Melanocyte stem cells: As an excellent model to study stem cell biology

Abstract

Elucidation of molecular mechanisms underlying stem cell regulation is of great importance for their clinical applications in regenerative medicine and cancer therapy. The function of stem cells is maintained by their specialized microenvironment, referred as the niche. Despite intensive studies of the stem cell niche, the molecular basis of stem cell regulation by the niche has still remained elusive. Since molecular interactions between stem cells and the niche can be analyzed only under in vivo conditions, one drawback that hampers stem cell research is the lack of an efficient in vivo assay system that allow to define an in vivo gene function for the regulation of stem cells. We have previously identified melanocyte stem cells (MSCs) in the mouse hair follicle, in which MSCs reside at a specific region of the hair follicle, termed as the lower permanent portion. MSCs offer an attractive model with which to study the molecular basis of stem cell regulation, because loss-of-function mutations in the genes responsible for MSC regulation are readily identifiable by a premature hair graying phenotype in mice. This implies the irresistible possibility that MSCs allows us to identify the genes involved in stem cell regulation by a phenotype-driven genetic screen in mice. Hence, we believe that MSC system is an excellent model to study stem cell biology. © 2008 Springer Netherlands.