Helicobacter pylori-induced expression of interleukin-8 and cyclooxygenase-2 in AGS gastric epithelial cells: mediation by nuclear factor-kappaB.

BACKGROUND: Helicobacter pylori infection might activate nuclear factor-kappaB (NF-kappaB), a transcriptional regulator of inducible expression of inflammatory genes, interleukin-8 (IL-8) and cyclooxygenase-2 (COX-2). We studied the role of NF-kappaB on expression of IL-8 and COX-2 in H. pylori-stimulated AGS gastric epithelial cells by using antisense oligonucleotide (AS ODN) for NF-kappaB subunit p50 and an antioxidant, glutathione (GSH) as well as a NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC).

METHODS: AGS cells were treated with p50 AS ODN, GSH or PDTC in the presence of H. pylori. mRNA expression and protein levels for IL-8 and COX-2 were determined by Northern blot analysis and Western blot analysis. Levels of IL-8, 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha) and thromboxane B2 (TXB2) were measured in the medium by enzyme-linked immunosorbent assay. NF-kappaB activation was examined by electrophoretic mobility shift assay.

RESULTS: H. pylori induced a time-dependent expression of mRNA and protein for IL-8 and COX-2 via activation of NF-kappaB and increased the levels of IL-8, 6-keto-PGF1alpha and TXB2, which were inhibited by GSH and PDTC. H. pylori-induced expression of IL-8 and COX-2 was blocked in AGS cells transfected with p50 AS ODN.

CONCLUSION: NF-kappaB may play a novel role in expression of IL-8 and COX-2 in H. pylori-induced gastric inflammation.