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Ouyang X, Reihill JA, Douglas LEJ, Martin SL. Airborne indoor allergen serine proteases and their contribution to sensitisation and activation of innate immunity in allergic airway disease. Eur Respir Rev 2024; 33:230126. [PMID: 38657996 PMCID: PMC11040391 DOI: 10.1183/16000617.0126-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 02/28/2024] [Indexed: 04/26/2024] Open
Abstract
Common airborne allergens (pollen, animal dander and those from fungi and insects) are the main triggers of type I allergic disorder in the respiratory system and are associated with allergic rhinitis, allergic asthma, as well as immunoglobulin E (IgE)-mediated allergic bronchopulmonary aspergillosis. These allergens promote IgE crosslinking, vasodilation, infiltration of inflammatory cells, mucosal barrier dysfunction, extracellular matrix deposition and smooth muscle spasm, which collectively cause remodelling of the airways. Fungus and insect (house dust mite and cockroaches) indoor allergens are particularly rich in proteases. Indeed, more than 40 different types of aeroallergen proteases, which have both IgE-neutralising and tissue-destructive activities, have been documented in the Allergen Nomenclature database. Of all the inhaled protease allergens, 85% are classed as serine protease activities and include trypsin-like, chymotrypsin-like and collagenolytic serine proteases. In this article, we review and compare the allergenicity and proteolytic effect of allergen serine proteases as listed in the Allergen Nomenclature and MEROPS databases and highlight their contribution to allergic sensitisation, disruption of the epithelial barrier and activation of innate immunity in allergic airways disease. The utility of small-molecule inhibitors of allergen serine proteases as a potential treatment strategy for allergic airways disease will also be discussed.
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Affiliation(s)
- Xuan Ouyang
- School of Pharmacy, Queen's University Belfast, Belfast, UK
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Krysko O, Teufelberger A, Van Nevel S, Krysko DV, Bachert C. Protease/antiprotease network in allergy: The role of Staphylococcus aureus protease-like proteins. Allergy 2019; 74:2077-2086. [PMID: 30888697 DOI: 10.1111/all.13783] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/10/2019] [Accepted: 02/22/2019] [Indexed: 12/18/2022]
Abstract
Staphylococcus aureus is being recognized as a major cofactor in atopic diseases such as atopic dermatitis, chronic rhinosinusitis with nasal polyps, and asthma. The understanding of the relationship between S aureus virulence factors and the immune system is continuously improving. Although the precise mechanism of the host's immune response adaptation to the variable secretion profile of S aureus strains continues to be a matter of debate, an increasing number of studies have reported on central effects of S aureus secretome in allergy. In this review, we discuss how colonization of S aureus modulates the innate and adaptive immune response, thereby predisposing the organism to allergic sensitization and disrupting immune tolerance in the airways of patients with asthma and chronic rhinosinusitis with nasal polyps. Next, we provide a critical overview of novel concepts dealing with S aureus in the initiation and persistence of chronic rhinosinusitis with nasal polyps and asthma. The role of the S aureus serine protease-like proteins in the initiation of a type 2 response and the contribution of the IL-33/ST2 signaling axis in allergic responses induced by bacterial allergens are discussed.
