Mechanism for Helicobacter pylori stimulation of interleukin-8 production in a gastric epithelial cell line (MKN 28): roles of mitogen-activated protein kinase and interleukin-1beta.
Although it is known that the pathogenic mechanism of Helicobacter pylori involves the stimulated production of interleukin-8 (IL-8) as an inflammatory mediator, the details of the pathway remain unclear. The role of mitogen-activated protein kinase (MAPK) in IL-8 production by H. pylori has been examined in an in vitro study. IL-8 mRNA expression in gastric epithelial cells (MKN 28) was determined by reverse transcriptase-polymerase chain reaction (RT-PCR). IL-8 production was examined by ELISA. The activation of p38 MAPK was assessed by western blotting. Neither IL-8 mRNA nor activated p38 MAPK or p44/42 MAPK was detected in cells not treated with H. pylori. In contrast, incubation of cells with H. pylori, or IL-1beta, or both, clearly stimulated the expression of IL-8 mRNA within 60 min in a concentration-dependent manner. Phosphorylation of p38 MAPK and p44/p42 MAPK, as well as IL-8 production, occurred within 30 min and 24 hr after co-culturing MKN 28 cells with H. pylori and IL-1beta, respectively. Pretreatment of cells with MAPK inhibitors [1-[7-(4-fluorophenyl)-1,2,3,4-tetra-hydro-8-pyridylpyrazolo[5,1-c][1,2,4]triazin-2-yl]-2-phenylethanedione sulfate monohydrate (FR167653), 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)imidazole (SB203580), or 2-(2'-amino-3'-methoxyphenyl)-oxanaphthalen-4-one (PD98059)] significantly inhibited IL-8 production stimulated by H. pylori or IL-1beta or both. The combination of H. pylori and IL-1beta additively stimulated IL-8 production. The additive effect of H. pylori and IL-1beta on IL-8 production was inhibited by treatment with a p38 MAPK inhibitor. It was revealed that the culturing of MKN 28 cells with H. pylori significantly stimulates IL-8 production to a degree sufficient for induction of neutrophil chemotaxis via activation of p38 and p44/42 MAPK.
Yamada
H
H
Department of Applied Pharmacology, Kyoto Pharmaceutical University, Misasagi, Yamashina, Kyoto 607-8414, Japan.
Aihara
T
T
Okabe
S
S
D051698:Activating Transcription Factor 2; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors; D016480:Helicobacter pylori / Q000502:physiology*; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases
D051698:Activating Transcription Factor 2; D000894:Anti-Inflammatory Agents, Non-Steroidal; D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; C104334:FR 167653; D007375:Interleukin-1; D016209:Interleukin-8; D011720:Pyrazoles; D011725:Pyridines; D012333:RNA, Messenger; D014157:Transcription Factors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases