Project description:We performed both transcriptomic and proteomic analyses on gastric cancer cells infected by H. pylori isolates from GML patients and the gastric ulcer strain 26695 to investigate the differentially expressed molecular signatures that were induced by GML isolates. Transcriptomicd analysis revealed fifteen pathways, including the Wnt signaling pathway, the mTOR signaling pathway, the NOD-like receptor signaling pathway and the Hippo signaling pathway, were revealed to be related to GML isolates.
Project description:Helicobacter pylori enhances the risk for ulcer disease and gastric cancer, yet only a minority of H. pylori-colonized individuals develop disease. We examined the ability of two H. pylori isolates to induce differential host responses in vivo or in vitro, and then used an H. pylori whole genome microarray to identify bacterial determinants related to pathogenesis. Gastric ulcer strain B128 induced more severe gastritis, proliferation, and apoptosis in gerbil mucosa than did duodenal ulcer strain G1.1, and gastric ulceration and atrophy occurred only in B128+ gerbils. In vitro, gerbil-passaged B128 derivatives significantly increased IL-8 secretion and apoptosis compared with G1.1 strains. DNA hybridization to the microarray identified several strain-specific differences in gene composition including a large deletion of the cag pathogenicity island in strain G1.1. Partial and complete disruption of the cag island in strain B128 attenuated induction of IL-8 in vitro and significantly decreased gastric inflammation in vivo. These results indicate that the ability of H. pylori to regulate epithelial cell responses related to inflammation depends on the presence of an intact cag pathogenicity island. Use of an H pylori whole genome microarray is an effective method to identify differences in gene content between H. pylori strains that induce distinct pathological outcomes in a rodent model of H. pylori infection. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
Project description:Chronic infection of the human stomach with Helicobacter pylori leads to a variety of pathologic sequelae including peptic ulcer and gastric cancer, resulting in significant human morbidity and mortality. Several genes have been implicated in disease related to H. pylori infection including the vacuolating cytotoxin and the cag pathogenicity island. Other factors important for establishment and maintenance of infection include urease enzyme production, motility, iron uptake and stress response. We utilized a C57BL/6 mouse infection model to query a collection of 2400 transposon mutants in two different bacterial strain backgrounds for H. pylori genetic loci contributing to colonization of the stomach. Microarray based tracking of transposon mutants allowed us to monitor the behavior of transposon insertions in 758 different gene loci. Of the loci measured 223 (29%) had a predicted colonization defect. These include previously described H. pylori virulence genes, genes implicated in virulence in other pathogenic bacteria and 81 hypothetical proteins. We have retested 10 previously uncharacterized candidate colonization gene loci by making independent null alleles and confirmed their colonization phenotype using competition experiments and determination of the dose required for 50% infection. Of the genetic loci retested, 60% have strain specific colonization defects while 40% had phenotypes in both strain backgrounds for infection, highlighting the profound effect of H. pylori strain variation on the pathogenic potential of this organism. This SuperSeries is composed of the SubSeries listed below.
Project description:Helicobacter pylori enhances the risk for ulcer disease and gastric cancer, yet only a minority of H. pylori-colonized individuals develop disease. We examined the ability of two H. pylori isolates to induce differential host responses in vivo or in vitro, and then used an H. pylori whole genome microarray to identify bacterial determinants related to pathogenesis. Gastric ulcer strain B128 induced more severe gastritis, proliferation, and apoptosis in gerbil mucosa than did duodenal ulcer strain G1.1, and gastric ulceration and atrophy occurred only in B128+ gerbils. In vitro, gerbil-passaged B128 derivatives significantly increased IL-8 secretion and apoptosis compared with G1.1 strains. DNA hybridization to the microarray identified several strain-specific differences in gene composition including a large deletion of the cag pathogenicity island in strain G1.1. Partial and complete disruption of the cag island in strain B128 attenuated induction of IL-8 in vitro and significantly decreased gastric inflammation in vivo. These results indicate that the ability of H. pylori to regulate epithelial cell responses related to inflammation depends on the presence of an intact cag pathogenicity island. Use of an H pylori whole genome microarray is an effective method to identify differences in gene content between H. pylori strains that induce distinct pathological outcomes in a rodent model of H. pylori infection. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
Project description:Helicobacter pylori is a highly successful and important human pathogen that causes chronic gastritis, peptic ulcer diseases and gastric cancer. Innate immunity plays an important role of the primary defense against pathogens and epidemiological studies have suggested a role of toll-like receptor 1 (TLR1) in the risk of H. pylori acquisition. We performed microarray analysis of gastric mucosal biopsy specimens from H. pylori-positive and uninfected subjects; infection was associated with an ~15-fold up-regulation of TLR10 (p <0.001). Quantitative RT-PCR confirmed TLR10 mRNA levels were increased 3-fold in H. pylori-infection (p <0.001) and immunohistochemistory using anti-TLR10 polyclonal antibodies showed increased TLR10 expression in gastric epithelial cells of infected individuals. In vitro experiments where H. pylori was co-cultured with NCI-N87 gastric cells showed significant H. pylori-specific up-regulation of TLR10 mRNA levels and a correlation with TLR2 mRNA levels (R = 0.87, P <0.001). We compared combinations of TLRs for their ability to mediate NF-_B activation. NF-_B activation was increased following exposure to heat killed H. pylori or H. pylori-LPS only with the TLR2/TLR10 heterodimer. These findings suggest TLR10 is a functional receptor involved in the innate immune response to H. pylori infection and that TLR2/TLR10 heterodimer possibly functions in the recognition of H. pylori-LPS.
