CagA-specific gastric CD8+ tissue-resident T cells control Helicobacter pylori during the early infection phase
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE216894 | GEO | 2022/12/17
REPOSITORIES: GEO
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Project description:Helicobacter pylori infection promotes chronic inflammation and plethora of DNA damages including strand breaks, base alterations, point mutations, microsatellite instability and epigenetic alterations. The gastric epitheliaI cells, in order to prevent genomic instability, require an integrous DNA damage repair (DDR) machinery which, however, has been reported to be modulated by the infection. CagA is a major Hp virulence factor that deregulates host cell functions such as proliferation, apoptosis and chromosomal integrity. Its pathogenic activity is partly regulated by tyrosine phosphorylation on repeated EPIYA-motifs. Our aim was to identify putative effects of H. pylori infection and CagA protein on DDR machinery, investigating the transcriptome of AGS cells, infected with P12 H. pylori wild-type strain, as well as, its corresponding CagA knock-out and the CagA phosphorylation-defective mutant following tyrosine (EPIYA) substitution by phenylalanine (EPIFA) in the EPIYA-C motifs. Upon RNA-Sequencing on polyA-selected transcripts we performed Differential Expression Analysis, Pathway Enrichment Analysis and visualization on KEGG Pathway Maps per DDR mechanism. Key DDR components that were observed to be downregulated in a CagA-related manner were validated via Western Blot utilizing AGS and the non-cancerous GES1 cell lines. Transcriptome analysis revealed that a notable number of DDR genes were downregulated during H. pylori infection resulting to potential modulation of Base Excision Repair, Mismatch Repair and a more intricate deregulation of Nucleotide Excision Repair, Homologous Recombination and Non-Homologous End-Joining. CagA contributes to MUTYH, FEN1, APE1, POLD1 and LIG1 downregulation and those observations were verified on the protein expression level, with the exception of APE1 that was on contrary observed to be upregulated. Our study accentuates the role of CagA, as a significant contributor of the H. pylori infection-mediated DDR modulation, disrupting the balance between DNA damage introduction and repair thus favoring genomic instability and potentially contributing to gastric carcinogenesis.
2020-12-17 | GSE162056 | GEO
Project description:The proteins from the Fanconi Anemia (FA) pathway of DNA repair maintain DNA replication fork integrity by preventing the unscheduled degradation of nascent DNA at regions of stalled replication forks. Here, we ask if the bacterial pathogen H. pylori exploits the fork stabilisation machinery to generate double stand breaks (DSBs) and genomic instability. Specifically, we study if the H. pylori virulence factor CagA generates host genomic DSBs through replication fork destabilisation and collapse. An inducible gastric cancer model was used to examine global CagA-dependent transcriptomic and proteomic alterations, using RNA sequencing and SILAC-based mass spectrometry, respectively. The transcriptional alterations were confirmed in gastric cancer cell lines infected with H. pylori. Functional analysis was performed using chromatin fractionation, pulsed-field gel electrophoresis (PFGE), and single molecule DNA replication/repair fiber assays. We found a core set of 31 DNA repair factors including the FA genes FANCI, FANCD2, BRCA1, and BRCA2 that were downregulated following CagA expression. H. pylori infection of gastric cancer cell lines showed downregulation of the aforementioned FA genes in a CagA-dependent manner. Consistent with FA pathway downregulation, chromatin purification studies revealed impaired levels of Rad51 but higher recruitment of the nuclease MRE11 on the chromatin of CagA-expressing cells, suggesting impaired fork protection. In line with the above data, fibre assays revealed higher fork degradation, lower fork speed, daughter strands gap accumulation, and impaired re-start of replication forks in the presence of CagA, indicating compromised genome stability. By downregulating the expression of key DNA repair genes such as FANCI, FANCD2, BRCA1, and BRCA2, H. pylori CagA compromises host replication fork stability and induces DNA DSBs through fork collapse. These data unveil an intriguing example of a bacterial virulence factor that induces genomic instability by interfering with the host replication fork stabilisation machinery.
