In vitro-induced differentiation of bone marrow mesenchymal stem cells into melanocytes

Large numbers of autogenous melanocytes (Mcs) are required when conducting studies on tissue engineering of skin and performing surgical treatment of depigmentation diseases. This study was conducted to explore the possibility of inducing differentiation of bone marrow mesenchymal stem cells (MSCs) into Mcs as a means of providing autogenous Mcs for purposes of tissue engineering and clinical treatment. MSCs were harvested from the bone marrows of black mice; and after six passages, hydrocortisone, insulin, transferrin and fibroblast growth factor were applied to induce their differentiation into Mcs. The morphological and ultrastructural characteristics of the newly differentiated cells were observed. The transcription and expression of multiple markers were examined using qRT-PCR, Western blot, and immunofluorescence analysis. Cell cycle phases and yields of Mcs were analyzed by flow cytometry. Following 120-180 days induction, differentiated cells were morphologically similar to Mcs, and mature melanosomes were observed. Multiple markers of Mcs, but not melanoma cells, were expressed by the differentiated cells. Most induced Mcs were in phase G1 or S, and yield of target cells was ∼80%. Mcs induced from bone marrow MSCs for periods of 120-180 days represent a potential source of autogenous Mcs.