Schwann-like cells from human melanocytes and their fate in sciatic nerve injury.

We induced human melanocyte dedifferentiation to Schwann cell-like cells in vitro by a combination of forskolin, neuregulin-β1, neurotrophin-3, platelet-derived growth factor-aa, basic fibroblast growth factor, laminin, and heparin. Cultured human melanocytes constitutively expressed neural cell and melanocyte markers but melanocyte-specific marker, including microphthalmia-associated transcription factor and tyrosinase, expression was selectively lost after induction. In the sciatic nerve injury site, the induced cells were engrafted and closely aligned to axons and P0-expressing myelin sheaths, whereas uninduced cells were not colocalized with axons and myelin sheaths and reexpressed melanocyte-specific tyrosinase activity in vivo. Human melanocytes lose their melanocyte phenotype and transdifferentiate into Schwann cells under specific induction conditions and display their Schwann cell phenotype after transplantation to injured sciatic nerve tissue.