Molecular mechanism of nontypeable Haemophilus influenzae stimulated MUC5AC production in NCI-H292 cells / 中国病理生理杂志

ABSTRACT

AIM:To investigate the molecular mechanism of nontypeable Haemophilus influenzae ( NTHi)-in-duced MUC5AC expression in the human airway NCI-H292 cells.METHODS:Bronchial epithelial NCI-H292 cells were cultured in vitro.The production of MUC5AC and matrix metalloproteinase 9 (MMP-9) after stimulation with NTHi was analyzed by enzyme-linked immunosorbent assay (ELISA).The enzymatic activity of MMP-9 was detected by gelatin zy-mography.In addition, the cells were pretreated with different inhibitors such as AG 1478, LY294002, DPI, NAC and GM6001 before stimulation, which specifically inhibit epidermal growth factor receptor (EGFR), phosphatiadylinositol 3-ki-nase (PI3K), NADPH oxidase, reactive oxygen species (ROS) and MMP-9, respectively, and then the production of MUC5AC or MMP-9 was determined.RESULTS:NTHi-stimulated NCI-H292 cells exhibited a time-dependent increase in MMP-9 secretion and activity .NTHi also increased the activity of Rac 1 and the production of ROS .Pretreatment of AG1478 and LY294002 decreased the Rac1 activity, and preincubation of DPI or Rac 1 inhibitor significantly abrogated ROS production.In addition, secretion of MMP-9 and the enzymatic activity was decreased by treatment of NAC and NSC23766.Furthermore, inhibition of the MMP-9 activity by GM6001 significantly inhibited MUC5AC production.CON-CLUSION:EGFR/PI3K/Rac1/NADPH oxidase/ROS/MMP-9 regulates MUC5AC production in NTHi-challenged NCI-H292 cells.