[Effects of c-src/Nox1/ROS on mucin5AC expression induced by neutrophil elastase in airway epithelial cells]

to explore the upper signaling pathway in neutrophil elastase (NE)-induced mucin5AC (MUC5AC) production in human BEAS-2B airway epithelial cells.

the BEAS-2B airway epithelial cells were cultured and divided into 7 groups: negative control group, NE stimulation group, negative siRNA control group treated with or without NE, NADPH oxidase 1(Nox1) siRNA group treated with NE, c-src siRNA group treated with NE, and c-src specific inhibitor PP2 group treated NE. The relative content of reactive oxygen species (ROS) was assayed with a special kit. The levels of MUC5AC protein in culture medium, Nox1 protein, phosphoralyted c-src (p-c-src) kinase and MUC5AC mRNA in culture cells were detected with enzyme-linked immunosorbent assay, Western blot, and RT-PCR, respectively.

there was an obvious increase of ROS production (0.76 +/- 0.09) in cells exposed to NE, with elevation of Nox1 protein (0.88 +/- 0.12) and MUC5AC protein production (0.82 +/- 0.09) and mRNA expression (0.77 +/- 0.05), all had significant differences when compared with normal control group, t = 6.13 - 9.44, P < 0.01. Nox1 siRNA inhibited ROS activity (0.19 +/- 0.06), reduced MUC5AC protein (0.31 +/- 0.05) and mRNA level (0.32 +/- 0.06), compared with single NE-stimulated group, P < 0.01. c-src siRNA and PP2 also showed the same effects, both of them decreased the NE-induced high activity of ROS, was 0.29 +/- 0.05, and 0.41 +/- 0.11, respectively, the MUC5AC protein in the c-src siRNA group and PP2 group were 0.38 +/- 0.09 and 0.48 +/- 0.08, MUC5AC mRNA level were 0.41 +/- 0.04 and 0.46 +/- 0.07, the Nox1 protein were 0.39 +/- 0.08 and 0.44 +/- 0.05, all P < 0.05, compared with single NE-treated group.

C-src/Nox1/ROS transduction cascade may be upper signal regulators in NE-mediated MUC5AC expression in BEAS-2B cells.