“Known Unknowns”: Current Questions in Muscle Satellite Cell Biology

Exercise promotes satellite cell contribution to myofibers in a load-dependent manner

“…Whether SCs are required for muscle hypertrophy is a heavily debated topic (Egner et al, 2017) and likely depends on age, genetic mutation, models used to induce hypertrophy and time of sampling after the applied stimulus (Cornelison, 2018;Goh et al, 2019;Goh and Millay, 2017;Mccarthy et al, 2017;Murach et al, 2018;O'Connor et al, 2007). Moreover, impairing SC contribution by the frequently used…”

“…Mice have a strong intrinsic drive to run large distances in their active phase (De Bono et al, 2005), which keeps stress and mouse handling at a minimum. Furthermore, by applying resistance to the running wheel, muscle hypertrophy can be induced without substantial muscle damage (Cornelison, 2018;Legerlotz et al, 2008;Mccarthy et al, 2017;Murach et al, 2018;O'Connor et al, 2007;Soffe et al, 2016;White et al, 2016) and reducing wheel resistance (free running) leads to favorable endurance adaptations without pronounced effects on muscle hypertrophy (Jackson et al, 2015;Manzanares et al, 2019). Thus, using this exercise model in combination with genetic lineage tracing experiments of SCs, we aimed to evaluate whether SC contribution to myonuclei is mediated by increasing load during exercise training and whether this manifests in SC-mediated myonuclear accretion.…”

Exercise promotes satellite cell contribution to myofibers in a load-dependent manner

“…Future studies will need to reveal the exact contribution of both mechanisms to exercise-induced myonuclear accumulation. Whether SCs are required for muscle hypertrophy is a heavily debated topic [51] and likely depends on age, genetic mutation, models used to induce hypertrophy and time of sampling after the applied stimulus [6,8,[19][20][21]25,52,53]. Moreover, impairing SC contribution by the frequently used Pax7 CreER-DTA model might evoke undesirable adaptations such as impairments of proprioception and reduced voluntary wheel running, which do not re ect physiological circumstances [16].…”

Exercise promotes satellite cell contribution to myofibers in a load-dependent manner

“…Whether SCs are required for muscle hypertrophy is a heavily debated topic [40] and likely depends on age, genetic mutation, models used to induce hypertrophy and time of sampling after the applied stimulus [6,8,[19][20][21]25]. Moreover, impairing SC contribution by the frequently used Pax7 CreER − DTA model might evoke undesirable adaptations such as impairments of proprioception and reduced voluntary wheel running, which do not reflect physiological circumstances [16].…”

“…Mice have a strong intrinsic drive to run large distances in their active phase [18], which keeps stress and mouse handling at a minimum. Furthermore, by applying resistance to the running wheel, muscle hypertrophy can be induced without substantial muscle damage [19][20][21][22][23][24][25] and reducing wheel resistance (free running) leads to favorable endurance adaptations without pronounced effects on muscle hypertrophy [16,26]. Thus, using this exercise model in combination with genetic lineage tracing experiments of SCs, we aimed to evaluate whether SC contribution to myonuclei is mediated by increasing load during exercise training and whether this manifests in SCmediated myonuclear accretion.…”