Project description:The histone 3 lysine 9 (H3K9)-specific methyltransferase (KMT) Setdb1 is essential for both stem cell pluripotency and terminal differentiation of different cell types. To shed light on Setdb1 role(s) in these mutually exclusive processes, we used mouse skeletal myoblasts as a model of terminal differentiation. Ex vivo studies on isolated single myofibres showed that Setdb1 is required for muscle adult stem cells expansion following activation and in vitro studies on skeletal myoblasts confirmed that Setdb1 suppresses terminal myoblast differentiation. We used genome-wide analyses to identify Setdb1 direct target genes in myoblasts and observed a release of Setdb1 from the promoter of selected target genes upon myoblast terminal differentiation, concomitant to a nuclear export of Setdb1 to the cytoplasm. We demonstrated that both genomic release and cytoplasmic Setdb1 relocalisation during differentiation were dependent on canonical Wnt signalling. Taken together, our findings uncover a functional link between Setdb1 and canonical Wnt signalling in skeletal muscle cells, which affects the expression of a subset of Setdb1 target genes. We revealed Wnt-dependent subcellular relocalisation of Setdb1 as a novel mechanism regulating Setdb1 functions. ChIP-seq of Setdb1 and H3K9me3 in Myoblast cells (C2C12)
Project description:The histone 3 lysine 9 (H3K9)-specific methyltransferase (KMT) Setdb1 is essential for both stem cell pluripotency and terminal differentiation of different cell types. To shed light on Setdb1 role(s) in these mutually exclusive processes, we used mouse skeletal myoblasts as a model of terminal differentiation. Ex vivo studies on isolated single myofibres showed that Setdb1 is required for muscle adult stem cells expansion following activation and in vitro studies on skeletal myoblasts confirmed that Setdb1 suppresses terminal myoblast differentiation. We used genome-wide analyses to identify Setdb1 direct target genes in myoblasts and observed a release of Setdb1 from the promoter of selected target genes upon myoblast terminal differentiation, concomitant to a nuclear export of Setdb1 to the cytoplasm. We demonstrated that both genomic release and cytoplasmic Setdb1 relocalisation during differentiation were dependent on canonical Wnt signalling. Taken together, our findings uncover a functional link between Setdb1 and canonical Wnt signalling in skeletal muscle cells, which affects the expression of a subset of Setdb1 target genes. We revealed Wnt-dependent subcellular relocalisation of Setdb1 as a novel mechanism regulating Setdb1 functions.
Project description:The histone 3 lysine 9 methyltransferase Setdb1 is essential for both stem cell pluripotency and terminal differentiation of different cell types. To shed light on Setdb1 roles in these mutually exclusive processes, we used mouse skeletal myoblasts as a model of terminal differentiation. Ex vivo studies on isolated single myofibres showed that Setdb1 is required for muscle adult stem cells expansion following activation. In vitro studies in skeletal myoblasts confirmed that Setdb1 suppresses terminal myoblast differentiation. Genomic binding analyses showed a release of Setdb1 from the promoter of selected target genes upon myoblast terminal differentiation, concomitant to a nuclear export of Setdb1 to the cytoplasm. Both genomic release and cytoplasmic Setdb1 relocalisation during differentiation were dependent on canonical Wnt signalling. Together, our findings revealed Wnt-dependent subcellular relocalisation of Setdb1 as a novel mechanism regulating Setdb1 functions and adult myogenesis.
Project description:The histone 3 lysine 9 methyltransferase Setdb1 is essential for both stem cell pluripotency and terminal differentiation of different cell types. To shed light on Setdb1 roles in these mutually exclusive processes, we used mouse skeletal myoblasts as a model of terminal differentiation. Ex vivo studies on isolated single myofibres showed that Setdb1 is required for adult muscle stem cells expansion following activation. In vitro studies in skeletal myoblasts confirmed that Setdb1 suppresses terminal differentiation. Genomic binding analyses showed a release of Setdb1 from selected target genes upon myoblast terminal differentiation, concomitant to a nuclear export of Setdb1 to the cytoplasm. Both genomic release and cytoplasmic Setdb1 relocalisation during differentiation were dependent on canonical Wnt signalling. Transcriptomic assays in myoblasts unravelled a significant overlap between Setdb1 and Wnt3a regulated genetic programs. Together, our findings revealed Wnt-dependent subcellular relocalisation of Setdb1 as a novel mechanism regulating Setdb1 functions and myogenesis. This SuperSeries is composed of the SubSeries listed below.
Project description:APC is a key regulator of canonical Wnt signalling since it participates to beta-catenin targeting to proteasomal degradation when the pathway is inactive. Moreover, independently of Wnt signaling, APC regulates several cellular functions such as mycrotubule dynamics, chromosome segregation, cell adhesion. Although APC has been widely studied for its implication in initation and progression of several cancers, its role in satellite cells (skeletal muscle stem cells) has never been investigated. Here we used microarrays and to clarify APC functions and we identified several pathways and cellular processes to be affected following APC silencing.
Project description:Mesenchymal stromal cells (MSCs) are located in bone marrow where they help to maintain bone homeostasis and repair through the ability to expand in response to mitotic stimuli and differentiate into skeletal linages. The signalling mechanisms that enable precise control of MSC function remain unclear. Here, we have identified a non-canonical epidermal growth factor (EGF) signalling pathway in MSCs, which acts via integrin-linked kinase (ILK) to activate β-catenin, a key component of Wnt signalling. EGF induces nuclear translocation of β-catenin in MSCs but does not drive T cell factor (TCF)-mediated transactivation of Wnt target genes, and we demonstrate by Design of Experiments statistical analysis that the EGF/β-catenin and Wnt/β-catenin pathways do not cross-talk following co-stimulation with multiple concentrations of both ligands. By examining EGF-regulated genes in MSCs by RNA-Sequencing, we identified gene sets that were exclusively regulated by the EGF/b-catenin pathway, which were distinct from canonical EGF-regulated genes. In contrast, the expression of subsets of canonical EGF signalling gene targets were significantly influenced by b-catenin activation. These newly-identified EGF signalling pathways cooperate to enable EGF-mediated proliferation of MSCs by alleviating the suppression of cell cycle pathways induced by canonical EGF signalling.
Project description:Regeneration of the adult skeletal muscle tissue relies on a population of muscle stem cells called satellite cells. During tisse repair, satellite cells exhibit active canonical Wnt/beta-catenin signaling. Rspo1 is a modulator of Wnt signaling in many tissue, and is expressed by muscle progenitor cells. To identify genes that become transcribed following activation of the Wnt/β-Catenin pathway in satellite cells, we performed microarray analysis of primary myoblasts expressing an active form of beta-catenin
Project description:Regeneration of the adult skeletal muscle tissue relies on a population of muscle stem cells called satellite cells. During tissue repair, satellite cells exhibit active canonical Wnt/beta-catenin signaling. To identify genes that become transcribed following activation of the Wnt/β-Catenin pathway in satellite cells, we performed microarray analysis of primary myoblasts expressing an active form of beta-catenin