The androgen metabolite, 5alpha-androstane-3beta, 17beta-diol, is a potent modulator of estrogen receptor-beta1-mediated gene transcription in neuronal cells.
5alpha-Androstane-3beta, 17beta-diol (3betaAdiol) is a metabolite of the potent androgen, 5alpha-dihydrotestosterone. Recent studies showed that 3betaAdiol binds to estrogen receptor (ER)-beta and regulates growth of the prostate gland through an estrogen, and not androgen, receptor-mediated pathway. These data raise the possibility that 3betaAdiol could regulate important physiological processes in other tissues that produce 3betaAdiol, such as the brain. Although it is widely accepted that the brain is a target for 5alpha-dihydrotestosterone action, there is no evidence that 3betaAdiol has a direct action in neurons. To explore the molecular mechanisms by which 3betaAdiol might act to modulate gene transcription in neuronal cells, we examined whether 3betaAdiol activates ER-mediated promoter activity and whether ER transactivation is facilitated by a classical estrogen response element (ERE) or an AP-1 complex. The HT-22 neuronal cell line was cotransfected with an expression vector containing ERalpha, ER-beta1, or the ERbeta splice variant, ER-beta2 and one of two luciferase-reporter constructs containing either a consensus ERE or an AP-1 enhancer site. Cells were treated with 100 nM 17beta-estradiol, 100 nM 3betaAdiol, or vehicle for 15 h. We show that 3betaAdiol activated ER-beta1-induced transcription mediated by an ERE equivalent to that of 17beta-estradiol. By contrast, 3betaAdiol had no effect on ERalpha- or ER-beta2-mediated promoter activity. Moreover, ER-beta1 stimulated transcription mediated by an ERE and inhibited transcription by an AP-1 site in the absence of ligand binding. These data provide evidence for activation of ER signaling pathways by an androgen metabolite in neuronal cells.
Pak
Toni R
TR
Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA. toni.pak@colostate.edu
Chung
Wilson C J
WC
Lund
Trent D
TD
Hinds
Laura R
LR
Clay
Colin M
CM
Handa
Robert J
RJ
D015113:Androstane-3,17-diol / Q000494:pharmacology*; D000818:Animals; D001667:Binding, Competitive; D002460:Cell Line; D047628:Estrogen Receptor alpha / Q000235:genetics; D047629:Estrogen Receptor beta / Q000235:genetics* / Q000378:metabolism; D004967:Estrogens / Q000502:physiology; D008024:Ligands; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D020033:Protein Isoforms / Q000235:genetics; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D020218:Response Elements / Q000502:physiology; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects*; D014162:Transfection
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D008024:Ligands; D020033:Protein Isoforms; D011960:Receptors, Estrogen; D018808:Transcription Factor AP-1; D015113:Androstane-3,17-diol; D008156:Luciferases