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Affiliation(s)
- Olga Krysko
- Upper Airways Research Laboratory, Department Head and Skin Ghent University Ghent Belgium
| | - Andrea Teufelberger
- Upper Airways Research Laboratory, Department Head and Skin Ghent University Ghent Belgium
| | - Sharon Van Nevel
- Upper Airways Research Laboratory, Department Head and Skin Ghent University Ghent Belgium
| | - Dmitri V. Krysko
- Institute of Biology and Biomedicine National Research Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod Russian Federation
- Cell Death Investigation and Therapy Laboratory, Department of Human Structure and Repair Ghent University Ghent Belgium
- Cancer Research Institute Ghent Ghent Belgium
| | - Claus Bachert
- Upper Airways Research Laboratory, Department Head and Skin Ghent University Ghent Belgium
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Lee KE, Jee HM, Hong JY, Kim MN, Oh MS, Kim YS, Kim KW, Kim KE, Sohn MH. German Cockroach Extract Induces Matrix Metalloproteinase-1 Expression, Leading to Tight Junction Disruption in Human Airway Epithelial Cells. Yonsei Med J 2018; 59:1222-1231. [PMID: 30450857 PMCID: PMC6240571 DOI: 10.3349/ymj.2018.59.10.1222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/01/2018] [Accepted: 10/16/2018] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Cockroach exposure is a pivotal cause of asthma. Tight junctions are intercellular structures required for maintenance of the barrier function of the airway epithelium, which is impaired in this disease. Matrix metalloproteinases (MMPs) digest extracellular matrix components and are involved in asthma pathogenesis: MMP1 is a collagenase with a direct influence on airway obstruction in asthmatics. This study aimed to investigate the mechanism by which German cockroach extract (GCE) induces MMP1 expression and whether MMP1 release alters cellular tight junctions in human airway epithelial cells (NCI-H292). MATERIALS AND METHODS mRNA and protein levels were determined using real-time PCR and ELISA. Tight junction proteins were detected using immunofluorescence staining. Epithelial barrier function was measured by transepithelial electrical resistance (TEER). The binding of a transcription factor to DNA molecules was determined by electrophoretic mobility shift assay, while the levels of tight junction proteins and phosphorylation were determined using Western blotting. RESULTS GCE was shown to increase MMP1 expression, TEER, and tight junction degradation. Both an inhibitor and small interfering RNA (siRNA) of MMP1 significantly decreased GCE-induced tight junction disruption. Furthermore, transient transfection with ETS1 and SP1 siRNA, and anti-TLR2 antibody pretreatment prevented MMP1 expression and tight junction degradation. An extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) inhibitor also blocked MMP1 release, ETS1/SP1 DNA binding, and tight junction alteration. CONCLUSION GCE treatment increases MMP1 expression, leading to tight junction disruption, which is transcriptionally regulated and influenced by the ERK/MAPK pathway in airway epithelial cells. These findings may contribute to developing novel therapeutic strategies for airway diseases.
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Affiliation(s)
- Kyung Eun Lee
- Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Hye Mi Jee
- Department of Pediatrics, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea
| | - Jung Yeon Hong
- Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Mi Na Kim
- Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Mi Seon Oh
- Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Yun Seon Kim
- Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Kyung Won Kim
- Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | | | - Myung Hyun Sohn
- Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
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Abstract
Proteases play an important role in health and disease of the lung. In the normal lungs, proteases maintain their homeostatic functions that regulate processes like its regeneration and repair. Dysregulation of proteases–antiproteases balance is crucial in the manifestation of different types of lung diseases. Chronic inflammatory lung pathologies are associated with a marked increase in protease activities. Thus, in addition to protease activities, inhibition of anti-proteolytic control mechanisms are also important for effective microbial infection and inflammation in the lung. Herein, we briefly summarize the role of different proteases and to some extent antiproteases in regulating a variety of lung diseases.
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Abstract
Allergic asthma is on the rise in developed countries, and cockroach exposure is a major risk factor for the development of asthma. In recent years, a number of studies have investigated the importance of allergen-associated proteases in modulating allergic airway inflammation. Many of the studies have suggested the importance of allergen-associated proteases as having a direct role on airway epithelial cells and dendritic cells. In most cases, activation of the protease activated receptor (PAR)-2 has been implicated as a mechanism behind the potent allergenicity associated with cockroaches. In this review, we focus on recent evidence linking cockroach proteases to activation of a variety of cells important in allergic airway inflammation and the role of PAR-2 in this process. We will highlight recent data exploring the potential mechanisms involved in the biological effects of the allergen.
