201
|
Chen ZG, Zhang TT, Li HT, Chen FH, Zou XL, Ji JZ, Chen H. Neutralization of TSLP inhibits airway remodeling in a murine model of allergic asthma induced by chronic exposure to house dust mite. PLoS One 2013; 8:e51268. [PMID: 23300949 PMCID: PMC3534685 DOI: 10.1371/journal.pone.0051268] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 10/31/2012] [Indexed: 12/28/2022] Open
Abstract
Chronic allergic asthma is characterized by Th2-typed inflammation, and contributes to airway remodeling and the deterioration of lung function. However, the initiating factor that links airway inflammation to remodeling is unknown. Thymic stromal lymphopoietin (TSLP), an epithelium-derived cytokine, can strongly activate lung dendritic cells (DCs) through the TSLP-TSLPR and OX40L-OX40 signaling pathways to promote Th2 differentiation. To determine whether TSLP is the underlying trigger of airway remodeling in chronic allergen-induced asthma, we induced allergic airway inflammation in mice by intranasal administration of house dust mite (HDM) extracts for up to 5 consecutive weeks. We showed that repeated respiratory exposure to HDM caused significant airway eosinophilic inflammation, peribronchial collagen deposition, goblet cell hyperplasia, and airway hyperreactivity (AHR) to methacholine. These effects were accompanied with a salient Th2 response that was characterized by the upregulation of Th2-typed cytokines, such as IL-4 and IL-13, as well as the transcription factor GATA-3. Moreover, the levels of TSLP and transforming growth factor beta 1 (TGF-β1) were also increased in the airway. We further demonstrated, using the chronic HDM-induced asthma model, that the inhibition of Th2 responses via neutralization of TSLP with an anti-TSLP mAb reversed airway inflammation, prevented structural alterations, and decreased AHR to methacholine and TGF-β1 level. These results suggest that TSLP plays a pivotal role in the initiation and persistence of airway inflammation and remodeling in the context of chronic allergic asthma.
Collapse
Affiliation(s)
- Zhuang-Gui Chen
- Department of Pulmonary Diseases, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Diseases of Sun Yat-Sen University, Guangzhou, China
- Department of Pediatrics, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Tian-Tuo Zhang
- Department of Pulmonary Diseases, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Diseases of Sun Yat-Sen University, Guangzhou, China
- * E-mail:
| | - Hong-Tao Li
- Department of Pulmonary Diseases, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Diseases of Sun Yat-Sen University, Guangzhou, China
| | - Fen-Hua Chen
- Department of Pediatrics, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Xiao-Ling Zou
- Department of Pulmonary Diseases, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Diseases of Sun Yat-Sen University, Guangzhou, China
| | - Jing-Zhi Ji
- Department of Pediatrics, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Hong Chen
- Department of Pediatrics, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| |
Collapse
|
202
|
Williams JW, Tjota MY, Clay BS, Lugt BV, Bandukwala HS, Hrusch CL, Decker DC, Blaine KM, Fixsen BR, Singh H, Sciammas R, Sperling AI. Transcription factor IRF4 drives dendritic cells to promote Th2 differentiation. Nat Commun 2013; 4:2990. [PMID: 24356538 PMCID: PMC4003872 DOI: 10.1038/ncomms3990] [Citation(s) in RCA: 288] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 11/21/2013] [Indexed: 12/12/2022] Open
Abstract
Atopic asthma is an inflammatory pulmonary disease associated with Th2 adaptive immune responses triggered by innocuous antigens. While dendritic cells (DCs) are known to shape the adaptive immune response, the mechanisms by which DCs promote Th2 differentiation remain elusive. Herein we demonstrate that Th2-promoting stimuli induce DC expression of IRF4. Mice with conditional deletion of Irf4 in DCs show a dramatic defect in Th2-type lung inflammation, yet retain the ability to elicit pulmonary Th1 antiviral responses. Using loss- and gain-of-function analysis, we demonstrate that Th2 differentiation is dependent on IRF4 expression in DCs. Finally, IRF4 directly targets and activates the Il-10 and Il-33 genes in DCs. Reconstitution with exogenous IL-10 and IL-33 recovers the ability of Irf4-deficient DCs to promote Th2 differentiation. These findings reveal a regulatory module in DCs by which IRF4 modulates IL-10 and IL-33 cytokine production to specifically promote Th2 differentiation and inflammation.
Collapse
Affiliation(s)
- Jesse W. Williams
- Committee on Molecular Pathogenesis and Molecular Medicine, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| | - Melissa Y. Tjota
- Committee on Immunology, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
- Medical Scientist Training Program, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| | - Bryan S. Clay
- Committee on Immunology, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| | - Bryan Vander Lugt
- Department of Discovery Immunology, Genentech Inc., 1 DNA Way, S. San Francisco, CA, 94080 USA
| | - Hozefa S. Bandukwala
- Committee on Immunology, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| | - Cara L. Hrusch
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| | - Donna C. Decker
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| | - Kelly M. Blaine
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| | - Bethany R. Fixsen
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| | - Harinder Singh
- Department of Discovery Immunology, Genentech Inc., 1 DNA Way, S. San Francisco, CA, 94080 USA
| | - Roger Sciammas
- Department of Surgery, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| | - Anne I. Sperling
- Committee on Molecular Pathogenesis and Molecular Medicine, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
- Committee on Immunology, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, 924 E. 57 St., Chicago, IL, 60637 USA
| |
Collapse
|
203
|
Mesnil C, Sabatel CM, Marichal T, Toussaint M, Cataldo D, Drion PV, Lekeux P, Bureau F, Desmet CJ. Resident CD11b(+)Ly6C(-) lung dendritic cells are responsible for allergic airway sensitization to house dust mite in mice. PLoS One 2012; 7:e53242. [PMID: 23300898 PMCID: PMC3534017 DOI: 10.1371/journal.pone.0053242] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 11/27/2012] [Indexed: 01/17/2023] Open
Abstract
Conventional dendritic cells (DCs) are considered to be the prime initiators of airway allergy. Yet, it remains unclear whether specific DC subsets are preferentially involved in allergic airway sensitization. Here, we systematically assessed the respective pro-allergic potential of individually sorted lung DC subsets isolated from house dust mite antigen (HDM)-treated donor mice, following transfer to naïve recipients. Transfer of lung CD11c(+)CD11b(+) DCs, but not CD11c(+)CD11b(-)CD103(+) DCs, was sufficient to prime airway allergy. The CD11c(+)CD11b(+) DC subpopulation was composed of CD11c(+)CD11b(+)Ly6C(+) inflammatory monocyte-derived cells, whose numbers increase in the lungs following HDM exposure, and of CD11c(+)CD11b(+)Ly6C(-) DCs, which remain stable. Counterintuitively, only CD11c(+)CD11b(+)Ly6C(-) DCs, and not CD11c(+)CD11b(+)Ly6C(+) DCs, were able to convey antigen to the lymph nodes and induce adaptive T cell responses and subsequent airway allergy. Our results thus support that lung resident non-inflammatory CD11c(+)CD11b(+)Ly6C(-) DCs are the essential inducers of allergic airway sensitization to the common aeroallergen HDM in mice.
Collapse
Affiliation(s)
- Claire Mesnil
- Laboratory of Cellular and Molecular Immunology, GIGA-Research and Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Catherine M. Sabatel
- Laboratory of Cellular and Molecular Immunology, GIGA-Research and Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Thomas Marichal
- Laboratory of Cellular and Molecular Immunology, GIGA-Research and Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Marie Toussaint
- Laboratory of Cellular and Molecular Immunology, GIGA-Research and Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Didier Cataldo
- Laboratory of Tumours and Developmental Biology, GIGA-Research, University of Liège, Liège, Belgium
| | - Pierre-Vincent Drion
- Laboratory of Preclinical and Biomedical Sciences, University Hospital Center, University of Liège, Liège, Belgium
| | - Pierre Lekeux
- Laboratory of Cellular and Molecular Immunology, GIGA-Research and Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Fabrice Bureau
- Laboratory of Cellular and Molecular Immunology, GIGA-Research and Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Christophe J. Desmet
- Laboratory of Cellular and Molecular Immunology, GIGA-Research and Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| |
Collapse
|
204
|
Macrophage-mediated inflammation and disease: a focus on the lung. Mediators Inflamm 2012; 2012:140937. [PMID: 23304058 PMCID: PMC3530802 DOI: 10.1155/2012/140937] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 10/30/2012] [Indexed: 12/24/2022] Open
Abstract
The lung is exposed to a vast array of inhaled antigens, particulate matter, and pollution. Cells present in the airways must therefore be maintained in a generally suppressive phenotype so that excessive responses to nonserious irritants do not occur; these result in bystander damage to lung architecture, influx of immune cells to the airways, and consequent impairment of gas exchange. To this end, the resident cells of the lung, which are predominantly macrophages, are kept in a dampened state. However, on occasion the suppression fails and these macrophages overreact to antigenic challenge, resulting in release of inflammatory mediators, induction of death of lung epithelial cells, deposition of extracellular matrix, and development of immunopathology. In this paper, we discuss the mechanisms behind this macrophage-mediated pathology, in the context of a number of inflammatory pulmonary disorders.
Collapse
|
205
|
Willart MAM, van Nimwegen M, Grefhorst A, Hammad H, Moons L, Hoogsteden HC, Lambrecht BN, KleinJan A. Ursodeoxycholic acid suppresses eosinophilic airway inflammation by inhibiting the function of dendritic cells through the nuclear farnesoid X receptor. Allergy 2012; 67:1501-10. [PMID: 23004356 DOI: 10.1111/all.12019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2012] [Indexed: 02/03/2023]
Abstract
BACKGROUND Ursodeoxycholic acid (UDCA) is the only known beneficial bile acid with immunomodulatory properties. Ursodeoxycholic acid prevents eosinophilic degranulation and reduces eosinophil counts in primary biliary cirrhosis. It is unknown whether UDCA would also modulate eosinophilic inflammation outside the gastrointestinal (GI) tract, such as eosinophilic airway inflammation seen in asthma. The working mechanism for its immunomodulatory effect is unknown. METHODS The immunosuppressive features of UDCA were studied in vivo, in mice, in an ovalbumin (OVA)-driven eosinophilic airway inflammation model. To study the mechanism of action of UDCA, we analyzed the effect of UDCA on eosinophils, T cells, and dendritic cell (DCs). DC function was studied in greater detail, focussing on migration and T-cell stimulatory strength in vivo and interaction with T cells in vitro as measured by time-lapse image analysis. Finally, we studied the capacity of UDCA to influence DC/T cell interaction. RESULTS Ursodeoxycholic acid treatment of OVA-sensitized mice prior to OVA aerosol challenge significantly reduced eosinophilic airway inflammation compared with control animals. DCs expressed the farnesoid X receptor for UDCA. Ursodeoxycholic acid strongly promoted interleukin (IL)-12 production and enhanced the migration in DCs. The time of interaction between DCs and T cells was sharply reduced in vitro by UDCA treatment of the DCs resulting in a remarkable T-cell cytokine production. Ursodeoxycholic acid-treated DCs have less capacity than saline-treated DCs to induce eosinophilic inflammation in vivo in Balb/c mice. CONCLUSION Ursodeoxycholic acid has the potency to suppress eosinophilic inflammation outside the GI tract. This potential comprises to alter critical function of DCs, in essence, the effect of UDCA on DCs through the modulation of the DC/T cell interaction.
