GI highlights from the literature

Basic scienceHelicobacter pylori infection evades gastric acidity Bugaytsova JA, Björnham O, Chernov YA, et al. Helicobacter pylori adapts to chronic infection and gastric disease via pH-responsive BabA-mediated adherence. Cell Host Microbe 2017;21:376–389. Helicobacter pylori (HP) infects billions of people worldwide and is linked to both peptic ulcer disease and gastric cancer. HP colonises the gastric epithelium and its overlying mucus and is partially protected against luminal acidity by epithelial secretions, intrinsic urease production and chemotaxis. In addition, tight adherence to mucosal glycan receptors assists in protection from luminal acidity. Bacterial attachment to these receptors is mediated by adhesins (attachment proteins) including BabA, which binds with high affinity to ABO/Leb blood group antigens to persist in the stomach mucosa. A multiauthor study by Bugaytsova and colleagues has shown that BabA-mediated HP adherence is acid sensitive, fully reversed when acidity is decreased. This is controlled by BabA adhesin protein's...
Source: Gut - Category: Gastroenterology Authors: Tags: JournalScan Source Type: research

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Authors: Zhang F, Chen C, Hu J, Su R, Zhang J, Han Z, Chen H, Li Y Abstract Helicobacter pylori (H. pylori) is a gram-negative pathogen that colonizes gastric epithelial cells. The drug resistance rates of H. pylori have dramatically increased, causing persistent infections. Chronic infection by H. pylori is a critical cause of gastritis, peptic ulcers and even gastric cancer. In host cells, autophagy is stimulated to maintain cellular homeostasis following intracellular pathogen recognition by the innate immune defense system. However, H. pylori-induced autophagy is not consistent during acute and chronic infectio...
Source: Oncology Letters - Category: Cancer & Oncology Tags: Oncol Lett Source Type: research
This study could provide usher in a new opportunity to understand the role of less studied gastric bacteria in the development of gastric diseases.
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research
man M Abstract Helicobacter pylori (H. pylori) is one of the most important human pathogens, infecting approximately half of the global population. Despite its high prevalence, only a subset of H. pylori infected individuals develop serious gastroduodenal pathology. The pathogenesis of H. pylori infection and disease outcome is thus thought to be mediated by an intricate interplay between host, environmental and bacterial virulence factors. H. pylori has adapted to the harsh milieu of the human stomach through possession of various virulence genes that enable survival of the bacteria in the acidic environment, mov...
Source: World Journal of Gastroenterology - Category: Gastroenterology Authors: Tags: World J Gastroenterol Source Type: research
Authors: Reyes VE, Peniche AG Abstract Helicobacter pylori is a prevalent human pathogen that successfully establishes chronic infection, which leads to clinically significant gastric diseases including chronic gastritis, peptic ulcer disease (PUD), and gastric cancer (GC). H. pylori is able to produce a persistent infection due in large part to its ability to hijack the host immune response. The host adaptive immune response is activated to strategically and specifically attack pathogens and normally clears them from the infected host. Since B and T lymphocytes are central mediators of adaptive immunity, in this c...
Source: Current Topics in Microbiology and Immunology - Category: Microbiology Tags: Curr Top Microbiol Immunol Source Type: research
Authors: Ying L, Ferrero RL Abstract The human pathogen Helicobacter pylori interacts intimately with gastric epithelial cells to induce inflammatory responses that are a hallmark of the infection. This inflammation is a critical precursor to the development of peptic ulcer disease and gastric cancer. A major driver of this inflammation is a type IV secretion system (T4SS) encoded by the cag pathogenicity island (cagPAI), present in a subpopulation of more virulent H. pylori strains. The cagPAI T4SS specifically activates signalling pathways in gastric epithelial cells that converge on the transcription factor, nuc...
Source: Current Topics in Microbiology and Immunology - Category: Microbiology Tags: Curr Top Microbiol Immunol Source Type: research
Authors: Rudnicka K, Backert S, Chmiela M Abstract Helicobacter pylori infection is associated with the development of a chronic inflammatory response, which may induce peptic ulcers, gastric cancer (GC), and mucosa-associated lymphoid tissue (MALT) lymphoma. Chronic H. pylori infection promotes the genetic instability of gastric epithelial cells and interferes with the DNA repair systems in host cells. Colonization of the stomach with H. pylori is an important cause of non-cardia GC and gastric MALT lymphoma. The reduction of GC development in patients who underwent anti-H. pylori eradication schemes has also been...
Source: Current Topics in Microbiology and Immunology - Category: Microbiology Tags: Curr Top Microbiol Immunol Source Type: research
by Connie Fung, Shumin Tan, Mifuyu Nakajima, Emma C. Skoog, Luis Fernando Camarillo-Guerrero, Jessica A. Klein, Trevor D. Lawley, Jay V. Solnick, Tadashi Fukami, Manuel R. Amieva Lifelong infection of the gastric mucosa byHelicobacter pylori can lead to peptic ulcers and gastric cancer. However, how the bacteria maintain chronic colonization in the face of constant mucus and epithelial cell turnover in the stomach is unclear. Here, we present a new model of howH.pylori establish and persist in stomach, which involves the colonization of a specialized microenvironment, or microniche, deep in the gastric glands. Using quant...
Source: PLoS Biology: Archived Table of Contents - Category: Biology Authors: Source Type: research
Cosmeri Rizzato1, Javier Torres2, Elena Kasamatsu3, Margarita Camorlinga-Ponce2, Maria Mercedes Bravo4, Federico Canzian5 and Ikuko Kato6* 1Department of Translation Research and of New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy 2Unidad de Investigación en Enfermedades Infecciosas, Unidades Médicas de Alta Especialidad Pediatría, Instituto Mexicano del Seguro Social, Mexico City, Mexico 3Instituto de Investigaciones en Ciencias de la Salud, National University of Asunción, Asunción, Paraguay 4Grupo de Investigación en Biología del C&aacut...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
Poshmaal Dhar1 and Julie McAuley2* 1Faculty of Health, School of Medicine, Deakin University, Geelong, VIC, Australia 2Department of Microbiology and Immunology, Peter Doherty Institute, University of Melbourne, Melbourne, VIC, Australia The family of cell surface (cs-) mucins are constitutively expressed at the cell surface by nearly all epithelial cells, beneath the gel-mucin layer. All cs-mucin family members have structural features that enable them to act as a releasable decoy barrier to mucosal pathogens, by providing ligands for pathogen binding and the ability to shed the bound extracellular domain. Due ...
Source: Frontiers in cellular and infection microbiology - Category: Microbiology Source Type: research
Helicobacter pylori VacA is a secreted pore-forming toxin that induces cell vacuolation in vitro and contributes to the pathogenesis of gastric cancer and peptic ulcer disease. We observed that purified VacA has relatively little effect on the viability of AGS gastric epithelial cells, but the presence of exogenous weak bases such as ammonium chloride (NH4Cl) enhances the susceptibility of these cells to VacA-induced vacuolation and cell death. Therefore, we tested the hypothesis that NH4Cl augments VacA toxicity by altering the intracellular trafficking of VacA or inhibiting intracellular VacA degradation. We observed Vac...
Source: Infection and Immunity - Category: Infectious Diseases Authors: Tags: Cellular Microbiology: Pathogen-Host Cell Molecular Interactions Source Type: research
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