Mayumi ITO, PhD
Assistant Professor of Dermatology
Ph.D. 2003 Nagoya University
Research Theme(s):Stem Cell Biology, Dermatology, Regenerative Medicine
Keywords: Tissue Regeneration, Stem Cell, Hair Follicle, Melanocytes
Epithelial stem cells in the hair follicle bulge contribute skin epidermal cells during wound healing (Ito et al., Nature Medicine 2005).
Our study demonstrated that epithelial bulge cells, which are responsible for hair follicle renewal during the hair cycle, significantly contribute to skin wound healing. This study also demonstrated that epithelial bulge cells are required for hair follicle renewal but not for skin epidermis under normal homeostatic conditions. These discoveries provided a novel model from which to study the mechanisms underlying cell fate decisions in adult stem cells during tissue regeneration.
De novo hair follicle formation in adult skin (Ito et al., Nature 2007)
It was thought that skin appendage cannot regenerate once it is lost by injury or diseases. We discovered that mammalian hair follicles can regenerate in adult skin following wounding. Our study also showed that epithelial stem cells are repopulated in the bulge area of de novo hair follicles. This discovery was received as the first example of amphibian-like organ regeneration in mammals and paved the way to our understanding of the molecular mechanisms that control organogenesis in adult mammals.
Heterotypic stem cell communication during hair follicle regeneration (Rabbani et al., Cell 2011)
Colored hair regeneration is a result of the collaboration between these two distinct stem cell populations in the hair follicle-epithelial stem cells and melanocyte stem cells. Epithelial stem cells regenerate hair. Melanocyte stem cells, on the other hand, become melanocytes that produce pigment for the hair. We asked how these different stem cell types coordinate their response during hair follicle regeneration. Utilizing mouse genetic models, we discovered that Wnt signal is essential for coordinated actions of stem cells of these two lineages. Wnt activation drives differentiation into pigment-producing melanocytes, whereas in epithelial stem cells, Wnt signaling not only dictates hair follicle formation but also regulates melanocyte stem cell proliferation. Our study provided a mechanism for how different cell types coordinate their response during the regeneration of a complex mammalian organ.
Selected Publications (2005-2011)
- Coordinated activation of Wnt in epithelial and melanocyte stem cells initiates pigmented hair regeneration. Rabbani P, Takeo M, Chou W, Myung P, Bosenberg M, Chin L, Taketo MM, Ito M. Cell. 2011 Jun 10;145(6):941-55. PMID: 21663796
- Defining hair follicle stem cell (Part I) (Review). Myung P, Andl T, Ito M. J Cutan Pathol. 2009; 36:1031-1034. PMID: 19674210
- Defining hair follicle stem cell (Part II) (Review). Myung P, Andl T, Ito M. J Cutan Pathol 2009; 36: 1134-1137. PMID: 19712246
- Wnt-dependent de novo hair follicle regeneration in adult mouse skin following wounding. Ito M, Yang Z, Andl T, Cui C, Kim N, Millar S, Cotsarelis G. Nature 2007; 17:316-320. PMID: 17507982
- Stem cells in the hair follicle bulge contribute to wound repair but not to homeostasis of the epidermis. Ito M, Liu Y, Yang Z, Nguyen J, Liang F, Morris R, Cotsarelis G . Nature Medicine 2005; 11:1351-1354. PMID: 16288281