In vivo dedifferentiation of human epidermal cells

Consistent with our previous study, we herein offer further evidence to demonstrate the dedifferentiation of differentiating epidermal cells into stem cells or stem cells-like in vivo. The epidermal sheets eliminated of basal cells were labeled with 6-diamidino-2-phenylindole (DAPI), and then were transplanted onto the full-thickness skin wounds nude mice. lmmunohistochemical examination of the survival sheets showed that some cells were positive for both DAPI and either cytokeratins (CK19, CK14) or beta 1 integrin in spinous and granular layers at day 7 after transplantation. Furthermore, there was a significant increase in the percentages of both alpha 6(bri) CDdim and alpha 6(bri) CD71(bri) populations in survival epidermal sheet grafts 7 d after transplantation compared with those before xenotransplantation (P < 0.05), as determined by flow cytometry. The results collectively indicated that some of the differentiated cells in engrafted epidermal sheets dedifferentiated into stem cells or stem cellslike in vivo, which offer us new evidence and insights into the dedifferentiation. (c) 2007 Published by Elsevier Ltd on behalf of International Federation for Cell Biology.