Collapse
Affiliation(s)
| | - M. van Nimwegen
- Department of Pulmonary Medicine; Erasmus MC; Rotterdam; The Netherlands
| | - A. Grefhorst
- Department of Internal Medicine; Erasmus MC; Rotterdam
| | | | - L. Moons
- Departments of Gastroenterology and Hepatology; Erasmus MC; Rotterdam; The Netherlands
| | - H. C. Hoogsteden
- Department of Pulmonary Medicine; Erasmus MC; Rotterdam; The Netherlands
| | | | - A. KleinJan
- Department of Pulmonary Medicine; Erasmus MC; Rotterdam; The Netherlands
| |
Collapse
|
206
|
Satpathy AT, Wu X, Albring JC, Murphy KM. Re(de)fining the dendritic cell lineage. Nat Immunol 2012; 13:1145-54. [PMID: 23160217 DOI: 10.1038/ni.2467] [Citation(s) in RCA: 326] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 09/27/2012] [Indexed: 12/12/2022]
Abstract
Dendritic cells (DCs) are essential mediators of innate and adaptive immune responses. Study of these critical cells has been complicated by their similarity to other hematopoietic lineages, particularly monocytes and macrophages. Progress has been made in three critical areas of DC biology: the characterization of lineage-restricted progenitors in the bone marrow, the identification of cytokines and transcription factors required during differentiation, and the development of genetic tools for the visualization and depletion of DCs in vivo. Collectively, these advances have clarified the nature of the DC lineage and have provided novel insights into their function during health and disease.
Collapse
Affiliation(s)
- Ansuman T Satpathy
- Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, Missouri, USA
| | | | | | | |
Collapse
|
207
|
Oertli M, Müller A. Helicobacter pylori targets dendritic cells to induce immune tolerance, promote persistence and confer protection against allergic asthma. Gut Microbes 2012; 3:566-71. [PMID: 22895083 PMCID: PMC3495795 DOI: 10.4161/gmic.21750] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The bacterial pathogen Helicobacter pylori is predominantly known for its tight association with peptic ulcer disease and gastric cancer. However, recent evidence suggests that chronic infection with H. pylori may also be beneficial to the host by conferring protection against allergies, asthma and inflammatory bowel diseases. The protective effects of H. pylori depend on highly suppressive regulatory T-cells. In this addendum, we summarize results showing that H. pylori infection efficiently re-programs dendritic cells (DCs) toward a tolerance-promoting phenotype; their "tolerogenic" activity requires inflammasome activation and the secretion of interleukin-18. H. pylori-experienced DCs fail to induce T-cell effector functions, but efficiently induce FoxP3 expression in naive T-cells in vitro and in vivo. The experimental depletion of DCs breaks tolerance and results in improved infection control, but also in aggravated T-cell-driven immunopathology. In summary, we propose that H. pylori evades adaptive immune responses by re-programming DCs in favor of tolerance over immunity.
Collapse
|
208
|
van Rijt LS, Logiantara A, Utsch L, Canbaz D, Boon L, van Ree R. House dust mite allergic airway inflammation facilitates neosensitization to inhaled allergen in mice. Allergy 2012; 67:1383-91. [PMID: 22994367 DOI: 10.1111/all.12017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2012] [Indexed: 12/30/2022]
Abstract
BACKGROUND The mechanism by which many monosensitized allergic individuals progress to polysensitization over time remains to be elucidated. Mouse models have contributed greatly to the understanding of sensitization to inhaled allergens in healthy airways but hardly any studies have addressed sensitization during established allergy. We hypothesized that an allergic inflammatory milieu might facilitate sensitization to inhaled allergens by the presence of mature dendritic cells (DCs) and IL-4. METHODS Mice with house dust mite (HDM)-induced allergic airway inflammation received a single intratracheal dose of ovalbumin (OVA), 2 days after the last HDM exposure. Ten days later, sensitization was assessed by rechallenge with OVA. We evaluated the following factors for their importance in neosensitization: (1) maturation and recruitment of DCs to the airways, (2) dependency on DCs using CD11cDTR conditional knockout mice, (3) presence of ongoing airway inflammation by comparing sensitization at day 2 and day 14 after the last HDM exposure and (4) dependency on IL-4 by treatment with blocking antibodies. RESULTS House dust mite -induced inflammation facilitated neosensitization to OVA. HDM-induced inflammation increased the number of airway DCs with a mature phenotype but a DC reduction of 93% did not inhibit sensitization. Neosensitization to OVA was dependent on ongoing inflammation and in particular on IL-4. CONCLUSIONS These findings show that HDM-induced allergic airway inflammation facilitates neosensitization to a second inhaled allergen in an IL-4-dependent manner and provide insight into the underlying mechanism of the frequently observed progression to polysensitization in HDM-monosensitized individuals.
Collapse
Affiliation(s)
- L. S. van Rijt
- Department Experimental Immunology; Academic Medical Centre; Amsterdam; The Netherlands
| | - A. Logiantara
- Department Experimental Immunology; Academic Medical Centre; Amsterdam; The Netherlands
| | - L. Utsch
- Department Experimental Immunology; Academic Medical Centre; Amsterdam; The Netherlands
| | - D. Canbaz
- Department Experimental Immunology; Academic Medical Centre; Amsterdam; The Netherlands
| | - L. Boon
- Bioceros B.V; Utrecht; The Netherlands
| | | |
Collapse
|
209
|
The contribution of allergen-specific IgG to the development of th2-mediated airway inflammation. J Allergy (Cairo) 2012; 2012:236075. [PMID: 23150737 PMCID: PMC3485540 DOI: 10.1155/2012/236075] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 09/18/2012] [Indexed: 01/01/2023] Open
Abstract
In both human asthmatics and animal models of allergy, allergen-specific IgG can contribute to Th2-mediated allergic inflammation. Mouse models have elucidated an important role for IgG and Fc-gamma receptor (FcγR) signaling on antigen presenting cells (APC) for the induction of airway inflammation. These studies suggest a positive feedback loop between IgG produced by the adaptive B cell response and FcγR signaling on innate immune cells. Studies of IgG and FcγRs in humans with asthma or allergic lung disease have been more controversial. Some reports have identified associations between allergen-specific IgG and severity of allergic responses, while other studies have found associations of IgG subclass IgG4 with allergic tolerance. In this paper, we review the literature to help define the nature of IgG and FcγR signaling on innate immune cells and how it contributes to the development of allergic immune responses.
Collapse
|
210
|
Brand JD, Ballinger CA, Tuggle KL, Fanucchi MV, Schwiebert LM, Postlethwait EM. Site-specific dynamics of CD11b+ and CD103+ dendritic cell accumulations following ozone exposure. Am J Physiol Lung Cell Mol Physiol 2012; 303:L1079-86. [PMID: 23087018 DOI: 10.1152/ajplung.00185.2012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pulmonary dendritic cells (DCs) are among the first responders to inhaled environmental stimuli such as ozone (O(3)), which has been shown to activate these cells. O(3) reacts with epithelial lining fluid (ELF) components in an anatomically site-specific manner dictated by O(3) concentration, airway flow patterns, and ELF substrate concentration. Accordingly, the anatomical distribution of ELF reaction products and airway injury are hypothesized to produce selective DC maturation differentially within the airways. To investigate how O(3) affects regional airway DC populations, we utilized a model of O(3)-induced pulmonary inflammation, wherein C57BL/6 mice were exposed to 0.8 ppm O(3) 8 h/day for 1, 3, and 5 days. This model induced mild inflammation and no remarkable epithelial injury. Tracheal, but not more distant airway sites, and mediastinal lymph node (MLN) DC numbers were increased significantly after the third exposure day. The largest increase in each tissue was of the CD103(+) DC phenotype. After 3 days of exposure, fewer DCs expressed CD80, CD40, and CCR7, and, at this same time point, total MLN T cell numbers increased. Together, these data demonstrate that O(3) exposure induced site-specific and phenotype changes in the pulmonary and regional lymph node DC populations. Possibly contributing to ozone-mediated asthma perturbation, the phenotypic changes to DCs within pulmonary regions may alter responses to antigenic stimuli. Decreased costimulatory molecule expression within the MLN suggests induction of tolerance mechanisms; increased tracheal DC number may raise the potential for allergic sensitization and asthmatic exacerbation, thus overcoming O(3)-induced decrements in costimulatory molecule expression.
Collapse
Affiliation(s)
- Jeffrey D Brand
- Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | | | | | | | | |
Collapse
|
211
|
Dendritic cells, viruses, and the development of atopic disease. J Allergy (Cairo) 2012; 2012:936870. [PMID: 23118777 PMCID: PMC3478734 DOI: 10.1155/2012/936870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 09/17/2012] [Indexed: 12/21/2022] Open
Abstract
Dendritic cells are important residents of the lung environment. They have been associated with asthma and other inflammatory diseases of the airways. In addition to their antigen-presenting functions, dendritic cells have the ability to modulate the lung environment to promote atopic disease. While it has long been known that respiratory viral infections associate with the development and exacerbation of atopic diseases, the exact mechanisms have been unclear. Recent studies have begun to show the critical importance of the dendritic cell in this process. This paper focuses on these data demonstrating how different populations of dendritic cells are capable of bridging the adaptive and innate immune systems, ultimately leading to the translation of viral illness into atopic disease.
Collapse
|
212
|
Spertini F, Reymond C, Leimgruber A. Allergen-specific immunotherapy of allergy and asthma: current and future trends. Expert Rev Respir Med 2012; 3:37-51. [PMID: 20477281 DOI: 10.1586/17476348.3.1.37] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Allergen-specific immunotherapy is the only immunomodulatory and etiological therapy of allergy and asthma. Conventional specific immunotherapy (SIT) with whole-allergen extract is antigen specific, effective on multiple organs, efficient on asthma in defined conditions, provides long-lasting protection and is cost effective. Moreover, SIT is able to prevent the course of rhinitis to asthma. SIT has its drawbacks: the long duration of treatment, the unsatisfactory standardization of allergen extracts and a questionable safety level. Novel approaches are aimed at drastically reducing adverse anaphylactic events, shortening the duration of therapy and improving its efficacy. Novel promising approaches have based their formulation on a limited set of recombinant allergens or chimeric molecules as well as on hypoallergenic allergen fragments or peptides. The simultaneous use of adjuvants with immunomodulatory properties may contribute to improve both the safety and efficacy of allergen-SIT of allergy and asthma.
