Prostaglandin F2α suppresses rat steroidogenic acute regulatory protein expression via induction of Yin Yang 1 protein and recruitment of histone deacetylase 1 protein

Prostaglandin F2 alpha (PGF2 alpha) plays a pivotal role in ovarian luteolysis by inhibiting the expression of steroidogenic acute regulatory ( StAR) protein, leading to a decrease in intracellular cholesterol transport and luteal steroid production. Previously we have demonstrated that the transcription factor Yin Yang 1 (YY1) bound to three regions in the StAR promoter in vitro and repressed promoter activity. This study further defined the YY1-mediated PGF2 alpha effect on the inhibition of StAR protein expression through YY1 interaction with a single region in the StAR promoter in vivo. PGF2 alpha consistently suppressed StAR mRNA and protein expression in cultured luteal cells in a dose-dependent manner. PGF2 alpha also enhanced YY1 protein expression and binding to its cis-element in a time-dependent pattern that preceded the decline in StAR protein levels. The StAR promoter region bound by YY1 was also associated with histone deacetylase 1 (HDAC1). PGF2 alpha treatment promoted HDAC1 binding to and suppressed the histone H3 acetylation in this region. On the contrary, YY1 knockdown decreased HDAC1 binding, increased histone H3 acetylation, enhanced StAR protein expression, and negated PGF2 alpha effect on StAR protein expression. Luciferase assays showed that YY1 overexpression inhibited StAR promoter activity and the addition of a HDAC inhibitor, trichostatin A, abrogated the effect of YY1. Trichostatin A-treated luteal cells displayed increased StAR protein expression. These data indicate that PGF2 alpha enhances a direct YY1/StAR promoter interaction and the recruitment of HDAC1 to the promoter, thereby preventing transcriptional activation of the StAR gene.