Helicobacter pylori-derived outer membrane vesicles stimulate interleukin 8 secretion through nuclear factor kappa B activation

BACKGROUND/AIMS: Bacteria-derived outer membrane vesicles (OMVs) are commonly associated with various biological activities and functions. Helicobacter pylori-derived OMVs are thought to contribute to pathogenesis. This study aimed to investigate the effects of H. pylori-derived OMVs. METHODS: H. pylori strains were isolated from patients with gastritis, gastric ulcer, or gastric cancer using endoscopic biopsy. The U-937, AGS, and MKN-45 cell lines were exposed to H. pylori and H. pylori-derived OMVs. The expression of interleukin 8 (IL-8) messenger RNA (mRNA) was assessed using reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR, and IL-8 secretion was analyzed using enzyme-linked immunosorbent assay. Nuclear factor kappa B (NF-κB) activation was evaluated by Western blotting. RESULTS: H. pylori and H. pylori-derived OMVs induced the expression of IL-8 mRNA and protein. Importantly, the bacteria induced higher IL-8 mRNA and protein expression than the OMVs. IL-8 expression was induced to different levels in response to H. pylori-derived OMVs from hosts with different gastric diseases. Western blotting revealed the increased phosphorylation and reduced degradation of inhibitor of NF-κB alpha in cells exposed to OMVs. CONCLUSIONS: H. pylori-derived OMVs may aid the development of various gastric diseases by inducing IL-8 production and NF-κB activation.