Helicobacter pylori activates gastric epithelial cells to produce interleukin-8 via protease-activated receptor 2.
OBJECTIVE
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.


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.
Kajikawa
Hirokazu
H
Inflammation and Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Yoshida
Norimasa
N
Katada
Kazuhiro
K
Hirayama
Fumihiro
F
Handa
Osamu
O
Kokura
Satoshi
S
Naito
Yuji
Y
Yoshikawa
Toshikazu
T
D000906:Antibodies / Q000494:pharmacology; D001550:Benzamidines; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000378:metabolism* / Q000382:microbiology; D005753:Gastric Mucosa / Q000378:metabolism* / Q000382:microbiology; D015870:Gene Expression; D006146:Guanidines / Q000494:pharmacology; D016481:Helicobacter Infections / Q000378:metabolism*; D016480:Helicobacter pylori / Q000201:enzymology*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D044464:Receptor, PAR-2 / Q000819:agonists / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D014162:Transfection
D000906:Antibodies; D001550:Benzamidines; D006146:Guanidines; D016209:Interleukin-8; D034741:RNA, Small Interfering; D044464:Receptor, PAR-2; D015842:Serine Proteinase Inhibitors; C032855:nafamostat