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TLR3-driven IFN-β antagonizes STAT5-activating cytokines and suppresses innate type 2 response in the lung. J Allergy Clin Immunol 2022; 149:1044-1059.e5. [PMID: 34428519 PMCID: PMC8859010 DOI: 10.1016/j.jaci.2021.07.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 07/16/2021] [Accepted: 07/29/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND Group 2 innate lymphoid cells (ILC2s) are involved in type 2 immune responses in mucosal organs and are associated with various allergic diseases in humans. Studies are needed to understand the molecules and pathways that control ILC2s. OBJECTIVE The aims of this study were to develop a mouse model that limits the innate type 2 immune response in the lung and to investigate the immunologic mechanisms involved in regulation of lung ILC2s. METHODS Naive BALB/c mice were administered various Toll-like receptor agonists and exposed intranasally to the fungal allergen Alternaria alternata. The mechanisms were investigated using gene knockout mice as well as cultures of lung cells and isolated lung ILC2s. RESULTS Polyinosinic-polycytidylic acid, or poly (I:C), effectively inhibited innate type 2 response to A alternata. Poly (I:C) promoted production of IFNα, -β, and -γ, and its inhibitory effects were dependent on the IFN-α/β receptor pathway. IFN-β was 100 times more potent than IFN-α at inhibiting type 2 cytokine production by lung ILC2s. Signal transducer and activator of transcription 5 (STAT5)-activating cytokines, including IL-2, IL-7, and thymic stromal lymphopoietin, but not IL-33, promoted survival and proliferation of lung ILC2s in vitro, while IFN-β blocked these effects. Expression of the transcription factor GATA3, which is critical for differentiation and maintenance of ILC2s, was inhibited by IFN-β. CONCLUSIONS IFN-β blocks the effects of STAT5-activating cytokines on lung ILC2s and inhibits their survival and effector functions. Administration of IFN-β may provide a new strategy to treat diseases involving ILC2s.
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Hernandez-Ramirez G, Barber D, Tome-Amat J, Garrido-Arandia M, Diaz-Perales A. Alternaria as an Inducer of Allergic Sensitization. J Fungi (Basel) 2021; 7:jof7100838. [PMID: 34682259 PMCID: PMC8539034 DOI: 10.3390/jof7100838] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 01/02/2023] Open
Abstract
Alternaria alternata is a saprophytic mold whose spores are disseminated in warm dry air, the typical weather of the Mediterranean climate region (from 30° to 45°), with a peak during the late summer and early autumn. Alternaria spores are known to be biological contaminants and a potent source of aeroallergens. One consequence of human exposure to Alternaria is an increased risk of developing asthma, with Alt a 1 as its main elicitor and a marker of primary sensitization. Although the action mechanism needs further investigation, a key role of the epithelium in cytokine production, TLR-activated alveolar macrophages and innate lymphoid cells in the adaptive response was demonstrated. Furthermore, sensitization to A. alternata seems to be a trigger for the development of co-sensitization to other allergen sources and may act as an exacerbator of symptoms and an elicitor of food allergies. The prevalence of A. alternata allergy is increasing and has led to expanding research on the role of this fungal species in the induction of IgE-mediated respiratory diseases. Indeed, recent research has allowed new perspectives to be considered in the assessment of exposure and diagnosis of fungi-induced allergies, although more studies are needed for the standardization of immunotherapy formulations.
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Affiliation(s)
- Guadalupe Hernandez-Ramirez
- Centro de Biotecnología Y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain; (G.H.-R.); (J.T.-A.); (M.G.-A.)
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
| | - Domingo Barber
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Instituto de Medicina Molecular Aplicada (IMMA), Universidad San Pablo CEU, CEU Universities, 28925 Madrid, Spain;
| | - Jaime Tome-Amat
- Centro de Biotecnología Y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain; (G.H.-R.); (J.T.-A.); (M.G.-A.)
| | - Maria Garrido-Arandia
- Centro de Biotecnología Y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain; (G.H.-R.); (J.T.-A.); (M.G.-A.)
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
| | - Araceli Diaz-Perales
- Centro de Biotecnología Y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain; (G.H.-R.); (J.T.-A.); (M.G.-A.)
