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.
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. Two-condition experiment, Normoxic MSCs vs. Hypoxic MSCs.
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: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:Bone marrow stromal cells (BMSCs) can be expanded by serial passage, but expansion is limited by cell senescence. The nature of changes associated with BMSC serial passages was assessed. Transcriptome analysis of 10 early and 15 late passage samples from 5 subjects revealed 2193 differentially expressed genes; those highly expressed in early passage cells were overrepresented in skeletal system development, embryonic morphogenesis, tube morphogenesis, etc, while those highly expressed in the late passage BMSCs were overrepresented in nucleosome assembly; chromatin assembly, DNA packaging, etc. 57 BMSC samples from 7 donors were further analyzed for the transition from an early to late passage; 155 genes were highly correlated with BMSC senescence and a set of 24 genes was predictive of BMSCs lifespan. The change from an early to a late passage molecular signature occurred between passage 3 and 5. In contrast, senescence associated beta-galactosidase staining began to increase after passage 6 or 7 and colony formation efficiency began to fall after passage 7. These data indicated that the onset of molecular changes associated with BMSC passage varied among individuals and preceded changes in commonly used indicators of BMSC senescence. The set of 24 BMSC lifespan predictive genes will be useful in assessing the quality of clinical BMSC products.
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.