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Golebski K, Röschmann KIL, Toppila-Salmi S, Hammad H, Lambrecht BN, Renkonen R, Fokkens WJ, van Drunen CM. The multi-faceted role of allergen exposure to the local airway mucosa. Allergy 2013; 68:152-60. [PMID: 23240614 DOI: 10.1111/all.12080] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2012] [Indexed: 12/13/2022]
Abstract
Airway epithelial cells are the first to encounter aeroallergens and therefore have recently become an interesting target of many studies investigating their involvement in the modulation of allergic inflammatory responses. Disruption of a passive structural barrier composed of epithelial cells by intrinsic proteolytic activity of allergens may facilitate allergen penetration into local tissues and additionally affect chronic and ongoing inflammatory processes in respiratory tissues. Furthermore, the ability of rhinoviruses to disrupt and interfere with epithelial tight junctions may alter the barrier integrity and enable a passive passage of inhaled allergens through the airway epithelium. On the other hand, epithelial cells are no longer considered to act only as a physical barrier toward inhaled allergens, but also to actively contribute to airway inflammation by detecting and responding to environmental factors. Epithelial cells can produce mediators, which may affect the recruitment and activation of more specialized immune cells to the local tissue and also create a microenvironment in which these activated immune cells may function and propagate the inflammatory processes. This review presents the dual role of epithelium acting as a passive and active barrier when encountering an inhaled allergen and how this double role contributes to the start of local immune responses.
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Affiliation(s)
- K. Golebski
- Department of Otorhinolanyngology; Academic Medical Center, University of Amsterdam; Amsterdam; The Netherlands
| | - K. I. L. Röschmann
- Department of Otorhinolanyngology; Academic Medical Center, University of Amsterdam; Amsterdam; The Netherlands
| | - S. Toppila-Salmi
- Helsinki University Central Hospital, Skin and Allergy Hospital & Transplantation Laboratory, Haartman Institute, University of Helsinki; Helsinki; Finland
| | | | | | - R. Renkonen
- Transplantation Laboratory, Haartman Institute, University of Helsinki & Helsinki University Central Hospital, HUSLAB; Helsinki; Finland
| | - W. J. Fokkens
- Department of Otorhinolanyngology; Academic Medical Center, University of Amsterdam; Amsterdam; The Netherlands
| | - C. M. van Drunen
- Department of Otorhinolanyngology; Academic Medical Center, University of Amsterdam; Amsterdam; The Netherlands
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Day SB, Ledford JR, Zhou P, Lewkowich IP, Page K. German cockroach proteases and protease-activated receptor-2 regulate chemokine production and dendritic cell recruitment. J Innate Immun 2011; 4:100-10. [PMID: 21876326 DOI: 10.1159/000329132] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 05/08/2011] [Indexed: 12/28/2022] Open
Abstract
We recently showed that serine proteases in German cockroach (GC) feces (frass) decreased experimental asthma through the activation of protease-activated receptor (PAR)-2. Since dendritic cells (DCs) play an important role in the initiation of asthma, we queried the role of GC frass proteases in modulating CCL20 (chemokine C-C motif ligand 20) and granulocyte macrophage colony-stimulating factor (GM-CSF) production, factors that regulate pulmonary DCs. A single exposure to GC frass resulted in a rapid, but transient, increase in GM-CSF and a steady increase in CCL20 in the airways of mice. Instillation of protease-depleted GC frass or instillation of GC frass in PAR-2-deficient mice significantly decreased chemokine release. A specific PAR-2-activating peptide was also sufficient to induce CCL20 production. To directly assess the role of the GC frass protease in chemokine release, we enriched the protease from GC frass and confirmed that the protease was sufficient to induce both GM-CSF and CCL20 production in vivo. Primary airway epithelial cells produced both GM-CSF and CCL20 in a protease- and PAR-2-dependent manner. Finally, we show a decreased percentage of myeloid DCs in the lung following allergen exposure in PAR-2-deficient mice compared to wild-type mice. However, there was no difference in GC frass uptake. Our data indicate that, through the activation of PAR-2, allergen-derived proteases are sufficient to induce CCL20 and GM-CSF production in the airways. This leads to increased recruitment and/or differentiation of myeloid DC populations in the lungs and likely plays an important role in the initiation of allergic airway responses.
