Project description:To investigate whether YAP upregulates MYC via miRNA repression, we sequenced miRNAs from gastric epithelial cells (HFE-145) either expressed with vector or YAP-5SA.
Project description:We performed genome-wide mRNA and miRNA expression analysis in gastric epithelial cell line AGS infected with Helicobacter pylori at 100 Multiplicity of Infection (MOI), comparing the expression profile of infected cells with uninfected cells. Differentially expressed mRNAs and miRNAs were identified, which showed a 1.5 fold change in expression in infected cells compared to uninfected cells. We performed in silico analysis of miRNA-mRNA target interactions among the inversely correlated differentially expressed miRNAs and mRNAs, and performed functional enrichment analysis of the target genes, to identify important cellular pathways that reflect the patho-biology of H. pylori infected cells. Among the important miRNA-mRNA target pairs, PHLPP1, reported to be associated with poor prognosis in cancer, was predicted to be a putative target of miR-29b-1-5p. Therefore, we focused on the miR-29b-1-5p/PHLPP1 miRNA/target pair for detailed investigation into their role in H. pylori-mediated signalling in gastric epithelial cells. This study demonstrates that an integrated analysis of global mRNA and miRNA expression patterns, combined with miRNA-mRNA target prediction and functional analysis of miRNA target genes can yield an understanding of the critical pathways regulating the behaviour of gastric epithelial cells challenged with H. pylori.
Project description:We performed genome-wide mRNA and miRNA expression analysis in gastric epithelial cell line AGS infected with Helicobacter pylori at 100 Multiplicity of Infection (MOI), comparing the expression profile of infected cells with uninfected cells. Differentially expressed mRNAs and miRNAs wered identified, which showed a 1.5 fold change in expression in infected cells compared to uninfected cells. We performed in silico analysis of miRNA-mRNA target interactions among the inversely correlated differentially expressed miRNAs and mRNAs, and performed functional enrichment analysis of the target genes, to identify important cellular pathways that reflect the patho-biology of H. pylori infected cells. Among the important miRNA-mRNA target pairs, PHLPP1, reported to be associated with poor prognosis in cancer, was predicted to be a putative target of miR-29b-1-5p. Therefore, we focused on the miR-29b-1-5p/PHLPP1 miRNA/target pair for detailed investigation into their role in H. pylori-mediated signalling in gastric epithelial cells. This study demonstrates that an integrated analysis of global mRNA and miRNA expression patterns, combined with miRNA-mRNA target prediction and functional analysis of miRNA target genes can yield an understanding of the critical pathways regulating the behaviour of gastric epithelial cells challenged with H. pylori.
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.
Project description:Genome wide DNA methylation profiling of normal gastric epuithelial cells and gastric cancer cell lines. The Illumina Infinium 450k Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles across approximately 450,000 CpGs. Samples included 2 normal gastric epithelial cells and 14 gastric cancer cells.
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.
Project description:Colonization by H. pylori is associated with a wide range of gastric diseases, ranging from superficial gastritis to more severe pathologies, including intestinal metaplasia and adenocarcinoma. The interplay of the host response and the pathogen affect the outcome of disease. One major component of the mucosal response to H. pylori is the activation of a strong, but inefficient immune response that fails to control the infection and frequently causes tissue damage. We have shown that polyamines can regulate H. pylori-induced inflammation. Chemical inhibition of ornithine decarboxylase (ODC), which generates putrescine from L-ornithine, reduces gastritis in mice and adenocarcinoma incidence in gerbils infected with H. pylori. However, we have also demonstrated that Odc deletion in myeloid cells enhances M1 macrophage activation and gastritis. Here we used a genetic approach to assess the specific role of gastric epithelial ODC during H. pylori infection. Deletion of Odc in gastric epithelial cells reduces gastritis, attenuates epithelial proliferaton, alters the metabolome, and dowregulates the expression of immune mediators induced by H. pylori. Inhibition of ODC activity in gastric epithelial cells reduces H. pylori-induced NF-B activation and CXCL8 mRNA expression. Chronic inflammation is a major risk factor for the progression to more severe pathologies associated with H. pylori infection and we now show that epithelial ODC plays an important role in mediating this inflammatory response.
Project description:Time-series comprehensive DNA methylation analysis after EBV infection in the immortalised normal gastric epithelial cell line, GES1, and low methylation gastric cancer cell line, MKN7. Infinium HumanMethylation450 BeadChip was used to obtain DNA methylation profiles across 485,577 CpG sites. Samples included 9 GES1 with and without EBV infection, 5 MKN7 with and without EBV infection, EBV+ gastric cancer cell and xenograft, SNU719 and KT, 2 normal gastric mucosae, 2 low-methylation gastric cancer cases, and 2 high-methylation gastric cancer cases.