Project description:Cellular differentiation and lineage commitment are considered to be robust and irreversible processes during development. Recent work has shown that mouse and human fibroblasts can be reprogrammed to a pluripotent state with a combination of four transcription factors. This raised the question of whether transcription factors could directly specify somatic cell fates in cells such as pancreatic ? cells, contractile cardiomyocytes and neurons. We hypothesized that combinatorial expression of chondrocyte-specific transcription factors could directly convert human amnion cells into chondrosarcoma. Starting from a pool of candidate genes, we identified a combination of only five genes (5F pool), BCL6, T (also called BRACHYURY), c-MYC, MITF and BAF60C (also called SMARCD3) that rapidly and efficiently convert postnatal human amnion into chondrosarcoma. The cells generated expressed multiple cartilage-specific genes such as collagen type II ?1, link protein-1 and aggrecan, and exhibited characteristics of cartilage both in vivo and in vitro. Expression of the endogenous genes for T and MITF was initiated, implying that the cell conversion is due to not only the forced expression of the transgenes, but also the cellular reprogramming by the transgenes. The same set of genes converted human placental artery-derived endothelial (hPAE) cells and menstrual blood-derived cells into chondrosarcoma cells, implying that this conversion is independent of cell types. Direct conversion system from non-cartilage tissue to cartilaginous tissue contributes substantially to a major advance toward cartilage development, oncogenesis of chondrocytes, and cell-based therapy. We hypothesized that combinatorial expression of chondrocyte-specific transcription factors could directly convert human amnion cells into chondrosarcoma. Starting from a pool of candidate genes, we identified a combination of only five genes that rapidly efficiently convert postnatal human amnion into chondrosarcoma.
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: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: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: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. One-condition experment, gene expression of 3A6