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Affiliation(s)
- Scottie B Day
- Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center and Cincinnati Children's Research Foundation, Cincinnati, Ohio, USA
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Erban T, Hubert J. Longterm persistence of proteolytic activities in frass of Blattella germanica increases its allergenic potential. MEDICAL AND VETERINARY ENTOMOLOGY 2011; 25:209-216. [PMID: 21198710 DOI: 10.1111/j.1365-2915.2010.00922.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Chromogenic microplate assays in 96 wells were used to determine the stability of enzyme activity in frass of Blattella germanica (Blattodea: Blattellidae). Frass samples were exposed to controlled conditions [temperature 15-35 °C and/or 53-100% relative humidity (RH)] and to household conditions (apartment). Exposure times were 0 (control), 90, 183 and 276 days. Starch digestion and cellulolytic activities decreased during exposure. Non-specific proteolytic activities were affected by changes in selective proteolytic activities. Activities towards AAPpNA and SA(3) pNA strongly increased at 100% RH, indicating the possible influence of microorganisms growing on frass. Activities towards BApNA and ArgpNA decreased with increasing decomposition time, whereas activity towards ZRRpNA was not influenced by exposure time. The largest decrease in activities towards ArgpNA and BApNA occurred at temperatures of 15 °C, 30 °C and 35 °C and at 100% RH. Activities towards BApNA and ZRRpNA were very stable under different temperature and RH conditions; this was confirmed by findings showing that these activities were stable in the experimental apartment. In comparison with the control, activities towards ZRRpNA and BApNA after 276 days decreased by 1% and 19%, respectively. The longterm persistence of proteolytic activities in cockroach frass increases their allergenic hazard potential.
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Affiliation(s)
- T Erban
- Department of Stored Product Pest and Food Safety, Crop Research Institute, Ruzyne, Czech Republic
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Jacquet A. Interactions of airway epithelium with protease allergens in the allergic response. Clin Exp Allergy 2010; 41:305-11. [PMID: 21121984 DOI: 10.1111/j.1365-2222.2010.03661.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Among the apparently innocuous environmental proteins routinely inhaled by human subjects, only a small proportion of these antigens triggers allergy in susceptible individuals. Although the molecular basis of the allergenicity of these airborne proteins remains to be fully characterized, numerous studies suggest that the ability of such proteins to promote allergic responses is at least due to their proteolytic activity. This review will summarize insights into the interactions of protease allergens with the respiratory epithelium. In addition to their capacity to facilitate their antigen presentation through epithelial barrier degradation, protease allergens can directly activate airway mucosal surfaces to recruit inflammatory cells and to initiate the airway remodelling process. A greater understanding of the effects of protease allergens in the airways inflammation as well as on the relevant targets could define novel therapeutic strategies for the treatment allergic asthma.
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Affiliation(s)
- A Jacquet
- Department of Medicine, Division of Allergy and Clinical Immunology, Faculty of Medicine, Chulalongkorn University, Pathumwan, Bangkok, Thailand.
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Day SB, Zhou P, Ledford JR, Page K. German cockroach frass proteases modulate the innate immune response via activation of protease-activated receptor-2. J Innate Immun 2010; 2:495-504. [PMID: 20588004 DOI: 10.1159/000317195] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 05/08/2010] [Indexed: 12/13/2022] Open
Abstract
Allergen exposure can induce an early innate immune response; however, the mechanism by which this occurs has not been addressed. In this report, we demonstrate a role for the active serine proteases in German cockroach (GC) feces (frass) and protease-activated receptor (PAR)-2 in modulating the innate immune response. A single exposure of GC frass induced inflammatory cytokine production and cellular infiltration in the airways of mice. In comparison, exposure to protease-depleted GC frass resulted in diminution of inflammatory cytokine production and airway neutrophilia, but had no effect on macrophage infiltration. Selective activation of PAR-2 confirmed that PAR-2 was sufficient to induce airway inflammation. Exposure of GC frass to PAR-2-deficient mice led to decreased immune responses to GC frass compared to wild-type mice. Using the macrophage as an early marker of the innate immune response, we found that GC frass induced significant release of tumor necrosis factor-alpha from primary alveolar macrophages. This effect was dependent on the intrinsic proteases in GC frass. We confirmed GC frass-induced cytokine expression was mediated by activation of NF-kappaB and ERK in a macrophage cell line. Collectively, these data suggest a central role for GC frass protease-PAR-2 activation in regulating the innate immune response through the activation of alveolar macrophages. Understanding the potential role of protease-PAR-2 activation as a danger signal or adjuvant could yield attractive therapeutic targets.
