Differentiation factors induce expression of muscle, fat, cartilage, and bone in a clone of mouse pluripotent mesenchymal stem cells.

Growth factors have been used experimentally to accelerate wound healing by increasing scar tissue formation at a wound site. These studies suggest that stimulation of fibroblastic differentiation and proliferation are essential components of adult tissue repair. Recent studies report the presence of mesenchymal stem cells within granulation tissue and as connective tissue-resident stem cells. This suggests that mesenchymal stem cells as well as fibroblasts may contribute to wound healing and repair. To determine the potential for mesenchymal stem cells to contribute to nonfibrogenic tissue repair, a clonal population of murine mesenchymal stem cells was examined with dexamethasone, a general differentiation agent, and muscle morphogenetic protein, a specific differentiation-inducing agent. Dexamethasone induced the expression of phenotypic markers for fat, cartilage, and bone in the stem cells. Muscle morphogenetic protein induced the expression of mRNAs for the muscle specific regulatory genes MyoD1 and myogenin in these cells. These results suggest that pluripotent mesenchymal stem cells within connective tissue compartments and granulation tissue have the potential to contribute to functional tissue restoration, rather than contributing solely to fibrogenic scar tissue formation during tissue repair.