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
- Correspondence:
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Didehdar M, Khoshbayan A, Vesal S, Darban-Sarokhalil D, Razavi S, Chegini Z, Shariati A. An overview of possible pathogenesis mechanisms of Alternaria alternata in chronic rhinosinusitis and nasal polyposis. Microb Pathog 2021; 155:104905. [PMID: 33930423 DOI: 10.1016/j.micpath.2021.104905] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/16/2021] [Accepted: 04/16/2021] [Indexed: 01/23/2023]
Abstract
Chronic Rhinosinusitis (CRS) is a multifactorial disease, and different etiologies like metabolism and immunity disorders, bacterial superantigens, biofilms, and fungal allergens are known to develop this disease, especially the CRS with nasal polyps. Alternaria alternata (Alternaria) is one of the most prevalent airborne fungal species in the nasal discharge, which might have vigorous immunologic activities in nasal epithelial cells and play an essential role in the pathogenesis of CRS. Moreover, the interaction between this fungus and the innate and adaptive immune systems leads to the development of chronic inflammation. This inflammation may consequently instigate the CRS and nasal polyposis. The attenuation of surfactant protein synthesis or intracellular reserves and mucus hypersecretion could prevent the clearance of Alternaria from sinuses and may be correlated with colonization and re-infection of airborne fungi. Furthermore, higher expression of cathelicidin, thymic stromal lymphopoietin, toll-like receptors, and T helper 2-dominant immune responses can result in an IgE-mediated pathway activation and eosinophils degranulation. Moreover, higher local Alternaria-specific IgE was shown to be correlated with eosinophilic cationic proteins and might relate to nasal polyps. However, the role of genetic and environmental factors affecting CRS and nasal polyposis is not well studied. Likewise, further animal and clinical studies are required to better understand the role of Alternaria in CRS disease. The current article reviews the recent findings around the Alternaria-induced CRS and nasal polyposis.
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Affiliation(s)
- Mojtaba Didehdar
- Department of Medical Parasitology and Mycology, Arak University of Medical Sciences, Arak, Iran
| | - Amin Khoshbayan
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Soheil Vesal
- Department of Molecular Genetics, Faculty of Basic Sciences and Advanced Technologies in Biology, University of Science and Culture, Tehran, Iran
| | - Davood Darban-Sarokhalil
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Shabnam Razavi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Microbial Biotechnology Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Zahra Chegini
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Aref Shariati
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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Decrease of IL-5 Production by Naive T Cells Cocultured with IL-18-Producing BCG-Pulsed Dendritic Cells from Patients Allergic to House Dust Mite. Vaccines (Basel) 2021; 9:vaccines9030277. [PMID: 33803752 PMCID: PMC8003153 DOI: 10.3390/vaccines9030277] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 12/22/2022] Open
Abstract
The only currently available anti-tuberculosis vaccine, Bacillus Calmette–Guérin (BCG), has been reported to also protect against unrelated diseases, including inflammatory diseases such as allergic asthma. Recombinant BCG strains that produce IL-18 have been shown to enhance Th1 responses over non-recombinant BCG and to reduce IL-5 production and bronchoalveolar eosinophilia in mice. However, their ability to decrease the immune polarization of human Th2 cells is not known. Here, we show that BCG and recombinant BCG producing human IL-18 (rBCG-hIL-18) induced the maturation of Der p 1-stimulated monocyte-derived dendritic cells (MD-DCs) from healthy controls and from patients allergic to house dust mites. After incubation with mycobacteria and Der p 1, MD-DCs produced significantly more IL-23 and IP-10 but had no effect on IL-12p70 or IL-10 production compared to Der p 1-pulsed MD-DCs in the absence of mycobacteria. In the presence of Der p 1, BCG- and rBCG-hIL-18-pulsed MD-DCs cocultured with naive, but not with memory T cells from allergic patients, resulted in a decrease in IL-5 production compared to non-pulsed MD-DCs cultured in the presence of Der p 1. BCG, and especially rBCG-hIL-18, may thus be potential therapeutic tools to reduce exacerbated Th2 responses in patients with allergic asthma.
