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.
Project description:Although sarcopenia is evident from the fifth decade, mechanisms leading to this phenomenon start earlier, emphasizing the importance of defining biomarkers related to the onset of muscle weakness. To this aim, a transcriptome analysis will be performed on muscle cell cultures (myoblasts) obtained from adult donors of different ages. Any biomarkers identified by this analysis will be confirmed by western blot and immunostatining. We will then assess the role of those biomarkers in muscle aging. Human myoblasts were extracted from the quadriceps of young (15-20 years old) and elderly (>70 years old) healthy subjects . The muscle cell population has been sorted using CD56 MACS beads. The myogenicity and the life span analysis of each muscle cell extract have been determined.
Project description:Asthma is a chronic inflammatory airway disease characterized by airway inflammation and remodeling. The role of 15-oxo-5Z,8Z,11Z,13E-eicosatetraenoic acid (15-oxoETE), a 15-HETE metabolite catalyzed by 15-prostaglandin dehydrogenase (15-PGDH), has been relatively unexplored in asthma. In this study, we used RNA-seq to explore the effect of 15-KETE on the transcriptome of airway epithelial cells, aiming to identify its potential downstream targets and mechanisms of action.
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:By satisfying bioenergetic demands, generating biomass, and providing metabolites serving as cofactors for chromatin modifiers, metabolism regulates adult stem cell biology. Here, we report that, branching off from glycolysis, the serine biosynthesis pathway (SBP) is activated in regenerating muscle stem cells (MuSCs). Gene inactivation and metabolomics revealed that Psat1, one of the three SBP enzymes, controls MuSCs activation and expansion of myogenic progenitors through production of the metabolite -ketoglutarate (-KG) and the -KG-generated amino acid glutamine. Genetic ablation of Psat1 in MuSCs resulted in defective expansion of MuSCs and impaired regeneration. Psat1, -KG, and glutamine were reduced in MuSCs of old mice and myoblasts of old individuals. -KG or glutamine re-established appropriate muscle regeneration of adult Psat1-/- mice, old mice, and improved proliferation of old human myoblasts. These findings contribute insights into the metabolic role of Psat1 during muscle regeneration and suggest -KG and glutamine as potential therapeutic interventions to ameliorate muscle regeneration during aging.