Severe asthma is a difficult disease to control by corticosteroids (CSs), which remain the mainstay of asthma therapy. This differential outcome in response to CS therapy, even when used at a high dose orally or parenterally, suggests a fundamental difference in the nature of the inflammatory response in the two subclasses of asthmatics. To understand the mechanisms and mediators that promote CS-refractory asthma, we have developed a mouse model of disease in which both airway inflammation and CS-unresponsiveness mimic the severe asthma phenotype in humans including high IFN-?/Th1, IL-27 and IL-17 responses. Our model involves exposure of mice to an allergen (house dust mite-HDM) with a mucosal adjuvant, cyclic-di- GMP (c-di-GMP), to promote a mixed granulocytic infiltration in the airways with induction of significantly higher IFN-? and IL-17 responses in the lung-draining lymph nodes and the lungs of the mice but a lower IL-13/IL-5 response compared to that induced by HDM alone. Administration of the CS, dexamethasone (Dex), in HDM+c-di-GMP-exposed mice did not subdue the IFN-?/IL-17/IL-13 response or the airway neutrophilia but partially attenuated the eosinophilia. Airway hyperreactivity in these mice was also only partially attenuated by CS. Collectively, our data lead us to hypothesize that 1) CS-refractory asthma is orchestrated by a high Th1 response often accompanied by a Th17 response that promotes airway neutrophilia. 2) Increased production of key Th1- and Th17-skewing cytokines such as IL-27 and IL-12 (Th1) and IL-6 and IL-23 (Th17) from innate cells such as dendritic cells (DCs) underlies the heightened Th1 and Th17 response. 3) The transcription factors IRF5, recently implicated in IL-6, IL-12 and IL-23 production from M1 macrophages, and STAT1, downstream of IFNs and IL-27, are involved in driving Th1 and Th17 development. The idea that CS refractory severe asthma might involve collaboration between IFN-?, IL-27 and Th17 cytokines in severe asthma has not been appreciated or investigated in prior studies. To address our hypotheses we will:
Aim 1. Investigate the role of the Th1 and Th17 pathways in promoting the CS-refractory severe asthma phenotype characterized by mixed granulocytic airway inflammation.
Aim 2. Determine the mechanisms by which high Th1 and Th17 responses are induced by exposure to HDM and c-di-GMP via effects on innate cells.
Aim 3. Identify the cellular source and role of IL-27 in initiation and perpetuation of CS-refractory severe asthma phenotype. The mouse model in conjunction with genetically engineered mice will allow us to investigate the role of key mediators in promoting the severe asthma phenotype. The model will be useful to test novel therapeutic modalities as and when they become available. Additionally, RNA sequencing data generated from this study will identify novel networks in SA for future interrogation in the experimental model and in translational studies.
|Das, Sudipta; Raundhal, Mahesh; Chen, Jie et al. (2017) Respiratory syncytial virus infection of newborn CX3CR1-deficent mice induces a pathogenic pulmonary innate immune response. JCI Insight 2:|
|Gauthier, Marc; Chakraborty, Krishnendu; Oriss, Timothy B et al. (2017) Severe asthma in humans and mouse model suggests a CXCL10 signature underlies corticosteroid-resistant Th1 bias. JCI Insight 2:|
|Ray, Anuradha; Kolls, Jay K (2017) Neutrophilic Inflammation in Asthma and Association with Disease Severity. Trends Immunol 38:942-954|
|Oriss, Timothy B; Raundhal, Mahesh; Morse, Christina et al. (2017) IRF5 distinguishes severe asthma in humans and drives Th1 phenotype and airway hyperreactivity in mice. JCI Insight 2:|
|Ray, Anuradha; Raundhal, Mahesh; Oriss, Timothy B et al. (2016) Current concepts of severe asthma. J Clin Invest 126:2394-403|
|Khare, Anupriya; Raundhal, Mahesh; Chakraborty, Krishnendu et al. (2016) Mitochondrial H2O2 in Lung Antigen-Presenting Cells Blocks NF-?B Activation to Prevent Unwarranted Immune Activation. Cell Rep 15:1700-14|
|Raundhal, Mahesh; Morse, Christina; Khare, Anupriya et al. (2015) High IFN-? and low SLPI mark severe asthma in mice and humans. J Clin Invest 125:3037-50|
|Oczypok, Elizabeth A; Milutinovic, Pavle S; Alcorn, John F et al. (2015) Pulmonary receptor for advanced glycation end-products promotes asthma pathogenesis through IL-33 and accumulation of group 2 innate lymphoid cells. J Allergy Clin Immunol 136:747-756.e4|
|Gauthier, Marc; Ray, Anuradha; Wenzel, Sally E (2015) Evolving Concepts of Asthma. Am J Respir Crit Care Med 192:660-8|
|Khare, Anupriya; Chakraborty, Krishnendu; Raundhal, Mahesh et al. (2015) Cutting Edge: Dual Function of PPAR? in CD11c+ Cells Ensures Immune Tolerance in the Airways. J Immunol 195:431-5|
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