Project description:Satellite cells (SC) are muscle stem cells which can regenerate adult muscles upon injury. Most SC originate from PAX7+ myogenic precursors set aside during development. Although myogenesis has been studied in mouse and chicken embryos, little is known about human muscle development. Here, we report the generation of human induced pluripotent stem cell (iPSC) reporter lines in which fluorescent proteins have been introduced into the PAX7 and MYOG loci. We use single cell RNA sequencing to analyze the developmental trajectory of the iPSC-derived PAX7+ myogenic precursors. We show that the PAX7+ cells generated in culture can produce myofibers and self-renew in vitro and in vivo. Together, we demonstrate that cells exhibiting characteristics of human fetal satellite cells can be produced in vitro from iPSC, opening interesting avenues for muscular dystrophy cell therapy. This work provides significant insights into the development of the human myogenic lineage.
Project description:The contribution of non-resident, non-satellite myogenic progenitors to postnatal muscle homeostasis and repair is controversial. Precursor cells with the capacity to generate striated muscle fibers in vitro have been isolated from diverse adult tissues, although their physiological role being currently unclear. Since murine dermis-derived precursor cell cultures generate striated muscle when transplanted in vivo, we pursued to identify and characterize the myogenic cell population present in dermis-derived sphere cultures. Lineage tracing experiments for myogenic, perivascular and dermal precursor cell lineages showed a major contribution of Myf5 and Pax7-positive cell progeny to the dermal myogenic precursor cell subset. Tracing, in situ localization and ultrastructural analyses unequivocally demonstrated that Panniculus carnosus muscle-derived satellite stem cells expand in the dermal sphere culture conditions and originate dermis-derived myofibers in vitro. These results highlight the importance of unraveling distinct lineages in sphere cultures to avoid wrong assumptions when determining the developmental potential of adult stem cells. strain: Crl:CD1(ICR), B6.129S4-Myf5tm3(cre)Sor /J, B6,FVB-Tg(Cspg4-cre)1Akik/J, B195AP-Cre
Project description:Skeletal muscle stem cells, called satellite cells, are responsible for postnatal muscle growth, homeostasis and regeneration. Attempts to utilize the regenerative potential of muscle stem cells for therapeutic purposes so far failed. The transcription factor Pax7 defines satellite cells across species 1-4 . We previously established human PAX7-positive cell colonies with high regenerative potential 5 . We now identified PAX7-negative human muscle-derived cell colonies (PAX7neg) also positive for the myogenic markers desmin and MYF5. These included cells from a unique myopathic patient with rigid spine and respiratory insufficiency due to a homozygous PAX7 c.86-1G>A mutation (PAX7null). Single cell and bulk transcriptome analysis showed high intra- and inter-donor heterogeneity and revealed the endothelial cell marker CLEC14A to be highly expressed in PAX7null cells. All PAX7neg cell populations, including PAX7null, formed myofibers after transplantation into mice, and regenerated muscle after reinjury. Transplanted PAX7neg cells repopulated the satellite cell niche where they re-expressed PAX7. Strikingly, PAX7null cells expressing CLEC14A were also identified below the basal lamina. In summary, transplanted human cells do not depend on PAX7 for muscle regeneration. Thus, Pax7 is not a suitable marker for selection of optimal cells for muscle regenerative therapies.
Project description:Mouse muscle stem cells, defined as Pax7+ satellite cells, can initiate rhabdomyosarcoma when transformed by oncogenic Kras and concomitant loss of p53. Mouse Pax7+ satellite cells were transformed in vitro and in vivo utilizing the Cre-ER/loxp system. We wanted to address two major questions: do the in vitro and in vivo tumors cluster together compared to another mouse to another mouse derived soft-tissue sarcoma AND which human soft-tissue sarcoma do the in vivo derived tumors resemble transcriptionally? Therefore, tumors from cells transformed in vitro and tumors from mice that restrict the oncogenic lesions to Pax7+ satellite cells in vivo were compared to answer these two questions.
Project description:Here, we report the generation of human induced Pluripotent Stem (iPS) cell reporter line in which a venus fluorescent protein have been introduced into the PAX7 locus. We use microarrays to compare the transcriptome of PAX7-venus+ cells after 3 weeks of myogenic differentiation to that of undifferentiated iPS Satellite cells (SC) are muscle stem cells which can regenerate adult muscles upon injury. Most SC originate from PAX7-positive myogenic precursors set aside during development. While myogenesis has been studied in mouse and chicken embryos, little is known about human muscle development. Here, we use microarrays to compare the transcriptome of myogenic cells differentiated in vitro from human and mouse ES and iPS cells reporter cell lines. We generated fluorescent reporter lines in which a fluorescent protein was introduced into the loci coding for Pax7 (mouse ES and human iPS) or MYOG (human iPS). Mouse ES and human iPS cells were differentiated to the myogenic lineage in vitro for three weeks according to the protocols described in Chal et al, Nature Biotech 2015 and to Chal, Al Tanoury et al, Nature Protocols, 2016. Fluorescent Pax7 or MYOG-positive cells were FACS-sorted after 3-weeks of differentiation in vitro and we used Affymetrix microarrays to analyze the transcriptome of the purified mouse and human cell populations and compare it to the transcriptome of undifferentiated mouse ES or human iPS cells.