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Affiliation(s)
- Scottie B Day
- Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
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Page K, Ledford JR, Zhou P, Dienger K, Wills-Karp M. Mucosal sensitization to German cockroach involves protease-activated receptor-2. Respir Res 2010; 11:62. [PMID: 20497568 PMCID: PMC2889872 DOI: 10.1186/1465-9921-11-62] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 05/24/2010] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Allergic asthma is on the rise in developed countries. A common characteristic of allergens is that they contain intrinsic protease activity, and many have been shown to activate protease-activated receptor (PAR)-2 in vitro. The role for PAR-2 in mediating allergic airway inflammation has not been assessed using a real world allergen. METHODS Mice (wild type or PAR-2-deficient) were sensitized to German cockroach (GC) feces (frass) or protease-depleted GC frass by either mucosal exposure or intraperitoneal injection and measurements of airway inflammation (IL-5, IL-13, IL-17A, and IFNgamma levels in the lung, serum IgE levels, cellular infiltration, mucin production) and airway hyperresponsiveness were performed. RESULTS Following systemic sensitization, GC frass increased airway hyperresponsiveness, Th2 cytokine release, serum IgE levels, cellular infiltration and mucin production in wild type mice. Interestingly, PAR-2-deficient mice had similar responses as wild type mice. Since these data were in direct contrast to our finding that mucosal sensitization with GC frass proteases regulated airway hyperresponsiveness and mucin production in BALB/c mice (Page et. al. 2007 Resp Res 8:91), we backcrossed the PAR-2-deficient mice into the BALB/c strain. Sensitization to GC frass could now occur via the more physiologically relevant method of intratracheal inhalation. PAR-2-deficient mice had significantly reduced airway hyperresponsiveness, Th2 and Th17 cytokine release, serum IgE levels, and cellular infiltration compared to wild type mice when sensitization to GC frass occurred through the mucosa. To confirm the importance of mucosal exposure, mice were systemically sensitized to GC frass or protease-depleted GC frass via intraperitoneal injection. We found that removal of proteases from GC frass had no effect on airway inflammation when administered systemically. CONCLUSIONS We showed for the first time that allergen-derived proteases in GC frass elicit allergic airway inflammation via PAR-2, but only when allergen was administered through the mucosa. Importantly, our data suggest the importance of resident airway cells in the initiation of allergic airway disease, and could make allergen-derived proteases attractive therapeutic targets.
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Affiliation(s)
- Kristen Page
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, USA.
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Page K, Ledford JR, Zhou P, Wills-Karp M. A TLR2 agonist in German cockroach frass activates MMP-9 release and is protective against allergic inflammation in mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 183:3400-8. [PMID: 19667087 PMCID: PMC2749560 DOI: 10.4049/jimmunol.0900838] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The role of TLR2 in modulating experimentally induced asthma is not fully understood. We recently identified that German cockroach (GC) frass contains a TLR2 ligand allowing us to investigate the role of a TLR2 agonist in a complex real world allergen in mediating allergic airway inflammation. GC frass exposure significantly increased airway inflammation, airway hyperresponsiveness and serum IgE levels in wild-type mice; however the same exposure in TLR2-deficient mice resulted in greatly exaggerated serum IgE and eosinophilia but diminished airway neutrophilia, suggesting a protective role for TLR2. Since GC frass inhalation usually induces airway neutrophilia, we queried the effect of neutrophil depletion on airway responses. Inhibition of neutrophil recruitment into the airways of naive wild-type mice before intratracheal inhalation of GC frass resulted in significantly increased levels of serum IgE and eosinophilia. Neutrophils are a rich source of MMP-9, and we found that MMP-9 levels were significantly increased in the airways of mice following exposure to GC frass. Importantly the levels of MMP-9 were significantly decreased in neutrophil-depleted and TLR2-deficient mice after exposure to GC frass, suggesting that TLR2 regulated MMP-9 release from neutrophils. Functionally, MMP-9-deficient mice had more acute allergic inflammation than wild-type mice, suggesting that MMP-9 was protective against experimentally induced asthma. These data suggest that TLR2 activation of neutrophils leads to release of MMP-9 which decreases allergic responses to GC frass. This suggests a protective role for TLR2 activation and MMP-9 release in the context of experimentally induced asthma in mice.
