Project description:We have previously reported human gastrin overexpressing transgenic mice (=INS-GAS mice) and Helicobacter felis (=H.felis) infection synergistically accelerated gastric cancer in mice stomachs. (Wang et al 2000) Using this mouse model, we employed microarray analysis of gene expression profiling to identify gastric cancer-specific genes. Keywords: disease state analysis
Project description:Forkhead box (Fox) proteins constitute an evolutionarily conserved family of transcriptional regulators whose deregulations lead to tumorigenesis. However, their regulation and function in gastric cancer are unknown. Promoter hypermethylation occurs during Helicobacter pylori (H pylori)-induced gastritis, but whether the deregulated genes contribute to the multi-step gastric carcinogenesis remains unclear. FOXD3 was found to be hypermethylated in a mouse model of H pylori infection and possess tumor-suppressive functions in gastric cancer cell lines. In order to characterize the direct targets of FOXD3 that confer its actions, we performed ChIP-chip in N87 gastric cancer cell line which express low level of FOXD3 in the nuclei of a sub-population of cells. Promoter hypermethylation occurs during Helicobacter pylori (H pylori)-induced gastritis, but whether the deregulated genes contribute to the multi-step gastric carcinogenesis remains unclear. We used MethylCap-microarray to identify hypermethylated genes in a mouse model of H pylori infection. human Samples: Human gastric tumor cell line, N87 was grown in RPMI1640 supplemented with 10% fetal bovine serum. ChIP assays were performed using anti-FOXD3 antibody. The immunoprecipitated-FOXD3 and -IgG DNA were used to probe the Agilent human ChIP-chip arrays. mouse Samples: Two-condition experiment, H pylori-infected vs. control gastric tissues. 2 dye-swap replicates.
Project description:Forkhead box (Fox) proteins constitute an evolutionarily conserved family of transcriptional regulators whose deregulations lead to tumorigenesis. However, their regulation and function in gastric cancer are unknown. Promoter hypermethylation occurs during Helicobacter pylori (H pylori)-induced gastritis, but whether the deregulated genes contribute to the multi-step gastric carcinogenesis remains unclear. FOXD3 was found to be hypermethylated in a mouse model of H pylori infection and possess tumor-suppressive functions in gastric cancer cell lines. In order to characterize the direct targets of FOXD3 that confer its actions, we performed ChIP-chip in N87 gastric cancer cell line which express low level of FOXD3 in the nuclei of a sub-population of cells. Promoter hypermethylation occurs during Helicobacter pylori (H pylori)-induced gastritis, but whether the deregulated genes contribute to the multi-step gastric carcinogenesis remains unclear. We used MethylCap-microarray to identify hypermethylated genes in a mouse model of H pylori infection.
Project description:We are now trying to elucidate the mechanism of Helicobacter-induced gastritis and gastric cancer. To identify genes involved in these Helicobacter-associated diseases, we infected Helicobacter felis to INS-GAS (insulin-gastrin transgenic) mice (C57BL/6 background) which shows accelerated development of gastritis and gastric cancer.
Project description:Background: Helicobacter pylori (H. pylori) infection is a known cause of many digestive diseases, including gastritis, peptic ulcers, and gastric cancer. However, the underlying mechanism(s)by which H. pylori infection triggers these disorders are still not clearly understood. Methods: We have developed an accelerated disease progression mouse model, which leverages mice deficient in the myeloid differentiation primary response 88 gene (Myd88-/-) infected with Helicobacter felis (H. felis) Findings: In this study, we found that H. felis-induced inflammation in Myd88-/- mice progressed to high-grade dysplasia, driven by activation of the type I interferon (IFN-I) signaling pathway and upregulation of its downstream targets, IFN-stimulated genes (ISGs). We also observed enrichment of IFN stimulated-response element (ISRE) motifs in the promoters of upregulated genes, further supporting the involvement of this pathway. In contrast, mice deficient in Toll/interleukin-1 receptor (TIR)-domain-containing adaptor inducing interferon-β (TRIF, TrifLps2) did not progress to severe gastric pathology after H. felis infection, implicating the TRIF signaling pathway in disease pathogenesis and progression. Additionally, analysis of gastric biopsy samples from human gastric cancer patients illustrated that low expression of Myd88 and high expression of Trif were both significantly correlated with poor survival. Interpretation: Our study using an accelerated animal model for gastric cancer and gastric biopsy samples from patients demonstrated that activation of the TRIF-IFN-I signaling pathway promotes Helicobacter-induced disease progression toward severe gastric pathology and gastric cancer development. This represents a potential target for therapeutic intervention, and further exploration may lead to the identification of novel treatment strategies.
Project description:Chronic infection with the bacterial pathogen Helicobacter pylori is a risk factor for the development of gastric cancer, yet remains asymptomatic in a majority of individuals. We report here that the C57Bl6 mouse model of experimental infection with the closely related H. felis recapitulates this wide range in host susceptibility. A majority of infected mice develop premalignant lesions such as gastric atrophy, compensatory epithelial hyperplasia and intestinal metaplasia, whereas a minority is completely protected from preneoplasia. Protection is associated with the failure to mount an IFN-gamma response to the infection and an associated high Helicobacter burden. We demonstrate that IFN-gamma is essential for clearance of Helicobacter, but also mediates the formation of preneoplastic lesions. We further provide evidence that IFN-gamma triggers a specific transcriptional program in murine gastric epithelial cells in vitro and in vivo, and induces their preferential transformation to the hyperplastic phenotype. In summary, our data suggest a dual role for IFN-gamma in Helicobacter pathogenesis that could provide an explanation for the differential susceptibility to H. pylori-induced gastric pathology in the human population. Keywords: response to in vitro stimulus / comparison of histopathological states We chose mice for gene expression profiling that following Helicobacter infection had (a) symptoms of gastritis, but no epithelial changes, (b) atrophic gastritis accompanied by corpus gland hyperplasia or (c) atrophic gastritis accompanied by intestinal metaplasia. An uninfected control group was also included in the analysis, as were two groups of mice that lacked mature T- and B-cells due to a deletion mutation in the rag1 gene (Rag-1-/-) and that were either experimentally infected or served as Rag-1-/- uninfected controls. To see the effects of IFNg on murine gastric epithelial cells we analysed an immortalized murine primary gastric epithelial cell line treated with three different concentrations of IFNg in comparison to an untreated control.
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:We are now trying to elucidate the mechanism of Helicobacter-induced gastritis and gastric cancer. To identify genes involved in these Helicobacter-associated diseases, we infected Helicobacter felis to INS-GAS (insulin-gastrin transgenic) mice (C57BL/6 background) which shows accelerated development of gastritis and gastric cancer. Three infected mice and three uninfected control mice (6 in total) were sacrificed periodically (2, 4, 6, 8 months after the infection), and total RNA was isolated from each stomach. These samples are subjected to gene microarray analysis. Samples were obtained from mouse stomachs at 2, 4, 6, and 8/9 month post infection intervals. Control time points were taken at 0, 2, 4, 6, and 8 months. All samples, 22 in total, were hybridized to the GLYCOv2 array.