Collapse
Affiliation(s)
- François Spertini
- Division of Immunology and Allergy, Centre Hospitalier Universitaire Vaudois, Rue du Bugnon 46, 1011 Lausanne, Switzerland.
| | | | | |
Collapse
|
213
|
Smith KA, Harcus Y, Garbi N, Hämmerling GJ, MacDonald AS, Maizels RM. Type 2 innate immunity in helminth infection is induced redundantly and acts autonomously following CD11c(+) cell depletion. Infect Immun 2012; 80:3481-9. [PMID: 22851746 PMCID: PMC3457557 DOI: 10.1128/iai.00436-12] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 07/16/2012] [Indexed: 11/20/2022] Open
Abstract
Infection with gastrointestinal helminths generates a dominant type 2 response among both adaptive (Th2) and innate (macrophage, eosinophil, and innate lymphoid) immune cell types. Two additional innate cell types, CD11c(high) dendritic cells (DCs) and basophils, have been implicated in the genesis of type 2 immunity. Investigating the type 2 response to intestinal nematode parasites, including Heligmosomoides polygyrus and Nippostrongylus brasiliensis, we first confirmed the requirement for DCs in stimulating Th2 adaptive immunity against these helminths through depletion of CD11c(high) cells by administration of diphtheria toxin to CD11c.DOG mice. In contrast, responsiveness was intact in mice depleted of basophils by antibody treatment. Th2 responses can be induced by adoptive transfer of DCs, but not basophils, exposed to soluble excretory-secretory products from these helminths. However, innate type 2 responses arose equally strongly in the presence or absence of CD11c(high) cells or basophils; thus, in CD11c.DOG mice, the alternative activation of macrophages, as measured by expression of arginase-1, RELM-α, and Ym-1 (Chi3L3) in the intestine following H. polygyrus infection or in the lung following N. brasiliensis infection, was unaltered by depletion of CD11c-expressing DCs and alveolar macrophages or by antibody-mediated basophil depletion. Similarly, goblet cell-associated RELM-β in lung and intestinal tissues, lung eosinophilia, and expansion of innate lymphoid ("nuocyte") populations all proceeded irrespective of depletion of CD11c(high) cells or basophils. Thus, while CD11c(high) DCs initiate helminth-specific adaptive immunity, innate type 2 cells are able to mount an autonomous response to the challenge of parasite infection.
Collapse
Affiliation(s)
- Katherine A. Smith
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Yvonne Harcus
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Natalio Garbi
- Division of Molecular Immunology, German Cancer Research Center, Heidelberg, Germany
- Institutes of Molecular Medicine and Experimental Immunology (IMMEI), University of Bonn, Bonn, Germany
| | - Günter J Hämmerling
- Division of Molecular Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Andrew S. MacDonald
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Rick M. Maizels
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
214
|
Schindler D, Gutierrez MG, Beineke A, Rauter Y, Rohde M, Foster S, Goldmann O, Medina E. Dendritic Cells Are Central Coordinators of the Host Immune Response to Staphylococcus aureus Bloodstream Infection. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:1327-37. [DOI: 10.1016/j.ajpath.2012.06.039] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 05/06/2012] [Accepted: 06/14/2012] [Indexed: 12/22/2022]
|
215
|
Voedisch S, Rochlitzer S, Veres TZ, Spies E, Braun A. Neuropeptides control the dynamic behavior of airway mucosal dendritic cells. PLoS One 2012; 7:e45951. [PMID: 23049899 PMCID: PMC3458805 DOI: 10.1371/journal.pone.0045951] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 08/23/2012] [Indexed: 01/14/2023] Open
Abstract
The airway mucosal epithelium is permanently exposed to airborne particles. A network of immune cells patrols at this interface to the environment. The interplay of immune cells is orchestrated by different mediators. In the current study we investigated the impact of neuronal signals on key functions of dendritic cells (DC). Using two-photon microscopic time-lapse analysis of living lung sections from CD11c-EYFP transgenic mice we studied the influence of neuropeptides on airway DC motility. Additionally, using a confocal microscopic approach, the phagocytotic capacity of CD11c(+) cells after neuropeptide stimulation was determined. Electrical field stimulation (EFS) leads to an unspecific release of neuropeptides from nerves. After EFS and treatment with the neuropeptides vasoactive intestinal peptide (VIP) or calcitonin gene-related peptide (CGRP), airway DC in living lung slices showed an altered motility. Furthermore, the EFS-mediated effect could partially be blocked by pre-treatment with the receptor antagonist CGRP(8-37). Additionally, the phagocytotic capacity of bone marrow-derived and whole lung CD11c(+) cells could be inhibited by neuropeptides CGRP, VIP, and Substance P. We then cross-linked these data with the in vivo situation by analyzing DC motility in two different OVA asthma models. Both in the acute and prolonged OVA asthma model altered neuropeptide amounts and DC motility in the airways could be measured. In summary, our data suggest that neuropeptides modulate key features motility and phagocytosis of mouse airway DC. Therefore altered neuropeptide levels in airways during allergic inflammation have impact on regulation of airway immune mechanisms and therefore might contribute to the pathophysiology of asthma.
Collapse
Affiliation(s)
- Sabrina Voedisch
- Department of Airway Immunology, Fraunhofer Institute for Toxicology and Experimental Medicine; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hannover, Germany
- Department of Immunology, Hannover Medical School (MHH), Hannover, Germany
| | - Sabine Rochlitzer
- Department of Airway Immunology, Fraunhofer Institute for Toxicology and Experimental Medicine; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hannover, Germany
| | - Tibor Z. Veres
- Department of Airway Immunology, Fraunhofer Institute for Toxicology and Experimental Medicine; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hannover, Germany
- University of Turku, MediCity Research Laboratory, Turku, Finland
| | - Emma Spies
- Department of Airway Immunology, Fraunhofer Institute for Toxicology and Experimental Medicine; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hannover, Germany
- Department of Immunology, Hannover Medical School (MHH), Hannover, Germany
| | - Armin Braun
- Department of Airway Immunology, Fraunhofer Institute for Toxicology and Experimental Medicine; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hannover, Germany
- Department of Immunology, Hannover Medical School (MHH), Hannover, Germany
| |
Collapse
|
216
|
Dahlin JS, Feinstein R, Cui Y, Heyman B, Hallgren J. CD11c+ cells are required for antigen-induced increase of mast cells in the lung. THE JOURNAL OF IMMUNOLOGY 2012; 189:3869-77. [PMID: 22972929 DOI: 10.4049/jimmunol.1201200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Patients with allergic asthma have more lung mast cells, which likely worsens the symptoms. In experimental asthma, CD11c(+) cells have to be present during the challenge phase for several features of allergic inflammation to occur. Whether CD11c(+) cells play a role for Ag-induced increases of lung mast cells is unknown. In this study, we used diphtheria toxin treatment of sensitized CD11c-diphtheria toxin receptor transgenic mice to deplete CD11c(+) cells. We demonstrate that recruitment of mast cell progenitors to the lung is substantially reduced when CD11c(+) cells are depleted during the challenge phase. This correlated with an impaired induction of endothelial VCAM-1 and led to a significantly reduced number of mature mast cells 1 wk after challenge. Collectively, these data suggest that Ag challenge stimulates CD11c(+) cells to produce cytokines and/or chemokines required for VCAM-1 upregulation on the lung endothelium, which in turn is crucial for the Ag-induced mast cell progenitor recruitment and the increase in mast cell numbers.
Collapse
Affiliation(s)
- Joakim S Dahlin
- Department of Medical Biochemistry and Microbiology, Uppsala University, SE-751 23 Uppsala, Sweden
| | | | | | | | | |
Collapse
|
217
|
Abstract
Surprisingly, the role(s) of eosinophils in health and disease is often summarized by clinicians and basic research scientists as a pervasive consensus opinion first learned in medical/graduate school. Eosinophils are rare white blood cells whose activities are primarily destructive and are only relevant in parasitic infections and asthma. However, is this consensus correct? This review argues that the wealth of available studies investigating the role(s) of eosinophils in both health and disease demonstrates that the activities of these granulocytes are far more expansive and complex than previously appreciated. In turn, this greater understanding has led to the realization that eosinophils have significant contributory roles in a wide range of diseases. Furthermore, published studies even implicate eosinophil-mediated activities in otherwise healthy persons. We suggest that the collective reports in the literature showing a role for eosinophils in an ever-increasing number of novel settings highlight the true complexity and importance of this granulocyte. Indeed, discussions of eosinophils are no longer simple and more often than not now begin with the question/statement "Did you know …?"
Collapse
|
218
|
Abstract
Nearly half of the world's population harbors helminth infections or suffers from allergic disorders. A common feature of this population is the so-called "type 2 immune response," which confers protection against helminths, but also promotes pathologic responses associated with allergic inflammation. However, the mechanisms that initiate and control type 2 responses remain enigmatic. Recent advances have revealed a role for the innate immune system in orchestrating type 2 responses against a bewildering array of stimuli, from nanometer-sized allergens to 20-meter-long helminth parasites. Here, we review these advances and suggest that the human immune system has evolved multiple mechanisms of sensing such stimuli, from recognition of molecular patterns via innate immune receptors to detecting metabolic changes and tissue damage caused by these stimuli.
Collapse
Affiliation(s)
- Bali Pulendran
- Department of Pathology, Emory Vaccine Center, Yerkes National Primate Research Center, 954 Gatewood Road, Atlanta, GA 30329, USA.
| | | |
Collapse
|
219
|
The role of dendritic cells in asthma. J Allergy Clin Immunol 2012; 129:889-901. [PMID: 22464668 DOI: 10.1016/j.jaci.2012.02.028] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/21/2012] [Accepted: 02/23/2012] [Indexed: 12/21/2022]
Abstract
Dendritic cells (DCs) are known to play a central role in sensing the presence of foreign antigens and infectious agents and in initiating appropriate immune responses. More recently, an additional role has been discovered for DCs in determining whether the response to potential environmental allergens will be one of tolerance or whether a vigorous response along allergic pathways will be initiated. This review discusses ways in which DCs participate specifically in initiating allergic responses, particularly those associated with allergic asthma, and how interventions focused on DCs might lead to new therapeutic approaches to asthma.
