Isolation and Characteristics of Human Muscle Stem Cells

Abstract

Objective: To establish the methods for purification, culture, and identification of adult human skeletal muscle stem cells in vitro and to explore the biological properties of the cells. Method: Muscle stem cells were obtained from the consenting donors and cultured in serum-free medium. Phenotypic characteristics of the cells and expression of cell-specific markers were determined using RT-PCR and immunocytochemistry. The cells were analyzed for their multi-lineage differentiation potential into osteoblastic, adipocyte, and smooth muscle cell lineages. Results: Primary cultured human skeletal muscle stem cells proliferated and formed the big spheres when cultured with serum-free medium. Immuno-fluorescent staining displayed PaX7 and ALDH1 positive expression in the cell spheres. Furthermore, Myod and Desmin showed positive expression in the monolayer cells derived from the spheres. The gene expressions of 0ct3/4, Nanog, Sox2, and Pax7 in the cells were determined by RT-PCR. The cell clones formed from single cells grew well. In addition, they were capable of spontaneous differentiation into myotubes in the differentiation medium and into other mesodermal cell lineages in induction medium. Conclusion: Human muscle stem cells with properties of self-renewal capacity and multidifferentiation could be successfully isolated and expanded in vitro.