The Injury Induced Population Of Muscle-Derived Stem Cell-Like Cells
Tissue repair after injury is a complex biological process, which involves the activation of tissue-resident precursors or/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 cells including satellite cells and muscle stem cells (MuSCs), which are populations of mononucleated cells located between the basal lamina and sarcolemma of muscle fibers. Those MuSCs are able to devise and differentiate to response the tissue regeneration and repair. However, the behaviors of MuSCs and their regulations within the injured environment have not been well studied. We recently discovered a novel population of stem cells from the injured murine muscles. These injury induced muscle-derived stem cell-like cells (iMuSCs) are partially reprogrammed from differentiated myogenic cells and display a pluripotent-like state. The iMuSCs exhibit stem cell properties including the ability to differentiate into multiple lineages, such as neurogenic and myogenic differentiation; they also display a superior migration capacity that demonstrating a strong ability of muscle engraftment in vivo. IMuSCs express several pluripotent and myogenic stem cell markers; have the capability to form embryoid bodies and teratomas, and can differentiate into all three germ layers. Moreover, blastocyst microinjection showed that the iMuSCs contributed to chimeric embryos but could not complete germline transmission. Our results indicate that the iMuSCs are in a partially reprogrammed state of pluripotency, which is generated by the microenvironment of injured skeletal muscle.