Collapse
|
220
|
Klein Wolterink RGJ, Kleinjan A, van Nimwegen M, Bergen I, de Bruijn M, Levani Y, Hendriks RW. Pulmonary innate lymphoid cells are major producers of IL-5 and IL-13 in murine models of allergic asthma. Eur J Immunol 2012; 42:1106-16. [PMID: 22539286 DOI: 10.1002/eji.201142018] [Citation(s) in RCA: 359] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Allergic asthma is characterized by chronic airway inflammation and hyperreactivity and is thought to be mediated by an adaptive T helper-2 (Th2) cell-type immune response. Here, we demonstrate that type 2 pulmonary innate lymphoid cells (ILC2s) significantly contribute to production of the key cytokines IL-5 and IL-13 in experimental asthma. In naive mice, lineage-marker negative ILC2s expressing IL-7Rα, CD25, Sca-1, and T1/ST2(IL-33R) were present in lungs and mediastinal lymph nodes (MedLNs), but not in broncho-alveolar lavage (BAL) fluid. Upon intranasal administration of IL-25 or IL-33, an asthma phenotype was induced, whereby ILC2s accumulated in lungs, MedLNs, and BAL fluid. After IL-25 and IL-33 administration, ILC2s constituted ∼50 and ∼80% of IL-5(+) /IL-13(+) cells in lung and BAL, respectively. Also in house dust mite-induced or ovalbumin-induced allergic asthma, the ILC2 population in lung and BAL fluid increased significantly in size and ILC2s were a major source of IL-5 or IL-13. Particularly in OVA-induced asthma, the contribution of ILC2s to the total population of intracellular IL-5(+) and IL-13(+) cells in the lung was in the same range as found for Th2 cells. We conclude that both ILC2s and Th2 cells produce large amounts of IL-5 and IL-13 that contribute to allergic airway inflammation.
Collapse
|
221
|
Abstract
To define the role of semaphorin 4A (Sema4A) in allergic response, we employed Sema4A⁻/⁻ and wild-type (WT) mice in the experimental model of ovalbumin (OVA)-induced allergic airway inflammation. We observed a selective increase in eosinophilic airway infiltration accompanied by bronchial epithelial cell hyperplasia in allergen-treated Sema4A⁻/⁻ mice relative to WT mice. This enhanced inflammatory response was associated with a selective increase in bronchoalveolar lavage (BAL) interleukin 13 (IL-13) content, augmented airway hyperreactivity, and lower regulatory T cell (Treg) numbers. In vivo allergen-primed Sema4A⁻/⁻ CD4+ T cells were more effective in transferring T helper type 2 (Th2) response to naive mice as compared with WT CD4+ T cells. T-cell proliferation and IL-13 productions in OVA₃₂₃₋₃₃₉-restimulated Sema4A⁻/⁻ cell cultures were upregulated. Generated bone marrow chimeras showed an equal importance of both lung-resident cell and inflammatory cell Sema4A expression in optimal disease regulation. These data provide a new insight into Sema4A biology and define Sema4A as an important regulator of Th2-driven lung pathophysiology.
Collapse
|
222
|
Chang HYS, Mitzner W, Watson J. Variation in airway responsiveness of male C57BL/6 mice from 5 vendors. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2012; 51:401-406. [PMID: 23043804 PMCID: PMC3400687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 10/11/2011] [Accepted: 12/12/2011] [Indexed: 06/01/2023]
Abstract
Mice are now the most commonly used animal model for the study of asthma. The mouse asthma model has many characteristics of the human pathology, including allergic sensitization and airway hyperresponsiveness. Inbred strains are commonly used to avoid variations due to genetic background, but variations due to rearing environment are not as well recognized. After a change in mouse vendors and a switch from C57BL/6J mice to C57BL/6N mice, we noted significant differences in airway responsiveness between the substrains. To further investigate the effect of vendor, we tested C57BL/6N mice from 3 other vendors and found significant differences between several of the substrains. To test whether this difference was due to genetic drift or rearing environment, we purchased new groups of mice from all 5 vendors, bred them in separate vendor-specific groups under uniform environmental conditions, and tested male first generation (F1) offspring at 8 to 10 wk of age. These F1 mice showed no significant differences in airway responsiveness, indicating that the rearing environment rather than genetic differences was responsible for the initial variation in pulmonary phenotype. The environmental factors that caused the phenotypic variation are unknown. However, differences between vendor in feed components, bedding type, or microbiome could have contributed. Whatever the basis, investigators using mouse models of asthma should be cautious in comparing data from mice obtained from different vendors.
Collapse
Affiliation(s)
| | | | - Julie Watson
- Departments of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, Maryland
| |
Collapse
|
223
|
Antigen-specific effector CD8 T cells regulate allergic responses via IFN-γ and dendritic cell function. J Allergy Clin Immunol 2012; 129:1611-20.e4. [DOI: 10.1016/j.jaci.2011.12.976] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 10/27/2011] [Accepted: 12/22/2011] [Indexed: 11/22/2022]
|
224
|
Zhang Y, Zhou X, Zhou B. DC-derived TSLP promotes Th2 polarization in LPS-primed allergic airway inflammation. Eur J Immunol 2012; 42:1735-43. [PMID: 22585305 DOI: 10.1002/eji.201142123] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 02/21/2012] [Accepted: 03/20/2012] [Indexed: 01/01/2023]
Abstract
Thymic stromal lymphopoietin (TSLP) plays important roles in the pathogenesis of allergic diseases. Whether and how TSLP is involved in the initial priming of T helper type-2 (Th2) differentiation against harmless antigen remains unclear. Using an intranasal sensitization protocol with OVA and LPS, we showed that TSLP signaling is required for low-dose LPS-induced Th2 inflammation, but not for high-dose LPS-induced Th1 immunity. We further demonstrated that low-dose LPS-activated bone marrow-derived dendritic cells expressed relatively high Tslp but low Il12a, and were able to prime naïve DO11.10 T cells to differentiate into Th2 cells in a TSLP-dependent manner. After transfer into wild-type recipient mice, the low-dose LPS-activated OVA-loaded dendritic cells (DCs) induced airway eosinophilia, but primed neutrophil-dominated airway inflammation when TSLP-deficient DCs were used. These studies demonstrate that TSLP released by DCs in response to a low concentration of LPS plays a role in priming Th2 differentiation and thus may serve as a polarizing third signal, in addition to antigen/MHC class II and co-stimulatory factors, from antigen-presenting DCs to direct effector T-cell differentiation.
Collapse
Affiliation(s)
- Yanlu Zhang
- Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | | | | |
Collapse
|
225
|
Satpathy AT, KC W, Albring JC, Edelson BT, Kretzer NM, Bhattacharya D, Murphy TL, Murphy KM. Zbtb46 expression distinguishes classical dendritic cells and their committed progenitors from other immune lineages. ACTA ACUST UNITED AC 2012; 209:1135-52. [PMID: 22615127 PMCID: PMC3371733 DOI: 10.1084/jem.20120030] [Citation(s) in RCA: 454] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The zinc finger transcription factor Zbtb46 specifically marks cDCs and their committed precursors and, when overexpressed in BM progenitors, promotes cDC development at the expense of granulocytes. Distinguishing dendritic cells (DCs) from other cells of the mononuclear phagocyte system is complicated by the shared expression of cell surface markers such as CD11c. In this study, we identified Zbtb46 (BTBD4) as a transcription factor selectively expressed by classical DCs (cDCs) and their committed progenitors but not by plasmacytoid DCs (pDCs), monocytes, macrophages, or other lymphoid or myeloid lineages. Using homologous recombination, we replaced the first coding exon of Zbtb46 with GFP to inactivate the locus while allowing detection of Zbtb46 expression. GFP expression in Zbtb46gfp/+ mice recapitulated the cDC-specific expression of the native locus, being restricted to cDC precursors (pre-cDCs) and lymphoid organ– and tissue-resident cDCs. GFP+ pre-cDCs had restricted developmental potential, generating cDCs but not pDCs, monocytes, or macrophages. Outside the immune system, Zbtb46 was expressed in committed erythroid progenitors and endothelial cell populations. Zbtb46 overexpression in bone marrow progenitor cells inhibited granulocyte potential and promoted cDC development, and although cDCs developed in Zbtb46gfp/gfp (Zbtb46 deficient) mice, they maintained expression of granulocyte colony-stimulating factor and leukemia inhibitory factor receptors, which are normally down-regulated in cDCs. Thus, Zbtb46 may help enforce cDC identity by restricting responsiveness to non-DC growth factors and may serve as a useful marker to identify rare cDC progenitors and distinguish between cDCs and other mononuclear phagocyte lineages.
Collapse
Affiliation(s)
- Ansuman T Satpathy
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | | | | | | | | | | | | | | |
Collapse
|
226
|
AMP affects intracellular Ca2+ signaling, migration, cytokine secretion and T cell priming capacity of dendritic cells. PLoS One 2012; 7:e37560. [PMID: 22624049 PMCID: PMC3356328 DOI: 10.1371/journal.pone.0037560] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 04/25/2012] [Indexed: 12/21/2022] Open
Abstract
The nucleotide adenosine-5'-monophosphate (AMP) can be released by various cell types and has been shown to elicit different cellular responses. In the extracellular space AMP is dephosphorylated to the nucleoside adenosine which can then bind to adenosine receptors. However, it has been shown that AMP can also activate A(1) and A(2a) receptors directly. Here we show that AMP is a potent modulator of mouse and human dendritic cell (DC) function. AMP increased intracellular Ca(2+) concentration in a time and dose dependent manner. Furthermore, AMP stimulated actin-polymerization in human DCs and induced migration of immature human and bone marrow derived mouse DCs, both via direct activation of A(1) receptors. AMP strongly inhibited secretion of TNF-α and IL-12p70, while it enhanced production of IL-10 both via activation of A(2a) receptors. Consequently, DCs matured in the presence of AMP and co-cultivated with naive CD4(+)CD45RA(+) T cells inhibited IFN-γ production whereas secretion of IL-5 and IL-13 was up-regulated. An enhancement of Th2-driven immune response could also be observed when OVA-pulsed murine DCs were pretreated with AMP prior to co-culture with OVA-transgenic naïve OTII T cells. An effect due to the enzymatic degradation of AMP to adenosine could be ruled out, as AMP still elicited migration and changes in cytokine secretion in bone-marrow derived DCs generated from CD73-deficient animals and in human DCs pretreated with the ecto-nucleotidase inhibitor 5'-(alpha,beta-methylene) diphosphate (APCP). Finally, the influence of contaminating adenosine could be excluded, as AMP admixed with adenosine desaminase (ADA) was still able to influence DC function. In summary our data show that AMP when present during maturation is a potent regulator of dendritic cell function and point out the role for AMP in the pathogenesis of inflammatory disorders.
