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:The molecular pathogenesis of orbital lymphoproliferative disorders, such as immunoglobulin G4-related ophthalmic disease (IgG4-ROD) and orbital mucosa-associated lymphoid tissue (MALT) lymphoma, remains essentially unknown. Differentiation between the two disorders, which is important since work-up and treatment can vary greatly, is often challenging due to the lack of specific biomarkers. Although miRNAs play an important role in the regulation of carcinogenesis and inflammation, the relationship between miRNA and orbital lymphoproliferative diseases remains unknown. A comprehensive analysis of 2,565 miRNAs was performed in biopsied specimens and serum of 17 cases with IgG4-ROD and 21 cases with orbital MALT lymphoma. We identified specific miRNA signatures, their miRNA target pathways, and network analysis associated with IgG4-ROD and orbital MALT lymphoma. Machine-learning analysis identified miR-202-3p and miR-7112-3p as the best discriminators of IgG4-ROD and orbital MALT lymphoma, respectively. In the tissue pathway, Longevity regulating pathway in IgG4-ROD and MAPK signaling pathway in orbital MALT lymphoma were most enriched by downregulated miRNAs. This is the first evidence of the miRNA profile in biopsied specimens and serum of patients with IgG4-ROD and orbital MALT lymphoma. These data will be useful for developing diagnostic and therapeutic interventions, as well as elucidating of these disorders.
Project description:To identify key tumour supressor miRNAs involed in MALT lymphoma pathogenesis Gastric mucosa-associated lymphoid tissue lymphoma develops in the chronically inflamed mucosa of Helicobacter pylori-infected patients. MicroRNA expression profiling of human MALT lymphoma revealed a 10-fold down-regulation of miR-203, which resulted from promoter hypermethylation and coincided with the dysregulation of the miR-203 target ABL1. Demethylating treatment of lymphoma B-cells led to an increase in miR-203 expression and concomitant ABL1 down-regulation. The lentiviral delivery of miR-203, as well as treatment with various ABL inhibitors, prevented primary MALT lymphoma cell proliferation in vitro. Finally, the treatment of tumor-bearing mice with imatinib induced MALT lymphoma regression in vivo. Our results show that MALT lymphomagenesis is epigenetically induced by miR-203 promoter methylation and identify ABL1 as a novel target for the treatment of this malignancy.
Project description:To obtain global miRNA expression signatures of gDLBCL and its precursor lesions, total RNA isolated from 7-8 cases each of Helicobacter-associated reactive gastritis, low grade MALT lymphoma and high grade gDLBCL was hybridized to Agilent miRNA microarrays representing 795 human mature miRNAs. Unsupervised hierarchical clustering analysis revealed a clear segregation of the gDLBCL cases from the low grade MALT lymphomas and the gastritis samples; the segregation of the latter two disease entities was only incomplete (Figure 1A), reflecting the relative biological similarity of gastritis and low grade lymphomas. Statistical analysis of the dataset revealed only 26 differentially expressed miRNAs between these two groups (p<0.05), whereas 57 miRNAs exhibited significant differences in expression between low and high grade lymphomas. 7 human gastritis, 8 lowgrade MALT lymphoma and 7 high grade MALT lymphoma samples were used in the microarray analysis
Project description:Comparison of gene expression profiling analysis of bone marrow isolated CD34+ cells from patients with MALT lymphoma vs. healthy individuals revealed a large number of differentially expressed genes that included NF-kB target genes, genes involved in inflamatory signalling and immunoglobulin genes, suggesting an early lymphoid B-cell priming. Chromosomal translocations involving MALT1 gene are hallmarks of mucosa-associated lymphoid tissue (MALT) lymphoma. However, targeting these translocations to mouse B-cells has failed to reproduce human disease. Here, we induced MALT1 expression in mouse Sca1+Lin- hematopoietic stem/progenitor cells (HS/PCs), leading to the development of tumors recapitulating the clinical, histopathological and molecular features of human MALT lymphomas. Ablation of the p53 gene induced transformation of MALT lymphoma to diffuse large-cell lymphoma of activated B-cell type (ABC-DLBCL). Human CD34+ cells isolated from MALT lymphoma patients displayed an abnormal transcriptional program that was shared by MALT lymphoma cells, transgenic mouse Sca1+Lin- cells and Sca1-MALT1-induced lymphomas. Our study shows that MALT lymphoma can be modeled in mice by targeting MALT1 oncogene to HS/PCs.
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 Sequence library of miRNAs from a single sample of human foetal mesenchymal stem cells. Results tested and confirmed by northern blotting. Please note that only raw data files are available for the embryonic and neual samples and thus, directly submitted to SRA (SRX547311, SRX548700, respectively under SRP042115/PRJNA247767)
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:Attempts at modeling chromosomal translocations involving MALT1 gene, hallmarks of human mucosa-associated lymphoid tissue (MALT) lymphoma, have failed to reproduce the disease in mice. Here we describe a transgenic model in which MALT1 expression was targeted to mouse hematopoietic stem/progenitor cells. In Sca1-MALT1 mice, MALT1 deregulation activated the NF-kappaB pathway in Sca1+ cells, promoting selective B-cell differentiation and mature lymphocyte accumulation in extranodal tissues, progressively leading to the development of clonal B-cell lymphomas. These tumors recapitulated the histopathological features of human MALT lymphomas, presenting typical lymphoepithelial lesions and plasmacytic differentiation. Transcriptional profiling of Sca1-MALT1 murine lymphomas revealed overlapping molecular signatures with human MALT lymphomas, including MALT1-mediated NF-kappaB activation, pro-inflammatory signaling and XBP1-induced plasmacytic differentiation. Moreover, murine Malt1 showed proteolytic activity by cleaving Bcl10 in Sca1-MALT1 lymphomas. Our novel technological approach has allowed modeling human MALT lymphoma in mice, which represent unique tools study MALT lymphoma biology and evaluate anti-MALT1 therapies. Keywords: lymphoma profiling, MALT lymphoma