Project description:The persistence of Glioblastoma Stem-like Cells (GSCs) may account for the high lethality of glioblastoma patients. The GSC reservoir typically resides close to blood vessels, where these cells receive maintenance signals. Upon unfavorable conditions, GSCs escape these niches and spread by exploiting the pre-existing brain vasculature. In both scenarios, GSCs interact with the vascular interface, including the endothelial cells and their matrix. How cell adhesion encountered in their microenvironment serves GSC fate remains ill-defined. By combining ex vivo models, including decellularized matrices, cell co-culture, and organotypic slices, we identified that Junctional Adhesion Molecule C (JAMC) tethers GSCs to endothelial surface. Functionally, JAMC-/- GSCs exhibit an extended spreading on various endothelial-borne supports, with exacerbated invasive, migratory, and mesenchymal-like behaviors, that eventually eroded the survival of GSC tumor-bearing mice. Label-free quantitative proteomics next unveiled that JAMC deletion elicits an up-regulation of integrin expression, concurrent to a down-regulation of the integrin negative regulator, SHARPIN. Data mining of spatial transcriptomics confirmed the association between glioblastoma invasion and the expression pattern of JAMC. While JAMC may provide a retention signal in endothelial niches, the landscape of adhesion molecules anchoring GSCs to vascular surfaces may ultimately coordinate cell migration in defined glioblastoma territories.
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: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)