Regulation of Ion Channels in Cultured Airway Epithelial Cells

Abstract

The airways are lined with pseudostratified columnar epithelium comprised predominantly of goblet, ciliated and basal cells. The goblet cells secrete mucus into the airway lumen (apical surface) contributing, in part, to the protective layer of mucus that traps infectious, particulate and chemical hazards of inspired air. The more abundant ciliated cells are covered with apical membrane projections (cilia) which propel mucus toward the oropharynx (mucociliary clearance)1. Basal cells anchor goblet and ciliated cells to the epithelial extracellular matrix2; they may also function as stem cells replenishing goblet and ciliated cells sloughed from the epithelium3. Adjacent epithelial cells are attached along their apical-basolateral borders by an elaborate complex of adherence proteins, including tight junctions (zonula occludens)4. These junctions limit the diffusion of water, ions and neutral molecules between the cells (paracellular transport). This cellular architecture allows the epithelium to function as a barrier between the airway lumen and the submucosal fluid compartment.