scholarly journals In Vivo Study of Key Transcription Factors in Muscle Satellite Cells by CRISPR/Cas9/AAV9-sgRNA Mediated Genome Editing

2019 ◽  
Author(s):  
Liangqiang He ◽  
Yingzhe Ding ◽  
Yu Zhao ◽  
Karl K. So ◽  
Xianlu L. Peng ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Genome Editing ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Molecular Mechanisms ◽  
Early Stage ◽  
Muscle Stem Cells ◽  
Muscle Satellite Cells ◽  
Regulatory Functions

ABSTRACTSkeletal muscle satellite cells (SCs) are adult muscle stem cells responsible for injury induced muscle regeneration. Despite advances in the knowledge of molecular mechanisms regulating SC lineage progression, our understanding of key transcription factors (TFs) and their regulatory functions in SCs in particularly the quiescent and early activation stages remains incomplete due to the lack of efficient method to screen and investigate the stage-specific key TFs. In this study, we succeeded in defining a distinct list of key TFs in early stages of SC fate transition using the paradigm of super enhancers (SEs). Particularly, leveraging the Cre-dependent Cas9 knockin mice and AAV9 mediated sgRNAs delivery, we generated a facile muscle specific genome editing system which allows gene depletion in SCs in vivo. Using MyoD locus as a proof of concept, we demonstrated that this CRISPR/Cas9/AAV9-sgRNA system can efficiently introduce mutagenesis at target locus and recapture the phenotypes reported in knockout mice. Further application of the system on key TFs, Myc, Bcl6 and Pknox2, revealed their distinct functions in the early stage of SC activation and damage induced muscle regeneration. Altogether our findings have proven the CRISPR/Cas9/AAV9-sgRNA system as a robust way for in vivo genome editing and elucidation of key factors governing SC activities.

scholarly journals In Vivo Activation of STAT3 Signaling in Satellite Cells and Myofibers in Regenerating Rat Skeletal Muscles

2002 ◽  
Vol 50 (12) ◽  
pp. 1579-1589 ◽  
Author(s):  
Katsuya Kami ◽  
Emiko Senba
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Intracellular Signaling ◽  
Skeletal Muscles ◽  
Early Stage ◽  
Skeletal Muscle Regeneration ◽  
Stat3 Signaling

Although growth factors and cytokines play critical roles in skeletal muscle regeneration, intracellular signaling molecules that are activated by these factors in regenerating muscles have been not elucidated. Several lines of evidence suggest that leukemia inhibitory factor (LIF) is an important cytokine for the proliferation and survival of myoblasts in vitro and acceleration of skeletal muscle regeneration. To elucidate the role of LIF signaling in regenerative responses of skeletal muscles, we examined the spatial and temporal activation patterns of an LIF-associated signaling molecule, the signal transducer and activator transcription 3 (STAT3) proteins in regenerating rat skeletal muscles induced by crush injury. At the early stage of regeneration, activated STAT3 proteins were first detected in the nuclei of activated satellite cells and then continued to be activated in proliferating myoblasts expressing both PCNA and MyoD proteins. When muscle regeneration progressed, STAT3 signaling was no longer activated in differentiated myoblasts and myotubes. In addition, activation of STAT3 was also detected in myonuclei within intact sarcolemmas of surviving myofibers that did not show signs of necrosis. These findings suggest that activation of STAT3 signaling is an important molecular event that induces the successful regeneration of injured skeletal muscles.

scholarly journals Sustained expression of HeyL is critical for the proliferation of muscle stem cells in overloaded muscle

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Sumiaki Fukuda ◽  
Akihiro Kaneshige ◽  
Takayuki Kaji ◽  
Yu-taro Noguchi ◽  
Yusei Takemoto ◽  
...  
Keyword(s):  
Stem Cells ◽  
Basal Lamina ◽  
Satellite Cells ◽  
Knockout Mice ◽  
Muscle Stem Cells ◽  
Muscle Satellite Cells ◽  
Effector Gene ◽  
Injury Model ◽  
Myod Expression

