075 Antisense Oligonucleotides Targeting Fibroblast Growth Factor Receptor (FGFR)-1 Stimulate Hair Follicle Growth in an in vitro Organ Culture System

R. Tsuboi, R Ueki, H Ogawa. Dept. of Dermatology, Juntendo University School of Medicine, Tokyo, Japan

The hair cycle is regulated by various molecules, among which FGF-5 has been shown to promote the transition from anagen to catagen. FGFR-1, a trans-membrane receptor of FGF-5 with the tyrosine kinase activity, was found to be localized in the follicular papilla of hair follicles. In order to apply antisense oligonucleotides targeting FGFR-1 as a treatment for baldness, we examined the effect of the oligonucleotides on hair follicle growth in a serum-free organ culture system. Vibrissal hair follicles isolated from variously aged C3H/He mice were cultured in the presence of a reagent at 31°C in 95% O2-5% CO2 for 72 h. Several 20-mer antisense nucleotides and their randomly arranged counterparts were prepared by predicting the effective target site of FGFR-1 mRNA. Elongation of the hair shaft was measured and cellular activity in the hair bulb was estimated by measuring the fluorescence intensity (FI) of the medium after incubation with AlamarBlue dye. Incorporation of the oligonucleotides into the outer root sheath, hair matrix and follicular papilla was histologically confirmed by incubation with FITC-labeled oligonucleotides for 24 h. Addition of 30µM of antisense oligonucleotides (A1561TS) to the media, but not their control (RA1561TS), increased FI by AlamarBlue from 30 to 50%. This effect was reproducible and dose dependent with maximal stimulation at 30µM. However, significant elongation of the hair shaft was not observed during the 72 h incubation. Treatment with antisense nucleotides maintained the intact morphological structure of the hair bulb after 72 h incubation. These results suggest the clinical utility of antisense nucleotides targeting FGFR-1. Further experiments using the mouse model are now underway.