Fusion and beyond: Satellite cell contributions to loading‐induced skeletal muscle adaptation

Abstract

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Positional Context of Myonuclear Transcription During Injury-Induced Muscle Regeneration

“…Myonuclear accretion facilitates myofiber hypertrophy during development ( Moss and Leblond, 1971 ; White et al, 2010 ; Bachman et al, 2018 ; Cramer et al, 2020 ) and after resistance exercise ( Egner et al, 2016 ; Goh and Millay, 2017 ; Murach et al, 2021 ). To explore the extent to which myonuclear accretion facilitates regenerating myofiber hypertrophy after injury, we performed correlational analyses using myonuclear number and myofiber volume (mm 3 ).…”

“…Myonuclear accretion occurs during postnatal development ( Moss and Leblond, 1971 ; White et al, 2010 ; Bachman et al, 2018 ; Cramer et al, 2020 ) and after resistance exercise training ( Egner et al, 2016 ; Goh and Millay, 2017 ; Murach et al, 2021 ). In both cases, myonuclei appear to be added to existing myofibers and positioned in a peripheral location.…”

RhoA within myofibers controls satellite cell microenvironment to allow hypertrophic growth

“…The contribution of SCs in skeletal muscle hypertrophic growth has been highly debated and one factor that could explain the discrepancies toward the necessity of new myonuclei accretion is the age of the mice, as young mice (less than 4 months old) and not mature mice (more that 4 months old) require SC fusion to support myofiber hypertrophy ( Murach et al., 2017 , 2021a ). Because age dependence was not the main focus of this study, we pointed our attention on 2- to 3-month-old mice.…”

Preserved stem cell content and innervation profile of elderly human skeletal muscle with lifelong recreational exercise

“…Given their role as the sole source of myonuclei, satellite cells are also involved in the hypertrophic response to exercise (Murach et al . 2021 a ). Studies using satellite cell‐depleted mice have shown that some hypertrophy can be achieved without satellite cells, but in order to maximize the response to long‐term training, satellite cells are required (Englund et al .…”

“…Satellite cells are indispensable during embryonic myogenesis and for muscle regeneration during adulthood (Engquist & Zammit, 2021), due to their ability to proliferate, fuse and form myotubes. Given their role as the sole source of myonuclei, satellite cells are also involved in the hypertrophic response to exercise (Murach et al 2021a). Studies using satellite cell-depleted mice have shown that some hypertrophy can be achieved without satellite cells, but in order to maximize the response to long-term training, satellite cells are required (Englund et al 2020).…”