Rat hair follicle-constituting cells labeled by a newly-developed somatic stem cell-recognizing antibody: a possible marker of hair follicle development
Chisa Ichikawa1, Takeshi Izawa1, Vetnizah Juniantito1, Miyuu Tanaka1, Mayuka Hori1, Katsuhiro Tanaka2, Shigeo Takenaka2, Mitsuru Kuwamura1 and Jyoji Yamate1
1Laboratories of Veterinary Pathology and 2Cellular and Molecular Biology, Division of Veterinary Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano-shi, Osaka, Japan.
Offprint requests to: Jyoji Yamate, DVM, Ph.D., Professor in Laboratory of Veterinary Pathology, Division of Veterinary Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Rinkuu Ourai Kita 1-58, Izumisano-shi, Osaka-598 8531, Japan. e-mail: yamate@vet.osakafu-u.ac.jp
Summary. A3 was generated as an antibody recognizing somatic stem cells in rat tissues. We investigated the distribution of A3-positive cells in developing rat hair follicles by immunolabeling. A3-positive cells began to be seen in the hair germ and peg in fetuses and neonates; the positive cells were epithelial cells above basal cells. Furthermore, A3-positive cells were seen in the outer root sheath adjacent to the bulge in mature hair follicles. Double immunofluorescence revealed that these A3-positive epithelial cells reacted to E-cadherin (for all epithelial elements) but not to CK15 (for basal cells/epithelial stem cells) or to nestin (for stem cells), indicating that A3-positive epithelial cells are suprabasal cells in the developing epidermic hair follicle. Additionally, spindle-shaped mesenchymal cells surrounding the hair peg and mature hair follicle reacted to A3; in double immunofluorescence, the A3-positive cells were located outside collagen type IV-positive glassy membrane, and reacted to vimentin (for mesenchmal cells), Thy-1 (for immature mesenchymal cells), CD34 (for stem cells) and nestin, but not to α-smooth muscle actin (for myofibroblasts); the positive cells were regarded as immature mesenchymal cells with stem cell nature in the connective tissue sheath of developing hair follicles. A3-positive epithelial and mesenchymal cells did not show proliferating activity. Collectively, it is considered that A3-positive cells seen in developing rat hair follicles may be quiescent post-progenitor cells with the potential to differentiate into either highly-differentiated epithelial or mesenchymal cells. A3 would become a useful antibody to know the kinetics of rat hair follicle-constituting cells. Histol Histopathol 28, 257-268 (2013)
Key words: Antibody, Immunohistochemistry, Rat hair follicle, Somatic stem cells, Suprabasal cells
DOI: 10.14670/HH-28.257