Conditional TGF-β1 treatment increases stem cell-like cell population in myoblasts.
Bottom Line: The limitation in successfully acquiring large populations of stem cell has impeded their application.In addition to the C2C12 myoblasts, similar effects of TGF-β(1) were also observed in the primary myoblasts of mice.Our results suggest that TGF-β(1) is effective as a molecular trigger for the dedifferentiation of skeletal muscle myoblasts and could be used to generate a large pool of progenitor cells that collectively behave as multipotent stem cell-like cells for regenerative medicine applications.
Affiliation: The Laboratory of Molecular Pathology, Stem Cell Research Center, Children's Hospital of UPMC, Pittsburgh, PA, USA.Show MeSH
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Mentions: C2C12 myoblasts were cultured in serum-free DMEM for 24 hrs to allow for proliferation arrest and differentiation. Cells were then transiently treated with hrTGF-β1 (0, 0.1, 0.5 and 2.0 ng/ml) before being cultured with BrdU in the growth medium for 12 hrs. The ratio of cells with newly synthesized DNA (BrdU+) can indicate if and what dosage of TGF-β1 treatment can induce S-phase re-entry of proliferation-arrested C2C12 myoblasts. Results showed that TGF-β1 treatment, especially at 0.5 ng/ml, resulted in a greater number of BrdU+ cells than the control non-treated groups (Fig. 2A–E), indicating that S-phase re-entry occurred after treatment. In another experiment, proliferation-arrested C2C12 myoblasts were treated with hrTGF-β1 (0.5 ng/ml) and then cultured for another 5 hrs in growth medium before being harvested for PI staining. Compared to control groups, more cells were detected in S-phase (47.13%versus 29.33%) in the TGF-β1 treated groups (Fig. 2F), indicating the S-phase re-entry of some cells after TGF-β1 treatment. The promoted cell cycle re-entry by TGF-β1 stimulation may also indicate improved capabilities of self-renewal and long-term proliferation, which are similar to the characteristics of muscle stem cells .
Affiliation: The Laboratory of Molecular Pathology, Stem Cell Research Center, Children's Hospital of UPMC, Pittsburgh, PA, USA.