title: Helicobacter pylori infection: host immune response, implications on gene expression and microRNAs.
abstract: Helicobacter pylori (H. pylori) infection is the most common bacterial infection worldwide. Persistent infection of the gastric mucosa leads to inflammatory processes and may remain silent for decades or progress causing more severe diseases, such as gastric adenocarcinoma. The clinical consequences of H. pylori infection are determined by multiple factors, including host genetic predisposition, gene regulation, environmental factors and heterogeneity of H. pylori virulence factors. After decades of studies of this successful relationship between pathogen and human host, various mechanisms have been elucidated. In this review, we have made an introduction on H. pylori infection and its virulence factors, and focused mainly on modulation of host immune response triggered by bacteria, changes in the pattern of gene expression in H. pylori-infected gastric mucosa, with activation of gene transcription involved in defense mechanisms, inflammatory and immunological response, cell proliferation and apoptosis. We also highlighted the role of bacteria eradication on gene expression levels. In addition, we addressed the recent involvement of different microRNAs in precancerous lesions, gastric cancer, and inflammatory processes induced by bacteria. New discoveries in this field may allow a better understanding of the role of major factors involved in the pathogenic mechanisms of H. pylori.
authors.affiliation: Aline Cristina Targa Cadamuro, Ana Flávia Teixeira Rossi, Nathália Maciel Maniezzo, Ana Elizabete Silva, Department of Biology, UNESP-São Paulo State University, Campus São José do Rio Preto, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Aline Cristina Targa
authors.initials: AC
authors.lastname: Cadamuro
authors.affiliation: Aline Cristina Targa Cadamuro, Ana Flávia Teixeira Rossi, Nathália Maciel Maniezzo, Ana Elizabete Silva, Department of Biology, UNESP-São Paulo State University, Campus São José do Rio Preto, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Ana Flávia Teixeira
authors.initials: AF
authors.lastname: Rossi
authors.affiliation: Aline Cristina Targa Cadamuro, Ana Flávia Teixeira Rossi, Nathália Maciel Maniezzo, Ana Elizabete Silva, Department of Biology, UNESP-São Paulo State University, Campus São José do Rio Preto, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Nathália Maciel
authors.initials: NM
authors.lastname: Maniezzo
authors.affiliation: Aline Cristina Targa Cadamuro, Ana Flávia Teixeira Rossi, Nathália Maciel Maniezzo, Ana Elizabete Silva, Department of Biology, UNESP-São Paulo State University, Campus São José do Rio Preto, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Ana Elizabete
authors.initials: AE
authors.lastname: Silva
mesh_terms: D017209:Apoptosis; D005753:Gastric Mucosa / Q000382:microbiology; D015870:Gene Expression; D016481:Helicobacter Infections / Q000276:immunology* / Q000382:microbiology*; D016480:Helicobacter pylori / Q000472:pathogenicity; D054884:Host-Pathogen Interactions; D006801:Humans; D007107:Immune System; D007249:Inflammation / Q000382:microbiology; D035683:MicroRNAs / Q000378:metabolism*; D012307:Risk Factors; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000382:microbiology; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D035683:MicroRNAs; D037521:Virulence Factors
keywords: Gastric cancer; Gastric lesions; Gene expression; Helicobacter pylori; Immune response; Inflammation; MicroRNAs; Virulence factors