Effect of Helicobacter pylori on ATM-dependent DNA damage responses [biopsy]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE60662 | GEO | 2014/08/23
SECONDARY ACCESSION(S): PRJNA259348
REPOSITORIES: GEO
Similar Datasets
Project description:Carcinogenic bacteria, Helicobacter pylori, induce DNA double-strand breaks in infected host cells, while ATM-dependent DNA damage responses in host cells suppress genome instabilities caused by DNA breakages, which resulting in the suppression of H. pylori-induced gastric cancers. Although Helicobacter pylori infection is etiologically related to the inflammation-related malignancy, gastric cancers, it role in the molecular pathogenesis of disease remains unclear. In vitro studies have suggested the infection may cause breaks in double-stranded DNA. We used microarray analysis of H. pylori-infected human gastric biopsies to investigate the effect of H. pylori on gene expression genes involved in DNA repair and DNA damage response. Micro-array analysis and immunohistochemistory showed that ATM (ataxia-telangiectasia mutated) was upregulated in H. pylori gastritis but down regulated in the premalignant lesion, intestinal metaplasia. Studies in gastric cancer cell lines showed that H. pylori-infection induced activation of ATM and formation of γ-H2AX. γ-H2AX formation was present following infection with bout cag pathogenicity island (PAI)- positive and negative strains but more robust with cag PAI positive strains consistent with the fact that both cag PAI positive negative strains are associated with gastric cancer but the risk is higher with cag PAI positive strains. Eradication of H. pylori infection is associated with a reduction in cancer risk even in the most high risk populations. These data provide a plausible molecular mechanism for a direct bacterial-host interaction increasing cancer risk. To identify tumor suppressors affected by H. pylori-infection, microarray screening was used to compare the gene expression profiles of gastric mucosa obtained from individuals with H. pylori-gastritis and with intestinal metaplasia with tissue from uninfected controls.
2014-08-18 | E-GEOD-47797 | biostudies-arrayexpress
Project description:Carcinogenic bacteria, Helicobacter pylori, induce DNA double-strand breaks in infected host cells, while ATM-dependent DNA damage responses in host cells suppress genome instabilities caused by DNA breakages, which resulting in the suppression of H. pylori-induced gastric cancers. Although Helicobacter pylori infection is etiologically related to the inflammation-related malignancy, gastric cancers, it role in the molecular pathogenesis of disease remains unclear. In vitro studies have suggested the infection may cause breaks in double-stranded DNA. We used microarray analysis of H. pylori-infected human gastric biopsies to investigate the effect of H. pylori on gene expression genes involved in DNA repair and DNA damage response. Micro-array analysis and immunohistochemistory showed that ATM (ataxia-telangiectasia mutated) was upregulated in H. pylori gastritis but down regulated in the premalignant lesion, intestinal metaplasia. Studies in gastric cancer cell lines showed that H. pylori-infection induced activation of ATM and formation of γ-H2AX. γ-H2AX formation was present following infection with bout cag pathogenicity island (PAI)- positive and negative strains but more robust with cag PAI positive strains consistent with the fact that both cag PAI positive negative strains are associated with gastric cancer but the risk is higher with cag PAI positive strains. Eradication of H. pylori infection is associated with a reduction in cancer risk even in the most high risk populations. These data provide a plausible molecular mechanism for a direct bacterial-host interaction increasing cancer risk. To identify tumor suppressors affected by H. pylori-infection, microarray screening was used to compare the gene expression profiles of gastric mucosa obtained from individuals with H. pylori-gastritis and with intestinal metaplasia with tissue from uninfected controls.
2014-08-23 | E-GEOD-60662 | biostudies-arrayexpress
Project description:Carcinogenic bacteria, Helicobacter pylori, induce DNA double-strand breaks in infected host cells. Therefore, we have investigated which genes are upregulated after the infection. Although Helicobacter pylori infection is etiologically related to the inflammation-related malignancy, gastric cancers, it role in the molecular pathogenesis of disease remains unclear. In vitro studies have suggested the infection may cause breaks in double-stranded DNA. We used microarray analysis of H. pylori-infected human gastric biopsies to investigate the effect of H. pylori on gene expression genes involved in DNA repair and DNA damage response. Micro-array analysis and immunohistochemistory showed that ATM (ataxia-telangiectasia mutated) was upregulated in H. pylori gastritis but down regulated in the premalignant lesion, intestinal metaplasia. Studies in gastric cancer cell lines showed that H. pylori-infection induced activation of ATM and formation of ?-H2AX. ?-H2AX formation was present following infection with bout cag pathogenicity island (PAI)- positive and negative strains but more robust with cag PAI positive strains consistent with the fact that both cag PAI positive negative strains are associated with gastric cancer but the risk is higher with cag PAI positive strains. Eradication of H. pylori infection is associated with a reduction in cancer risk even in the most high risk populations. These data provide a plausible molecular mechanism for a direct bacterial-host interaction increasing cancer risk. To identify tumor suppressors affected by H. pylori-infection, microarray screening was used to compare the gene expression profiles of AGS cells, a gastric cancer cell line, infected with various mutants of H. pylori.
