Identification of Hsf1 as a novel androgen receptor-regulated gene in mouse Sertoli cells.

Androgen signaling plays a crucial role in spermatogenesis, yet few downstream targets for this signaling pathway have been identified. In the current study, we found that the expression of heat-shock transcription factor 1 (Hsf1) was increased in the testes of Sertoli cell-selective androgen receptor knockout (S-AR(-/y) ) mice compared with wild-type mice by quantitative real-time PCR, and the expression of HSF1 in the S-AR(-/y) Sertoli cells was significantly increased, based on immunofluorescence analysis. In vitro cell-culture studies showed that testosterone repressed the expression of Hsf1 in TM4 cells, a mouse Sertoli cell line. Moreover, a luciferase assay, electrophoretic mobility shift assay, and chromatin immunoprecipitation assay showed that testosterone repressed Hsf1 expression by facilitating the binding of androgen receptor to the Hsf1 promoter. Our experiments also demonstrated that testosterone-mediated inhibition of Hsf1 transcription down-regulated the expression of heat-shock proteins HSP105 and HSP60. Taken together, these results reveal that Hsf1 is a novel target of androgen receptor in mouse Sertoli cells, and testosterone and its receptor regulate the process of spermatogenesis partially by inhibiting Hsf1 expression.