Project description:Absent in Melanoma 2 (AIM2) is a member of the HIN-200 family of hematopoietic, IFN-inducible nuclear proteins associated with infection defense and tumor pathology. Recently, AIM2 was found to act as a DNA sensor in innate immunity. In addition, a high frequency of AIM2-alterations was observed in microsatellite unstable tumors. To elucidate AIM2 function in colorectal tumors, we here addressed AIM2-responsive genes by microarray. Among genes up-regulated by AIM2, there were a number of interferon-stimulated genes (ISGs: IFIT1, IFIT2, IFIT3, IFI6, IRF7, ISG15, HLA-DRA, HLA-DRB, TLR3 and CIITA) as well as genes involved in intercellular adhesion and matrix remodeling. Expression of ISGs correlated with expression of AIM2 in ten different IFN-γ treated colorectal cancer cell lines. Moreover, knock-down of AIM2 resulted in reduced expression of HLA-DRA, HLA-DRB, and CIITA in IFN-γ treated cells. IFN-γ independent induction of HLA-DR genes and their encoded proteins was also demonstrated upon transient induction of AIM2. STAT-signaling was not involved in IFN-γ independent induction of ISGs, arguing against participation of cytokines released in an autocrine manner. Our data indicate that AIM2 mediates IFN-γ dependent and independent induction of several Interferon stimulated genes (ISGs) including genes encoding the MHC II antigens HLA-DRα and β. we used microarray techniques to define genes responsive to AIM2 expression in colorectal tumor cells. HCT116 is a colorectal tumour cell line with no evidence for AIM2 expression which served as background for gene transfection. B8 and D1 were transfected subclones with persisting expression of AIM2. Gene expression of B8 and D1 was compared with that of mock transfected control cells.
Project description:Absent in Melanoma 2 (AIM2) is a member of the HIN-200 family of hematopoietic, IFN-inducible nuclear proteins associated with infection defense and tumor pathology. Recently, AIM2 was found to act as a DNA sensor in innate immunity. In addition, a high frequency of AIM2-alterations was observed in microsatellite unstable tumors. To elucidate AIM2 function in colorectal tumors, we here addressed AIM2-responsive genes by microarray. Among genes up-regulated by AIM2, there were a number of interferon-stimulated genes (ISGs: IFIT1, IFIT2, IFIT3, IFI6, IRF7, ISG15, HLA-DRA, HLA-DRB, TLR3 and CIITA) as well as genes involved in intercellular adhesion and matrix remodeling. Expression of ISGs correlated with expression of AIM2 in ten different IFN-γ treated colorectal cancer cell lines. Moreover, knock-down of AIM2 resulted in reduced expression of HLA-DRA, HLA-DRB, and CIITA in IFN-γ treated cells. IFN-γ independent induction of HLA-DR genes and their encoded proteins was also demonstrated upon transient induction of AIM2. STAT-signaling was not involved in IFN-γ independent induction of ISGs, arguing against participation of cytokines released in an autocrine manner. Our data indicate that AIM2 mediates IFN-γ dependent and independent induction of several Interferon stimulated genes (ISGs) including genes encoding the MHC II antigens HLA-DRα and β. we used microarray techniques to define genes responsive to AIM2 expression in colorectal tumor cells.
Project description:Colorectal cancer is a leading cause of cancer-related deaths. Mutations in the innate immune receptor AIM2 are frequently identified in patients with colorectal cancer, but how AIM2 modulates colonic tumorigenesis is unknown. Here, we found that Aim2-deficient mice were hypersusceptible to colonic tumor development. Production of inflammasome-associated cytokines and other inflammatory mediators were largely intact in Aim2-deficient mice, however, intestinal stem cells were prone to uncontrolled proliferation. Aberrant Wnt signaling expanded a population of tumor-initiating stem cells in the absence of AIM2. Susceptibility of Aim2-deficient mice to colorectal tumorigenesis was enhanced by a dysbiotic gut microbiota, which was reduced by reciprocal exchange of gut microbiota with wild-type healthy mice. These findings uncover a synergy between a specific host genetic factor and gut microbiota in determining the susceptibility to colorectal cancer. Therapeutic modulation of AIM2 expression and microbiota has the potential to prevent colorectal cancer. We used microarrays to compare the transcriptome Aim2 deficent mice to wild type mice in colon tumor and colitis samples. Here were 12 mice in total, 3 for each genotype and tissue combination.
Project description:Colorectal cancer is a leading cause of cancer-related deaths. Mutations in the innate immune receptor AIM2 are frequently identified in patients with colorectal cancer, but how AIM2 modulates colonic tumorigenesis is unknown. Here, we found that Aim2-deficient mice were hypersusceptible to colonic tumor development. Production of inflammasome-associated cytokines and other inflammatory mediators were largely intact in Aim2-deficient mice, however, intestinal stem cells were prone to uncontrolled proliferation. Aberrant Wnt signaling expanded a population of tumor-initiating stem cells in the absence of AIM2. Susceptibility of Aim2-deficient mice to colorectal tumorigenesis was enhanced by a dysbiotic gut microbiota, which was reduced by reciprocal exchange of gut microbiota with wild-type healthy mice. These findings uncover a synergy between a specific host genetic factor and gut microbiota in determining the susceptibility to colorectal cancer. Therapeutic modulation of AIM2 expression and microbiota has the potential to prevent colorectal cancer.
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.