2022-02-22 | PXD031168 | Pride
Project description:H. pylori infection of human gastric epithelial cells (GEC) represses H,K-ATPase alpha subunit (HK-alpha) gene transcription through NF-Kappa B p50 homodimer binding to HK-alpha promoter. The bacterial cagA and slt gene products have been implicated in HK-alpha repression, which facilitates gastric H. pylori colonization and may underlie transient clinical hypochlorhydria. We hypothesized that H. pylori also regulates H,K-ATPase expression post-transcriptionally by micro-RNA interaction with HK-alpha mRNA. Our microarray experiment examined the effect of infection by wildtype H. pylori infection or a delta-cagA H. pylori mutant on miRNA expression of human gastric cells (AGS). Our results indicate that H. pylori infection up-regulates GEC miRNAs that target the HK-alpha 3' UTR and block translation, and that CagA activity is implicated in the miRNA up-regulation.
2016-01-18 | GSE51306 | GEO
Project description:H. pylori infection of human gastric epithelial cells (GEC) represses H,K-ATPase alpha subunit (HK-alpha) gene transcription through NF-Kappa B p50 homodimer binding to HK-alpha promoter. The bacterial cagA and slt gene products have been implicated in HK-alpha repression, which facilitates gastric H. pylori colonization and may underlie transient clinical hypochlorhydria. We hypothesized that H. pylori also regulates H,K-ATPase expression post-transcriptionally by micro-RNA interaction with HK-alpha mRNA. Our microarray experiment examined the effect of infection by wildtype H. pylori infection or a delta-cagA H. pylori mutant on miRNA expression of human gastric cells (AGS). Our results indicate that H. pylori infection up-regulates GEC miRNAs that target the HK-alpha 3' UTR and block translation, and that CagA activity is implicated in the miRNA up-regulation. Three types of samples were generated for microarray analysis: 1) AGS cells infected with wildtype H. pylori; 2) AGS cells infected with cagA-deficient H. pylori; 3) a mock-infected sample, prepared as a control by combining total RNA from uninfected AGS cells with total RNA from wildtype H. pylori, with relative eukaryotic and prokaryotic RNA amounts matching those observed in infected samples, based on proportional ribosomal peak heights quantified by Bioanalyzer. Three experimental replicates were generated for each type of treatment.
2016-01-18 | E-GEOD-51306 | biostudies-arrayexpress
Project description:H. pylori virulence factors have been suggested to be important in determining the outcome of infection. The H. pylori adhesion protein BabA2 is thought to play an crucial role in bacterial colonization and in induction of a severe gastric inflammation, particularly in combination with expression of CagA and VacA. However, the influence of these virulence factors on the pathogenesis of H. pylori infection, is still poorly understood. To address this question, the inflammatory gene expression profiles from two groups of patients infected with triple-negative strains (lacking expression of CagA, BabA2 and VacAs1, but expressing VacAs2) and triple-positive strains (expressing CagA, VacAs1 and BabA2, but lacking expression of VacAs2) were investigated. The gene expression pattern in the antrum gastric mucosa from patients infected with different H. pylori strains was very similar, and no differentially expressed genes could be identified by pair-wise comparisons. Our data thus suggest a lack of correlation between the host inflammatory responses in the gastric mucosa and expression of the BabA2, CagA and VacAs1 genes. Two groups of patients who infected with double-positive strains (type I strains, expressing CagA and VacAs1 genes) and triple-negative strains (lacking the CagA, BabA2 and VacAs1, but expressing VacAs2) were investigated in this study.
2008-05-01 | E-GEOD-6143 | biostudies-arrayexpress
Project description:H. pylori virulence factors have been suggested to be important in determining the outcome of infection. The H. pylori adhesion protein BabA2 is thought to play an crucial role in bacterial colonization and in induction of a severe gastric inflammation, particularly in combination with expression of CagA and VacA. However, the influence of these virulence factors on the pathogenesis of H. pylori infection, is still poorly understood. To address this question, the inflammatory gene expression profiles from two groups of patients infected with triple-negative strains (lacking expression of CagA, BabA2 and VacAs1, but expressing VacAs2) and triple-positive strains (expressing CagA, VacAs1 and BabA2, but lacking expression of VacAs2) were investigated. The gene expression pattern in the antrum gastric mucosa from patients infected with different H. pylori strains was very similar, and no differentially expressed genes could be identified by pair-wise comparisons. Our data thus suggest a lack of correlation between the host inflammatory responses in the gastric mucosa and expression of the BabA2, CagA and VacAs1 genes. Keywords: diseases analysis
2008-05-01 | GSE6143 | 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.
2005-06-30 | E-SMDB-1587 | 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. 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
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
2005-08-16 | GSE3135 | GEO