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Twaroch TE, Curin M, Sterflinger K, Focke-Tejkl M, Swoboda I, Valenta R. Specific Antibodies for the Detection of Alternaria Allergens and the Identification of Cross-Reactive Antigens in Other Fungi. Int Arch Allergy Immunol 2016; 170:269-278. [PMID: 27780168 PMCID: PMC5321516 DOI: 10.1159/000449415] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 08/24/2016] [Indexed: 12/13/2022] Open
Abstract
Background The mould Alternaria alternata is an important source of respiratory allergens. A. alternata extracts show great variations regarding allergenic potency. The aim of this study was to generate antibody probes specific for important Alternaria allergens and to use them to study allergen expression, depending on different culture conditions, as well as to search for cross-reactive allergens in other mould species. Methods Synthetic peptides from antigenic regions of A. alternata allergens (Alt a 1, Alt a 2, Alt a 3, Alt a 6 and Alt a 8) were used to raise highly specific rabbit antibodies. These antibodies and IgE from allergic patients were used to detect allergens by immunoblotting in extracts of 4 A. alternata strains grown under varying culturing conditions, in commercial skin-prick extracts and in closely (Cladosporium herbarum and Aureobasidium pullulans) or distantly related (Aspergillus niger and Penicillium chrysogenum) mould species. Results There was a wide variation of expression of the individual A. Alternata allergens, depending on the strain and culture conditions, but the antibody probes allowed us to distinguish strains and culture conditions with low and high allergen expression. In the commercial skin-prick solutions, varying levels of Alt a 1 were found, but no other allergens were detectable. Alt a 1 was identified as species-specific A. Alternata allergen, whereas Alt a 3, 6- and Alt a 8-cross-reactive antigens were found in C. herbarum and/or A. pullulans. Conclusions and Clinical Relevance Peptide-specific antibodies are useful to analyze diagnostic and therapeutic mould extracts, to study the presence of A. Alternata allergens in biological samples and to search for cross-reactive allergens in other mould species.
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Affiliation(s)
- Teresa E Twaroch
- Christian Doppler Laboratory for Allergy Research, Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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Selected CC and CXC chemokines in children with atopic asthma. Postepy Dermatol Alergol 2016; 33:96-101. [PMID: 27279817 PMCID: PMC4884777 DOI: 10.5114/ada.2016.59150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/28/2015] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION There are only limited data on CC and CXC chemokines regulation in children with asthma. AIM We compared the serum profile of selected CC and CXC chemokines in patients with atopic asthma and healthy children. MATERIAL AND METHODS Serum concentration of CC chemokines RANTES, MCP-1, and CXC chemokines IP-10, MIG, IL-8, RANTES was measured using cytometric bead array in 44 children with atopic asthma and 17 healthy subjects. RESULTS The concentration of RANTES was significantly higher and the MIG level was lower in all children with asthma as compared to their control counterparts. We observed increased RANTES and decreased MIG levels also in patients with stable asthma when compared with children in the control group. The IP-10 concentration was similar between the whole asthma group and healthy controls, while significantly increased levels of this chemokine in acute asthma have been observed when compared to stable asthma. For MCP-1 and IL-8, the serum concentration was similar in all compared groups. The MIG concentration correlated positively with IP-10, IL-8, and CRP levels and negatively with the eosinophil count. A negative correlation between the IP-10 and eosinophil count and a negative correlation between FEV1 and IP-10 were found. CONCLUSIONS An increased serum RANTES level in children with asthma may result in enhancement of Th2 lymphocyte recruitment into the airway. A decreased expression of Th1 chemokine MIG in children with stable asthma may contribute to a diminished antagonizing effect on Th2 cytokine production and hence intensify Th2 predominance. An increased IP-10 level in children during an asthma attack suggest that this chemokine is a serological marker of disease exacerbation.
