Decidualisation of endometrial stromal cells in the mid-late secretory phase of each menstrual cycle is essential for proper blastocyst implantation and placental invasion. Decidualisation of Human Endometrial Stromal Cells (HESCs) in vitro is induced by the combined treatment of progesterone, estradiol and cyclic AMP (cAMP). Previous studies from our laboratory have demonstrated that decidualisation of HESCs in vitro is associated with increased prorenin (REN) mRNA expression. Renin is the rate-limiting enzyme of the RAS and expression of its precursor, prorenin, is highest in human decidua compared to all other intrauterine tissues. We propose that prorenin may play a role in decidualisation. We aimed to determine whether the increase in REN expression was due to steroidal stimulation (by progesterone or estradiol) or by cAMP stimulation alone, as cAMP is a know regulator of kidney REN.
HESCs were cultured in DMEM/F12 media with 10% fetal bovine serum for 10 days with one of two treatments; 1µM medroxyprogesterone acetate (MPA), 10nM estradiol-17β (E2) with or without 0.5mM dibutyryl cyclic AMP (cAMP), along with control. qPCR was used to determine the mRNA concentrations of prorenin (REN), prorenin receptor (ATP6AP2), angiotensinogen (AGT), angiotensin converting enzymes 1 and 2 (ACE1, ACE2) and angiotensin type 1 receptor (AGTR1) relative to β-actin (ACTB) using the standard curve method.
REN expression was significantly upregulated in HESCs following treatment with the combination of E2, MPA and cAMP in comparison to both the control and the E2 + MPA treatment without cAMP (both P<0.001). Gene expression of the other RAS components were not affected by any treatment. Overall, these findings suggest that the increase in REN expression observed during decidualisation of the human endometrium is not regulated by progesterone and estradiol but requires cAMP.