ABSTRACT
BACKGROUND AND OBJECTIVES: The nasal epithelium is the first barrier encountered by airborne allergens and an active participant in airway inflammation. Fungi have been increasingly recognized as important pathogens in sinusitis and consists of several allergenic proteins. We hypothesized that fungi induce the release of inflammatory mediators, and tried to find out the mechanism of epithelial cell activation. SUBJECTS AND METHOD: The epithelial cells of nasal polyp were obtained from patients and stimulated with Alternaria, Aspergillus, and Cladosporium. Interleukin-8 (IL-8), granulocyte-macrophage colony stimulating factor (GM-CSF), regulated on activation and normal T expressed and secreted (RANTES) were measured to determine the activation of epithelial cells. Nasal epithelial cell activation was inhibited with serine and cystein protease inhibitors. Reverse transcriptase-polymerase chain reaction (RT-PCR) test for protease-activated receptors (PARs) mRNA expression in nasal epithelial cells were performed. RESULTS: Fungi enhanced the production of chemical mediators from nasal epithelial cells. Serine protease inhibitors inhibited the activation of nasal epithelial cells. When nasal epithelial cells were activated, PAR2 and PAR3 mRNAs were more strongly expressed than non-activated cells. CONCLUSION: Serine proteases in fungi interact with nasal epithelial cells and enhance the production of inflammatory cytokines. PARs might play a role in the process of epithelial cell activation.