Serially Passaged Normal Human Nasal Epithelial Cells: Morphology and Mucous Secretory Differentiation

ABSTRACT

BACKGROUND AND OBJECTIVES: The purpose of this study was to develop a subculturing technique that allows the formation of large amounts of normal human nasal epithelial (NHNE) cells without compromising the cells' ability to differentiate into secretory and ciliated cells. MATERIALS AND METHODS: Freshly isolated nasal epithelial cells, collected from normal inferior turbinates, were subcultured repeatedly in a serum-free medium on plastic culture dishes. The subcultured cells were tested for growth curve and electromicroscopic characteristics in air-liquid interface (ALI) cultures and for mucous secretory differentiation. RESULTS: The cultures grew rapidly during the first three passages, demonstrating a 20- to 40-fold expansion with each subculture. Ciliogenesis usually started on day 12 and the cultured cells formed cellular sheets exhibiting microvilli in the apical membrane, intracytoplasmic secretory granules, electron lucent, scant endoplasmic reticulum and complex tight junctions on the basolateral side. Passage-1 (P-1) and passage-2 (P-2) cells maintained their potential to differentiate into mucin-secretory and ciliated epithelial cells, and this potential was confirmed by immunocytochemistry with H6C5 and transmission electron microscopy. Although the number of NHNE cells on day 16 of culture decreased as the passage progressed from P-1 to P-3, the relative number of secretory cells did not significantly change. CONCLUSION: In conclusion, P-2 NHNE cell cultures retain the features of normal epithelium and are suitable for conducting many studies on upper airway cell biology.