Project description:Airway epithelial cells are crucial for mucosal and adaptive immunity as they produce mucins that trap and clear inhaled particulates by mucociliary activity, and also secrete diverse inflammatory mediators. But whether these cells respond in a memory-dependent manner to a secondary exposure is poorly studied. Our recent studies have highlighted the role of 'memory-based' or ‘trained’ immune responses. In this proposal we would like to probe for the molecular basis underlying the memory-based response in AECs. We will first establish an in-vitro model of memory-based responses using differentiated AECs. Here we will delineate the kinetics of memory-based response in AECs using a microbial ligand, LPS or endotoxin. The cells will be grown in air-liquid interface to study the effect of memory response on mucous phenotype. The RNAseq analyses will be performed on AECs exposed to endotoxin and compared to that of non-exposed AECs to determine the changes in coding and noncoding RNA regions.
Project description:We report the application of RNA sequencing technology for high-throughput profiling of gene expression responses to human rhinovirus infection at 24 hours in air-liquid interface human airway epithelial cell cultures derived from 6 asthmatic and 6 non-asthmatic donors. RNA-seq analysis identified sets of genes associated with asthma specific viral responses. These genes are related to inflammatory pathways, epithelial remodeling and cilium assembly and function, including those described previously (e.g. CCL5, CXCL10 and CX3CL1), and novel ones that were identified for the first time in this study (e.g. CCRL1, CDHR3). We concluded that air liquid interface cultured human airway epithelial cells challenged with live HRV are a useful in vitro model for the study of rhinovirus induced asthma exacerbation, given that our findings are consistent with clinical data sets. Furthermore, our data suggest that abnormal airway epithelial structure and inflammatory signaling are important contributors to viral induced asthma exacerbation. Differentiated air-liquid interface cultured human airway epithelial cell mRNA profiles from 6 asthmatic and 6 non-asthmatic donors after 24 hour treatment with either HRV or vehicle control were generated by deep sequencing, using Illumina HiSeq 2000.
Project description:We report the application of RNA sequencing technology for high-throughput profiling of gene expression responses to human rhinovirus infection at 24 hours in air-liquid interface human airway epithelial cell cultures derived from 6 asthmatic and 6 non-asthmatic donors. RNA-seq analysis identified sets of genes associated with asthma specific viral responses. These genes are related to inflammatory pathways, epithelial remodeling and cilium assembly and function, including those described previously (e.g. CCL5, CXCL10 and CX3CL1), and novel ones that were identified for the first time in this study (e.g. CCRL1, CDHR3). We concluded that air liquid interface cultured human airway epithelial cells challenged with live HRV are a useful in vitro model for the study of rhinovirus induced asthma exacerbation, given that our findings are consistent with clinical data sets. Furthermore, our data suggest that abnormal airway epithelial structure and inflammatory signaling are important contributors to viral induced asthma exacerbation.
Project description:Introduction: Thymic Stromal Lymphopoietin (TSLP) is a primarily epithelial-derived cytokine that drives type 2 allergic immune responses. Early life viral respiratory infections elicit high TSLP production, which leads to the development of type 2 inflammation and airway hyperreactivity. The goal of this study was to examine in vivo and in vitro the human airway epithelial responses leading to high TSLP production during viral respiratory infections in early infancy. Methods: A total of 129 infants (<1m – 24m, median age 10m) with severe viral respiratory infections were enrolled for in vivo (n=113), and in vitro studies (n=16). Infants were classified as “high TSLP” or “low TSLP” for values above or below the 50th percentile. High vs. low TSLP groups were compared in terms of type I-III IFN responses and production of chemokines promoting antiviral (CXCL10), neutrophilic (CXCL1, CXCL5, CXCL8), and type 2 responses (CCL11, CCL17, CCL22). Human infant airway epithelial cell (AEC) cultures were used to define the transcriptomic (RNAseq) profile leading to high vs. low TSLP responses in vitro. Results: Infants in the high TSLP group had greater in vivo type III IFN airway production (median type III IFN in high TSLP 183.2 pg/ml vs. 63.4 pg/ml in low TSLP group, p= 0.007) and increased in vitro type I-III IFN AEC responses after stimulation with a viral mimic (poly I:C). Our RNAseq data showed that infants in the high TSLP group had significant baseline upregulation of IFN signature genes (e.g., IFIT2, IFI6, MX1) and pro-inflammatory chemokine genes prior to viral mimic stimulation. Infants in the high TSLP group also showed a baseline AEC pro-inflammatory state characterized by increased production of all the chemokines assayed (e.g., CXCL10, CXCL8) in the absence of viral stimuli. Conclusion: High TSLP responses in the human infant airways are associated with pre-activated airway epithelial IFN antiviral immunity and increased baseline AEC production of pro-inflammatory chemokines. These findings present a new paradigm underlying the high production of TSLP in the human infant airway epithelium and shed light on the pathogenesis of viral respiratory illnesses during early infancy and beyond childhood.
