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Exercise promotes satellite cell contribution to myofibers in a load-dependent manner
Evi Masschelein1, Gommaar D'Hulst1, Joel Zvick2
1Department Health Sciences and Technology, Laboratory of Exercise and Health, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland.
Skeletal Muscle
|July 11, 2020
Summary
Mechanical load from exercise drives satellite cell (SC) contribution to muscle fibers, independent of fiber type. DNA-level tracing confirmed SCs mirror myonuclear accretion during exercise.
Area of Science:
- Muscle physiology
- Cell biology
- Exercise science
Background:
- Satellite cells (SCs) are crucial for muscle repair and remodeling.
- Exercise stimulates SCs and increases myonuclear accretion.
- The precise role of mechanical load in SC contribution to myonuclei remains unclear.
Purpose of the Study:
- To investigate how varying mechanical loads during exercise influence satellite cell contribution to myonuclei.
- To determine if exercise-induced SC contribution is fiber type-dependent.
- To evaluate the accuracy of fluorescent reporter models for quantifying SC contribution.
Main Methods:
- SC fate tracing experiments in mice.
- Voluntary wheel running with varying mechanical loads.
- DNA-level fate tracing for precise quantification.
- Analysis of SC contribution to myofibers and myonuclear accretion.
Main Results:
- Eight weeks of exercise increased SC contribution to myofibers in a load-dependent manner.
- SC contribution was independent of muscle fiber type.
- SC fusion occurred even without significant muscle hypertrophy.
- DNA-level tracing revealed SC contribution mirrors myonuclear accretion.
- Fluorescent reporter models were found to be inadequate due to nuclear propagation.
Conclusions:
- Mechanical load independently promotes SC contribution to existing myofibers.
- Exercise can increase SC contribution without significant muscle hypertrophy.
- Caution is advised when using fluorescent reporter mouse models for quantitative SC analysis.
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