Mechanisms of adipose stem cell interactions with muscle cells and Schwann cells
(English)Manuscript (preprint) (Other academic)
Peripheral nerve injury leads to muscle atrophy due to prolonged denervation. In a previous study, we showed the benefits of injecting Schwann cell and Schwann cell-like differentiated adipose stem cells (dASC) into the muscle to help nerve regeneration and prevent muscle atrophy. In this in vitro study, we have analyzed the possible mechanisms of how adipose stem cells interact with muscle cells and Schwann cells. Myoblast cell lines (C2C12 and L6) or rat primary Schwann cells treated with conditioned media prepared from either undifferentiated adipose stem cells or dASC proliferated more than control cultures. Stem cell mediated proliferation of myoblasts and Schwann cells was blocked by the inhibition of MAP kinase signaling (using U0126 drug) whereas the PKA pathway (inhibited with H89 drug) was only involved in myoblast proliferation. In order to assess the direct interaction of the stem cells with the muscle, we established direct in vitro co-culture of L6 myoblasts and stem cells for 2 weeks. Under these conditions a small fraction of cells fused together forming multi-nucleated elongated structures, characteristic of myotubes. These structures stained positive for fast type myosin heavy chain protein and myogenin. These effects were most pronounced in the dASC-myoblast co-cultures. ELISA analysis of the co-cultures showed high levels of secreted vascular endothelial growth factor-A (VEGF-A) and insulin like growth factor 1 proteins. Western blot analysis of denervated rat muscle tissue also showed elevated levels of VEGF-A expression in animals treated with stem cell injections. In conclusion, this study provides evidence of possible mechanisms how stem cells might influence cells of the neuromuscular system and supports the beneficial effect of using these cells for future clinical application in treatment of peripheral nerve injuries.
IdentifiersURN: urn:nbn:se:umu:diva-106897OAI: oai:DiVA.org:umu-106897DiVA: diva2:845625