Project description:Optimal cell-based therapies for the treatment of muscle degenerative disorders should not only regenerate fibers, but provide a quiescent satellite cell pool ensuring long-term maintenance and regeneration. Conditional expression of Pax3/Pax7 in differentiating pluripotent stem cells (PSC) allows the generation of myogenic progenitors endowed with satellite cell-like abilities. To identify the molecular determinants underlying their regenerative potential, we performed transcriptome analyses of these cells along with primary myogenic cells from several developmental stages. Here we show that in vitro generated PSC-derived myogenic progenitors possess a molecular signature similar to embryonic/fetal myoblasts. However, compared to fetal myoblasts, following transplantation they show superior myofiber engraftment and ability to seed the satellite cell niche, respond to multiple re-injuries and contribute to long-term regeneration. Upon engraftment, the transcriptome of Pax3/Pax7-induced PSC-derived myogenic progenitors changes dramatically, acquiring similarity to that of satellite cells, particularly in genes involved in extracellular matrix remodeling. Single cell profiling reveals that these changes are induced, not selected, by the in vivo environment. These findings demonstrate that Pax3/Pax7-induced PSC-derived myogenic progenitors possess proliferative and migratory abilities characteristic of earlier developmental stages, and an intrinsic ability to respond to environmental cues upon skeletal muscle regeneration.
Project description:Satellite cells are responsible for the long-term regenerative capacity of adult skeletal muscle. The diminished muscle performance and regenerative capacity of aged muscle is thought to reflect progressive fibrosis and atrophy. Whether this reduction in muscle competency also involves a diminishment in the intrinsic regulation of satellite cell self-renewal remains unknown. We used microarray to identify gene expression changes underlying the marked reduction in the capacity of satellite cells to self-renew, contribute to regeneration and repopulate the niche as they age. Skeletal muscles from heterozygous Pax7-ZsGreen mice were isolated at defined stages: E17.5 (fetal - whole forelimb and hindlimb), postnatal day 21 (adolescent - hindlimb), 2-3 month old (young adult - hindlimb) and >1 year old (older adult - hindlimb) mice. ZsGreen-positive skeletal muscle satellite cells were isolated by FACS and pooled (fetal n=4, adolescent n=6, young adult n=8 and older adult n=8 mice).
Project description:Muscle satellite cells are a self-renewing pool of stem cells that give rise to daughter myogenic precursor cells in adult skeletal muscle. Published and preliminary data indicated that MyoD and p53 genes are involved in satellite cell differentiation. We would like to know what downstream genes of both transcription factors are affected in satellite cell-derived myoblasts (MyoD-/-, p53 -/-). Experiment Overall Design: this experiment include 3 samples and 25 replicates
Project description:Following skeletal muscle injury, muscle stem cells (satellite cells) are activated, proliferate, and differentiate to form myofibers. We show that mRNA decay protein AUF1 regulates satellite cell function through targeted degradation of specific mRNAs. AUF1 targets certain mRNAs containing 3 AU-rich elements (AREs) for rapid decay. Auf1-/- (KO) mice undergo accelerated skeletal muscle wasting with age and impaired muscle repair following injury. Satellite cell mRNA analysis and regeneration studies demonstrate that auf1-/- satellite cell self-renewal is impaired due to increased stability and overexpression of ARE-mRNAs. Control of ARE-mRNA decay by AUF1 and potentially other ARE-binding proteins represents a mechanism for adult stem cell regulation and is implicated in human muscle wasting diseases. We report the RNA transcript expression profiles from sorted satellite cells isolated from wild type (WT) and AUF1-null (KO) mice hindlimb muscles Examination of RNA transcript expression from satellite cells of two genotypes Please note that mice are bred through a C57BL/6 strain of 129 background.
Project description:To understand the effect of LncMyod knockdown on cultured satellite cells, we isolated satellite cells from mouse hindlimb and cultured them in vitro with siRNA treatment targeting LncMyod. Following RNA-seq showed that loss of LncMyod leads to difficiencies in myogenic differentiation.
Project description:LCMS analysis of rat hindlimb buds (e14, e16) and transversus abdominis muscle (e18, e20, adult). Small (mg) pieces of tissue were solubilized with RapiGest (Waters), reduced, alkylated, and digested with trypsin. The resultant peptides were separated by HPLC and analyzed in data dependent MS mode using a Q Exactive mass spectrometer. The .raw LCMS files have been deposited.
Project description:Following skeletal muscle injury, muscle stem cells (satellite cells) are activated, proliferate, and differentiate to form myofibers. We show that mRNA decay protein AUF1 regulates satellite cell function through targeted degradation of specific mRNAs. AUF1 targets certain mRNAs containing 3 AU-rich elements (AREs) for rapid decay. Auf1-/- (KO) mice undergo accelerated skeletal muscle wasting with age and impaired muscle repair following injury. Satellite cell mRNA analysis and regeneration studies demonstrate that auf1-/- satellite cell self-renewal is impaired due to increased stability and overexpression of ARE-mRNAs. Control of ARE-mRNA decay by AUF1 and potentially other ARE-binding proteins represents a mechanism for adult stem cell regulation and is implicated in human muscle wasting diseases. We report the RNA transcript expression profiles from sorted satellite cells isolated from wild type (WT) and AUF1-null (KO) mice hindlimb muscles
Project description:Muscle satellite cells are a self-renewing pool of stem cells that give rise to daughter myogenic precursor cells in adult skeletal muscle. Published and preliminary data indicated that MyoD and p53 genes are involved in satellite cell differentiation. We would like to know what downstream genes of both transcription factors are affected in satellite cell-derived myoblasts (MyoD-/-, p53 -/-). Keywords: other
Project description:Global gene expression patterns were determined from microarray results from sham surgery or following 1 week of plantaris muscle hypertrophy induced by synergist ablation in young adult Pax7-DTA mice (4 months). Vehicle treated mice have their full complement of satellite cells; tamoxifen treated mice have had their satellite cells genetically depleted through Cre-loxP technology After sham surgery or 1 week of overload, Affymetrix chips (mouse430_2.0) were used with 1 µg of total RNA derived from a pooled sample of the right and left plantaris muscles from 11 animals.
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.