The Role of DNMT1 and C/EBPα in the Regulation of CYP11A1 Expression During Syncytialization of Human Placental Trophoblasts.

Progesterone synthesized in the placenta is essential for pregnancy maintenance. CYP11A1 is a key enzyme in progesterone synthesis, and its expression increases greatly during trophoblast syncytialization. However, the underlying mechanism remains elusive.

Amnion-derived serum amyloid A1 participates in sterile inflammation of fetal membranes at parturition.

Objectives: Sterile inflammation of fetal membranes is an indispensable event of normal parturition. However, triggers of sterile inflammation are not fully resolved. Serum amyloid A1 (SAA1) is an acute phase protein produced primarily by the liver.

Role of EZH2-mediated H3K27me3 in placental ADAM12-S expression: implications for fetoplacental growth.

Background: Enhancer of zeste homolog 2 (EZH2)-mediated histone 3 lysine 27 trimethylation (H3K27me3) is a transcription silencing mark, which is indispensable for cell lineage specification at the early blastocyst stage. This epigenetic repression is maintained in placental cytotrophoblasts but is lifted when cytotrophoblasts differentiate into syncytiotrophoblasts. However, the physiological impact of this lift remains elusive.

Synthesis of SAA1 in the Placenta Participates in Parturition.

Serum amyloid A1 (SAA1) is an acute phase protein produced mainly by the liver to participate in immunomodulation in both sterile and non-sterile inflammation. However, non-hepatic tissues can also synthesize SAA1. It remains to be determined whether SAA1 synthesized locally in the placenta participates in parturition via eliciting inflammatory reactions.

Activation of prostaglandin EP4 receptor attenuates the induction of cyclooxygenase-2 expression by EP2 receptor activation in human amnion fibroblasts: implications for parturition.

Human amnion fibroblasts produce abundant prostaglandin E2 (PGE2), which plays a crucial role in parturition by stimulating not only myometrial contraction and cervical ripening but also the expression of the rate-limiting enzyme in PGE2 synthesis-namely, cyclooxygenase-2 (COX-2). This feed-forward induction of COX-2 expression by PGE2 is mediated its receptors coupled with the cAMP and PKA pathway and subsequent phosphorylation of the transcription factors cAMP-response element binding protein (CREB) and signal transducer and activator of transcription 3 (STAT3). Although prostaglandin E receptor (EP)-2 and EP4 for PGE2 are coupled with activation of the cAMP and PKA pathway, the exact roles of these 2 receptors in the regulation of COX-2 expression in amnion fibroblasts remain to be determined.