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Bhushan B, Homma T, Norton JE, Sha Q, Siebert J, Gupta DS, Schroeder JW, Schleimer RP. Suppression of epithelial signal transducer and activator of transcription 1 activation by extracts of Aspergillus fumigatus. Am J Respir Cell Mol Biol 2015; 53:87-95. [PMID: 25474274 DOI: 10.1165/rcmb.2014-0333oc] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Aspergillus fumigatus (AF) is often pathogenic in immune-deficient individuals and can cause life-threatening infections such as invasive aspergillosis. The pulmonary epithelial response to AF infection and the signaling pathways associated with it have not been completely studied. BEAS-2B cells or primary human bronchial epithelial cells were exposed to extracts of AF and challenged with IFN-β or the Toll-like receptor 3 agonist double-stranded RNA (dsRNA). Cytokine release (B-cell activating factor of the TNF family [BAFF], IFN-γ-induced protein-10 [IP-10], etc.) was assessed. AF extract was separated into low-molecular-weight (LMW) and high-molecular-weight (HMW) fractions using ultra 4 centrifugal force filters to characterize the activity. Real-time PCR was performed with a TaqMan method, and protein estimation was performed using ELISA techniques. Western blot was performed to assess phosphorylation of signal transducer and activator of transcription 1 (STAT1). IFN-β and dsRNA induced messenger RNA (mRNA) expression of BAFF (350- and 452-fold, respectively [n = 3]) and IP-10 (1,081- and 3,044-fold, respectively [n = 3]) in BEAS-2B cells. When cells were pretreated with AF extract for 1 hour and then stimulated with IFN-β or dsRNA for 6 hours, induction of BAFF and IP-10 mRNA was strongly suppressed relative to levels produced by IFN-β and dsRNA alone. When compared with control, soluble BAFF and IP-10 protein levels were maximally suppressed in dsRNA-stimulated wells treated with 1:320 wt/vol AF extract (P < 0.005). Upon molecular size fractionation, a LMW fraction of AF extract had no measurable suppressive effect on IP-10 mRNA expression. However, a HMW fraction of the AF extract significantly suppressed IP-10 expression in BEAS-2B cells that were stimulated with dsRNA or IFN-β. When BEAS-2B cells were pretreated with AF extract and then stimulated with IFN-β, reduced levels of pSTAT1 were observed, with maximum suppression at 4 and 6 hours. Our results show that AF extracts suppressed expression of inflammatory cytokines in association with inhibition of the IFN-β signaling pathway and suppression of the formation of pSTAT1.
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Affiliation(s)
- Bharat Bhushan
- 1 Division of Otolaryngology-Head and Neck Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago and the Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Tetsuya Homma
- 2 Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,3 Department of Internal Medicine, Division of Respiratory Medicine and Allergology, Showa University School of Medicine, Tokyo, Japan
| | - James E Norton
- 2 Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Quan Sha
- 4 Allergy and Immunology Research Center, Anhui Medical University, Anhui, China
| | - Jason Siebert
- 5 Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Dave S Gupta
- 6 Division of Allergy and Immunology, National Jewish Health, Denver, Colorado
| | - James W Schroeder
- 1 Division of Otolaryngology-Head and Neck Surgery, Ann & Robert H. Lurie Children's Hospital of Chicago and the Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Robert P Schleimer
- 2 Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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Twaroch TE, Curin M, Valenta R, Swoboda I. Mold allergens in respiratory allergy: from structure to therapy. ALLERGY, ASTHMA & IMMUNOLOGY RESEARCH 2015; 7:205-20. [PMID: 25840710 PMCID: PMC4397360 DOI: 10.4168/aair.2015.7.3.205] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 09/23/2014] [Indexed: 11/25/2022]
Abstract
Allergic reactions to fungi were described 300 years ago, but the importance of allergy to fungi has been underestimated for a long time. Allergens from fungi mainly cause respiratory and skin symptoms in sensitized patients. In this review, we will focus on fungi and fungal allergens involved in respiratory forms of allergy, such as allergic rhinitis and asthma. Fungi can act as indoor and outdoor respiratory allergen sources, and depending on climate conditions, the rates of sensitization in individuals attending allergy clinics range from 5% to 20%. Due to the poor quality of natural fungal allergen extracts, diagnosis of fungal allergy is hampered, and allergen-specific immunotherapy is rarely given. Several factors are responsible for the poor quality of natural fungal extracts, among which the influence of culture conditions on allergen contents. However, molecular cloning techniques have allowed us to isolate DNAs coding for fungal allergens and to produce a continuously growing panel of recombinant allergens for the diagnosis of fungal allergy. Moreover, technologies are now available for the preparation of recombinant and synthetic fungal allergen derivatives which can be used to develop safe vaccines for the treatment of fungal allergy.
