Abstract
Tissue stem cells have great potential as a source of tissue for regenerative medicine. Epidermal stem cells (EpSCs) are the most accessible population of tissue stem cells that can regenerate the specialized cell types of tissues including the epidermis, smooth muscle and the sciatic nerve. However, the difficulties in isolation of the high numbers of EpSCs and their long-term culture have hampered the development of wider clinical applications of EpSCs. Here, we present a novel approach to EpSC culture that utilizes a feeder layer of Swiss 3T3 cells expressing the putative EpSC niche-specific molecule, CD200R. The colony forming efficiency of CD34+, α6-integrin+ EpSCs was increased on CD200R-expressing Swiss 3T3 feeder cells compared with normal Swiss 3T3 feeder cells. Furthermore, treatment with glycogen synthase kinase (GSK)-3 inhibitor, an activator of Wnt signaling, synergistically enhanced the proliferation of EpSCs. These results raise the possibility that an artificial microenvironment equivalent to in vivo niches will enable the persistent culture of EpSCs, thereby increasing the utility of EpSCs for tissue engineering and regeneration.
