Satellite cells were isolated as previously described [27 (link)] from hindlimb muscles. Cells were labeled using the following antibodies: 1:400 CD31-PE (clone 390; eBiosciences), 1:400 CD45-PE (clone 30-F11; BD Pharmingen), 1:4000 Sca-1-PE-Cy7 (clone D7; BD Pharmingen), 1:500 α7-integrin-APC (Clone R2F2; AbLab). Dead cells were excluded by propidium iodide (PI) staining. Cell sorting was performed using a BD FACSAria II cell sorter (Becton-Dickinson). Sorted cells were immediately reanalyzed to ensure purity. Analyses of flow cytometry data were performed using FACSDiva (BD version 8.0.1).