Satellite cells preparation and culture

Primary satellite cells were prepared from extensor digitorum longus (EDL) muscles from C57BL/6 or C57BL/6-GFP mice by dissociation with type 1 collagenase (Worthington), as described previously [19]. Briefly, isolated muscles were dissociated by incubation in 0.2% type 1 collagenase/DMEM for 80–90 min and unraveled by gentle pipetting. Single muscle fibers were then isolated and plated on Matrigel-coated plastic dishes. Isolated muscle fibers with primary satellite cells were cultured in DMEM (high-glucose, sodium pyruvate and GlutaMAX supplement, Thermo Fisher Scientific) supplemented with 20% fetal bovine serum, 1% chicken embryo extract (US Biological) and 1% penicillin-streptomycin (Thermo Fisher Scientific) at 37°C with 5% CO₂ with or without 5 ng/ml LIF (PROSPEC) for 5 days.