In overloaded and regenerating muscle, the generation of new myonuclei depends on muscle satellite cells (MuSCs). Because MuSC behaviors in these two environments have not been considered separately, MuSC behaviors in overloaded muscle remain unexamined. Here, we show that most MuSCs in overloaded muscle, unlike MuSCs in regenerating muscle, proliferate in the absence of MyoD expression. Mechanistically, MuSCs in overloaded muscle sustain the expression of Heyl, a Notch effector gene, to suppress MyoD expression, which allows effective MuSC proliferation on myofibers and beneath the basal lamina. Although Heyl-knockout mice show no impairment in an injury model, in a hypertrophy model, their muscles harbor fewer new MuSC-derived myonuclei due to increased MyoD expression and diminished proliferation, which ultimately causes blunted hypertrophy. Our results show that sustained HeyL expression is critical for MuSC proliferation specifically in overloaded muscle, and thus indicate that the MuSC-proliferation mechanism differs in overloaded and regenerating muscle.

scholarly journals The role of Pitx2 and Pitx3 in muscle stem cells gives new insights into P38α MAP kinase and redox regulation of muscle regeneration

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Aurore L'honoré ◽  
Pierre-Henri Commère ◽  
Elisa Negroni ◽  
Giorgia Pallafacchina ◽  
Bertrand Friguet ◽  
...  
Keyword(s):  
Stem Cells ◽  
Map Kinase ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Redox Regulation ◽  
Primary Cultures ◽  
Rapid Expansion ◽  
Skeletal Muscle Regeneration ◽  
Muscle Stem Cells ◽  
P38α Map Kinase

Skeletal muscle regeneration depends on satellite cells. After injury these muscle stem cells exit quiescence, proliferate and differentiate to regenerate damaged fibres. We show that this progression is accompanied by metabolic changes leading to increased production of reactive oxygen species (ROS). Using Pitx2/3 single and double mutant mice that provide genetic models of deregulated redox states, we demonstrate that moderate overproduction of ROS results in premature differentiation of satellite cells while high levels lead to their senescence and regenerative failure. Using the ROS scavenger, N-Acetyl-Cysteine (NAC), in primary cultures we show that a physiological increase in ROS is required for satellite cells to exit the cell cycle and initiate differentiation through the redox activation of p38α MAP kinase. Subjecting cultured satellite cells to transient inhibition of P38α MAP kinase in conjunction with NAC treatment leads to their rapid expansion, with striking improvement of their regenerative potential in grafting experiments.

scholarly journals MiR-27b Promotes Muscle Development by Inhibiting MDFI Expression

2018 ◽  
Vol 46 (6) ◽  
pp. 2271-2283 ◽  
Author(s):  
Lianjie Hou ◽  
Jian Xu ◽  
Yiren Jiao ◽  
Huaqin Li ◽  
Zhicheng Pan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Western Blot ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Muscle Injury ◽  
Target Gene ◽  
Muscle Development ◽  
Muscle Satellite Cells ◽  
Qrt Pcr

Background/Aims: Skeletal muscle plays an essential role in the body movement. However, injuries to the skeletal muscle are common. Lifelong maintenance of skeletal muscle function largely depends on preserving the regenerative capacity of muscle. Muscle satellite cells proliferation, differentiation, and myoblast fusion play an important role in muscle regeneration after injury. Therefore, understanding of the mechanisms associated with muscle development during muscle regeneration is essential for devising the alternative treatments for muscle injury in the future. Methods: Edu staining, qRT-PCR and western blot were used to evaluate the miR-27b effects on pig muscle satellite cells (PSCs) proliferation and differentiation in vitro. Then, we used bioinformatics analysis and dual-luciferase reporter assay to predict and confirm the miR-27b target gene. Finally, we elucidate the target gene function on muscle development in vitro and in vivo through Edu staining, qRT-PCR, western blot, H&E staining and morphological observation. Result: miR-27b inhibits PSCs proliferation and promotes PSCs differentiation. And the miR-27b target gene, MDFI, promotes PSCs proliferation and inhibits PSCs differentiation in vitro. Furthermore, interfering MDFI expression promotes mice muscle regeneration after injury. Conclusion: our results conclude that miR-27b promotes PSCs myogenesis by targeting MDFI. These results expand our understanding of muscle development mechanism in which miRNAs and genes work collaboratively in regulating skeletal muscle development. Furthermore, this finding has implications for obtaining the alternative treatments for patients with the muscle injury.

