Molecular mechanism of hyaluronan and CD44 on regulation of airway mucous hypersecretion / 上海交通大学学报（医学版）

ABSTRACT

Objective To investigate the effects of hyaluronan (HA) and CD44 on airway mucous hypersecretion,and explore the molecular mechanism of activation of epidermal growth factor(EGF)/epidermal growth factor receptor(EGFR) signal transduction pathway by signal factors. Methods BEAS-2 B airway epithelial cells were cultured in vitro,and were stimulated by neutrophil elastase(NE).Reactive oxygen species(ROS)scavenger(DMTU),hyaluronidase(Hase),CD44 antibody and tissue kallikrein(TK)inhibitor(PI)were served as interventional factors,and control group(serum free culture),NE stimulation group(50 nmol/L NE),DMTU+NE group(20μmol/L DMTU+50 nmol/L NE),DMTU+Hase+NE group(20 μmol/L DMTU+10μg/mL Hase+50 nmol/L NE),CD44Ab+NE group(5 μg/mL CD44Ab+50 nmol/LNE)and PI+NE group(1 00μg/mL PI+50 nmol/L NE)were established.The expression of mucin(MUC)5AC mRNA was detected by RT-PCR,the expression of MUC5AC and EGF protein was determined by ELISA,and the expression of phosphorylated epidermal growth factor receptor(p-EGFR)protein was analysed by Western blotting. Results The expression of MUC5AC,EGF and p-EGFR protein and MUC5AC mRNA in NE stimulation group was significantly higher than that in control group(P<0.01),the expression in DMTU+NE group was significantly lower than that in NE stimulation group(P<0.01),the expression in MTU+Hase+NE group was significantly higher than that in DMTU+NE group(P<0.05 for MUC5AC and p-EGFR protein and MUC5AC mRNA,and P<0.01 for EGF protein),the expression in CD44Ab+NE group and PI+NE group was significantly higher than that in NE stimulation group(P<0.05 for MUC5AC and p-EGFR protein and MUC5AC mRNA,and P<0.01 for EGF protein). Conclusion NE up-regulates the expression of MUC5AC gene via ROS/HA/CD44/TK/EGF/EGFR signal transduction pathway in airway epithelial cells.