Project description:Respiratory syncytial virus (RSV) causes severe disease mostly in infants; however, mechanisms of age association remain elusive. Here, employing human bronchial epithelium models generated from tracheal aspirate-derived basal stem cells of neonates and adults, we investigate whether age regulates RSV-epithelium interaction to determine disease severity. We show that following RSV infection, only neonatal epithelium model exhibits cytopathy and mucus hyperplasia, and neonatal epithelium has more robust viral spread and inflammatory responses than adult epithelium. Mechanistically, RSV-infected neonatal ciliated cells display age-related impairment of STAT3 activation, rendering susceptibility to apoptosis, which facilitates viral spread. In contrast, SARS-CoV-2 infection of ciliated cells has no effect on STAT3 activation and is not affected by age. Taken together, our findings identify an age-related and RSV-specific interaction with neonatal bronchial epithelium that critically contributes to severity of infection, and STAT3 activation offers a potential strategy to battle severe RSV disease in infants.
Project description:Purpose: To understand how dexamethasone has beneficial effects on reducing mucus production but inhibits viral defense mechanisms Methods: RSV-infected mouse lungs and various cell lines, plus and minus dexamethason, were examined by RNAseq, and pathway analysis of differentially-expressed genes were compared Results: Using RNA-seq we identified a subset of cytokines that were induced by RSV and repressed by dexamethasone. Interestingly, while RSV induced interferons (IFNs) and IFN stimulated genes (ISGs), dexamethasone treatment did not affect the expression of these genes or antiviral IFN signaling pathways as has been observed with glucocorticoid treatment of other respiratory viruses [13]. Using an unbiased approach, we found that certain RSV-driven gene expression networks and genes were specifically modulated by dexamethasone treatment. Importantly, dexamethasone also reduced RSV clearance in vivo, which correlated with a reduction in specific immune response markers. Conclusion: Our results support the possibility that the beneficial anti-inflammatory effects of dexamethasone treatment are counterbalanced by the increased viral load in patients, accounting for the lack of clinical benefit derived from treatment during RSV infection.
Project description:Respiratory syncytial virus (RSV) is a major cause of morbidity and mortality. Previous studies have suggested that T cell responses may contribute to RSV immunopathology, which could be driven by dendritic cells (DCs). DCs are productively infected by RSV, and during RSV infections, there is an increase of DCs in the lungs with a decrease in the blood. Pediatric populations are particularly susceptible to severe RSV infections, however DC responses to RSV from pediatric populations have not been examined. In this study, primary isolated DCs from cord blood and adult peripheral blood were compared after RSV-infection. Transcriptional profiling and biological network analysis identified transforming growth factor (TGF)-b and associated signaling molecules as differentially regulated in the two age groups. TGF-b1 was decreased in RSV-infected adult blood DCs, but increased in RSV-infected cord blood DCs. Co-culture of adult RSV-infected DCs with autologous T-cells induced secretion of interferon gamma (IFNg), IL-12p70, IL-2, and tumor necrosis factor alpha (TNFa). Conversely, co-culture of cord RSV-infected DCs and autologous T-cells induced secretion of IL-4, IL-6, IL-1b, and IL-17. Addition of purified TGF-b1 to adult DC-T cell co-cultures reduced secretion of IFNg, IL-12p70, IL-2, and TNFa, which addition of a TGF-b chemical inhibitor to cord DC-T cell co-cultures increased secretion of IL-12p70. These data suggest that TGF-b acts as a major regulator of RSV DC-T cell responses, which could contribute to immunopathology during infancy. Three sets of adult peripheral DCs were analyzed and three sets of cord blood DCs. The DCs from each donor were divided in half and either mock infected or infected with RSV and each (12 samples total) were used for affymetrix array analsis. The donor-matched mock infected DC hybridyzation was used as the reference sample for the RSV infected.