scholarly journals Muscle satellite cells are functionally impaired in myasthenia gravis: consequences on muscle regeneration

2017 ◽  
Vol 134 (6) ◽  
pp. 869-888 ◽  
Author(s):  
Mohamed Attia ◽  
Marie Maurer ◽  
Marieke Robinet ◽  
Fabien Le Grand ◽  
Elie Fadel ◽  
...  
Keyword(s):  
Myasthenia Gravis ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Muscle Satellite Cells ◽  
Functionally Impaired

scholarly journals Satellite Cells CD44 Positive Drive Muscle Regeneration in Osteoarthritis Patients

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Manuel Scimeca ◽  
Elena Bonanno ◽  
Eleonora Piccirilli ◽  
Jacopo Baldi ◽  
Alessandro Mauriello ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stem Cells ◽  
Transmission Electron Microscopy ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Bone Diseases ◽  
Mineral Density ◽  
Muscle Stem Cells ◽  
Age Related ◽  
Transmission Electron

Age-related bone diseases, such as osteoarthritis and osteoporosis, are strongly associated with sarcopenia and muscle fiber atrophy. In this study, we analyzed muscle biopsies in order to demonstrate that, in osteoarthritis patients, both osteophytes formation and regenerative properties of muscle stem cells are related to the same factors. In particular, thanks to immunohistochemistry, transmission electron microscopy, and immunogold labeling we investigated the role of BMP-2 in muscle stem cells activity. In patients with osteoarthritis both immunohistochemistry and transmission electron microscopy allowed us to note a higher number of CD44 positive satellite muscle cells forming syncytium. Moreover, the perinuclear and cytoplasmic expression of BMP-2 assessed byin situmolecular characterization of satellite cells syncytia suggest a very strict correlation between BMP-2 expression and muscle regeneration capability. Summing up, the higher BMP-2 expression in osteoarthritic patients could explain the increased bone mineral density as well as decreased muscle atrophy in osteoarthrosic patients. In conclusion, our results suggest that the control of physiological BMP-2 balance between bone and muscle tissues may be considered as a potential pharmacological target in bone-muscle related pathology.

scholarly journals Intact satellite cells lead to remarkable protection against Smn gene defect in differentiated skeletal muscle

2003 ◽  
Vol 161 (3) ◽  
pp. 571-582 ◽  
Author(s):  
Sophie Nicole ◽  
Benedicte Desforges ◽  
Gaelle Millet ◽  
Jeanne Lesbordes ◽  
Carmen Cifuentes-Diaz ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Motor Performance ◽  
Muscular Atrophy ◽  
Early Death ◽  
Mutant Mice ◽  
Mild Phenotype

Deletion of murine Smn exon 7, the most frequent mutation found in spinal muscular atrophy, has been directed to either both satellite cells, the muscle progenitor cells and fused myotubes, or fused myotubes only. When satellite cells were mutated, mutant mice develop severe myopathic process, progressive motor paralysis, and early death at 1 mo of age (severe mutant). Impaired muscle regeneration of severe mutants correlated with defect of myogenic precursor cells both in vitro and in vivo. In contrast, when satellite cells remained intact, mutant mice develop similar myopathic process but exhibit mild phenotype with median survival of 8 mo and motor performance similar to that of controls (mild mutant). High proportion of regenerating myofibers expressing SMN was observed in mild mutants compensating for progressive loss of mature myofibers within the first 6 mo of age. Then, in spite of normal contractile properties of myofibers, mild mutants develop reduction of muscle force and mass. Progressive decline of muscle regeneration process was no more able to counterbalance muscle degeneration leading to dramatic loss of myofibers. These data indicate that intact satellite cells remarkably improve the survival and motor performance of mutant mice suffering from chronic myopathy, and suggest a limited potential of satellite cells to regenerate skeletal muscle.

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