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:Transfection of dsDNA into many mammalian cell types indues the production of type I interferons and interferon-stimulated genes. We performed an siRNA screen to identify genes involved in this innate immune response, and identified Abcf1. We used microarrays to determine which genes are regulated by ABCF1 following dsDNA stimulation. We treated p53-/- mouse embryonic fibroblasts (MEFs) with siRNAs targeting Abcf1 or Irf3 (positive control) or a negative control siRNA (siCtrl), and then stimulated the cells with 45-base pair dsDNA for 6 hrs or left the cells unstimulated. We then lysed the cells and hybridized the RNA to Affymetrix microarrays.
Project description:Transfection of dsDNA into many mammalian cell types indues the production of type I interferons and interferon-stimulated genes. We performed an siRNA screen to identify genes involved in this innate immune response, and identified Abcf1. We used microarrays to determine which genes are regulated by ABCF1 following dsDNA stimulation.
Project description:Background: The airway epithelium represents a critical component of the human lung that helps orchestrate defenses 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 on 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-β 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. Methods: Expression and localization experiments were performed using in situ hybridization and immunohistochemistry in human lung tissue, while confirmatory transcript and protein expression was performed in human airway epithelial cells. Functional experiments were performed with siRNA methods in a human airway epithelial cell line. Complementary transcriptomic analyses were performed to explore the contributions of ABCF1 to gene expression patterns. Results: Using archived human lung and human airway epithelial cells, we confirm expression of ABCF1 gene and protein expression in these tissue samples, with a role for mediating CXCL10 production in response to dsDNA viral mimic challenge. Although, ABCF1 knockdown was associated with an attenuation of select genes involved in the antiviral responses, Gene Ontology analyses revealed a greater interaction of ABCF1 with TLR signaling suggesting a multifactorial role for ABCF1 in innate immunity in human airway epithelial cells. Conclusion: ABCF1 is a candidate cytosolic nucleic acid sensor and modulator of TLR signaling that is expressed at gene and protein levels in human airway epithelial cells. The precise level where ABCF1 protein functions to modulate immune responses to pathogens remains to be determined but is anticipated to involve IRF-3 and CXCL10 production.
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: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.