Project description:Satellite cells (SC) are muscle stem cells that can regenerate adult muscles upon injury. Most SC originate from PAX7+ myogenic precursors set aside during development. Although myogenesis has been studied in mouse and chicken embryos, little is known about human muscle development. Here, we report the generation of human induced pluripotent stem cell (iPSC) reporter lines in which fluorescent proteins have been introduced into the PAX7 and MYOG loci. We use single cell RNA sequencing to analyze the developmental trajectory of the iPSC-derived PAX7+ myogenic precursors. We show that the PAX7+ cells generated in culture can produce myofibers and self-renew in vitro and in vivo Together, we demonstrate that cells exhibiting characteristics of human fetal satellite cells can be produced in vitro from iPSC, opening interesting avenues for muscular dystrophy cell therapy. This work provides significant insights into the development of the human myogenic lineage.
Project description:Here, we use microarrays to compare the transcriptome of mouse Pax7-GFP ES reporter cell line after 3 weeks of myogenic differentiation in vitro to that of undifferentiated ES Satellite cells (SC) are muscle stem cells which can regenerate adult muscles upon injury. Most SC originate from PAX7-positive myogenic precursors set aside during development. While myogenesis has been studied in mouse and chicken embryos, little is known about human muscle development. Here, we use microarrays to compare the transcriptome of myogenic cells differentiated in vitro from human and mouse ES and iPS cells reporter cell lines. We generated fluorescent reporter lines in which a fluorescent protein was introduced into the loci coding for Pax7 (mouse ES and human iPS) or MYOG (human iPS). Mouse ES and human iPS cells were differentiated to the myogenic lineage in vitro for three weeks according to the protocols described in Chal et al, Nature Biotech 2015 and to Chal, Al Tanoury et al, Nature Protocols, 2016. Fluorescent Pax7 or MYOG-positive cells were FACS-sorted after 3-weeks of differentiation in vitro and we used Affymetrix microarrays to analyze the transcriptome of the purified mouse and human cell populations and compare it to the transcriptome of undifferentiated mouse ES or human iPS cells.
Project description:Skeletal myogenic commitment of human pluripotent cells can be achieved by doxycycline-inducible expression of the transcription factor PAX7. To gain further insights on PAX7 function during this process, we performed a time course whole transcriptome analysis of differentiating H9 human embryonic stem cells from doxycycline-treated and untreated cultures. In addition, we identified the genomic binding of PAX7 in one of the selected time point (referred as PAX7+ proliferating myogenic progenitors).
Project description:Mouse muscle stem cells, defined as Pax7+ satellite cells, can initiate rhabdomyosarcoma when transformed by oncogenic Kras and concomitant loss of p53. Mouse Pax7+ satellite cells were transformed in vitro and in vivo utilizing the Cre-ER/loxp system.
Project description:Here, we report the generation of human induced Pluripotent Stem (iPS) cell reporter line in which a venus fluorescent protein have been introduced into the MYOGENIN (MYOG) locus. We use microarrays to compare the transcriptome of MYOG-venus+ cells after 3 weeks of myogenic differentiation to that of undifferentiated iPS Satellite cells (SC) are muscle stem cells which can regenerate adult muscles upon injury. Most SC originate from PAX7-positive myogenic precursors set aside during development. While myogenesis has been studied in mouse and chicken embryos, little is known about human muscle development. Here, we use microarrays to compare the transcriptome of myogenic cells differentiated in vitro from human and mouse ES and iPS cells reporter cell lines. We generated fluorescent reporter lines in which a fluorescent protein was introduced into the loci coding for Pax7 (mouse ES and human iPS) or MYOG (human iPS). Mouse ES and human iPS cells were differentiated to the myogenic lineage in vitro for three weeks according to the protocols described in Chal et al, Nature Biotech 2015 and to Chal, Al Tanoury et al, Nature Protocols, 2016. Fluorescent Pax7 or MYOG-positive cells were FACS-sorted after 3-weeks of differentiation in vitro and we used Affymetrix microarrays to analyze the transcriptome of the purified mouse and human cell populations and compare it to the transcriptome of undifferentiated mouse ES or human iPS cells.