| Tissue repair after injury is a complex biological process, which involves the activation of tissue-resident precursors and stem cells, and a variety of infiltrating cells responding to local and systemic signals. Mammalian skeletal muscle regeneration relies on the activation and proliferation of the resident muscle precursor cells1,2 including satellite cells and muscle stem cells (MuSCs), which are populations of mononucleated cells located between the basal lamina and sarcolemma of muscle fibers. MuSCs are a functionally heterogeneous population of cells and have variable proliferation rates, marker expression profiles, self-renewal capacities, clonogenicity and differentiation capacities2,3. We have previously discovered that among MuSCs, a small population of iMuSCs exist and can be isolated from injured murine skeletal muscles using a Cre-LoxP system established in our laboratory4. We have shown that iMuSCs not only express CD34, Sca1 (Stem cell antigen-1), and Pax7 (Paired box protein 7), but also presented strong myogenic differentiation and muscle regeneration abilities in vivo5. In addition, we demonstrated that iMuSCs demonstrate stem cell behaviors, and are capable of differentiating into non-myogenic lineages, such as CD31+ endothelial-like cells in the healed skeletal muscle4. Here, we further investigate the unique nature of the iMuSCs, focusing on their morphology, marker expression profile, pluripotency, migratory abilities and differentiation potential. |
