Synoptic view on the skeletal muscle interstitial space. Different stem cell populations become activated after acute injury (green), differentiate, and fuse to form myotubes with the support provided by various interstitial and blood derived cells (blue) either by physical contact or paracrine signalling. Satellite cell (SC); endothelial cell (endo); adipocyte (adip); mesenchymal progenitors (MPs) include the PDGFRα+ progenitors, the FAPs, and Tie2+; skeletogenic progenitors; PW1+/Pax7–interstitial cells (PICs); SK-34 cells (SK-34); telocytes (TCs); SDF-1 skeletal muscle-derived fibroblast (fib SDF-1); macrophages (M1/M2); neutrophils (Ne); myogenic endothelial cells (MECs); Tcf4 positive fibroblasts (Tcf4); adventitial cells (ACs); smooth muscle cells (SMC).
