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Hair follicle stem cells are specified and function in early skin morphogenesis.
Cell Stem Cell. 2008 Jul 3; 3(1):33-43
Manabu Ohyama, Keio University School of Medicine, Japan. F1000 Dermatology
10 Sep 2008 | New Finding
This study provides new important concepts and represents one of the most significant contributions to epithelial stem cell biology.
It has been reported that the bulge region of hair follicles harbors multipotent epithelial stem cells that not only regenerate hair follicles in hair cycles but also provide a cellular input to epidermal and sebaceous lineages in a wound condition. However, the origin of the adult bulge stem cells and the mechanisms underlying the niche architecture formation have remained unclear. In this paper, the authors revealed that Sox9 plays a crucial role in the specification of early hair follicle stem cells, which contribute to all epithelial lineages.
Using label retaining cell (LRC) techniques, they first demonstrated that quiescent stem cells were present in the earliest stage of hair morphogenesis, and those cells persisted in the adult bulge. Sox9 was detected in those LRCs, and the cells marked by Sox9 were required for the completion of hair morphogenesis. In addition, Sox9-positive cells contributed to all epithelial lineages. Embryonic conditional ablation of Sox9 resulted in the loss of bulge stem cells, the loss of hair matrix to form hair shaft and the loss of sebaceous glands in adult hair follicles. Furthermore, wound healing was significantly impaired without Sox9 expression.
Competing interests: No potential interests relevant to this article were reported.
Ohyama M: "This study provides new important concepts and represents one of the most significant contributions to..." Evaluation of: [Nowak JA et al. Hair follicle stem cells are specified and function in early skin morphogenesis. Cell Stem Cell. 2008 Jul 3; 3(1):33-43; doi: 10.1016/j.stem.2008.05.009]. Faculty of 1000, 10 Sep 2008. F1000.com/1119521#eval575727
Short form
Ohyama M: 2008. F1000.com/1119521#eval575727
Faculty of 1000 evaluations, dissents and comments for [Nowak JA et al. Hair follicle stem cells are specified and function in early skin morphogenesis. Cell Stem Cell. 2008 Jul 3; 3(1):33-43; doi: 10.1016/j.stem.2008.05.009]. Faculty of 1000, 10 Sep 2008. F1000.com/1119521
Short form
Faculty of 1000: 2008. F1000.com/1119521
In adult skin, epithelial hair follicle stem cells (SCs) reside in a quiescent niche and are essential for cyclic bouts of hair growth. Niche architecture becomes pronounced postnatally at the start of the first hair cycle. Whether SCs exist or function earlier is unknown. Here we show that slow-cycling cells appear early in skin development, express SC markers, and later give rise to the adult SC population. To test whether these early slow-cycling cells function as SCs, we use Sox9-Cre for genetic marking and K14-Cre to embryonically ablate Sox9, an essential adult SC gene. We find that the progeny of Sox9-expressing cells contribute to all skin epithelial lineages and Sox9 is required for SC specification. In the absence of early SCs, hair follicle and sebaceous gland morphogenesis is blocked, and epidermal wound repair is compromised. These findings establish the existence of early hair follicle SCs and reveal their physiological importance in tissue morphogenesis.
DOI: 10.1016/j.stem.2008.05.009
PMID: 18593557
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