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Affiliation(s)
- Teresa E Twaroch
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Mirela Curin
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Rudolf Valenta
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
| | - Ines Swoboda
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.; The Molecular Biotechnology Section, University of Applied Sciences, Campus Vienna Biocenter, Vienna, Austria
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Zhu L, Lee B, Zhao F, Zhou X, Chin V, Ling SC, Chen Y. Modulation of airway epithelial antiviral immunity by fungal exposure. Am J Respir Cell Mol Biol 2014; 50:1136-43. [PMID: 24428709 DOI: 10.1165/rcmb.2013-0357oc] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Multiple pathogens, such as bacteria, fungi, and viruses, have been frequently found in asthmatic airways and are associated with the pathogenesis and exacerbation of asthma. Among these pathogens, Alternaria alternata (Alt), a universally present fungus, and human rhinovirus have been extensively studied. However, their interactions have not been investigated. In the present study, we tested the effect of Alt exposure on virus-induced airway epithelial immunity using live virus and a synthetic viral mimicker, double-stranded RNA (dsRNA). Alt treatment was found to significantly enhance the production of proinflammatory cytokines (e.g., IL-6 and IL-8) induced by virus infection or dsRNA treatment. In contrast to this synergistic effect, Alt significantly repressed type I and type III IFN production, and this impairment led to elevated viral replication. Mechanistic studies suggested the positive role of NF-κB and mitogen-activated protein kinase pathways in the synergism and the attenuation of the TBK1-IRF3 pathway in the inhibition of IFN production. These opposite effects are caused by separate fungal components. Protease-dependent and -independent mechanisms appear to be involved. Thus, Alt exposure alters the airway epithelial immunity to viral infection by shifting toward more inflammatory but less antiviral responses.
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Affiliation(s)
- Lingxiang Zhu
- 1 Department of Pharmacology and Toxicology, School of Pharmacy, University of Arizona, Tucson, Arizona; and
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Aryan Z, Holgate ST, Radzioch D, Rezaei N. A new era of targeting the ancient gatekeepers of the immune system: toll-like agonists in the treatment of allergic rhinitis and asthma. Int Arch Allergy Immunol 2014; 164:46-63. [PMID: 24853609 DOI: 10.1159/000362553] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Toll-like receptors (TLR) belong to a large family of pattern recognition receptors known as the ancient 'gatekeepers' of the immune system. TLRs are located at the first line of defense against invading pathogens as well as aeroallergens, making them interesting targets to modulate the natural history of respiratory allergy. Agonists of TLRs have been widely employed in therapeutic or prophylactic preparations useful for asthma/allergic rhinitis (AR) patients. MPL® (a TLR4 agonist) and the CpG oligodeoxynucleotide of 1018 ISS, a TLR9 agonist, show strong immunogenicity effects that make them appropriate adjuvants for allergy vaccines. Targeting the TLRs can enhance the efficacy of specific allergen immunotherapy, currently the only available 'curative' treatment for respiratory allergies. In addition, intranasal administration of AZD8848 (a TLR7 agonist) and VTX-1463 (a TLR8 agonist) as stand-alone therapeutics have revealed efficacy in the relief of the symptoms of AR patients. No anaphylaxis has been so far reported with such compounds targeting TLRs, with the most common adverse effects being transient and local irritation (e.g. redness, swelling and pruritus). Many other compounds that target TLRs have been found to suppress airway inflammation, eosinophilia and airway hyper-responsiveness in various animal models of allergic inflammation. Indeed, in the future a wide variability of TLR agonists and even antagonists that exhibit anti-asthma/AR effects are likely to emerge.
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Affiliation(s)
- Zahra Aryan
- Molecular Immunology Research Center and Department of Immunology, School of Medicine, Tehran, Iran
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