Protease-activated receptor 2 (PAR 2) has been shown to be responsible for trypsin and mast cell tryptase-induced airway inflammation. Here, the present study aimed to explore the expression of PAR 2 in the nasal mucosa of seasonal allergic rhinitis (SAR).Methods
Study subjects were recruited for the study by medical history, physical examination and laboratory screening tests. Using immunohistochemistry, laser-assisted cell picking and subsequently real-time PCR, nasal mucosa biopsies of SAR patients were investigated for PAR 2 gene and protein expression in complex tissues of the nasal mucosa.Results
Gene and protein expression of PAR 2 was firstly detected in nasal mucosa of SAR patients. The relative gene expression level of PAR 2 was significantly increased in complex tissues of the nasal mucosa of SAR (6.21±4.02 vs. controls: 1.38±0.86, P = 0.004). Moreover, PAR 2 mRNA expression in epithelial cells (SAR: 4.78±4.64 vs. controls: 0.84±0.61, P = 0.003) but not in mucus (SAR: 1.51±1.15 vs. controls: 1.35±1.02, P = 0.78) and endothelial cells (SAR: 1.20±0.57 vs. controls: 1.73±1.30, P = 0.5) was found to be significantly changed in the nasal mucosa in SAR. Using double immunohistochemistry the present study demonstrated that the total numbers of mast cells (P = 0.0003) and eosinophils (P = 0.03) and the numbers of eosinophils expressing PAR 2 (P = 0.006) were significantly elevated in the nasal mucosa of SAR compared with the controls.Conclusion
The abundant presence and distribution of gene and protein expression of PAR 2 in different cell types in the nasal mucosa under normal situation, the increased expression of PAR 2 in epithelial cells and the increased number of eosinophils with PAR 2 suggest that PAR 2 may contribute to the pathogenesis of allergic diseases such as SAR.