RRC ID 43792
Author Tabassam FH, Graham DY, Yamaoka Y.
Title Helicobacter pylori-associated regulation of forkhead transcription factors FoxO1/3a in human gastric cells.
Journal Helicobacter
Abstract BACKGROUND:Interaction of Helicobacter pylori with gastric mucosa leads to marked cellular and humoral host immunologic responses. The signaling pathways initiated by bacteria-host interaction that result in perturbations in cell structure and function remain unclear. Forkhead transcription factors of class O (FoxO) are implicated in the regulation of apoptosis, cell survival, and pathogenesis. H. pylori infection of gastric epithelial cells induces phosphoinositide-3 kinase (PI3K)-dependent Akt activation and cell survival signaling. We investigated the role of H. pylori-activated PI3K/Akt in the regulation of FoxO1/3a in gastric cells.
METHODS:Immunoblot, immunoprecipitation, and fluorescence microscopy were used to assess the effect of infection of gastric epithelial cells with wild-type H. pylori and their isogenic cag pathogenicity island (PAI) or oipA mutants on the FoxO1/3a signaling pathways. Interleukin-8 release was determined by enzyme-linked immunosorbent assays.
RESULTS: H. pylori infection resulted in activation of the PI3K p85 subunit and inactivation of FoxO1 and FoxO3a by their phosphorylation and translocation of from the nucleus to the cytoplasm. Inhibition of PI3K or Akt kinase activity reduced FoxO1/3a phosphorylation. Akt, FoxO1, or FoxO3a siRNA reduced H. pylori-induced interleukin-8 production. Infection with oipA mutants reduced PI3K/Akt activation and inhibited FoxO1/3a phosphorylation, whereas infection with cag PAI mutants reduced PI3K/Akt activity but did not inhibit FoxO1/3a activation.
CONCLUSIONS:FoxO1 and FoxO3a are novel nuclear substrates of H. pylori-induced PI3K/Akt cell survival signaling pathways that partially control interleukin-8 production. OipA-regulated interleukin-8 release through PI3K/Akt is dependent on FoxO1/3a inactivation, whereas cag PAI-mediated interleukin-8 production employs FoxO1/3-independent signaling.
Volume 17(3)
Pages 193-202
Published 2012-6-1
DOI 10.1111/j.1523-5378.2012.00939.x
PMID 22515357
PMC PMC3335761
MeSH Cell Line, Tumor Epithelial Cells / metabolism Epithelial Cells / microbiology Forkhead Box Protein O1 Forkhead Box Protein O3 Forkhead Transcription Factors / genetics Forkhead Transcription Factors / metabolism* Gastric Mucosa / cytology Gastric Mucosa / metabolism* Gastric Mucosa / microbiology Gene Expression Regulation Helicobacter Infections / enzymology Helicobacter Infections / genetics Helicobacter Infections / metabolism* Helicobacter Infections / microbiology* Helicobacter pylori / genetics Helicobacter pylori / physiology* Humans Interleukin-8 / genetics Interleukin-8 / metabolism Phosphatidylinositol 3-Kinases / genetics Phosphatidylinositol 3-Kinases / metabolism Phosphorylation Proto-Oncogene Proteins c-akt / genetics Proto-Oncogene Proteins c-akt / metabolism Signal Transduction
IF 4.0
Times Cited 19
WOS Category GASTROENTEROLOGY & HEPATOLOGY MICROBIOLOGY
Resource
Human and Animal Cells