The coregulator, repressor of Estrogen Receptor Activity (REA), is a crucial regulator of the timing and magnitude of uterine decidualization.. Homo sapiens

Our findings establish a key role for the coregulator, Repressor of Estrogen receptor Activity (REA), in controlling the timing and magnitude of decidualization in human endometrial stromal cells in vitro and in the mouse uterus in vivo, and suggest that REA functions to synchronize uterine differentiation with concurrent embryo development, which is essential for optimal implantation and fertility. The findings highlight that REA physiologically restrains endometrial stromal cell decidualization, controlling the timing and magnitude of decidualization to enable proper synchronization of uterine differentiation with concurrent embryo development that is essential for implantation and optimal fertility. Overall design: Human endometrial stromal cells (hESCs) were isolated from biopsies taken from the early proliferative stage endometrium of regularly cycling women on no hormonal medications. Cells were cultured in DMEM/F-12 mediumcontaining 5% charcoal stripped fetal bovine serum. To induce in vitro decidualization, hESCs were treated with a hormone cocktail containing 10 nM estradiol (E2), 1 μM progesterone (P4) and 0.5 uM 8-bromo-cAMP for up to 10 days, and media were changed every 48 h. For siRNA experiments, hESCs were transfected with REA siRNA or GL3 luciferase control siRNA following the Silent-Fect kit protocol. After 48 h of transfection, hESCs were exposed to the hormone cocktail for 24 hours or 96 hours of differentiation. key words; siRNA knock-down, hormone cocktail treatment