Previous studies have shown that lipopolysaccharides (LPS), a major outer surface membrane component of Gram-negative bacteria such as Pseudomonas aeruginosa, stimulate MUC5AC production via epidermal growth factor receptor (EGFR) in human airway
igf lr3 [4], [5], [6] and [7]. LPS-stimulated MUC5AC production was also shown to be dependent on the expression and activity of matrix metalloproteinase-9 (MMP-9), also known as gelatinase B [6] and [7]. Notoriously, MMP-9 has been found increased not only in sputum, but also in serum of COPD patients [8] and [9]. Furthermore, higher MMP-9 serum concentration is connected with higher airway obstruction and disease progression [9]. In the present study we investigated the signaling pathway mediating LPS-stimulated secretion and activation of MMP-9, and the regulatory effects of this pathway on the production of MUC5AC in the human airway
cells NCI-H292. Materials and methods Antibodies and reagents. Mouse monoclonal anti-MUC5AC was from Sigma Chemical Co. (St. Louis, MO). Roswell Park Memorial Institute medium (RPMI 1640) and fetal calf serum were from GIBCO/Invitrogen (Carisbad, CA). CM-H2DCFDA was from Molecular Probes (Burlington, Ontario, Canada). NSC23766 was from Tocris (Bristol, UK). Lipopolysaccharides (LPS) from P. aeruginosa and specific inhibitors of EGFR (AG147
cool , PI3K (LY294002), NADPH (DPI), ROS (NAC), and MMP (GM6001) were from Sigma Chemical Co.
