Project description:There is a life-long relationship between rhinovirus (RV) infection and the development and clinical manifestations of asthma. In this study we demonstrate that cultured primary bronchial epithelial cells from adults with asthma (n = 9) show different transcriptional and chromatin responses to RV infection compared to those without asthma (n = 9). Both the number and magnitude of transcriptional and chromatin responses to RV were muted in cells from asthma cases compared to controls. Pathway analysis of the transcriptionally responsive genes revealed enrichments of apoptotic pathways in controls but inflammatory pathways in asthma cases. Using promoter capture Hi-C we tethered regions of RV-responsive chromatin to RV-responsive genes and showed enrichment of these regions and genes at asthma GWAS loci. Taken together, our studies indicate a delayed or prolonged inflammatory state in cells from asthma cases and highlight genes that may contribute to genetic risk for asthma.
Project description:There is a life-long relationship between rhinovirus (RV) infection and the development and clinical manifestations of asthma. In this study we demonstrate that cultured primary bronchial epithelial cells from adults with asthma (n = 9) show different transcriptional and chromatin responses to RV infection compared to those without asthma (n = 9). Both the number and magnitude of transcriptional and chromatin responses to RV were muted in cells from asthma cases compared to controls. Pathway analysis of the transcriptionally responsive genes revealed enrichments of apoptotic pathways in controls but inflammatory pathways in asthma cases. Using promoter capture Hi-C we tethered regions of RV-responsive chromatin to RV-responsive genes and showed enrichment of these regions and genes at asthma GWAS loci. Taken together, our studies indicate a delayed or prolonged inflammatory state in cells from asthma cases and highlight genes that may contribute to genetic risk for asthma.
Project description:Human Rhinovirus (HRV) infection can trigger exacerbations of asthma. Understanding of the mechanisms provoking airway inflammation and remodeling in asthma, as well as the pathogenic mechanisms of HRV infection and its association with asthma exacerbations, may offer significant opportunities for improved disease management. Genome-wide expression analysis of HRV type 1A-infected primary bronchial epithelial (PBE) cells from normal and asthmatic donors was performed to determine whether asthma is associated with a unique pattern of gene expression after HRV infection in vitro. Keywords: response to rhinovirus infection
Project description:Rhinovirus infections exacerbate chronic respiratory inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD). Airway epithelial cells are the primary site of rhinovirus replication and responsible for initiating the host immune response to infection. Numerous studies have reported that the anti-viral innate immune response in asthma is deficient leading to the conclusion that epithelial innate immunity is a key determinant of disease severity during a rhinovirus induced exacerbation. However, deficient rhinovirus-induced epithelial interferon production in asthma has not always been observed. We hypothesised that disparate in vitro airway epithelial infection models lacking genome-wide, time-course analyses have obscured the role of epithelial innate anti-viral immunity in asthma and COPD. To address this, we developed a low multiplicity of infection (MOI) rhinovirus model of differentiated primary epithelial cells obtained from healthy, asthma and COPD donors. Using genome-wide gene expression following infection, we demonstrated that gene expression patterns are similar across patient groups, but that the kinetics of induction are delayed in cells obtained from asthma and COPD donors. Rhinovirus-induced innate immune responses were defined by interferons (type-I, II and III), interferon response factors (IRF1, IRF3 and IRF7), TLR signalling and NF‐kB and STAT1 activation. Induced gene expression was evident at 24 hours and peaked at 48 hours post‐infection in cells from healthy subjects. In contrast, in cells from donors with asthma or COPD induction was maximal at or beyond 72-96 hours post infection. Thus, we propose that propensity for viral exacerbations of asthma and COPD relate to delayed (rather than deficient) expression of epithelial cell innate anti-viral immune genes which in turns leads to a delayed and ultimately more inflammatory host immune response.
Project description:Balanced immune responses in airways of patients with asthma are crucial to succesful clearance of viral infection and proper asthma control. We used microarrays to detail the global programme of gene expression data from bronchial brushings from control individuals and patients with asthma after rhinovirus infection in vivo.
Project description:Rhinovirus infections are the most common cause of asthma exacerbations. The complex responses by the airway epithelium to rhinovirus can be captured by gene expression profiling. We hypothesized that the upper and lower airway epithelium exhibit differential responses to double-stranded RNA (dsRNA), and that this is modulated by the presence of asthma and allergic rhinitis. Identification of dsRNA-induced gene expression profiles by microarray of primary nasal and bronchial epithelial cells from the same individuals and examining the impact of allergic rhinitis with and without concomitant allergic asthma on expression profiles. 17 subjects were included in a cross-sectional study (6 allergic asthma and allergic rhinitis; 5 allergic rhinitis; 6 healthy controls). RNA was extracted from isolated and cultured epithelial cells that were stimulated with Poly(I:C) for 24 hours from bronchial brushes and nasal biopsies, and analyzed by microarray (Affymetrix U133+ PM Genechip Array).
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:Rhinovirus infections are the most common cause of asthma exacerbations. The complex responses by the airway epithelium to rhinovirus can be captured by gene expression profiling. We hypothesized that the upper and lower airway epithelium exhibit differential responses to double-stranded RNA (dsRNA), and that this is modulated by the presence of asthma and allergic rhinitis. Identification of dsRNA-induced gene expression profiles by microarray of primary nasal and bronchial epithelial cells from the same individuals and examining the impact of allergic rhinitis with and without concomitant allergic asthma on expression profiles.
Project description:Major- and minor-group rhinoviruses enter their host by binding to the cell surface molecules ICAM-1 and LDL-R, respectively, which are present on both macrophages and epithelial cells. Although epithelial cells are the primary site of productive HRV infection, previous studies have implicated macrophages in establishing the cytokine dysregulation that occurs during rhinovirus-induced asthma exacerbations. Even though major- and minor-group rhinoviruses are nearly genetically identical, these viruses do not replicate with equal success in monocyte-lineage cell lines. In human primary macrophages, differential mitochondrial activity and signaling pathway activation was observed between major- and minor-group rhinovirus upon initial HRV binding, indicating discordant receptor-dependent response to these rhinovirus types. As well, variances in phosphorylation of kinases (p38, JNK, ERK5) and transcription factors (ATF-2, CREB, CEBP-alpha) were observed between the major- and minor- group HRV treatments. The difference between major- and minor- group HRV activation of signaling pathways was confirmed through RNA-sequencing and observation of differential production of the asthma-relevant cytokines CCL20, CCL2, and IL-10. This is the first report of genetically similar viruses eliciting dissimilar cytokine release, transcription factor phosphorylation, and MAPK activation from macrophages. These results suggest that receptor dependence plays a role in establishing the inflammatory microenvironment initiated in part by monocytic-lineage cells in the human airway upon exposure to rhinovirus. RNA sequencing of monocyte-derived macrophages after mock infection or infection by HRV16 or HRV1A