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2612714 
Journal Article 
Abstract 
House dust mite-induced CCL20 release from bronchial epithelial cells is chloride dependent 
Webb, M; Nathan, A; Dienger, K; Wu, D; Wills-Karp, M 
2010 
Yes 
American Journal of Respiratory and Critical Care Medicine
ISSN: 1073-449X
EISSN: 1535-4970 
181 
A1445 
English 
WOS:000208771000446 
is part of a larger document 3452678 Proceedings of the American Thoracic Society 2010 International Conference, May 14-19, 2010, New Orleans
Asthma is a chronic inflammatory disease of the lung mediated by TH2 cells. Recent evidence suggests pulmonary dendritic cells (DCs) are important in driving initial T cell activation, and thus promote the development of airway hyperreactivity. Previously we found that bronchial epithelial cells exposed to the common allergen house dust mite (HDM) released CCL20, a chemokine that is important in the recruitment of immature DCs, within minutes after exposure. The mechanism for this fast release remains unknown, however its rapidity suggests protein synthesis is not required. As CFTR has recently been linked to regulating the release of the chemokine IL-8 from the bronchial epithelium, we hypothesized that rapid release of CCL20 may also be dependent on ion channel activity. To identify general ion channel involvement in CCL20 release, we treated human bronchial epithelial cells with vehicle control, or inhibitors of anion and cation channel activity, and subsequently exposed the cells to HDM. To determine if blockade of these channels inhibited chemokine release, we collected supernatants and assayed CCL20 levels via ELISA. Interestingly, we found that HDM-induced CCL20 release was inhibited by the chloride channel inhibitors DIDS, NPPB, and niflumic acid, but not cation channel inhibitors amiloride and bumetanide, suggesting an that release is dependent on an anion dependent mechanism. To test the specific dependence of chemokine release on the presence of chloride ions, we treated cells in physiological solutions containing replacement anions gluconate and nitrate. Replacement of chloride anions with gluconate reduced CCL20 release in a reversible fashion, while nitrate replacement increased release, demonstrating that more permeable anions such as nitrate increase CCL20 release, while less permeable anions such as gluconate reduce release. Finally, the chloride ionophore TTPMn(III) was applied to cells to test whether free movement of chloride was sufficient to overcome DIDS inhibition. Cells treated with the chloride ionophore showed no difference in chemokine release in either DIDS-treated or media controls, suggesting that CCL20 release is dependent on chloride movement through a specific DIDS-inhibited channel. These data suggest that the mechanism of early CCL20 release from bronchial epithelial cells exposed to HDM is through chloride channel activity that may include coupled transport. Identification of this channel may lead to pharmacological targets for asthma treatment and prevention. 
American Thoracic Society 2010 International Conference 
New Orleans, LA 
May 14-19, 2010