title: Helicobacter pylori gamma-glutamyl transpeptidase and its pathogenic role.
abstract: Helicobacter pylori (H. pylori) gamma-glutamyl transpeptidase (GGT) is a bacterial virulence factor that converts glutamine into glutamate and ammonia, and converts glutathione into glutamate and cysteinylglycine. H. pylori GGT causes glutamine and glutathione consumption in the host cells, ammonia production and reactive oxygen species generation. These products induce cell-cycle arrest, apoptosis, and necrosis in gastric epithelial cells. H. pylori GGT may also inhibit apoptosis and induce gastric epithelial cell proliferation through the induction of cyclooxygenase-2, epidermal growth factor-related peptides, inducible nitric oxide synthase and interleukin-8. H. pylori GGT induces immune tolerance through the inhibition of T cell-mediated immunity and dendritic cell differentiation. The effect of GGT on H. pylori colonization and gastric persistence are also discussed.
authors.affiliation: Vittorio Ricci, Department of Molecular Medicine, Human Physiology Section, University of Pavia Medical School, 27100 Pavia, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Ricci
authors.affiliation: Vittorio Ricci, Department of Molecular Medicine, Human Physiology Section, University of Pavia Medical School, 27100 Pavia, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Giannouli
authors.affiliation: Vittorio Ricci, Department of Molecular Medicine, Human Physiology Section, University of Pavia Medical School, 27100 Pavia, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Romano
authors.affiliation: Vittorio Ricci, Department of Molecular Medicine, Human Physiology Section, University of Pavia Medical School, 27100 Pavia, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Zarrilli
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D005753:Gastric Mucosa / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D005756:Gastritis / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D016481:Helicobacter Infections / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D016480:Helicobacter pylori / Q000201:enzymology* / Q000276:immunology / Q000472:pathogenicity; D006801:Humans; D007111:Immunity, Cellular; D018928:Immunity, Mucosal; D013601:T-Lymphocytes / Q000276:immunology / Q000382:microbiology; D037521:Virulence Factors / Q000378:metabolism; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors; D005723:gamma-Glutamyltransferase
keywords: Bacterial virulence factor; Gamma-glutamyl transpeptidase; Gastric epithelial cell damage; Helicobacter pylori; T cell-mediated immunity