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Affiliation(s)
- Kristen Page
- Division of Critical Care Medicine, Cincinnati Children's Research Foundation, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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Page K, Lierl KM, Hughes VS, Zhou P, Ledford JR, Wills-Karp M. TLR2-mediated activation of neutrophils in response to German cockroach frass. THE JOURNAL OF IMMUNOLOGY 2008; 180:6317-24. [PMID: 18424755 DOI: 10.4049/jimmunol.180.9.6317] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
It is becoming increasingly clear that innate immune mediators play a role in regulating adaptive immune responses in asthma pathogenesis. Cockroach exposure is a major risk factor for the development of asthma. In this study we asked whether German cockroach (GC) feces (frass) could initiate an innate immune response. Naive BALB/c mice were challenged with a single intratracheal inhalation of GC frass. Proinflammatory cytokines were significantly increased in the bronchoalveolar lavage fluid at 3 h and were maintained at higher than baseline levels for at least 24 h. Neutrophil migration into the airways was evident as early as 3 h but was maximal between 6 and 24 h postinhalation. The early increase in cytokine expression was independent of TLR2 or TLR4. Newly infiltrated airway neutrophils were responsible for maintaining high levels of cytokines in the airways. Using neutrophils as an early marker of the innate immune response, we show that show that neutrophils isolated from the airways following GC frass inhalation express TLR2 and release cytokines. GC frass directly affected neutrophil cytokine production via TLR2, but not TLR4, as evidenced by the use of TLR-neutralizing Abs and neutrophils from TLR-deficient mice. Activation of cytokine expression occurred via GC frass-induced NF-kappaB translocation and DNA binding. These data show that GC frass contains a TLR2 agonist and, to our knowledge, this is the first report of an allergen directly activating cells of the innate immune system via TLR2 and suggests an important link between innate and adaptive immunity.
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Affiliation(s)
- Kristen Page
- Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center and Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
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Page K, Lierl KM, Herman N, Wills-Karp M. Differences in susceptibility to German cockroach frass and its associated proteases in induced allergic inflammation in mice. Respir Res 2007; 8:91. [PMID: 18067672 PMCID: PMC2222603 DOI: 10.1186/1465-9921-8-91] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Accepted: 12/08/2007] [Indexed: 12/20/2022] Open
Abstract
Background Cockroach exposure is a major risk factor for the development of asthma. Inhalation of fecal remnants (frass) is the likely sensitizing agent; however isolated frass has not been tested for its ability to induce experimental asthma in mice. Methods Mice (Balb/c or C57Bl/6) were sensitized and challenged with GC frass or GC frass devoid of proteases and measurements of airway inflammation and hyperresponsiveness were performed (interleukin (IL)-5, -13, and interferon gamma (IFNγ) levels in bronchoalveolar lavage fluid, serum IgE levels, airway hyperresponsiveness, cellular infiltration, and mucin production). Results Sensitization and challenge of Balb/c mice with GC frass resulted in increased airway inflammation and hyperresponsiveness. C57Bl/6 mice were not susceptible to this model of sensitization; however they were sensitized to GC frass using a more aggressive sensitization and challenge protocol. In mice that were sensitized by inhalation, the active serine proteases in GC frass played a role in airway hyperresponsiveness as these mice had less airway hyperresponsiveness to acetylcholine and less mucin production. Proteases did not play a role in mediating the allergic inflammation in mice sensitized via intraperitoneal injection. Conclusion While both strains of mice were able to induce experimental asthma following GC frass sensitization and challenge, the active serine proteases in GC frass only play a role in airway hyperresponsiveness in Balb/c mice that were susceptible to sensitization via inhalation. The differences in the method of sensitization suggest genetic differences between strains of mice.
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Affiliation(s)
- Kristen Page
- Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
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