Project description:This work examines sarcoma formation within discrete subsets of KRAS(G12V)-expressing p16p19null myogenic and mesenchymal cells found normally in skeletal muscle. We show that prospectively isolated skeletal muscle precursor cells (SMPs) within the satellite cell pool can serve as cancer cells-of-origin for mouse rhabdomyosarcomas (soft tissue sarcomas with features of myogenic differentiation). Alternatively, non-myogenic progenitors (ScaPCs) induce sarcomas lacking myogenic differentiation markers. We used Affymetrix whole mouse genome 430 2.0 microarrays to gain deeper insights into the molecular underpinnings of the three types of KRAS; p16p19null mouse soft-tissue sarcomas (originating from SMPs, ScaPCs and CD45-MAC1-TER119-Sca1-CXCR4- cells). Four replicates of each type.
Project description:This work examines sarcoma formation within discrete subsets of KRAS(G12V)-expressing p16p19null myogenic and mesenchymal cells found normally in skeletal muscle. We show that prospectively isolated skeletal muscle precursor cells (SMPs) within the satellite cell pool can serve as cancer cells-of-origin for mouse rhabdomyosarcomas (soft tissue sarcomas with features of myogenic differentiation). Alternatively, non-myogenic progenitors (ScaPCs) induce sarcomas lacking myogenic differentiation markers.
Project description:To investigate transcriptomes of skeletal muscle cells in health and Duchene muscular dystrophy (DMD), we performed RNA sequencing of DMD-K2957fs and CRISPR-corrected (CORR-K2957fs ) myogenic cultures during secondary differentiation at 5 time points.
Project description:Skeletal muscle holds an intrinsic capability of growth and regeneration both in physiological conditions and in case of injury. Chronic muscle illnesses, generally caused by genetic and acquired factors, lead to deconditioning of the skeletal muscle structure and function, and are associated with a significant loss in muscle mass. At the same time, progressive muscle wasting is a hallmark of aging. Given the paracrine properties of myogenic stem cells, extracellular vesicle-derived signals have been studied for their potential implication in both the pathogenesis of degenerative neuromuscular diseases and as a possible therapeutic target. In this study, we screened the content of extracellular vesicles from animal models of muscle hypertrophy and muscle wasting associated with chronic disease and aging. Analysis of the transcriptome, protein cargo and microRNAs (miRNAs) allowed us to identify a hypertrophic miRNA signature amenable for targeting muscle wasting, consisting of miR-1 and miR-208a. We tested this signature among others in vitro on mesoangioblasts (MABs), vessel-associated adult stem cells, and we observed an increase in the efficiency of myogenic differentiation. Furthermore, injections of miRNA-treated MABs in aged mice resulted in an improvement in skeletal muscle features, such as muscle weight, strength and cross-sectional area compared to controls. Overall, we provide evidence that the extracellular vesicle-derived miRNA signature we identified enhances the myogenic potential of myogenic stem cells.
Project description:Skeletal muscle stem cells, or satellite cells (SCs), are essential to regenerate and maintain muscle. Quiescent SCs reside in an asymmetric niche between the basal lamina and myofiber membrane. To repair muscle, SCs activate, proliferate, and differentiate, fusing to repair myofibers or reacquiring quiescence to replenish the SC niche. Little is known about when SCs reacquire quiescence during regeneration or the cellular processes that direct SC fate decisions and progression through myogenesis. Single cell sequencing of myogenic cells in regenerating muscle identifies SCs reacquiring quiescence and reveals that non-cell autonomous signaling networks influence SC fate decisions during regeneration. Single cell RNA-sequencing of regenerating skeletal muscle reveals that RBP expression, including numerous neuromuscular disease-associated RBPs, is temporally regulated in skeletal muscle stem cells and correlates to stages of myogenic differentiation. By combining machine learning with RBP engagement scoring, we discover that the neuromuscular disease associated RBP Hnrnpa2b1 is a differentiation-specifying regulator of myogenesis controlling myogenic cell fate transitions during terminal differentiation.
Project description:Stem cell-derived tissues have wide potential for modelling developmental and pathological processes as well as cell-based therapy. However, it has proven difficult to generate several key cell types in vitro, including skeletal muscle. In vertebrates, skeletal muscles derive during embryogenesis from the presomitic mesoderm (PSM). Treatment of mouse ES cells with a combination of the secreted Wnt activator R-Spondin3 and the BMP inhibitor Noggin generated cells expressing the early PSM marker Mesogenin1 (Msgn1) with high efficiency. To confirm their identity, we mapped gene expression profiles at successive stages of PSM differentiation in vivo and showed that the differentiated ES cells closely corresponded to the posterior PSM domain that expresses Msgn1 and then with time in culture matured to acquire the profile of the anterior Pax3 domain. When grafted into injured adult muscle in vivo these Pax3-expressing-cells generated large numbers of muscle fibers. Our system therefore efficiently produces myogenic precursors in vitro by recapitulating stepwise early myogenic differentiation in vivo. These findings should advance the development of cellular therapies for muscle degenerative diseases. ES cellline E14 129P2/OlaHsd with DMSO, Rspo, and Noggin at Days 3 and 4
Project description:Driving efficient and pure skeletal muscle cell differentiation from pluripotent stem cells has been challenging. Here, we report an optimized protocol that generates skeletal muscle progenitor cells with high efficiency and purity, in a short period of time. Human induced pluripotent stem cells (hiPSC) and mouse embryonic stem cells (mESC) were specified into the mesodermal myogenic fate using distinct and species-specific protocols. We used a specific Maturation Medium to promote terminal differentiation of both human and mouse myoblast populations, and generated myotubes associated with a large pool of cell cycle-arrested PAX7+ cells. We further show that myotube maturation is modulated by the dish coating properties, cell density and percentage of myogenic progenitor cells. Given the high efficiency in the generation of myogenic progenitors and differentiated myofibers, this protocol provides an attractive strategy for tissue engineering, modeling of muscle dystrophies and evaluation of new therapeutic approaches in vitro.
Project description:Skeletal muscle stem cells are essential to muscle homeostasis and regeneration after injury. An attractive approach to obtain these cells is via differentiation of pluripotent stem cells (PSCs). We have recently reported that teratomas derived from mouse PSCs are a rich source of skeletal muscle stem cells. Here, we showed that the teratoma formation method is also capable of producing skeletal myogenic progenitors from human PSCs. Using single-cell transcriptomics, we discovered multiple lineages in human PSC-derived teratomas. Interestingly, we observed several distinct skeletal myogenic subpopulations. Trajectory analysis revealed that these subpopulations represented progressive stages of skeletal myogenic development. We further discovered that ERBB3 and CD82 are effective surface markers for prospective isolation of the skeletal myogenic lineage in human PSC-derived teratomas. Therefore, teratoma formation provides an accessible model for obtaining human skeletal myogenic progenitors from PSCs.