Project description:A functional placental barrier is crucial for the supply of the embryo or foetus throughout pregnancy. It is formed by the syncytiotrophoblast, which develops via fusion of cytotrophoblast cells. How this “differentiation-by-fusion” is regulated is only partially understood. Here we analysed transcriptome changes during in vitro cytotrophoblast fusion. Pathway analyses yielded the tumor suppressor p53 as upstream negative regulator and indicated an upregulation of autophagy-related genes. We further showed that, during differentiation, p53 is downregulated on the mRNA and protein levels, while the autophagy marker LC3B-II (lipidated LC3B) is increased. In first-trimester placentae, we find reciprocal expression patterns of p53 and LC3B, with p53 expression primarily in cytotrophoblasts and predominant LC3B expression in the apical side of the syncytiotrophoblast layer. Furthermore, in the syncytiotrophoblast, we could show increased autophagic flux, which is alleviated by ectopically overexpression of p53. This was also shown in placental explants treated with a pharmacological p53 activator. On the contrary, in a fusion-deficient trophoblast cell line we could not see an interdependency of p53 and LC3B lipidation. In summary our data suggests, that the downregulation of p53 during syncytialization is a prerequisite for the activation of autophagy in the placental barrier.
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 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. 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: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