Project description:Background: Helicobacter pylori has been shown to alter the secretion of gastric hormones that modulate body fat deposition. Since cag-positive H. pylori strains interact intimately with the host gastric epithelial cells and trigger higher inflammation than cag-negative strains, we hypothesized that gastric colonization with H. pylori strains without functional cagA ameliorates obesity and its complications by modulating gastric gene expression and inflammation. Methodology/Principal Findings: To test this hypothesis we examined the effects of gastric colonization on metabolic and inflammatory markers in mice infected with two isogenic strains of H. pylori: 26695 strain 98-325 (cagA+ wild-type) and its cag pathogenicity island (cagPAI) mutant strain 99-305, a knockout made by inserting a chloramphenicol resistance cassette. Only the cagPAI mutant decreased fasting blood glucose levels, improved glucose tolerance and suppressed weight gain in db/db mice and mice with diet-induced obesity. These effects were associated with increased gastric leptin levels, suppressed infiltration of macrophages, enhanced influx of regulatory T cells (Treg) in adipose tissue and suppressed gastric inflammation. Gene set enrichment analyses of gastric mucosal samples identified six differentially modulated pathways, including the Hedgehog signaling pathway that is associated with control of cellular proliferation and gastric carcinogenesis as well as the insulin signaling pathway. Conclusions/Significance: Gastric colonization with cagPAI-negative strains of H. pylori ameliorate obesity and inflammation by modulating gastric gene expression, suggesting that cag-negative H. pylori strains might be beneficial in ameliorating obesity and its co-morbidities.
Project description:Despite the high prevalence of gastric diseases like gastric cancer and peptic ulcer disease, largely attributed to Helicobacter pylori infections, an understanding of the underlying mechanisms remains limited. Current in vitro models suffer from poor physiological relevance and limitations in live, long-term observations and experimental access. In this study, we introduce a homeostatic human gastric organoid-on-a-chip system with bilateral access, capable of modelling H. pylori niche establishment and persistent colonization of the gastric epithelium.We show that in physiological apical acidic conditions, the model is able to generate mature pit cells, which are absent in traditionally grown organoids. Upon infection with H. pylori for up to 6 days, these mature pit cells exhibit a distinctive response, contrary to existing paradigms. Beyond its immediate relevance for studying H. pylori infection, this model with structurally and functionally increased relevance holds broader significance by providing a versatile platform to advance our understanding of gastric epithelial cell interactions as well as gastric mucosal immunity and host-pathogen interactions.
Project description:Background: Helicobacter pylori has been shown to alter the secretion of gastric hormones that modulate body fat deposition. Since cag-positive H. pylori strains interact intimately with the host gastric epithelial cells and trigger higher inflammation than cag-negative strains, we hypothesized that gastric colonization with H. pylori strains without functional cagA ameliorates obesity and its complications by modulating gastric gene expression and inflammation. Methodology/Principal Findings: To test this hypothesis we examined the effects of gastric colonization on metabolic and inflammatory markers in mice infected with two isogenic strains of H. pylori: 26695 strain 98-325 (cagA+ wild-type) and its cag pathogenicity island (cagPAI) mutant strain 99-305, a knockout made by inserting a chloramphenicol resistance cassette. Only the cagPAI mutant decreased fasting blood glucose levels, improved glucose tolerance and suppressed weight gain in db/db mice and mice with diet-induced obesity. These effects were associated with increased gastric leptin levels, suppressed infiltration of macrophages, enhanced influx of regulatory T cells (Treg) in adipose tissue and suppressed gastric inflammation. Gene set enrichment analyses of gastric mucosal samples identified six differentially modulated pathways, including the Hedgehog signaling pathway that is associated with control of cellular proliferation and gastric carcinogenesis as well as the insulin signaling pathway. Conclusions/Significance: Gastric colonization with cagPAI-negative strains of H. pylori ameliorate obesity and inflammation by modulating gastric gene expression, suggesting that cag-negative H. pylori strains might be beneficial in ameliorating obesity and its co-morbidities. Gastric mucosa from three groups of mice: uninfected, infected with H. pylori 26695 strain 98-325 (cagA+ wild-type) or infected with H. pylori mutant strain 99-305 (lacking cag pathogenicity island; cagA-)