Objective:To investigate the anti-inflammatory effects of bitter taste receptor (TAS2Rs) in the treatment of chronic airway inflammation by bitter Chinese medicine.Methods: The experiment was divided into three groups (n=8),namely blank control group,PM2.5 group (the rat models of chronic airway inflammation were established by aerosolized PM2.5 suspension) and PM2.5+limonin group (intervening with the extract from Tangerine peel).The expression of mRNA and protein of inflammatory cytokines and TAS2Rs in bronchial/pulmonary tissue were detected by ELISA,RT-PCR and Western blot respectively.Results: The mRNA and protein expression levels of TNF-α and IL-13 in PM2.5 stimulated group were significantly higher than those in control group,while the TAS2R14 were not significantly changed.The mRNA and protein expression levels of TNF-α and IL-13 in the limonin intervention group was lower than that in the PM2.5 group,and the TAS2R14 were significantly increased.Conclusion: The production and release of inflammatory cytokines in the chronic inflammatory airway can be curbed by inhaling the components of bitter Chinese herbal medicine.And then,the TAS2Rs in the lungs can be activated by the bitter components to increase its expression.Therefore,it is considered that bitter Chinese herbal medicine to play the airway anti-inflammatory effect is achieved through the activation of the airway TAS2Rs.

To explore the role of cortical actin-binding protein (cortactin) in shear stress-induced mucin (MUC) 5AC secretion in human airway epithelial cells and the effect of phosphorylation of cortactin at different sites.
 Methods: HBE16 airway epithelial cells were cultured, and then transfected with mutation carrier, such as pEGFP-N1-cortactin (Cort), pEGFP-N1-Cort-Y421A, pEGFP-N1-Cort-Y470A and pEGFP-N1-Cort-Y486A. The cells were divided into a normal control group, a shear stress group, a shear stress + pEGFP-N1 group, a shear stress + PEGFP-N1-Cort group, a shear stress + pEGFP-N1-Cort-Y421A group, a shear stress + pEGFP-N1-Cort-Y470A group, and a shear stress + pEGFP-N1-Cort-Y486A group. The shear stress were set at 4 dynes/cm2. The levels of MUC5AC protein and mRNA in cells and culture supernatant were assayed with enzyme-linked immunosorbent assay (ELISA) and real-time PCR. The cortactin and phosphorylated cortactin were detected by Western blot. F-actin was stained by fluorescein isothiocyanate (FITC)-phalloidin.
 Results: There was an obvious increase of phosphorylated cortactin in cells exposed to 4 dynes/cm2 of shear stress for 30 min, which reached climax at 2 hours concomitant with elevation of MUC5AC protein production and mRNA expression in the different experiment groups (all P<0.05). Compared with single shear stress-stimulated group, MUC5AC in supernatant was increased obviously, and the distribution of F-actin in cytomembrane was also increased in the pEGFP-N1-Cort group (both P<0.05), while there were no changes in the MUC5AC protein and mRNA levels in cytoplasm. Compared with the shear stress+pEGFP-N1-Cort group, the MUC5AC protein in the culture supernatant was decreased, and the polymerization of F-actin at cell membranes were also attenuated in the shear stress+pEGFP-N1-Cort-Y421A group and the shear stress + pEGFP-N1-Cort-Y470A group (both P<0.05), while there was no significant effect in the shear stress + pEGFP-N1-Cort-Y486A group (P>0.05).
 Conclusion: Cortactin is involved in shear stress-mediated MUC5AC secretion in human airway epithelial cells, and the phosphorylated site of Tyr421 and Tyr470 may play an important role in it.
Cortactin ; Epithelial Cells ; Humans ; Mucin 5AC ; Mucus ; Phosphorylation