL-4-producing NK1.1+ T cells increased in the DEX-injected mice. These results suggest that DEX induced IL-4 production through the preferential survival of IL-4-producing NK1.1+ T cells. In investigating the reason for the preferential survival of NK1.1+ T cells, we found that NK1.1+ T cells were resistant to DEX-induced apoptosis and expressed a higher level of intracellular Bcl-2 compared with conventional NK1.1− T cells. In addition, splenic and hepatic NK1.1+ T cells were resistant to radiation-induced apoptosis. Collectively, our findings revealed an important role for NK1.1+ T cells in the regulation of Th1/Th2 balance by glucocorticoids and their possible functions under various apoptotic stimuli.
Collapse
Affiliation(s)
| | - Mamoru Harada
- †Department of Virology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | | | | | | |
Collapse
|
10
|
Thomas LH, Friedland JS, Sharland M, Becker S. Respiratory Syncytial Virus-Induced RANTES Production from Human Bronchial Epithelial Cells Is Dependent on Nuclear Factor-κB Nuclear Binding and Is Inhibited by Adenovirus-Mediated Expression of Inhibitor of κBα. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.2.1007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Respiratory syncytial virus (RSV) infection is an important cause of lower respiratory tract illness, the severity of which may be partly due to cellular recruitment. RSV infection activates chemokine secretion from airway epithelial cells by largely unknown mechanisms. We investigated the regulation of RSV-induced activation of the chemokine RANTES in the bronchial epithelial cell line BEAS-2B and primary normal human tracheobronchial epithelial cultures. RANTES protein and mRNA were detected at 24 h and up until 72 h from cultures of BEAS-2B infected with replicating virus, but not with UV-inactivated RSV. RSV infection of BEAS-2B or normal human tracheobronchial epithelial cells stimulated NF-κB translocation to the nucleus and binding to the RANTES-specific κB-binding sequences within 2 h, with levels peaking at 24 h. Supershift assays indicated that binding was due to p50/p65 heterodimers. BEAS-2B cells were transfected with a replication-deficient adenoviral vector, expressing a mutated, nondegradable form of IκBα. IκBα overexpression specifically blocked NF-κB translocation and inhibited mRNA accumulation and secretion of RANTES induced by RSV or TNF-α plus IFN-γ. Adenoviral transfection did not interfere with RSV replication or significantly induce apoptosis. Further, a control adenovirus, expressing the β-galactosidase gene, did not alter cellular functions. Thus, NF-κB nuclear translocation is a critical step in RSV induction of RANTES secretion. Elucidating the mechanisms of cellular activation by RSV and targeting specific areas may lead to novel therapeutic approaches in the treatment of RSV.
Collapse
Affiliation(s)
- L. H. Thomas
- *Department of Infectious Diseases, Imperial College School of Medicine (Hammersmith Campus), and
| | - J. S. Friedland
- *Department of Infectious Diseases, Imperial College School of Medicine (Hammersmith Campus), and
| | - M. Sharland
- †Pediatric Infectious Diseases Unit, St. George’s Hospital Medical School, London, United Kingdom; and
| | - S. Becker
- ‡Environmental Protection Agency, Chapel Hill, NC 27514
| |
Collapse
|