BACKGROUND/AIM: Recently, it has been shown that serine proteases derived from microorganisms stimulate epithelial cells to produce inflammatory mediators through protease-activated receptor (PAR). We investigated the involvement of PAR2 in the interleukin (IL)-8 production by Helicobacter pylori-infected gastric epithelial cells. METHODS AND RESULTS: Human gastric epithelial cells, MKN45 cells, were used. The expression of PAR2 was assessed by real-time PCR and immunocytochemistry, and IL-8 protein was measured by an enzyme-linked immunosorbent assay. PAR2 mRNA and protein were constitutively expressed on unstimulated MKN45 cells. The treatment of cells with H. pylori resulted in a significant increase in PAR2 expression. In addition, trypsin (a natural PAR2 agonist), SLIGKV amide (a synthetic PAR2 agonist), H. pylori live bacteria or H. pylori culture supernatant significantly induced IL-8 production from MKN45 cells. H. pylori-induced IL-8 production was inhibited by nafamostat mesilate (a serine protease inhibitor), neutralizing antibody to PAR2 and in PAR2-deficient cells treated with siRNA. CONCLUSIONS: These results reveal that H. pylori-derived protease activates gastric epithelial cells to produce inflammatory cytokines through PAR2, suggesting an important role for PAR2 in the modulation of gastric inflammation associated with H. pylori.
BACKGROUND/AIM: Recently, it has been shown that serine proteases derived from microorganisms stimulate epithelial cells to produce inflammatory mediators through protease-activated receptor (PAR). We investigated the involvement of PAR2 in the interleukin (IL)-8 production by Helicobacter pylori-infected gastric epithelial cells. METHODS AND RESULTS:Human gastric epithelial cells, MKN45 cells, were used. The expression of PAR2 was assessed by real-time PCR and immunocytochemistry, and IL-8 protein was measured by an enzyme-linked immunosorbent assay. PAR2 mRNA and protein were constitutively expressed on unstimulated MKN45 cells. The treatment of cells with H. pylori resulted in a significant increase in PAR2 expression. In addition, trypsin (a natural PAR2 agonist), SLIGKV amide (a synthetic PAR2 agonist), H. pylori live bacteria or H. pylori culture supernatant significantly induced IL-8 production from MKN45 cells. H. pylori-induced IL-8 production was inhibited by nafamostat mesilate (a serine protease inhibitor), neutralizing antibody to PAR2 and in PAR2-deficient cells treated with siRNA. CONCLUSIONS: These results reveal that H. pylori-derived protease activates gastric epithelial cells to produce inflammatory cytokines through PAR2, suggesting an important role for PAR2 in the modulation of gastric inflammation associated with H. pylori.
Authors: Marcel R de Zoete; Lieneke I Bouwman; A Marijke Keestra; Jos P M van Putten Journal: Proc Natl Acad Sci U S A Date: 2011-03-07 Impact factor: 11.205