title: Clarithromycin modulates Helicobacter pylori-induced activation of nuclear factor-κB through classical and alternative pathways in gastric epithelial cells.
abstract: Infection of gastric epithelial cells by Helicobacter pylori stimulates the activation of nuclear factor-κB (NF-κB) and the upregulation of interleukin-8 (IL-8) expression. Activation of NF-κB can occur through classical (p50/p65) and alternative (p52/RelB) pathways. The role of the bacterial cag pathogenicity island (PAI) in these events is controversial. This study aimed to evaluate the hypothesis that the CagA protein is required for H. pylori-induced activation of NF-κB and upregulation of IL-8 expression, and for clarithromycin (CAM) to exert its molecular effects. Cultured KATO-III human gastric cancer cells were treated with extracts of H. pylori strains ATCC43504 (cag PAI(+)) and ATCC51932 (cag PAI(-)) for 24 h. NF-κB and phospho-IκB protein expression was then evaluated using western blotting. IL-8 mRNA expression was evaluated using the reverse transcription polymerase chain reaction. Following the separation of the proteins using two-dimensional gel electrophoresis, proteomes of the two bacterial extracts were compared using nanoflow liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) analysis. Although the protein profiles of the two extracts differed, both extracts induced IκBα phosphorylation, upregulation of IL-8 expression, and NF-κB activation through classical and alternative pathways. In cells treated with either of the bacterial extracts, CAM inhibited H. pylori-induced activation of NF-κB and upregulation of IL-8 expression. These results suggested that CagA is not required for H. pylori-induced activation of NF-κB and upregulation of IL-8 expression in gastric epithelial cells. H. pylori-induced NF-κB signaling can occur through classical and alternative activation pathways, and that CAM inhibits these two pathways.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Yen-Chun
authors.initials: YC
authors.lastname: Peng
authors.forename: Shu-Peng
authors.initials: SP
authors.lastname: Ho
authors.forename: Ching-Lin
authors.initials: CL
authors.lastname: Shyu
authors.forename: Chi-Sen
authors.initials: CS
authors.lastname: Chang
authors.forename: Lan-Ru
authors.initials: LR
authors.lastname: Huang
mesh_terms: D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002853:Chromatography, Liquid; D017291:Clarithromycin / Q000494:pharmacology*; D015180:Electrophoresis, Gel, Two-Dimensional; D004847:Epithelial Cells / Q000187:drug effects / Q000276:immunology / Q000382:microbiology*; D020869:Gene Expression Profiling; D016480:Helicobacter pylori / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology*; D016209:Interleukin-8 / Q000096:biosynthesis*; D016328:NF-kappa B / Q000378:metabolism*; D020543:Proteome / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053719:Tandem Mass Spectrometry
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007155:Immunologic Factors; D016209:Interleukin-8; D016328:NF-kappa B; D020543:Proteome; C080866:cagA protein, Helicobacter pylori; D017291:Clarithromycin