Project description:Gram negative bacteria release outer membrane vesicles (OMVs) as part of their natural growth. These OMVs take part in a biological functions including bacterial communication, exchange of genetic material and bacterial pathogenesis. However, the relationship between bacterial growth stage and OMV protein composition has not been explored before nor how their proteome is different to their parent bacterium. In this study, we examined the proteome of Helicobacter pylori and its OMVs from early log, late log or stationary phase of growth and found that globally, the protein content of OMVs over time is vastly different to one another as well as to their parent bacterium. OMVs purified from early log phase of growth contained the greatest number of unique proteins and a significant upregulation of virulence and pathogenic proteins. However, when compared back to their parent bacterium, OMVs from later stages of growth contained more unique proteins than those from earlier stages of growth. We show for the first time the regulation of OMV protein composition by H. pylori that is dependent on bacterial growth stage. Our results have expanded our understanding of the fundamental production of OMVs and the selective packaging of cargo in OMVs that result in specific functions.
Project description:The genome of the gastric pathogen Helicobacter pylori harbors a remarkably low number of regulatory genes, including three and five open reading frames encoding two-component histidine kinases and response regulators, respectively, which are putatively involved in transcriptional regulation. Inactivation of the response regulator gene hp1021 resulted in a severe growth defect, as indicated by a small-colony phenotype. Recently we found that phosphorylation of the receiver domain HP1021 is not needed for its response regulator function and may not occur at all. No target genes have been identified so far. In this study we define the HP1021-dependent regulon consisting of 79 genes (51 activated, 28 repressed) by global transcriptional profiling of an HP1021-deficient H. pylori mutant. Keywords: Identification of an HP1021-Regulon
Project description:Helicobacter pylori (H. pylori) is a human pathogen that infects almost half of the world’s population. Infection with H. pylori is frequently associated with chronic gastritis and can even lead to gastric and duodenal ulcers and gastric cancer. Although the persistent colonization of H. pylori and the development of H. pylori-associated gastritis remain poorly understood, it is believed that, in gastric mucosa, the modulated gastric epithelial cells (GECs) by H. pylori are key contributors. We used microarrays to detail the global programme of gene expression in Helicobacter pylori infected-gastric epithelial cell line AGS cells and identified up-regulated genes induced by Helicobacter pylori infection.
Project description:This SuperSeries is composed of the following subset Series: GSE25146: Changes in gene expression in AGS cells in response to Helicobacter pylori lipopolysaccharide GSE25147: Changes in gene expression in MKN45 cells in response to Helicobacter pylori lipopolysaccharide GSE25148: Changes in gene expression in HEK-TLR2 cells in response to Helicobacter pylori lipopolysaccharide Refer to individual Series
Project description:Helicobacter pylori genome is rich in restriction - modification (R-M) systems. Around 4 % of the genome codes for components of R-M systems. hpyAVIBM, which codes for a putative phase-variable C5 - cytosine methyltransferase (MTase) from H. pylori lacks a cognate restriction enzyme.
Project description:Helicobacter pylori infection reprograms host gene expression and influences various cellular processes, which have been investigated by cDNA microarray in vitro culture cells and in vivo patients of the chronic abdominal complaint. In this study,the effects of H. pylori infection on host gene expression in the gastric antral mucosa of patients with chronic gastritis were examined.
Project description:Helicobacter pylori γ-glutamyltransferase (gGT) is a conserved virulence factor promoting bacterial colonization and immune tolerance. Although some studies addressed potential mechanisms explaining its function, the supportive role of gGT for in-vivo colonization remains unclear. In addition, it is unknown how differences in gGT expression observed for different strains may lead to compensatory mechanisms to ensure infection and persistence. Hence, it is of high importance to understand more profoundly the in-vivo function of this enzyme. In this study, we assessed acid survival under physiologic conditions mimicking the human gastric fluid and elevated the pH in the murine stomach prior to H. pylori infection to link gGT-mediated acid resistance to colonization. Furthermore, by comparing protein expression levels between wildtype and gGT-deficient H. pylori isolates before and after infecting mice, we systematically investigated proteomic adaptations of gGT-deficient bacteria during infection. Our data indicate that gGT plays a crucial role in sustaining urease activity in acidic environments, thereby supporting bacterial survival and successful colonization. The absence of gGT triggers the expression of proteins involved in nitrogen and iron metabolism, indicating a potential functional role of gGT in these metabolic pathways. Moreover, we observed an impaired growth of gGT-deficient strains in iron-restricted medium. In addition, the absence of gGT during infection leads to a significant overexpression of H. pylori adhesins and flagellar proteins, resulting in increased motility and adhesion capacity. In summary, we identified gGT-dependent mechanisms conferring a growth advantage to the bacterium in the gastric environment, which renders gGT a valuable target for the development of new treatments against H. pylori infection.
Project description:Helicobacter pylori genome is rich in restriction - modification (R-M) systems. Around 4 % of the genome codes for components of R-M systems. hpyAVIBM, which codes for a putative phase-variable C5 - cytosine methyltransferase (MTase) from H. pylori lacks a cognate restriction enzyme. To analysis the effect of deleting hpyAVIBM on the Helicobacter pylori transcriptome, microarray analysis was done with the wild type strains and corresponding hpyAVIBM deletion strains
Project description:Helicobacter pylori causes chronic gastritis and avoids elimination by the immune system of the infected host. The commensal bacterium Lactobacillus acidophilus has been reported to exert beneficial effects as a supplement during H. pylori eradication therapy. In the present study, we applied whole genome microarray analysis to compare the immune response induced in murine bone marrow derived macrophages (BMDM) stimulated with L. acidophilus, H. pylori, or with both bacteria in combination Microarray expression profiling was performed to analyze stimulation of bone marrow derived macrophages with Helicobacter pylori 251, Lactobacillus acidophilus NCFM or Lactobacillus acidophilus NCFM co-stimulated with Helicobacter pylori 251 were analyzed 5 hours after infection.
Project description:The human gastric pathogen Helicobacter pylori is extremely well adapted to the highly acidic conditions encountered in the stomach. The pronounced acid resistance of H. pylori relies mainly on the ammonia-producing enzyme urease, however, urease-independent mechanisms are likely to contribute to acid adaptation. Acid-responsive gene regulation is mediated at least in part by the ArsRS two-component system consisting of the essential OmpR-like response regulator ArsR and the non-essential cognate histidine kinase ArsS whose autophosphorylation is triggered in response to low pH. In this study by global transcriptional profiling of an ArsS-deficient H. pylori mutant grown at pH 5.0 we define the ArsR~P- dependent regulon consisting of 110 genes including the urease gene cluster, the genes encoding the aliphatic amidases AmiE and AmiF and the rocF gene encoding arginase. Keywords: Identification of an ArsRS-Regulon