CFTR, MDR1, and MRP1 immunolocalization in normal human nasal respiratory mucosa

CFTR (cystic fibrosis transmembrane conductance regulator), MDR1 (multidrug resistance), and MRP1 (multidrug resistance-associated protein), members o f the ABC transporter superfamily, possess multiple functions, particularly Cl-, anion, and glutathione conjugate transport and cell detoxification. T hey are also hypothesized to have a number of complementary functions. It i s generally accepted that data obtained from nasal mucosa can be extrapolat ed to lower airway cell physiology. The aim of the present study was to inv estigate by immunohistochemistry the differential localization of CFTR, MDR 1, acid MRP1 in the normal mucosa of 10 human nasal turbinates. In ciliated epithelial cells, CFTR was inconstantly expressed at the apical cell surfa ce, intense membranous labeling was observed for MDR1, and intense cytoplas mic labeling was observed for MRP1. In the glands, a higher level of expres sion was observed on serous cells, at the apical surface (for CFTR), on lat eral membranes (for MDR1), and with an intracytoplasmic distribution (for M RP1). in conclusion, CFTR, MDR1 and MRP1 are expressed in the epithelium an d glands of the nasal respiratory mucosa, but with different patterns of ex pression. These results suggest major roles for CFTR, MDR1, and MRP1 in ser ous glandular cells and a protective function for MDR1 and MRP1 in respirat ory ciliated cells.