Changes in expression of ion channels and aquaporins mRNA during differentiation in normal human nasal epithelial cells

Integrity of the airway epithelium is important for pulmonary defense mecha nisms to infection. The lining of the airway contains a diverse population of cell types. Understanding about progenitor-progeny relationships during renewal of airway epithelium is important for elucidating mechanisms of inj ury repair or oncogenesis. Primary culture of airway epithelia is a good mo del for studying differentiation process of epithelial cells. Ion channels and aquaporins(AQPs) play a critical role on ion and fluid transport across airway epithelia. However, changes in their expression during differentiat ion of airway epithelial cells have not been reported yet. This study was u ndertaken to identify isoforms of aquaporins in cultured normal human nasal epithelial cells (NHNE) and effects of various culture conditions on expre ssion of differentiation markers and channels. 1. Degenerative RT-PCR revea led that AQP3 and AQP4 are expressed in cultured NHNE cells. 2. Culture of NHNE cells on permeable filters induced expression of mucin, aquaporins and CFTR. 3. Retinoic acid induced morphological changes in NHNE cells and inh ibited their proliferation. The treatment of retinoic acid induced expressi on of mucin and CFTR, whereas it inhibited expression of cornifin. The effe ct of retinoic acid was enhanced by culture of cells on permeable filters. 4. Dexamethasone induced ENaC expression in NHNE cells grown on permeable s upports only, but did not affect expression of mucin, aquaporins and CFTR. These results indicate that cultured NHNE cells express aquaporins (AQP3 an d 4), CFTR and ENaC, and culture of NHNE cells on permeable filters induces differentiation in to mucosecretory and surface epithelial cells, and that effects of retinoic acid and dexamethasone on gene expression are affected by culture conditions. (C) 2001 Elsevier Science Inc. All rights reserved.