Androgen receptor co-activator Hic-5/ARA55 as a molecular regulator of androgen sensitivity in dermal papilla cells of human hair follicles.
Androgen site-specifically affects human hair growth after puberty through androgen receptors in the dermal papilla, which transactivate target genes acting in conjunction with co-activators. To examine the regulation of androgen sensitivity in hair follicles, we focused on androgen receptor co-activator Hic-5/ARA55. Its interaction with transfected androgen receptor in beard dermal papilla cells was confirmed with mammalian two-hybrid assays. The semiquantitative reverse transcriptase-polymerase chain reaction showed that Hic-5/ARA55 mRNA expression was high in dermal papilla cells from the beard and bald frontal scalp but low in cells from the occipital scalp. To determine whether Hic-5/ARA55 mRNA level correlates with its endogenous activity, we studied the effect of dominant negative Hic-5/ARA55 on transfected androgen receptor transactivation induced by R1881 using mouse mammary tumor virus-luciferase assays. We found that it suppressed the transactivation by 64.5 and 71.4% in dermal papilla cells from the beard and bald frontal scalp, respectively, whereas it showed no significant effect in cells from the occipital scalp. Our findings suggest that Hic-5/ARA55 is a molecular regulator for androgen sensitivity in human hair follicles.
Inui
Shigeki
S
Department of Regenerative Dermatology, Graduate School of Medicine, Osaka University, Osaka, Japan.
Fukuzato
Yoko
Y
Nakajima
Takeshi
T
Kurata
Sotaro
S
Itami
Satoshi
S
D000293:Adolescent; D000328:Adult; D000728:Androgens / Q000502:physiology*; D002478:Cells, Cultured; D005145:Face; D006197:Hair / Q000254:growth & development / Q000502:physiology; D018859:Hair Follicle / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D060588:LIM Domain Proteins; D008297:Male; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011944:Receptors, Androgen / Q000502:physiology*; D012535:Scalp / Q000166:cytology / Q000378:metabolism; D015533:Transcriptional Activation; D014162:Transfection
D000728:Androgens; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; D012333:RNA, Messenger; D011944:Receptors, Androgen; C490351:TGFB1I1 protein, human