title: Intrinsic phenotypic differences of asthmatic epithelium and its inflammatory responses to respiratory syncytial virus and air pollution.
abstract: A substantial proportion of healthcare cost associated with asthma is attributable to exacerbations of the disease. Within the airway, the epithelium forms the mucosal immune barrier, the first structural cell defense against common environmental insults such as respiratory syncytial virus (RSV) and particulate matter. We sought to characterize the phenotype of differentiated asthmatic-derived airway epithelial cultures and their intrinsic inflammatory responses to environmental challenges. Air-liquid interface (ALI) cultures were generated from asthmatic (n = 6) and nonasthmatic (n = 6) airway epithelial cells. Airway tissue and ALI cultures were analyzed by immunohistochemistry for cytokeratin-5, E-cadherin, Ki67, Muc5AC, NF-κB, the activation of p38, and apoptosis. ALI cultures were exposed to RSV (4 × 10(6) plaque forming unit/ml), particulate matter collected by Environmental Health Canada (EHC-93, 100 μg/ml), or mechanically wounded for 24, 48, and 96 hours and basolateral supernatants analyzed for inflammatory cytokines, using Luminex and ELISA. The airway epithelium in airway sections of patients with asthma as well as in vitro ALI cultures demonstrated a less differentiated epithelium, characterized by elevated numbers of basal cells marked by the expression of cytokeratin-5, increased phosphorylation of p38 mitogen-activated protein kinase, and less adherens junction protein E-cadherin. Transepithelial resistance was not different between asthmatic and nonasthmatic cultures. In response to infection with RSV, exposure to EHC-93, or mechanical wounding, asthmatic ALI cultures released greater concentrations of IL-6, IL-8, and granulocyte macrophage colony-stimulating factor, compared with nonasthmatic cultures (P < 0.05). This parallel ex vivo and in vitro study of the asthmatic epithelium demonstrates an intrinsically altered phenotype and aberrant inflammatory response to common environmental challenges, compared with nonasthmatic epithelium.
authors.affiliation: James Hogg Research Centre, St. Paul's Hospital, University of British Columbia, Vancouver, BC, Canada. Tillie.Hackett@hli.ubc.ca
authors.forename: Tillie-Louise
authors.initials: TL
authors.lastname: Hackett
authors.forename: Gurpreet K
authors.initials: GK
authors.lastname: Singhera
authors.forename: Furquan
authors.initials: F
authors.lastname: Shaheen
authors.forename: Patrick
authors.initials: P
authors.lastname: Hayden
authors.forename: George R
authors.initials: GR
authors.lastname: Jackson
authors.forename: Richard G
authors.initials: RG
authors.lastname: Hegele
authors.forename: Stephan
authors.initials: S
authors.lastname: Van Eeden
authors.forename: Tony R
authors.initials: TR
authors.lastname: Bai
authors.forename: Delbert R
authors.initials: DR
authors.lastname: Dorscheid
authors.forename: Darryl A
authors.initials: DA
authors.lastname: Knight
mesh_terms: D000328:Adult; D000397:Air Pollution / Q000009:adverse effects*; D017209:Apoptosis; D001249:Asthma / Q000139:chemically induced / Q000378:metabolism* / Q000821:virology*; D015820:Cadherins / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000378:metabolism; D005260:Female; D006801:Humans; D053555:Keratin-5 / Q000378:metabolism; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D055271:Mucin 5AC / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D052638:Particulate Matter / Q000009:adverse effects*; D010766:Phosphorylation; D020545:Respiratory Mucosa / Q000378:metabolism* / Q000821:virology*; D012136:Respiratory Syncytial Viruses / Q000378:metabolism*; D055815:Young Adult; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D015820:Cadherins; D016207:Cytokines; D053555:Keratin-5; D019394:Ki-67 Antigen; C524678:MUC5AC protein, human; D055271:Mucin 5AC; D016328:NF-kappa B; D052638:Particulate Matter; D048051:p38 Mitogen-Activated Protein Kinases