title: Fibroblast growth factor 5 inhibits hair growth by blocking dermal papilla cell activation.
abstract: Fibroblast growth factor (FGF) 5 inhibits hair growth and induces catagen in mouse hair follicles, in vivo. Given that FGF-5 receptor (FGFR1) is expressed in dermal papilla cells (DPCs), which are known to stimulate outer root sheath cell (ORSC) proliferation, we hypothesized that FGF-5 attenuates DPC-mediated ORSC proliferation. In the present study, DPCs and ORSCs were isolated from rat vibrissae, after which the effects of FGF-5 on proliferation of ORSCs cultured in DPC-conditioned medium were assessed. We first confirmed that FGFR1 was expressed in cultured DPCs and detected FGFR2-4 as well. ORSC proliferation was increased approximately twofold when the cells were cultured in DPC-conditioned medium, and the effect was unaltered by FGF-5. In addition, FGF-5 did not directly inhibit ORSC proliferation; indeed, it actually promoted proliferation of both DPCs and ORSCs. When DPCs were first activated by exposure to FGF-1 and FGF-2, which are expressed in hair follicles during anagen, ORSC proliferation observed in the resultant conditioned medium was substantially greater than in medium conditioned by unstimulated DPCs. The FGF-1-induced enhancement was reversed by FGF-5, diminishing ORSC proliferation to control levels. By contrast, the enhancement of DPC-mediated ORSC proliferation by FGF-2 was not suppressed by FGF-5. Proliferation of ORSCs did not depend on DPC proliferation, nor did FGF-1 directly promote ORSC proliferation. Dermal papillae thus appear to require activation before they will efficiently stimulate hair growth, and FGF-5 appears to inhibit hair growth and induce catagen by blocking that activation.
authors.affiliation: POLA Laboratories, POLA Chemical Institute Inc., 560 Kashio-cho, Totsuka-ku, Yokohama 244-0812, Japan. yota@pola.co.jp
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ota
authors.forename: Yuko
authors.initials: Y
authors.lastname: Saitoh
authors.forename: Satoshi
authors.initials: S
authors.lastname: Suzuki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ozawa
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Kawano
authors.forename: Toru
authors.initials: T
authors.lastname: Imamura
mesh_terms: D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005343:Fibrinolytic Agents / Q000494:pharmacology; D016220:Fibroblast Growth Factor 1 / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D051521:Fibroblast Growth Factor 5; D005346:Fibroblast Growth Factors / Q000378:metabolism* / Q000494:pharmacology; D006197:Hair / Q000166:cytology*; D018859:Hair Follicle / Q000166:cytology*; D006493:Heparin / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor / Q000096:biosynthesis / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013997:Time Factors
chemical_list: C496451:Fgf5 protein, rat; D005343:Fibrinolytic Agents; D017468:Receptors, Fibroblast Growth Factor; D011994:Recombinant Proteins; D016222:Fibroblast Growth Factor 2; D016220:Fibroblast Growth Factor 1; D051521:Fibroblast Growth Factor 5; D005346:Fibroblast Growth Factors; D006493:Heparin; C496350:Fgfr1 protein, rat; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1