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2626197 
Journal Article 
Abstract 
Aberrant differentiation of the asthmatic airway epithelium influences its responses to respiratory syncytial virus and particulate matter exposure in asthma 
Hackett, TL; Shaheen, F; Singhera, GK; Dorscheid, D; Van Eeden, S; Hegele, R; Bai, T; Knight, DA 
2010 
Yes 
American Journal of Respiratory and Critical Care Medicine
ISSN: 1073-449X
EISSN: 1535-4970 
181 
A6445 
English 
WOS:000208771005064 
is part of a larger document 3452678 Proceedings of the American Thoracic Society 2010 International Conference, May 14-19, 2010, New Orleans
The airway epithelium is the first cell of contact and a physical barrier to the external environment. Detailed cellular examination of bronchial biopsies and lavage fluid has provided convincing evidence of epithelial damage and aberrant repair in asthma. Excessive epithelial damage and fragility could arise from an enhanced susceptibility to injury, inappropriate repair or a combination of both. The aim of this study was to characterize the response of stratified airway epithelial cells from asthmatic and non-asthmatic subjects to respiratory Syncytial virus (RSV) and particulate matter (PM) challenge.

Methods: Differentiated air-liquid interface (ALI) cultures were generated from primary airway epithelial cells obtained from non-transplantable lungs of normal (n=5) and asthmatic donors (n=5). Bronchial sections and ALI cultures generated from the same individuals were analyzed by immunohistochemistry for Cytokeratin (CK) 5, CK-18, MUC5AC, E-cadherin and p63 and specific staining was evaluated using ImagePro Plus software. For RSV and PM10 challenge ALIs were infected with RSV (MOI3) or 1 mg/ml EHC-93 for 24, 48, and 96 hours and supernatants were analyzed by ELISA.

Results: The airway epithelium of asthmatics in vivo and in ALI culture demonstrated a less differentiated epithelium characterized by significantly elevated number of cells expressing the basal cell markers CK-5 and p63 and decreased number of cells expressing the ciliated cell marker CK-18 compared to controls (p<0.001). Asthmatic airways and ALIs contained more cells positive for MUC5AC but expressed less adherens junctional protein E-cadherin (p<0.01). All epithelial cells were screened for contamination with viral RNA and were found to be negative for prior infections. Basal expression of inflammatory cytokines IL-6 and IL-8 were significantly higher from asthmatic ALIs (P<0.05). In response to RSV infection and PM exposure, asthmatic ALI cultures released even higher levels of IL-6 and IL-8 compared to controls (P<0.05).

Conclusion: This parallel in vivo and in vitro study of asthmatic airways demonstrates that the airway epithelium in asthmatics is altered and displays an altered inflammatory response following challenge to viral infection or ambient particulate matter. Our data suggests that the asthmatic epithelium is unable to form an appropriate mucosal immune barrier and that future work is required to determine the factor/s involved in this inappropriate phenotype.

Funded by: CIHR-NCE-AllerGen 
American Thoracic Society 2010 International Conference 
New Orleans, LA 
May 14-19, 2010