title: Helicobacter pylori gamma-glutamyltranspeptidase upregulates COX-2 and EGF-related peptide expression in human gastric cells.
abstract: Gastric mucosa responds to Helicobacter pylori-induced cell damage by increasing the expression of COX-2 and EGF-related peptides. We sought to investigate the bacterial virulence factor/s and the host cellular pathways involved in the upregulation of COX-2, HB-EGF and amphiregulin in MKN 28 and AGS gastric mucosal cells. H. pylori strain CCUG 17874 was grown in Brucella broth supplemented with 0.2% (2,6-dimethyl)-beta-cyclodextrins. The soluble proteins released in the culture medium by the bacterium were fractionated by exclusion size and anion exchange chromatography. A single peak retaining the ability to upregulate COX-2 and HB-EGF mRNA and protein expression was obtained. SDS-PAGE analysis of the peak showed two peptides with an apparent molecular weight of 38 and 22 kDa, which were identified by automated Edman degradation analysis as the N-terminal and C-terminal peptides of H. pylori gamma-glutamyltranspeptidase respectively. Acivicin, a selective gamma-glutamyltranspeptidase inhibitor, counteracted H. pylori-induced upregulation of COX-2 and EGF-related peptide mRNA expression. An H. pylori isogenic mutant gamma-glutamyltranspeptidase-deficient strain did not exert any effect on COX-2, HB-EGF and amphiregulin mRNA expression. Blockade of phosphatidylinositol-3 kinase and p38 kinase, but not MAP kinase kinase, inhibited H. pylori gamma-glutamyltranspeptidase-induced upregulation of COX-2 and EGF-related peptide mRNA expression.
authors.affiliation: Dipartimento di Biologia e Patologia Cellulare e Molecolare 'L. Califano', Universitá di Napoli 'Frederico II', Napoli, Italy.
authors.forename: Immacolata
authors.initials: I
authors.lastname: Busiello
authors.forename: Renato
authors.initials: R
authors.lastname: Acquaviva
authors.forename: Anna
authors.initials: A
authors.lastname: Di Popolo
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Blanchard
authors.forename: Vittorio
authors.initials: V
authors.lastname: Ricci
authors.forename: Marco
authors.initials: M
authors.lastname: Romano
authors.forename: Raffaele
authors.initials: R
authors.lastname: Zarrilli
mesh_terms: D002460:Cell Line; D051546:Cyclooxygenase 2; D004815:Epidermal Growth Factor / Q000096:biosynthesis*; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology; D016480:Helicobacter pylori / Q000201:enzymology*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D014774:Virulence; D005723:gamma-Glutamyltransferase / Q000494:pharmacology*
chemical_list: D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D005723:gamma-Glutamyltransferase