Project description:Background: There is limited data on how different RSV genotypes and associated viral loads influence disease phenotypes. We characterized the genetic variability of RSV strains during five non-consecutive respiratory seasons, and evaluated the role of RSV subtypes, genotypes and viral loads on clinical disease severity. Methods: Healthy infants hospitalized with RSV bronchiolitis were prospectively enrolled and nasopharyngeal samples obtained within 24h of hospitalization for RSV load quantitation by PCR, typing and genotyping. Parameters of disease severity were assessed, and multivariate models constructed to identify virologic and clinical factors predictive of clinical outcomes. Results: From March 2004 to April 2011, we enrolled 253 patients (56.5 % males; median age 2.1 (1.1-4.0) months). RSV A infections predominated over RSV B (69% vs. 31%; p<0.001) and showed greater genotype variability. The most common genotypes were RSV A/GA2, A/GA5 and RSV B/BA. Infants infected with RSV GA5 had higher viral loads compared with GA2 or BA infection (p<0.01), independent of duration of symptoms. After adjusting for other covariates, RSV A/GA5 infections were associated with longer hospital stay. Conclusions: RSV A infections were more frequent than RSV B infections and displayed greater genetic variability. Infections with GA5 were independently associated with clinical disease severity.
Project description:Respiratory syncytial virus (RSV) is a major cause of morbidity and mortality. Previous studies have suggested that T cell responses may contribute to RSV immunopathology, which could be driven by dendritic cells (DCs). DCs are productively infected by RSV, and during RSV infections, there is an increase of DCs in the lungs with a decrease in the blood. Pediatric populations are particularly susceptible to severe RSV infections, however DC responses to RSV from pediatric populations have not been examined. In this study, primary isolated DCs from cord blood and adult peripheral blood were compared after RSV-infection. Transcriptional profiling and biological network analysis identified transforming growth factor (TGF)-b and associated signaling molecules as differentially regulated in the two age groups. TGF-b1 was decreased in RSV-infected adult blood DCs, but increased in RSV-infected cord blood DCs. Co-culture of adult RSV-infected DCs with autologous T-cells induced secretion of interferon gamma (IFNg), IL-12p70, IL-2, and tumor necrosis factor alpha (TNFa). Conversely, co-culture of cord RSV-infected DCs and autologous T-cells induced secretion of IL-4, IL-6, IL-1b, and IL-17. Addition of purified TGF-b1 to adult DC-T cell co-cultures reduced secretion of IFNg, IL-12p70, IL-2, and TNFa, which addition of a TGF-b chemical inhibitor to cord DC-T cell co-cultures increased secretion of IL-12p70. These data suggest that TGF-b acts as a major regulator of RSV DC-T cell responses, which could contribute to immunopathology during infancy.
Project description:Rationale: Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections and hospitalizations in infants worldwide. Known risk factors, however, incompletely explain the variability of RSV disease severity among children. We postulate that severity of RSV infection is influenced in part by modulation of the host immune response by the local microbial ecosystem at the time of infection. Objectives: To define whether different nasopharyngeal microbiota profiles are associated with distinct host transcriptome profiles and severity in children with RSV infection. Methods: We analyzed the nasopharyngeal microbiota profiles of young children with mild and severe RSV disease and healthy matched controls by 16S-rRNA sequencing. In parallel, we analyzed whole blood gene expression profiles to study the relationship between microbial community composition, the RSV-induced host transcriptional response and clinical disease severity. Measurements and Main results: We identified five nasopharyngeal microbiota profiles characterized by enrichment of H. influenzae, Streptococcus, Corynebacterium, Moraxella or S. aureus. RSV infection and RSV hospitalization were positively associated with H. influenzae and Streptococcus, and negatively associated with S. aureus abundance, independent of age. The host response to RSV was defined by overexpression of interferon-related genes, and this was independent of the microbiota composition. On the other hand, transcriptome profiles of RSV infected children with H. influenzae and Streptococcus-dominated microbiota were characterized by greater overexpression of genes linked to toll-like receptor-signaling and neutrophil activation and were more frequently hospitalized Conclusions: Our data suggest an immunomodulatory role for the resident nasopharyngeal microbial community early in RSV infection, potentially affecting RSV disease severity.
Project description:This study perfromed RNAseq on two FFPE lung samples from deceased participants from the 1867 RSV vaccine trial and compared these data to age and race matched controls from LungMAP.