#60 Mechanical Regulation of Airway Epithelial Cell Permeability in Asthma
Neilloy Roy, University of Manitoba; Emily Turner-Brannen, University of Manitoba; Adrian R West, University of Manitoba
Asthma is an obstructive airway disease that afflicts more than 2.4 million Canadians. In Manitoba it is the number one reason children visit emergency rooms. Asthmatic airway obstruction is ultimately caused by the contraction of airway smooth muscle, which is normally attenuated by an intact airway epithelial barrier. Airway epithelial barrier impairment is hallmark of asthma as is stiffening of the airway wall. We hypothesize airway wall stiffening drives epithelial barrier impairment.
Stiffening of the airway wall was recapitulated using a new platform developed in our laboratory that permits stiffness modulation of the cellular microenvironment and epithelial permeability measurements. Adenovirus-transformed airway epithelial cell layers were maintained in microenvironments with stiffnesses between 300 Pa and 19200 Pa. Permeability of these epithelial layers exposed to the different microenvironments was determined by measuring the transepithelial migration rate of fluorescent molecules.
Microenvironment stiffness had a significant impact on (p<0.05) on airway epithelial permeability. Epithelium in 300 Pa microenvironments were more permeable (18.4 ± 4.0 cm/s) than epithelium in 2400 Pa (8.6 ± 1.4 cm/s; p<0.05) and 19200 Pa (7.5 ± 0.9 cm/s; p<0.05) microenvironments. The permeability of epithelium in 2400 Pa and 19200 Pa microenvironments were not statistically different (p=0.9524).
Airway epithelial permeability was measured to be greater in softer microenvironments than in stiffer microenvironments. Therefore contrary to the hypothesis, stiff microenvironments promote airway epithelial barrier integrity not impairment. These results are a proof of concept as they were obtained using adenovirus-transformed cells. In the future primary airway epithelial cells from multiple asthmatic and non-asthmatic donors will be used to investigate the influence of microenvironment stiffness on airway epithelial barrier integrity. Exploring and exploiting this novel pathway upstream of airway obstruction may yield new and better therapeutic options for patients burdened with asthma.