2014-08-23 | E-GEOD-60661 | biostudies-arrayexpress
Project description:Carcinogenic bacteria, Helicobacter pylori, induce DNA double-strand breaks in infected host cells. Therefore, we have investigated which genes are upregulated after the infection. Although Helicobacter pylori infection is etiologically related to the inflammation-related malignancy, gastric cancers, it role in the molecular pathogenesis of disease remains unclear. In vitro studies have suggested the infection may cause breaks in double-stranded DNA. We used microarray analysis of H. pylori-infected human gastric biopsies to investigate the effect of H. pylori on gene expression genes involved in DNA repair and DNA damage response. Micro-array analysis and immunohistochemistory showed that ATM (ataxia-telangiectasia mutated) was upregulated in H. pylori gastritis but down regulated in the premalignant lesion, intestinal metaplasia. Studies in gastric cancer cell lines showed that H. pylori-infection induced activation of ATM and formation of γ-H2AX. γ-H2AX formation was present following infection with bout cag pathogenicity island (PAI)- positive and negative strains but more robust with cag PAI positive strains consistent with the fact that both cag PAI positive negative strains are associated with gastric cancer but the risk is higher with cag PAI positive strains. Eradication of H. pylori infection is associated with a reduction in cancer risk even in the most high risk populations. These data provide a plausible molecular mechanism for a direct bacterial-host interaction increasing cancer risk.
2014-08-23 | GSE60661 | GEO
Project description:We used the rhesus macaque model to study the effects of the cag pathogenicity island (cag PAI) on the H. pylori host-pathogen interaction. Specific pathogen free (SPF) monkeys with no prior exposure to H. pylori were experimentally challenged with wild type (WT) H. pylori strain J166 (N=4) or its cag PAI isogenic knockout (KO, N=4). Animals underwent endoscopy before and 1, 4, 8, and 13 wks after challenge. Gastric biopsies were collected for quantitative culture, histopathology, and host gene expression. Quantitative cultures showed that all experimentally challenged animals were infected with WT H. pylori or its isogenic cag PAI KO. Histopathology demonstrated that inflammation and expansion of the lamina propria were attenuated in animals infected with KO compared to WT. Microarray analysis was performed on challenged animals before and 1 and 13 wks after challenge, and on unchallenged control animals (N=4). Of the 119 up-regulated genes in the WT-infected animals, several encode innate antimicrobial effector proteins, including elafin, siderocalin, DMBT, DUOX2, and several novel paralogues of human defensin-2. Quantitative RT-PCR analysis showed that high level induction of each of these genes was dependent upon the presence of the cag PAI. Immunohistochemistry confirmed increased defensin epithelial cell staining in animals challenged with WT H. pylori compared to either KO-challenged or uninfected control animals. We propose that one function of the cag PAI is to induce an antimicrobial host response that serves to increase the competitive advantage of H. pylori in the gastric niche. Keywords: Transcript profiling , Wild type H. pylori, cag-PAI KO H. pylori
2008-02-01 | GSE8749 | GEO
Project description:We used the rhesus macaque model to study the effects of the cag pathogenicity island (cag PAI) on the H. pylori host-pathogen interaction. Specific pathogen free (SPF) monkeys with no prior exposure to H. pylori were experimentally challenged with wild type (WT) H. pylori strain J166 (N=4) or its cag PAI isogenic knockout (KO, N=4). Animals underwent endoscopy before and 1, 4, 8, and 13 wks after challenge. Gastric biopsies were collected for quantitative culture, histopathology, and host gene expression. Quantitative cultures showed that all experimentally challenged animals were infected with WT H. pylori or its isogenic cag PAI KO. Histopathology demonstrated that inflammation and expansion of the lamina propria were attenuated in animals infected with KO compared to WT. Microarray analysis was performed on challenged animals before and 1 and 13 wks after challenge, and on unchallenged control animals (N=4). Of the 119 up-regulated genes in the WT-infected animals, several encode innate antimicrobial; effector proteins, including elafin, siderocalin, DMBT, DUOX2, and several novel paralogues of human defensin-2. Quantitative RT-PCR analysis showed that high level induction of each of these genes was dependent upon the presence of the cag PAI. Immunohistochemistry confirmed increased defensin epithelial cell staining in animals challenged with WT H. pylori compared to either KO-challenged or uninfected control animals. We propose that one function of the cag PAI is to induce an antimicrobial host response that serves to increase the competitive advantage of H. pylori in the gastric niche. Experiment Overall Design: Twelve male and female rhesus macaques (Macaca mulatta) housed at the California National Primate Research Center (CNPRC) were hand raised by nursery staff to obtain Specific Pathogen (Helicobacter pylori) Free (SPF) experimental animals. At six months of age the animals were documented to be uninfected with H. pylori by serology, histology, and cultures of gastric biopsies using methods reported previously (Solnick et al., 1999). Two experimental groups of four SPF animals were challenged with either wild type (WT) H. pylori J166 or an isogenic PAI knockout (KO). A third group of four SPF animals served as uninoculated controls. Monkeys were housed indoors in separate cages throughout the duration of the experiment. All experiments were approved by the Research Advisory Committee of the CNPRC and the Institutional Animal Care and Use Committee at the University of California.Antrum and corpus stomach biopsies from rhesus macaques infected with wild type Helicobacter pylori J166, isogenic cag-PAI knockout strain, or mock infected were pooled. Biopsies were taken prior to bacterial inoculation and at 1 and 13 weeks post infection. Control biopsies were taken according to the same time line. Four animals were used for each experimental condition.
2008-06-16 | E-GEOD-8749 | biostudies-arrayexpress
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.
2005-06-30 | E-SMDB-1587 | biostudies-arrayexpress
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.
2010-11-13 | GSE21833 | GEO
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
2005-08-16 | E-GEOD-3135 | biostudies-arrayexpress
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-)
2010-11-13 | E-GEOD-21833 | biostudies-arrayexpress