Expression of mRNA transcripts of the Na+/H+ and Cl-/HCO3- exchanger isoforms in human nasal mucosa

Electrolyte transport by nasal epithelia has been suggested to be important for controlling the quantity and composition of the nasal fluid and may play an important role in the development of nasal polyps. One of a number of mechanisms involving translocation of Na+ and Cl- across cell membranes includes electroneutral processes, such as Na+/H+ exchange (NHE) and Cl-/HCO3- exchange (AE). The present study evaluated the presence of mRNAs for various members of the human NHE and AE gene families in human inferior turbinate mucosa and nasal polyp using reverse transcriptase polymerase chain reaction and in situ hybridization. The mRNA for NHE1 was detected in human turbinate mucosa and nasal polyp while the mRNAs for NHE2 and NHE3 could not be detected in any of the samples examined. Of the AE isoforms, AE2 mRNA was expressed in inferior turbinate mucosa but not in nasal polyp. In situ hybridization revealed that NHE1 mRNA in the turbinate mucosa and nasal polyp was localized in the epithelial layer and submucosal glands. AE2 mRNA was also expressed in the epithelial layer and submucosal glands of inferior turbinate mucosa. Taken together, these results indicate that the expression of AE2 mRNA is altered in nasal polyp compared with inferior turbinate mucosa, suggesting that the altered expression of these genes in nasal polyp may cause impaired electrolyte and water transport across the epithelial cells.