Collapse
|
227
|
Thornton EE, Looney MR, Bose O, Sen D, Sheppard D, Locksley R, Huang X, Krummel MF. Spatiotemporally separated antigen uptake by alveolar dendritic cells and airway presentation to T cells in the lung. ACTA ACUST UNITED AC 2012; 209:1183-99. [PMID: 22585735 PMCID: PMC3371730 DOI: 10.1084/jem.20112667] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In the mouse lung, dendritic cells in the alveolar region but not the airway extend dendrites and take up antigen; antigen-loaded alveolar DCs then move to and accumulate in the airway where they encounter T cells. Asthma pathogenesis is focused around conducting airways. The reasons for this focus have been unclear because it has not been possible to track the sites and timing of antigen uptake or subsequent antigen presentation to effector T cells. In this study, we use two-photon microscopy of the lung parenchyma and note accumulation of CD11b+ dendritic cells (DCs) around the airway after allergen challenge but very limited access of these airway-adjacent DCs to the contents of the airspace. In contrast, we observed prevalent transepithelial uptake of particulate antigens by alveolar DCs. These distinct sites are temporally linked, as early antigen uptake in alveoli gives rise to DC and antigen retention in the airway-adjacent region. Antigen-specific T cells also accumulate in the airway-adjacent region after allergen challenge and are activated by the accumulated DCs. Thus, we propose that later airway hyperreactivity results from selective retention of allergen-presenting DCs and antigen-specific T cells in airway-adjacent interaction zones, not from variation in the abilities of individual DCs to survey the lung.
Collapse
Affiliation(s)
- Emily E Thornton
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA
| | | | | | | | | | | | | | | |
Collapse
|
228
|
Kuo CH, Lin CH, Yang SN, Huang MY, Chen HL, Kuo PL, Hsu YL, Huang SK, Jong YJ, Wei WJ, Chen YP, Hung CH. Effect of prostaglandin I2 analogs on cytokine expression in human myeloid dendritic cells via epigenetic regulation. Mol Med 2012; 18:433-44. [PMID: 22231731 DOI: 10.2119/molmed.2011.00193] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 12/06/2011] [Indexed: 01/15/2023] Open
Abstract
Prostaglandin I(2) (PGI(2)) analog is regarded as a potential candidate for treating asthma. Human myeloid dendritic cells (mDCs) play a critical role in the pathogenesis of asthma. However, the effects of PGI(2) analog on human mDCs are unknown. In the present study, circulating mDCs were isolated from six healthy subjects. The effects of PGI(2) analogs iloprost and treprostinil on cytokine production, maturation and T-cell stimulatory function of human mDCs were investigated. Tumor necrosis factor (TNF)-α and interleukin (IL)-10 were measured by enzyme-linked immunosorbent assay. The expression of costimulatory molecules was investigated by flow cytometry. T-cell stimulatory function was investigated by measuring interferon (IFN)-γ, IL-13 and IL-10 production by T cells cocultured with iloprost-treated mDCs. Intracellular signaling was investigated by Western blot and chromatin immunoprecipitation. We found that iloprost and treprostinil induced IL-10, but suppressed TNF-α production in polyinosinic-polycytidylic acid (poly I:C)-stimulated mDCs. This effect was reversed by the I-prostanoid (IP), E-prostanoid (EP) receptor antagonists or intracellular free calcium (Ca(2+)) chelator. Forskolin, an adenyl cyclase activator, conferred a similar effect. Iloprost and treprostinil increased intracellular adenosine 3',5'-cyclic monophosphate (cAMP) levels, and iloprost also increased intracellular Ca(2+). Iloprost suppressed poly I:C-induced mitogen-activated protein kinase (MAPK) phospho-p38 and phospho-activating transcription factor (ATF)2 expression. Iloprost downregulated poly I:C-induced histone H3K4 trimethylation in the TNFA gene promoter region via suppressing translocation of histone 3 lysine 4 (H3K4)-specific methyltransferases MLL (mixed lineage leukemia) and WDR5 (WD repeat domain 5). Iloprost-treated mDCs inhibited IL-13, IFN-γ and IL-10 production by T cells. In conclusion, PGI(2) analogs enhance IL-10 and suppress TNF-α expression through the IP/EP2/EP4 receptors-cAMP and EP1 receptor-Ca(2+) pathway. Iloprost suppressed TNF-α expression via the MAPK-p38-ATF2 pathway and epigenetic regulation by downregulation of histone H3K4 trimethylation.
Collapse
Affiliation(s)
- Chang-Hung Kuo
- Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
229
|
Abstract
Asthma is a T lymphocyte-controlled disease of the airway wall caused by inflammation, overproduction of mucus and airway wall remodeling leading to bronchial hyperreactivity and airway obstruction. The airway epithelium is considered an essential controller of inflammatory, immune and regenerative responses to allergens, viruses and environmental pollutants that contribute to asthma pathogenesis. Epithelial cells express pattern recognition receptors that detect environmental stimuli and secrete endogenous danger signals, thereby activating dendritic cells and bridging innate and adaptive immunity. Improved understanding of the epithelium's function in maintaining the integrity of the airways and its dysfunction in asthma has provided important mechanistic insight into how asthma is initiated and perpetuated and could provide a framework by which to select new therapeutic strategies that prevent exacerbations and alter the natural course of the disease.
Collapse
|
230
|
Eckl-Dorna J, Ellinger A, Blatt K, Ghanim V, Steiner I, Pavelka M, Valent P, Valenta R, Niederberger V. Basophils are not the key antigen-presenting cells in allergic patients. Allergy 2012; 67:601-8. [PMID: 22335568 DOI: 10.1111/j.1398-9995.2012.02792.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2012] [Indexed: 12/01/2022]
Abstract
BACKGROUND Recent data obtained in mouse models have initiated a controversy whether basophils are the key antigen-presenting cells (APCs) in allergy. Here, we investigate whether basophils are of importance for the presentation of allergen and the induction of T cell proliferation in allergic patients. METHODS T cells, basophils, and APCs depleted of basophils were purified from allergic patients. Co-culture systems based on purified major allergens were established to study allergen-specific T cell responses using proliferation assays. RESULTS Only co-cultures of T cells with APCs depleted of basophils but not with basophils proliferated in response to allergen. Even addition of IL-3 to T cell-basophil co-cultures failed to induce allergen-specific T cell proliferation. CONCLUSIONS Our data demonstrate by classical in vitro proliferation assays that basophils are not key antigen-presenting cells that promote T cell proliferation in secondary immune responses to allergen in allergic patients.
Collapse
Affiliation(s)
- J. Eckl-Dorna
- Department of Otorhinolaryngology; Medical University of Vienna, AKH; Vienna; Austria
| | - A. Ellinger
- Department of Cell Biology and Ultrastructure Research; Center for Anatomy and Cell Biology; Medical University of Vienna; Vienna; Austria
| | - K. Blatt
- Division of Hematology and Hemostaseology; Department of Internal Medicine I; Medical University of Vienna, AKH; Vienna; Austria
| | - V. Ghanim
- Division of Hematology and Hemostaseology; Department of Internal Medicine I; Medical University of Vienna, AKH; Vienna; Austria
| | - I. Steiner
- Center for Medical Statistics, Informatics, and Intelligent Systems; Medical University of Vienna; Vienna; Austria
| | - M. Pavelka
- Department of Cell Biology and Ultrastructure Research; Center for Anatomy and Cell Biology; Medical University of Vienna; Vienna; Austria
| | - P. Valent
- Division of Hematology and Hemostaseology; Department of Internal Medicine I; Medical University of Vienna, AKH; Vienna; Austria
| | - R. Valenta
- Division of Immunopathology; Department of Pathophysiology and Allergy Research; Center for Pathophysiology, Infectiology and Immunology; Medical University of Vienna, AKH; Vienna; Austria
| | - V. Niederberger
- Department of Otorhinolaryngology; Medical University of Vienna, AKH; Vienna; Austria
| |
Collapse
|
231
|
Defective aeroallergen surveillance by airway mucosal dendritic cells as a determinant of risk for persistent airways hyper-responsiveness in experimental asthma. Mucosal Immunol 2012; 5:332-41. [PMID: 22354321 DOI: 10.1038/mi.2012.13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A hallmark of atopic asthma is development of chronic airways hyper-responsiveness (AHR) that persists in the face of ongoing exposure to perennial aeroallergens. We investigated underlying mechanisms in sensitized rats focusing on a strain expressing the high-allergen-responder phenotype characteristic of human atopic asthmatics, and find that their high susceptibility to aeroallergen-induced persistent AHR is associated with deficiencies in the immunoregulatory and mucosal trafficking properties of inducible T-regulatory cells (iTregs). Counterintuitively, AHR susceptibility was inversely related to aeroallergen exposure level, high exposures conferring protection. We demonstrate that underlying this AHR-susceptible phenotype is reduced capacity of airway mucosal dendritic cells (AMDCs) for allergen sampling in vivo; this defect is microenvironmentally acquired, as allergen uptake by these cells in vitro is normal. Moreover, intranasal transfer of in vitro aeroallergen-loaded AMDC from naïve animals into AHR-susceptible animals during prolonged aerosol challenge markedly boosts subsequent accumulation of iTregs in the airway mucosa and rapidly resolves their chronic AHR, suggesting that compromised antigen surveillance by AMDC resulting in defective functional programming of iTreg may be causally related to AHR susceptibility.
Collapse
|
232
|
Li H, Demetris AJ, McNiff J, Matte-Martone C, Tan HS, Rothstein DM, Lakkis FG, Shlomchik WD. Profound depletion of host conventional dendritic cells, plasmacytoid dendritic cells, and B cells does not prevent graft-versus-host disease induction. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012. [PMID: 22422880 DOI: 10.4049/jimmunol.1102795.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The efficacy of allogeneic hematopoietic stem cell transplantation is limited by graft-versus-host disease (GVHD). Host hematopoietic APCs are important initiators of GVHD, making them logical targets for GVHD prevention. Conventional dendritic cells (DCs) are key APCs for T cell responses in other models of T cell immunity, and they are sufficient for GVHD induction. However, we report in this article that in two polyclonal GVHD models in which host hematopoietic APCs are essential, GVHD was not decreased when recipient conventional DCs were inducibly or constitutively deleted. Additional profound depletion of plasmacytoid DCs and B cells, with or without partial depletion of CD11b(+) cells, also did not ameliorate GVHD. These data indicate that, in contrast with pathogen models, there is a surprising redundancy as to which host cells can initiate GVHD. Alternatively, very low numbers of targeted APCs were sufficient. We hypothesize the difference in APC requirements in pathogen and GVHD models relates to the availability of target Ags. In antipathogen responses, specialized APCs are uniquely equipped to acquire and present exogenous Ags, whereas in GVHD, all host cells directly present alloantigens. These studies make it unlikely that reagent-based host APC depletion will prevent GVHD in the clinic.
