Calcitonin gene-related peptide regulates the growth of epidermal stem cells in vitro

Epidermal stem cells are characterized as slow-cycling, multi-potent, self-renewing cells that not only maintain somatic homeostasis, but also participate in tissue regeneration and repair. Various factors can influence the growth of epidermal stem cells. Recently, dysregulation of epidermal stem cells has been reported to be involved in epidermal hyperproliferative diseases and skin tumors. To determine the effect of calcitonin gene-related protein (CGRP), a cutaneous nerve neuropeptide, on the growth of human epidermal stem cells, epidermal stem cells were isolated from human skin and cultured in vitro. Epidermal stem cells grow well and maintain a high proliferative ability in Epilife medium, and express high levels of beta 1-integrin. CGRP (10(-8) M) can promote epidermal stem cells to enter the S phase and increase the number of bromodeoxyuridine (BrdU)-labeled cells; the expression of beta-catenin and c-myc genes are deregulated during this process, which can be compromised by CGRP8-37 peptide, an antagonist of CGRP receptor. Experimental evidence suggests that epidermal stem cells can be cultured in vitro for a period of time with preservation of stem cell characteristics. CGRP can stimulate epidermal stem cells to detach from their niche, break quiescence, and undergo division; beta-catenin and c-myc may functionally be involved in the process. (C) 2010 Elsevier Inc. All rights reserved.