Expression of Androgen and Estrogen Receptors in Sertoli Cells: Studies Using the Mouse SK11 Cell Line

Abstract

Sertoli cells (Sc) play a major role in the establishment and maintenance of spermatogenesis. In the adult testis, Sc contain androgen receptor (AR) and estrogen receptor (ER)-β but exhibit a loss of steroid responsiveness when maintained in primary culture. In the present study, we demonstrated that a transformed murine cell line (SK11) has retained a Sc phenotype and remains steroid responsive. SK11 cells expressed mRNAs found in Sc (aromatase, sulfated glycoprotein-1, sulfated glycoprotein-2, GATA-1, Sry-type high-mobility-group box transcription factor-9, testatin, dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1) including those for AR and ERβ but not ERα. AR and ERβ were immunolocalized to cell nuclei, and their ability to activate gene expression was investigated using transient transfections with reporter constructs containing either 3xERE or pem-androgen-responsive element promoters. Expression of the 3xERE reporter was induced after incubation with 17β-estradiol (E2), 5α-androstane-3-β, 17β-diol (3βAdiol), or testosterone (T); up-regulation of the pem-androgen-responsive element reporter was detected only in the presence of T or dihydrotestosterone. Activation of the ERE reporter did not occur after targeted knockdown of ERβ mRNA. Expression of AR and ERβ mRNAs was increased after incubation of cells with T or E2, respectively. In conclusion, we have demonstrated that the SK11 Sc cell line contains functional AR and ERβ and that treatment of the cells with their respective steroids results in an increase in the amount of their mRNAs. Our results suggest that E2 or 3βAdiol acting via ERβ might modulate Sc function in vivo and that SK11 cells provide a useful model that can be used to complement studies using Sc selective gene ablation.