Expression in induced sputum during acute exacerbations in asthmatic children with/without chronic airflow obstruction
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ABSTRACT: Asthma exacerbations are associated with subsequent deficits in lung function. Here, we tested the hypothesis that a specific pattern of inflammatory responses during acute exacerbations may be associated with susceptibility to chronic airway obstruction.
Project description:Asthma is a very frequent airway disease that affects 6 to 20% of the population. Severe asthma, represents 3 to 5% of all asthmatic patients and is histologically characterized by an increased bronchial smooth muscle (BSM) mass and clinically by viral exacerbations. Functionally, BSM remodeling had a poor prognostic value in asthma, since higher BSM mass was associated with lower lung function and increased exacerbation rate. However, the role of BSM as a potential actor of asthma exacerbation has only been sparsely suggested. We thus hypothesis that asthmatic BSM cells could act on bronchial epithelium and modified its response to rhinovirus infection.
Project description:Asthma exacerbations in children are associated with respiratory viral infection and atopy, resulting in systemic immune activation and infiltration of immune cells into the airways. The gene networks driving the immune activation and subsequent migration of immune cells into the airways remains incompletely understood. Cellular and molecular profiling of PBMC was employed on paired samples obtained from atopic asthmatic children (n = 19) during acute virus-associated exacerbations and later during convalescence. Systems level analyses were employed to identify coexpression networks and infer the drivers of these networks, and validation was subsequently obtained via independent samples from asthmatic children. During exacerbations, PBMC exhibited significant changes in immune cell abundance and upregulation of complex interlinked networks of coexpressed genes. These were associated with priming of innate immunity, inflammatory and remodelling functions. We identified activation signatures downstream of bacterial LPS, glucocorticoids and TGFB1. We also confirmed that LPS binding protein was upregulated at the protein-level in plasma. Multiple gene networks known to be involved positively or negatively in asthma pathogenesis, are upregulated in circulating PBMC during acute exacerbations, supporting the hypothesis that systemic pre-programming of potentially pathogenic as well as protective functions of circulating immune cells preceeds migration into the airways. Enhanced sensitivity to LPS is likely to modulate the severity of acute asthma exacerbations through exposure to environmental LPS.
Project description:Asthma is a very frequent airway disease that affects 6 to 20% of the population. Severe asthma, represents 3 to 5% of all asthmatic patients and is histologically characterized by an increased bronchial smooth muscle (BSM) mass and clinically by viral exacerbations. Functionally, BSM remodeling had a poor prognostic value in asthma, since higher BSM mass was associated with lower lung function and increased exacerbation rate. However, the role of BSM as a potential actor of asthma exacerbation has only been sparsely suggested. Thus, we hypothesis that asthmatic BSM cell metabolism is modified compare to that of non-asthmatic and that could be a potential target to reduce asthmatic BSM cell proliferation and remodeling in asthma.
Project description:To understand why asthma remit with aging, we exposed mice across a range of ages to viral and allergic triggers of asthma exacerbations and inflammatory airway pathology. We found that pathology induced by Sendai virus (SeV) or influenza A virus (IAV) occurred selectively in juvenile mice in a microbiome-independent manner, while the same phenotypes induced by allergens were relatively insensitive to age. Age-specific responses to SeV included a juvenile bias towards type-2 airway inflammation that emerged early in infection and was lost with maturation. With aging, we observed progressive transcriptional changes to alveolar macrophages (AMs) including the acquisition of high-level MHC-II expression. Importantly, depleting AMs before SeV infection canceled the protective effects of maturity on post-viral airway pathology. Thus, age-related changes to the lung immune micro-environment alter host responses to viruses and may drive childhood asthma remission.
Project description:Severe asthma exacerbations in children requiring hospitalisation are typically associated with viral infection, and occur almost exclusively amongst atopics, but the significance of these comorbidities is unknown. We hypothesised that underlying interactions between immunoinflammatory pathways related to responses to aeroallergen and virus are involved, and that evidence of these interactions is detectable in circulating cells during exacerbations. To address this hypothesis we used a genomics-based approach involving profiling of PBMC subpopulations collected during acute exacerbation versus convalescence by microarray and flow cytometry.
Project description:Investigation of gene expression profiles among patients with COPD frequent exacerbations and to find gene targets as predictors of exacerbations COPD patient samples analysed by microarray, followed by PCR testing to identify gene predictors
Project description:We leverage a systems-scale network analysis approach to demonstrate repertoires of cellular transcriptional pathways underlying loss of asthma control, and show how these pathways differ in viral associated and non-viral exacerbations.
Project description:We leverage a systems-scale network analysis approach to demonstrate repertoires of cellular transcriptional pathways underlying loss of asthma control, and show how these pathways differ in viral associated and non-viral exacerbations.
Project description:Investigation of gene expression profiles among patients with COPD frequent exacerbations and to find gene targets as predictors of exacerbations