Functional characterization of quiescent keratinocyte stem cells and their progeny reveals a hierarchical organization in human skin epidermis

Abstract

Although homeostatic renewal of human skin epidermis is achieved by the combined activity of quiescent stem cells (SCs) and their actively cycling progeny, whether these two populations are equipotent in their capacity to regenerate tissue has not been determined in biological assays that mimic lifelong renewal. Using fluorescence activated cell separation strategy validated previously by us, human epidermis was fractionated into three distinct subsets: that is, α 6 bri CD71 dim, α 6 bri CD71 bri, and α 6 dim with characteristics of keratinocyte stem, transient amplifying, and early differentiating cells, respectively. The global gene expression profile of these fractions was determined by m..