Collapse
Affiliation(s)
- Hongmei Li
- Cancer Center, Yale University School of Medicine, New Haven, CT 06520, USA
| | | | | | | | | | | | | | | |
Collapse
|
233
|
Schlereth S, Lee HS, Khandelwal P, Saban DR. Blocking CCR7 at the ocular surface impairs the pathogenic contribution of dendritic cells in allergic conjunctivitis. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:2351-60. [PMID: 22507838 DOI: 10.1016/j.ajpath.2012.02.015] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 12/13/2011] [Accepted: 02/09/2012] [Indexed: 01/13/2023]
Abstract
CCR7 plays a key role in mobilizing tissue dendritic cells (DCs) to the lymphoid compartment for consequent elicitation of adaptive immunity. Interfering with CCR7 function therapeutically would therefore be anticipated to inhibit the progression of atopic conditions, for example, allergic conjunctivitis (AC). However, the CCR7-CCL19/CCL21 system in the ocular surface is poorly understood as is the precise role of DCs in AC immunopathogenesis. T cells from ovalbumin (OVA)-primed mice were adoptively transferred into wild-type (WT) hosts. Exogenous WT (eGFP(+)) versus CCR7(-/-) DCs were engrafted subconjunctivally (SCJ), and hosts were challenged with OVA (Texas-Red+) eye drops. AC immunopathogenesis was evaluated via clinical examinations, infiltration of mast cells and eosinophils, Th2 reactivity, and serum IgE levels. AC was also assessed in actively immunized mice challenged with OVA eye drops containing 1% anti-CCR7 antibody or isotype control. In eye-draining lymph nodes (LNs), OVA(+) SCJ engrafted WT DCs conferred upregulated CCR7 and caused augmentation of clinical signs. This result was corroborated by increased conjunctival infiltration, Th2 cytokines in LNs, and serum OVA-specific IgE. Strikingly, this was completely reversed with SCJ engrafted CCR7(-/-) DCs in all parameters tested. Furthermore, topical antibody blockade of CCR7 in actively immunized mice significantly inhibited AC. Ocular surface DCs via CCR7 expression contribute to the immunopathogenesis of AC, thereby allowing significant inhibition of this experimental condition via topical CCR7 antibody blockade.
Collapse
|
234
|
Abstract
The mucosal system is the first line of defense against many pathogens. It is continuously exposed to dietary and microbial antigens, and thus the host must maintain a homeostatic environment between commensal microbiota and pathogenic infections. Following infections and inflammatory events, a rapid innate immune response is evoked to dampen the inflammatory processes. Type I interferons, a family of pleiotropic cytokines and major products of the innate immune response, have a key role in these early immune events at the mucosa, as reviewed here. With the emergence of new discoveries of immune cell types in mucosal tissues and their reactions to commensal and pathogenic organisms, we also review the opportunities for exciting research in this field.
Collapse
|
235
|
Li H, Demetris AJ, McNiff J, Matte-Martone C, Tan HS, Rothstein DM, Lakkis FG, Shlomchik WD. Profound depletion of host conventional dendritic cells, plasmacytoid dendritic cells, and B cells does not prevent graft-versus-host disease induction. THE JOURNAL OF IMMUNOLOGY 2012; 188:3804-11. [PMID: 22422880 DOI: 10.4049/jimmunol.1102795] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The efficacy of allogeneic hematopoietic stem cell transplantation is limited by graft-versus-host disease (GVHD). Host hematopoietic APCs are important initiators of GVHD, making them logical targets for GVHD prevention. Conventional dendritic cells (DCs) are key APCs for T cell responses in other models of T cell immunity, and they are sufficient for GVHD induction. However, we report in this article that in two polyclonal GVHD models in which host hematopoietic APCs are essential, GVHD was not decreased when recipient conventional DCs were inducibly or constitutively deleted. Additional profound depletion of plasmacytoid DCs and B cells, with or without partial depletion of CD11b(+) cells, also did not ameliorate GVHD. These data indicate that, in contrast with pathogen models, there is a surprising redundancy as to which host cells can initiate GVHD. Alternatively, very low numbers of targeted APCs were sufficient. We hypothesize the difference in APC requirements in pathogen and GVHD models relates to the availability of target Ags. In antipathogen responses, specialized APCs are uniquely equipped to acquire and present exogenous Ags, whereas in GVHD, all host cells directly present alloantigens. These studies make it unlikely that reagent-based host APC depletion will prevent GVHD in the clinic.
Collapse
Affiliation(s)
- Hongmei Li
- Cancer Center, Yale University School of Medicine, New Haven, CT 06520, USA
| | | | | | | | | | | | | | | |
Collapse
|
236
|
Kool M, Hammad H, Lambrecht BN. Cellular networks controlling Th2 polarization in allergy and immunity. F1000 BIOLOGY REPORTS 2012; 4:6. [PMID: 22403589 PMCID: PMC3292286 DOI: 10.3410/b4-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In contrast to the development of Th1 (type 1 T helper cells), Th17 and Treg (regulatory T cells), little is known of the mechanisms governing Th2 development, which is important for immunity to helminths and for us to understand the pathogenesis of allergy. A picture is emerging in which mucosal epithelial cells instruct dendritic cells to promote Th2 responses in the absence of IL-12 (interleukin 12) production and provide instruction through thymic stromal lymphopoieitin (TSLP) or granulocyte-macrophage colony stimulating factor (GM-CSF). At the same time, allergens, helminths and chemical adjuvants elicit the response of innate immune cells like basophils, which provide more polarizing cytokines and IL-4 and reinforce Th2 immunity. This unique communication between cells will only be fully appreciated if we study Th2 immunity in vivo and in a tissue-specific context, and can only be fully understood if we compare several models of Th2 immune response induction.
Collapse
Affiliation(s)
- Mirjam Kool
- Laboratory of Immunoregulation and Mucosal Immunology, Department of Respiratory Diseases, University HospitalGhentBelgium
- Department of Pulmonary Medicine, Erasmus University Medical CentreRotterdamThe Netherlands
| | - Hamida Hammad
- Laboratory of Immunoregulation and Mucosal Immunology, Department of Respiratory Diseases, University HospitalGhentBelgium
- Department of Molecular Biomedical Research, Flemish Institute of BiotechnologyVIB, GhentBelgium
| | - Bart N. Lambrecht
- Laboratory of Immunoregulation and Mucosal Immunology, Department of Respiratory Diseases, University HospitalGhentBelgium
- Department of Pulmonary Medicine, Erasmus University Medical CentreRotterdamThe Netherlands
- Department of Molecular Biomedical Research, Flemish Institute of BiotechnologyVIB, GhentBelgium
| |
Collapse
|
237
|
Tittel AP, Heuser C, Ohliger C, Llanto C, Yona S, Hämmerling GJ, Engel DR, Garbi N, Kurts C. Functionally relevant neutrophilia in CD11c diphtheria toxin receptor transgenic mice. Nat Methods 2012. [PMID: 22367054 DOI: 10.1038/nmeth.1905.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transgenic mice expressing the diphtheria toxin receptor (DTR) in specific cell types are key tools for functional studies in several biological systems. B6.FVB-Tg(Itgax-DTR/EGFP)57Lan/J (CD11c.DTR) and B6.Cg-Tg(Itgax-DTR/OVA/EGFP)1Gjh/Crl (CD11c.DOG) mice express the DTR in CD11c(+) cells, allowing conditional depletion of dendritic cells. We report that dendritic-cell depletion in these models caused polymorphonuclear neutrophil (PMN) release from the bone marrow, which caused chemokine-dependent neutrophilia after 6-24 h and increased bacterial clearance in a mouse pyelonephritis model. We present a transgenic mouse line, B6.Cg-Tg(Itgax-EGFP-CRE-DTR-LUC)2Gjh/Crl (CD11c.LuciDTR), which is unaffected by early neutrophilia. However, CD11c.LuciDTR and CD11c.DTR mice showed late neutrophilia 72 h after dendritic cell depletion, which was independent of PMN release and possibly resulted from increased granulopoiesis. Thus, the time point of dendritic cell depletion and the choice of DTR transgenic mouse line must be considered in experimental settings where neutrophils may be involved.
Collapse
Affiliation(s)
- André P Tittel
- Institutes of Molecular Medicine and Experimental Immunology, Rheinische Friedrich Wilhelms University, Bonn, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
238
|
Functionally relevant neutrophilia in CD11c diphtheria toxin receptor transgenic mice. Nat Methods 2012; 9:385-90. [PMID: 22367054 DOI: 10.1038/nmeth.1905] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 01/12/2012] [Indexed: 12/15/2022]
Abstract
Transgenic mice expressing the diphtheria toxin receptor (DTR) in specific cell types are key tools for functional studies in several biological systems. B6.FVB-Tg(Itgax-DTR/EGFP)57Lan/J (CD11c.DTR) and B6.Cg-Tg(Itgax-DTR/OVA/EGFP)1Gjh/Crl (CD11c.DOG) mice express the DTR in CD11c(+) cells, allowing conditional depletion of dendritic cells. We report that dendritic-cell depletion in these models caused polymorphonuclear neutrophil (PMN) release from the bone marrow, which caused chemokine-dependent neutrophilia after 6-24 h and increased bacterial clearance in a mouse pyelonephritis model. We present a transgenic mouse line, B6.Cg-Tg(Itgax-EGFP-CRE-DTR-LUC)2Gjh/Crl (CD11c.LuciDTR), which is unaffected by early neutrophilia. However, CD11c.LuciDTR and CD11c.DTR mice showed late neutrophilia 72 h after dendritic cell depletion, which was independent of PMN release and possibly resulted from increased granulopoiesis. Thus, the time point of dendritic cell depletion and the choice of DTR transgenic mouse line must be considered in experimental settings where neutrophils may be involved.
