l-Ascorbic acid 2-phosphate promotes elongation of hair shafts via the secretion of insulin-like growth factor-1 from dermal papilla cells through phosphatidylinositol 3-kinase.
BACKGROUND
l-Ascorbic acid 2-phosphate (Asc 2-P), a derivative of l-ascorbic acid, promotes elongation of hair shafts in cultured human hair follicles and induces hair growth in mice.


OBJECTIVE
To investigate whether the promotion of hair growth by Asc 2-P is mediated by insulin-like growth factor-1 (IGF-1) and, if so, to investigate the mechanism of the Asc 2-P-induced IGF-1 expression.


METHODS
Dermal papilla (DP) cells were cultured and IGF-1 level was measured by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay after Asc 2-P treatment in the absence or presence of LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor. Also, hair shaft elongation in cultured human scalp hair follicles and proliferation of cocultured keratinocytes were examined after Asc 2-P treatment in the absence or presence of neutralizing antibody against IGF-1. In addition, keratinocyte proliferation in cultured hair follicles after Asc 2-P treatment in the absence or presence of LY294002 was examined by Ki-67 immunostaining.


RESULTS
IGF-1 mRNA in DP cells was upregulated and IGF-1 protein in the conditioned medium of DP cells was significantly increased after treatment with Asc 2-P. Immunohistochemical staining showed that IGF-1 staining is increased in the DP of cultured human hair follicles by Asc 2-P. The neutralizing antibody against IGF-1 significantly suppressed the Asc 2-P-mediated elongation of hair shafts in hair follicle organ culture and significantly attenuated Asc 2-P-induced growth of cocultured keratinocytes. LY294002 significantly attenuated Asc 2-P-inducible IGF-1 expression and proliferation of follicular keratinocytes in cultured hair follicles.


CONCLUSIONS
These data show that Asc 2-P-inducible IGF-1 from DP cells promotes proliferation of follicular keratinocytes and stimulates hair follicle growth in vitro via PI3K.
Department of Immunology, Kyungpook National University, Daegu, Korea.
M H
MH
Kwack
S H
SH
Shin
S R
SR
Kim
S U
SU
Im
I S
IS
Han
M K
MK
Kim
J C
JC
Kim
Y K
YK
Sung
D000818:Animals; D001205:Ascorbic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D020405:Dermis / Q000166:cytology / Q000187:drug effects; D006197:Hair / Q000254:growth & development*; D018859:Hair Follicle / Q000187:drug effects*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*
C011669:ascorbate-2-phosphate; D007334:Insulin-Like Growth Factor I; D019869:Phosphatidylinositol 3-Kinases; D001205:Ascorbic Acid