Project description:The airway epithelium represents a critical component of the human lung that helps orchestrate defences against respiratory tract viral infections, which are responsible for more than 2.5 million deaths/year globally. Innate immune activities of the airway epithelium rely Toll-like receptors (TLRs), nucleotide binding and leucine-rich-repeat pyrin domain containing (NLRP) receptors, and cytosolic nucleic acid sensors. ATP Binding Cassette (ABC) transporters are ubiquitous across all three domains of life – Archaea, Bacteria, and Eukarya – and expressed in the human airway epithelium. ABCF1, a unique ABC family member that lacks a transmembrane domain, has been defined as a cytosolic nucleic acid sensor that regulates CXCL10, interferon-b expression, and downstream type I interferon responses. We tested the hypothesis that ABCF1 functions as a dsDNA nucleic acid sensor in human airway epithelial cells important in regulating antiviral responses.
Project description:The airway epithelium of asthmatics is characterized by intrinsically abnormal wound repair that may contribute to disease pathobiology. In this study, we show that in asthma, the airway epithelial cells at the leading edge of a wound display aberrant migration patterns, reduced expression of α5 and β1 integrin subunits at baseline and during wound repair, resulting in dysregulated cell migration and an inability to fully repair. Transcriptional profiling identified the PI3K/Akt signaling pathway as the top upstream transcriptional regulator of integrin α5β1. Significantly, activation of Akt signaling enhanced airway epithelial repair in cultures derived from asthmatic children via upregulation of α5 and β1 integrin subunits. Conversely, inhibition of the PI3K/Akt signaling pathway in airway epithelial cultures from non-asthmatic children attenuated epithelial repair and reduced α5 and β1 integrin expression. Importantly, the FDA-approved drug celecoxib, and its non-COX2 inhibitory analogue dimethyl-celecoxib, also stimulated the PI3K/Akt/integrin α5β1 axis and restored airway epithelial repair in cells from asthmatics. Thus, targeting the PI3K/Akt pathway may represent a novel therapeutic avenue for asthma.
Project description:Background: Basal cells within the human airway epithelium constitute the stem/progenitor cells for other epithelial cell types. Basal cells respond to mucosal injury and damage to the airway mucosa in an ordered sequence of spreading, migration, proliferation and phenotype shifting (differentiation) to other needed cell types. However, dynamic gene transcription in the early events of injury and repair has not been examined in these cells. Methodology and findings: Airway epithelial cells were obtained from donated lungs and grown in submersion culture on pliable membranes to obtain a pure population of basal cells. Microarrays were used to assess the transcriptome of basal cells 8 and 24 hr after mechanical injury (MI), or to cyclic stretch (CS) in a Flexcell system (0.5 Hz, 20% distension), or both treatments. We identified 121 signature genes with > 2-fold higher differential expression (DE) 8 hr after MI; expression of nearly all of these genes returned to baseline at 24 hr after injury. In cells subjected to CS, little change in DE was noted at 8 hr, whereas at 24 hr a CS signature of 1430 DE genes were identified. The MI signature was characterized by genes encoding growth factor receptors related to the EGF pathway, IL-6, IL-8 and IL-33, extracellular matrix components, and NF-kB and p38-MAPK signaling pathways, whereas the CS signature was characterized by a broad range of genes that did not identify specific signaling pathways. Combined MI and CS at 8 hr elicited DE of down-regulated genes not seen with either stimulus alone, and at 24 hr elicited DE that was similar to that seen with CS alone. Conclusion and significance: The human airway basal epithelial cell transcription signature in the first hours after MI, after CS, and after both stimuli identifies unique differentially expressed genes and pathways that may be important in the early molecular response and biology to airway injury. Total RNA obtained from primary (AEC) and differentiated (dAEC) human airway epithelial cells subjected to 8 or 24 hours in vitro mechanical or cyclic stretch or both injuries compared to sham control as well as to type of injury. Cells were collected from four donated lungs and cultured separated in submission or air liquid interface condition prior to injury for various durations.
Project description:Early life viral infections are responsible for pulmonary exacerbations that can contribute to disease progression in young children with CF. The most common respiratory viruses detected in the CF airway are human rhinoviruses (RV) and susceptibility to infection has been attributed to dysregulated airway epithelial responses, although evidence has been conflicting. Here, we exposed airway epithelial cells from children with and without CF to RV in vitro. Using RNA-Seq, we profiled the transcriptomic differences of CF and non-CF airway epithelial cells at baseline and in response to RV. There were only modest differences between CF and non-CF cells at baseline. In response to RV there were 1442 and 896 differentially expressed genes in CF and non-CF airway epithelial cells respectively. The core antiviral responses in CF and non-CF airway epithelial cells were mediated through interferon signaling although type 1 and 3 interferon proteins were reduced in CF airway epithelial cells following viral challenge consistent with previous reports. The transcriptional responses in CF airway epithelial cells were more complex than in non-CF airway epithelial cells with more over-represented biological pathways ranging from cytokine signaling to metabolic and biosynthetic pathways. Network analysis highlighted that the differentially expressed genes of CF airway epithelial cells transcriptional responses were highly interconnected and formed a more complex network than observed in non-CF airway epithelial cells. These data provide novel insights to the CF airway epithelial cells responses to RV infection and highlight potential pathways that could be targeted to improve antiviral and anti-inflammatory responses in CF.