Project description:Bone marrow stromal cells (BMSCs) were isolated from the femora and tibiae of irtTA-GBD*-TAg transgenic mice. Using cellular cloning we established skeletal progenitors with unipotent osteogenic and adipogenic properties. Previous RNA-seq analysis of more progenitor types revealed differential expression in members of the Interferon-gamma (IFNγ) signaling pathway. Treatment of adipogenic progenitors with IFNγ inhibited adipogenesis and promoted osteogenesis. RNA-seq analysis of osteogenic, adipogenic and IFNγ treated adipogenic clones revealed factors controlling the osteogenic versus adipogenic commitment of bone marrow skeletal progenitors.
Project description:Bone regeneration involves skeletal stem/progenitor cells within periosteum and bone marrow, the formation of a fibrous callus followed by the deposition of cartilage and bone matrix to consolidate the fracture. Interactions between bone and skeletal muscle are known to play a role in bone repair but the underlying mechanisms are poorly understood. To better understand the role of skeletal muscle during bone repair, we characterized stem/progenitor cells within skeletal muscle that participate in bone repair. We show that cells originating from bone marrow, periosteum and skeletal muscle are all derived from the Prx1 embryonic lineage. We developed a mouse polytrauma model combining a non-stabilized tibial fracture and mechanical injury to adjacent skeletal muscles. In this polytrauma model, bone fracture healing is impaired. We characterized the Prx1-derived cell population within skeletal muscle in response to fracture and to polytrauma. To do so, we performed fracture and polytrauma in Prx1Cre;Rosa mTmG mice. We harvested skeletal muscle surrounding the tibia at d0 (uninjured), and surrounding the fracture site at d3 and d5 post-fracture or post-polytrauma. Following enzymatic and mechanical digestion of skeletal muscle tissue, we FACS sorted Prx1-derived GFP+ cells and sequenced them using the 10X Chromium technology.
Project description:Skeletal muscle harbors quiescent stem cells termed satellite cells and proliferative progenitors termed myoblasts, which play pivotal roles during muscle regeneration. However, current technology does not allow permanent capture of these cell populations in vitro. Here, we show that ectopic expression of the myogenic transcription factor MyoD, combined with exposure to small molecules, reprograms mouse fibroblasts into expandable induced myogenic progenitor cells (iMPCs). iMPCs express key skeletal muscle stem and progenitor cell markers including Pax7 and Myf5 and give rise to Dystrophin-expressing myofibers upon transplantation, a subset of which maintain Pax7 expression in vivo and sustain serial regenerative responses. Similar to satellite cells, iMPCs originate from Pax7+ cells and require Pax7 itself for maintenance. Finally, we show that iMPCs can be established from muscle tissue following small molecule exposure alone. This study thus reports on a robust approach to derive expandable myogenic stem/progenitor-like cells from multiple differentiated cell types.
Project description:Skeletal muscle harbors quiescent stem cells termed satellite cells and proliferative progenitors termed myoblasts, which play pivotal roles during muscle regeneration. However, current technology does not allow permanent capture of these cell populations in vitro. Here, we show that ectopic expression of the myogenic transcription factor MyoD, combined with exposure to small molecules, reprograms mouse fibroblasts into expandable induced myogenic progenitor cells (iMPCs). iMPCs express key skeletal muscle stem and progenitor cell markers including Pax7 and Myf5 and give rise to Dystrophin-expressing myofibers upon transplantation, a subset of which maintain Pax7 expression in vivo and sustain serial regenerative responses. Similar to satellite cells, iMPCs originate from Pax7+ cells and require Pax7 itself for maintenance. Finally, we show that iMPCs can be established from muscle tissue following small molecule exposure alone. This study thus reports on a robust approach to derive expandable myogenic stem/progenitor-like cells from multiple differentiated cell types.
Project description:Decoding heterogeneity of pluripotent stem cell (PSC)-derived neural progeny is fundamental for revealing the origin of diverse progenitors, for defining their lineages, and for identifying fate determinants driving transition through distinct potencies. Here we prospectively isolated consecutively appearing PSC-derived primary progenitors based on their Notch activation state. We first isolate early neuroepithelial cells and show their broad Notch-dependent developmental and proliferative potential. Neuroepithelial cells further yield successive Notch-dependent functional primary progenitors, from early and mid neurogenic radial glia and their derived basal progenitors, to gliogenic radial glia and adult-like neural progenitors, together recapitulating hallmarks of neural stem cell (NSC) ontogeny. Gene expression profiling reveals dynamic stage specific transcriptional patterns that may link development of distinct progenitor identities through Notch activation. Our observations provide a platform for characterization and manipulation of distinct progenitor cell types amenable for developing streamlined neural lineage specification paradigms for modeling development in health and disease.