Collapse
|
239
|
Crapster-Pregont M, Yeo J, Sanchez RL, Kuperman DA. Dendritic cells and alveolar macrophages mediate IL-13-induced airway inflammation and chemokine production. J Allergy Clin Immunol 2012; 129:1621-7.e3. [PMID: 22365581 DOI: 10.1016/j.jaci.2012.01.052] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 01/09/2012] [Accepted: 01/17/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND IL-13 in the airway induces pathologies that are highly characteristic of asthma, including mucus metaplasia, airway hyperreactivity (AHR), and airway inflammation. As such, it is important to identify the IL-13-responding cell types that mediate each of the above pathologies. For example, IL-13's effects on epithelium contribute to mucus metaplasia and AHR. IL-13's effects on smooth muscle also contribute to AHR. However, it has been difficult to identify the cell types that mediate IL-13-induced airway inflammation. OBJECTIVE We sought to determine which cell types mediate IL-13-induced airway inflammation. METHODS We treated the airways of mice with IL-13 alone or in combination with IFN-γ. We associated the inhibitory effect of IFN-γ on IL-13-induced airway inflammation and chemokine production with cell types in the lung that coexpress IL-13 and IFN-γ receptors. We then evaluated IL-13-induced responses in CD11c promoter-directed diphtheria toxin receptor-expressing mice that were depleted of both dendritic cells and alveolar macrophages and in CD11b promoter-directed diphtheria toxin receptor-expressing mice that were depleted of dendritic cells. RESULTS Dendritic cell and alveolar macrophage depletion protected mice from IL-13-induced airway inflammation and CCL11, CCL24, CCL22, and CCL17 chemokine production. Preferential depletion of dendritic cells protected mice from IL-13-induced airway inflammation and CCL22 and CCL17 chemokine production but not from IL-13-induced CCL11 and CCL24 chemokine production. In either case mice were not protected from IL-13-induced AHR and mucus metaplasia. CONCLUSIONS Pulmonary dendritic cells and alveolar macrophages mediate IL-13-induced airway inflammation and chemokine production.
Collapse
Affiliation(s)
- Margaret Crapster-Pregont
- Department of Medicine, Allergy-Immunology Division, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | | | | | | |
Collapse
|
240
|
Wills-Karp M, Rani R, Dienger K, Lewkowich I, Fox JG, Perkins C, Lewis L, Finkelman FD, Smith DE, Bryce PJ, Kurt-Jones EA, Wang TC, Sivaprasad U, Hershey GK, Herbert DR. Trefoil factor 2 rapidly induces interleukin 33 to promote type 2 immunity during allergic asthma and hookworm infection. ACTA ACUST UNITED AC 2012; 209:607-22. [PMID: 22329990 PMCID: PMC3302229 DOI: 10.1084/jem.20110079] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The repair protein trefoil factor 2 promotes Th2 responses to helminth infection and allergens in part by inducing IL-33. The molecular mechanisms that drive mucosal T helper type 2 (TH2) responses against parasitic helminths and allergens remain unclear. In this study, we demonstrate in mice that TFF2 (trefoil factor 2), an epithelial cell–derived repair molecule, is needed for the control of lung injury caused by the hookworm parasite Nippostrongylus brasiliensis and for type 2 immunity after infection. TFF2 is also necessary for the rapid production of IL-33, a TH2-promoting cytokine, by lung epithelia, alveolar macrophages, and inflammatory dendritic cells in infected mice. TFF2 also increases the severity of allergic lung disease caused by house dust mite antigens or IL-13. Moreover, TFF2 messenger RNA expression is significantly increased in nasal mucosal brushings during asthma exacerbations in children. These experiments extend the biological functions of TFF2 from tissue repair to the initiation and maintenance of mucosal TH2 responses.
Collapse
Affiliation(s)
- Marsha Wills-Karp
- Division of Immunobiology and 2 Division of Asthma Research, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
241
|
Murai H, Qi H, Choudhury B, Wild J, Dharajiya N, Vaidya S, Kalita A, Bacsi A, Corry D, Kurosky A, Brasier A, Boldogh I, Sur S. Alternaria-induced release of IL-18 from damaged airway epithelial cells: an NF-κB dependent mechanism of Th2 differentiation? PLoS One 2012; 7:e30280. [PMID: 22347372 PMCID: PMC3274547 DOI: 10.1371/journal.pone.0030280] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 12/13/2011] [Indexed: 01/17/2023] Open
Abstract
Background A series of epidemiologic studies have identified the fungus Alternaria as a major risk factor for asthma. The airway epithelium plays a critical role in the pathogenesis of allergic asthma. These reports suggest that activated airway epithelial cells can produce cytokines such as IL-25, TSLP and IL-33 that induce Th2 phenotype. However the epithelium-derived products that mediate the pro-asthma effects of Alternaria are not well characterized. We hypothesized that exposure of the airway epithelium to Alternaria releasing cytokines that can induce Th2 differentiation. Methodology/Principal Finding We used ELISA to measure human and mouse cytokines. Alternaria extract (ALT-E) induced rapid release of IL-18, but not IL-4, IL-9, IL-13, IL-25, IL-33, or TSLP from cultured normal human bronchial epithelial cells; and in the BAL fluids of naïve mice after challenge with ALT-E. Both microscopic and FACS indicated that this release was associated with necrosis of epithelial cells. ALT-E induced much greater IL-18 release compared to 19 major outdoor allergens. Culture of naïve CD4 cells with rmIL-18 induced Th2 differentiation in the absence of IL-4 and STAT6, and this effect was abrogated by disrupting NF- κB p50 or with a NEMO binding peptide inhibitor. Conclusion/Significance Rapid and specific release of IL-18 from Alternaria-exposed damaged airway epithelial cells can directly initiate Th2 differentiation of naïve CD4+ T-cells via a unique NF-κB dependent pathway.
Collapse
Affiliation(s)
- Hiroki Murai
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Huibin Qi
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Barun Choudhury
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jim Wild
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Nilesh Dharajiya
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Swapnil Vaidya
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Anjana Kalita
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Attila Bacsi
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - David Corry
- Division of Pulmonary and Critical Care, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alexander Kurosky
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Allan Brasier
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Istvan Boldogh
- Department of Microbiology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Sanjiv Sur
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
| |
Collapse
|
242
|
Cools N, Petrizzo A, Smits E, Buonaguro FM, Tornesello ML, Berneman Z, Buonaguro L. Dendritic cells in the pathogenesis and treatment of human diseases: a Janus Bifrons? Immunotherapy 2012; 3:1203-22. [PMID: 21995572 DOI: 10.2217/imt.11.110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Dendritic cells (DCs) represent the bridging cell compartment between a variety of nonself antigens (i.e., microbial, cancer and vaccine antigens) and adaptive immunity, orchestrating the quality and potency of downstream immune responses. Because of the central role of DCs in the generation and regulation of immunity, the modulation of DC function in order to shape immune responses is gaining momentum. In this respect, recent advances in understanding DC biology, as well as the required molecular signals for induction of T-cell immunity, have spurred many experimental strategies to use DCs for therapeutic immunological approaches for infections and cancer. However, when DCs lose control over such 'protective' responses - by alterations in their number, phenotype and/or function - undesired effects leading to allergy and autoimmune clinical manifestations may occur. Novel therapeutic approaches have been designed and currently evaluated in order to address DCs and silence these immunopathological processes. In this article we present recent concepts of DC biology and some medical implications in view of therapeutic opportunities.
Collapse
Affiliation(s)
- Nathalie Cools
- Laboratory of Experimental Hematology, Vaccine & Infectious Disease Institute (Vaxinfectio), University of Antwerp, B-2610 Wilrijk, Belgium
| | | | | | | | | | | | | |
Collapse
|
243
|
Wythe SE, Dodd JS, Openshaw PJ, Schwarze J. OX40 ligand and programmed cell death 1 ligand 2 expression on inflammatory dendritic cells regulates CD4 T cell cytokine production in the lung during viral disease. THE JOURNAL OF IMMUNOLOGY 2012; 188:1647-55. [PMID: 22266281 DOI: 10.4049/jimmunol.1103001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CD4 Th differentiation is influenced by costimulatory molecules expressed on conventional dendritic cells (DCs) in regional lymph nodes and results in specific patterns of cytokine production. However, the function of costimulatory molecules on inflammatory (CD11b(+)) DCs in the lung during recall responses is not fully understood, but it is important for development of novel interventions to limit immunopathological responses to infection. Using a mouse model in which vaccination with vaccinia virus vectors expressing the respiratory syncytial virus (RSV) fusion protein (rVVF) or attachment protein (rVVG) leads to type 1- or type 2-biased cytokine responses, respectively, upon RSV challenge, we found expression of CD40 and OX40 ligand (OX40L) on lung inflammatory DCs was higher in rVVF-primed mice than in rVVG-primed mice early after RSV challenge, whereas the reverse was observed later in the response. Conversely, programmed cell death 1 ligand 2 (PD-L2) was higher in rVVG-primed mice throughout. Inflammatory DCs isolated at the resolution of inflammation revealed that OX40L on type 1-biased DCs promoted IL-5, whereas OX40L on type 2-biased DCs enhanced IFN-γ production by Ag-reactive Th cells. In contrast, PD-L2 promoted IFN-γ production, irrespective of conditions, suppressing IL-5 only if expressed on type 1-biased DCs. Thus, OX40L and PD-L2 expressed on DCs differentially regulate cytokine production during recall responses in the lung. Manipulation of these costimulatory pathways may provide a novel approach to controlling pulmonary inflammatory responses.
Collapse
Affiliation(s)
- Sarah E Wythe
- Center for Respiratory Infections, National Heart and Lung Institute, St. Mary's Campus, Imperial College London, London W2 1PG, UK
| | | | | | | |
Collapse
|
244
|
Enomoto N, Hyde E, Ma JZI, Yang J, Forbes-Blom E, Delahunt B, Le Gros G, Ronchese F. Allergen-specific CTL require perforin expression to suppress allergic airway inflammation. THE JOURNAL OF IMMUNOLOGY 2012; 188:1734-41. [PMID: 22250087 DOI: 10.4049/jimmunol.1102699] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Allergen-specific CTL have a protective effect on allergic airway inflammation, a function thought to be mediated by cytokines, especially IFN-γ. However, the contribution of cytotoxic function to this protective effect has not been investigated. We examined the contribution of cytotoxic function to the therapeutic effect of allergen-specific CTL in allergic airway inflammation. We used a murine model of allergic airway inflammation in which mice were sensitized to OVA and then challenged with the same Ag via the intranasal route. CTL were elicited in these mice by immunization with dendritic cells (DC) or by adoptive transfer of in vitro-activated CD8(+) T cells. Hallmark features of allergic asthma, such as infiltration of eosinophils in the bronchoalveolar lavage fluid and mucus production, were assessed. Suppression of allergic airway inflammation by allergen-specific CTL was critically dependent on the expression of perforin, a key component of the cytotoxic machinery. Both perforin-sufficient and perforin-deficient allergen-specific CTL were recovered from the lungs of allergen-sensitized mice and upregulated CD69 expression and secreted the cytokines IFN-γ and TNF-α upon intranasal allergen challenge. However, only perforin-sufficient CTL inhibited eosinophil infiltration in the airway, mucus production, and cytokine accumulation in the bronchoalveolar lavage fluid. Treatment with allergen-specific CTL, but not their perforin-deficient counterparts, was also associated with a decrease in the number of DC in the mediastinal lymph node. Our data suggest that the cytotoxic function of allergen-specific CD8(+) T cells is critical to their ability to moderate allergic airway inflammation.
