Ephrin-A3 not only increases the density of hair follicles but also accelerates anagen development in neonatal mice.
BACKGROUND
Ephrins are cell-membrane-bound ligands for Eph receptor tyrosine kinases (Eph). Although ephrins are known to regulate a variety of developmental processes, little is known of their role in hair development. Previously, we studied the gene expression of dermal papilla cells from androgenetic alopecia and found that ephrin-A3 was significantly down-regulated.


OBJECTIVE
To characterize the expression of ephrin-A3 in the hair cycle and evaluate the effect of ephrin-A3 on hair growth.


METHODS
We investigated gene expression and protein expression of each ephrin-As and EphAs in the skin of neonatal mice through the first and second hair cycle using quantitative PCR and immunohistochemical analysis, respectively. We also injected ephrin-A3 protein into the skin of neonatal mice and demonstrated the effect of ephrin-A3 on hair follicle development.


RESULTS
Expression of ephrin-A3 revealed a rapid increase at the beginning of the anagen phase, a peak during the mid-anagen, and a rapid fading during the telogen phase. In addition, we found ephrin-A3 protein was expressed in the developing hair follicles with a characteristic spatiotemporal localization. Furthermore, injection of ephrin-A3 into the skin of neonatal mice markedly accelerated the differentiation process of hair follicles. In addition, injection of ephrin-A3 unexpectedly increased the number of hair follicles.


CONCLUSIONS
These findings demonstrated that ephrin-A3 not only accelerates anagen development but also increases the density of hair follicles, and also suggested that an ephrin-A-EphA signal pathway is closely involved in hair follicle development.
Yamada
Yuko
Y
Biological Science Research Center, Lion Corporation, Kanagawa 256-0811, Japan. yuko65@lion.co.jp
Midorikawa
Tatsuyuki
T
Oura
Hajimu
H
Yoshino
Teruhiko
T
Ohdera
Motoyasu
M
Kubo
Yoshiaki
Y
Arase
Seiji
S
D000818:Animals; D000831:Animals, Newborn; D042783:Endothelial Cells / Q000737:chemistry; D036384:Ephrin-A3 / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D005260:Female; D018859:Hair Follicle / Q000254:growth & development*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL
D036384:Ephrin-A3