Extracellular signal-regulated protein kinase mediates interleukin 17 (IL-17)-induced IL-8 secretion in Helicobacter pylori-infected human gastric epithelial cells.
Helicobacter pylori-induced mucosal inflammation results in high production of interleukin 17 (IL-17), a potent inducer of IL-8 in gastric epithelial cells. The aim of this study was to investigate signaling pathways by which IL-17 regulates IL-8 production in human gastric epithelial cells. Activation of mitogen-activated protein (MAP) kinases in both IL-17-stimulated MKN28 cells and epithelial cells isolated from H. pylori-colonized gastric mucosa was assessed by Western blotting. In IL-17-stimulated MKN28 cells the activation of activatior protein 1 (AP-1), nuclear factor (NF)-IL-6, and NF-kappaB was also assessed by electrophoretic mobility shift assay. IL-8 production was evaluated by reverse transcription-PCR and enzyme-linked immunosorbent assay (ELISA) both for IL-17-stimulated MKN28 cells treated with specific MAP kinase inhibitors and gastric biopsy cultures treated with a neutralizing IL-17 antibody. Serum from H. pylori-infected patients was tested for immunoglobulin G response to CagA by ELISA. Treatment of MKN28 cells with IL-17 caused activation of extracellular signal-regulated protein kinase 1/2 (ERK 1/2) but not other MAP kinases and had the downstream effects of AP-1 and NF-kappaB activation and IL-8 synthesis. Blocking ERK 1/2 activity inhibited AP-1-mediated, but not NF-kappaB-mediated, IL-8 induction. Enhanced activation of ERK 1/2 was seen in gastric epithelial cells isolated from H. pylori-infected patients in comparison to uninfected controls, and this was associated with high IL-8. These effects were even more pronounced in patients seropositive for CagA than in seronegative ones. In gastric biopsy cultures, the addition of a neutralizing IL-17 antibody decreased ERK 1/2 activation, thus resulting in a significant inhibition of IL-8. In H. pylori-colonized gastric epithelial cells, IL-17-induced IL-8 synthesis is associated with and depends at least in part on the activation of ERK 1/2 MAP kinase.
Dipartimento di Medicina Sperimentale e Clinica, Università di Catanzaro Magna Graecia, Via T Campanella, 88100 Catanzaro, Italy.
Ladislava
L
Sebkova
Antonia
A
Pellicanò
Giovanni
G
Monteleone
Barbara
B
Grazioli
Giovanni
G
Guarnieri
Maria
M
Imeneo
Francesco
F
Pallone
Francesco
F
Luzza
D000328:Adult; D000368:Aged; D002460:Cell Line; D002478:Cells, Cultured; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000382:microbiology*; D005260:Female; D005753:Gastric Mucosa / Q000166:cytology / Q000382:microbiology*; D005786:Gene Expression Regulation; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000472:pathogenicity*; D006801:Humans; D020381:Interleukin-17 / Q000378:metabolism* / Q000494:pharmacology; D016209:Interleukin-8 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*
D020381:Interleukin-17; D016209:Interleukin-8; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases