Expression of TLR2 and TLR4 messenger RNA in the epithelial cells of the nasal airway

Background: Epithelium of nasal mucosa is the first line of defense against invading pathogens. This study investigated the expression of Toll-like receptor (TLR) 2 and TLR4 in epithelial cells of nasal mucosa and understood the role of TLRs in the innate immunity of nasal mucosa. Methods: Human nasal epithelial cells were obtained by scraping the middle one-third of inferior turbinates from 30 patients with chronic rhinosinusitis and 20 healthy adult volunteers. The epithelial cells are made into smears. In situ hybridization was performed for TLR2 and TLR4 messenger RNA (mRNA). Results: TLR2 and TLR4 mRNA were expressed in the nasal epithelial cells. The expression of the two genes was significantly higher in the chronic rhinosinusitis group than in the normal control (TLR2, t = 8.605, p < 0.0005; TLR4, t = 9.050, p < 0.0005). Conclusion: This study is the first to establish the presence of both TLR2 and TLR4 mRNA on epithelial cells of nasal mucosa, and their expression can be up-regulated in infectious conditions. These results show that TLR2 and TLR4 may play a important role in local host defense of nasal mucosa.