Collapse
Affiliation(s)
- Noriyuki Enomoto
- Malaghan Institute of Medical Research, 6012 Wellington, New Zealand
| | | | | | | | | | | | | | | |
Collapse
|
245
|
Lambrecht BN, Hammad H. Lung dendritic cells in respiratory viral infection and asthma: from protection to immunopathology. Annu Rev Immunol 2012; 30:243-70. [PMID: 22224777 DOI: 10.1146/annurev-immunol-020711-075021] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lung dendritic cells (DCs) bridge innate and adaptive immunity, and depending on context, they also induce a Th1, Th2, or Th17 response to optimally clear infectious threats. Conversely, lung DCs can also mount maladaptive Th2 immune responses to harmless allergens and, in this way, contribute to immunopathology. It is now clear that the various aspects of DC biology can be understood only if we take into account the functional specializations of different DC subsets that are present in the lung in homeostasis or are attracted to the lung as part of the inflammatory response to inhaled noxious stimuli. Lung DCs are heavily influenced by the nearby epithelial cells, and a model is emerging whereby direct communication between DCs and epithelial cells determines the outcome of the pulmonary immune response. Here, we have approached DC biology from the perspective of viral infection and allergy to illustrate these emerging concepts.
Collapse
Affiliation(s)
- Bart N Lambrecht
- Laboratory of Immunoregulation and Mucosal Immunology, Department of Molecular Biomedical Research, VIB, 9052 Ghent, Belgium.
| | | |
Collapse
|
246
|
Abstract
Asthma is characterized by airflow obstruction that is usually completely reversible either spontaneously or in response to treatment. However, a small subset of patients with asthma display FAO (fixed airflow obstruction) despite optimal treatment, a feature more commonly associated with smoking-induced COPD (chronic obstructive pulmonary disease). Why some asthma patients develop FAO is not understood, and it is not clear whether (i) they represent a subset of patients with more severe disease, (ii) they share some characteristics of patients who develop COPD, or (iii) they represent a different disease entity altogether. The present review compares the pulmonary inflammatory profile of asthma patients with FAO with those without FAO, as well as COPD sufferers. The inflammation in asthma patients with FAO can vary from neutrophilic with CD8 T-cell involvement, similar to that of COPD, to eosinophilic with CD4 Th2 cell involvement, akin to that of asthma patients without FAO. Although studies of FAO in asthma sufferers would benefit hugely from consistent inclusion criteria, further research work is also required to shed more light on the immunological processes involved.
Collapse
|
247
|
Nakagome K, Imamura M, Kawahata K, Harada H, Okunishi K, Matsumoto T, Sasaki O, Tanaka R, Kano MR, Chang H, Hanawa H, Miyazaki JI, Yamamoto K, Dohi M. High expression of IL-22 suppresses antigen-induced immune responses and eosinophilic airway inflammation via an IL-10-associated mechanism. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2011; 187:5077-89. [PMID: 21998459 DOI: 10.4049/jimmunol.1001560] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Allergic inflammation in the airway is generally considered a Th2-type immune response. However, Th17-type immune responses also play important roles in this process, especially in the pathogenesis of severe asthma. IL-22 is a Th17-type cytokine and thus might play roles in the development of allergic airway inflammation. There is increasing evidence that IL-22 can act as a proinflammatory or anti-inflammatory cytokine depending on the inflammatory context. However, its role in Ag-induced immune responses is not well understood. This study examined whether IL-22 could suppress allergic airway inflammation and its mechanism of action. BALB/c mice were sensitized and challenged with OVA-Ag to induce airway inflammation. An IL-22-producing plasmid vector was delivered before the systemic sensitization or immediately before the airway challenge. Delivery of the IL-22 gene before sensitization, but not immediately before challenge, suppressed eosinophilic airway inflammation. IL-22 gene delivery suppressed Ag-induced proliferation and overall cytokine production in CD4(+) T cells, indicating that it could suppress Ag-induced T cell priming. Antagonism of IL-22 by IL-22-binding protein abolished IL-22-induced immune suppression, suggesting that IL-22 protein itself played an essential role. IL-22 gene delivery neither increased regulatory T cells nor suppressed dendritic cell functions. The suppression by IL-22 was abolished by deletion of the IL-10 gene or neutralization of the IL-10 protein. Finally, IL-22 gene delivery increased IL-10 production in draining lymph nodes. These findings suggested that IL-22 could have an immunosuppressive effect during the early stage of an immune response. Furthermore, IL-10 plays an important role in the immune suppression by IL-22.
Collapse
Affiliation(s)
- Kazuyuki Nakagome
- Department of Allergy and Rheumatology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
248
|
Repeated exposure to Aspergillus fumigatus conidia results in CD4+ T cell-dependent and -independent pulmonary arterial remodeling in a mixed Th1/Th2/Th17 microenvironment that requires interleukin-4 (IL-4) and IL-10. Infect Immun 2011; 80:388-97. [PMID: 22064716 DOI: 10.1128/iai.05530-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pulmonary arterial remodeling is a pathological process seen in a number of clinical disease states, driven by inflammatory cells and mediators in the remodeled artery microenvironment. In murine models, Th2 cell-mediated immune responses to inhaled antigens, such as purified Aspergillus allergen, have been reported to induce remodeling of pulmonary arteries. We have previously shown that repeated intranasal exposure of healthy C57BL/6 mice to viable, resting Aspergillus fumigatus conidia leads to the development of chronic pulmonary inflammation and the coevolution of Th1, Th2, and Th17 responses in the lungs. Our objective was to determine whether repeated intranasal exposure to Aspergillus conidia would induce pulmonary arterial remodeling in this mixed Th inflammatory microenvironment. Using weekly intranasal conidial challenges, mice developed robust pulmonary arterial remodeling after eight exposures (but not after two or four). The process was partially mediated by CD4+ T cells and by interleukin-4 (IL-4) production, did not require eosinophils, and was independent of gamma interferon (IFN-γ) and IL-17. Furthermore, remodeling could occur even in the presence of strong Th1 and Th17 responses. Rather than serving an anti-inflammatory function, IL-10 was required for the development of the Th2 response to A. fumigatus conidia. However, in contrast to previous studies of pulmonary arterial remodeling driven by the A. fumigatus allergen, viable conidia also stimulated pulmonary arterial remodeling in the absence of CD4+ T cells. Remodeling was completely abrogated in IL-10-/- mice, suggesting that a second, CD4+ T cell-independent, IL-10-dependent pathway was also driving pulmonary arterial remodeling in response to repeated conidial exposure.
Collapse
|
249
|
Sadik CD, Luster AD. Lipid-cytokine-chemokine cascades orchestrate leukocyte recruitment in inflammation. J Leukoc Biol 2011; 91:207-15. [PMID: 22058421 DOI: 10.1189/jlb.0811402] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Chemoattractants are pivotal mediators of host defense, orchestrating the recruitment of immune cells into sites of infection and inflammation. Chemoattractants display vast chemical diversity and include bioactive lipids, proteolytic fragments of serum proteins, and chemokines (chemotactic cytokines). All chemoattractants induce chemotaxis by activating seven-transmembrane-spanning GPCRs expressed on immune cells, establishing the concept that all chemoattractants are related in function. However, although chemoattractants have overlapping functions in vitro, recent in vivo data have revealed that they function, in many cases, nonredundantly in vivo. The chemically diverse nature of chemoattractants contributes to the fine control of leukocyte trafficking in vivo, with sequential chemoattractant use guiding immune cell recruitment into inflammatory sites. Lipid mediators frequently function as initiators of leukocyte recruitment, attracting the first immune cells into tissues. These initial responding immune cells produce cytokines locally, which in turn, induce the local release of chemokines. Local chemokine production then markedly amplifies subsequent waves of leukocyte recruitment. These new discoveries establish a paradigm for leukocyte recruitment in inflammation--described as lipid-cytokine-chemokine cascades--as a driving force in the effector phase of immune responses.
Collapse
Affiliation(s)
- Christian D Sadik
- Division of Rheumatology, Allergy, and Immunology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | | |
Collapse
|
250
|
Anzinger JJ, Chang J, Xu Q, Barthwal MK, Bohnacker T, Wymann MP, Kruth HS. Murine bone marrow-derived macrophages differentiated with GM-CSF become foam cells by PI3Kγ-dependent fluid-phase pinocytosis of native LDL. J Lipid Res 2011; 53:34-42. [PMID: 22058424 DOI: 10.1194/jlr.m018887] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Accumulation of cholesterol by macrophage uptake of LDL is a key event in the formation of atherosclerotic plaques. Previous research has shown that granulocyte-macrophage colony-stimulating factor (GM-CSF) is present in atherosclerotic plaques and promotes aortic lipid accumulation. However, it has not been determined whether murine GM-CSF-differentiated macrophages take up LDL to become foam cells. GM-CSF-differentiated macrophages from LDL receptor-null mice were incubated with LDL, resulting in massive macrophage cholesterol accumulation. Incubation of LDL receptor-null or wild-type macrophages with increasing concentrations of ¹²⁵I-LDL showed nonsaturable macrophage LDL uptake that was linearly related to the amount of LDL added, indicating that LDL uptake was mediated by fluid-phase pinocytosis. Previous studies suggest that phosphoinositide 3-kinases (PI3K) mediate macrophage fluid-phase pinocytosis, although the isoform mediating this process has not been determined. Because PI3Kγ is known to promote aortic lipid accumulation, we investigated its role in mediating macrophage fluid-phase pinocytosis of LDL. Wild-type macrophages incubated with LDL and the PI3Kγ inhibitor AS605240 or PI3Kγ-null macrophages incubated with LDL showed an ∼50% reduction in LDL uptake and cholesterol accumulation compared with wild-type macrophages incubated with LDL only. These results show that GM-CSF-differentiated murine macrophages become foam cells by fluid-phase pinocytosis of LDL and identify PI3Kγ as contributing to this process.
Collapse
Affiliation(s)
- Joshua J Anzinger
- Section of Experimental Atherosclerosis, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | | | | | |
Collapse
|