Decidual cell regulation of trophoblast is altered in pregnancies at risk of pre-eclampsia

Abstract

Successful implantation and placentation are dependent on the interaction between decidual stromal cells (DSC) and extravillous trophoblast (EVT) cells. The extent of trophoblast invasion relies on communication between the placenta and maternal decidua. The cyclical process of decidualisation induces a transformation of endometrial fibroblasts to secretory DSC; these secreted products have many functions including the control of trophoblast invasion. Inadequate trophoblast invasion and remodelling of the uterine vessels (the spiral arteries) are associated with pregnancy disorders such as pre-eclampsia. Uterine artery Doppler resistance index (RI) in the first trimester of pregnancy can be used as a proxy measure of remodelling. DSC were isolated from pregnancies with normal (normal RI) or impaired (high RI) spiral artery remodelling. Following isolation, DSC were re-decidualised using cAMP and MPA and secretion of the decidualisation markers IGFBP-1 and prolactin assessed. We examined the impact of DSC-secreted factors on trophoblast cell function, using the EVT cell line SGHPL-4. We demonstrated that DSC exposed to decidual factors were able to re-decidualise in vitro and that the chemoattraction of trophoblasts by DSC is impaired in pregnancies with high RI. This study provides new insights into the role that DSC play in regulating EVT functions during the first trimester of pregnancy. This is the first study to demonstrate that DSC from pregnancies with impaired vascular remodelling in the first trimester secrete factors that inhibit the directional movement of trophoblast cells. This finding may be important in understanding aberrant trophoblast invasion in pregnancies where vascular remodelling is impaired.

Keywords: chemotaxis; decidua; pre-eclampsia; stromal; trophoblast.

Figure 1

Isolated first trimester DSC expression of the decidual markers IGFBP1 and PRL. Isolated DSC were stimulated with cAMP and MPA (re-decidualised, rDSC) or a vehicle control (DSC) for 72 h. Conditioned media was collected and levels of decidual markers IGFBP1 and PRL measured by ELISA. Secretion of (A) IGFBP1 (n = 53) and (B) PRL (n = 40) was found to be significantly different between DSC and rDSC. Data were log-transformed to ensure equal variance. Paired t-test, data shown as mean ± s.e.m., ****P < 0.0001.

Figure 2

Secretion of IGFBP1 and PRL from normal resistance index (RI) and high RI DSC. Isolated DSC, from normal RI and high RI pregnancies, were stimulated with cAMP and MPA to stimulate decidualisation, after 72 h conditioned media was collected and levels of IGFBP1 and PRL measured by ELISA. Secretion of IGFBP1 was significantly increased in re-decidualised (rDSC) compared to DSC from normal RI (A) (n = 33) and high RI (B) (n = 15) pregnancies. Levels of PRL were significantly increased in rDSC compared to DSC CM from normal RI (C) (n = 25) and high RI (D) (n = 19) pregnancies. Secretion of (E) IGFBP1 or (F) PRL from rDSC from normal RI and high RI did not differ. Data were log transformed to ensure equal variance. Paired t-test (A, B, C and D), unpaired t-test (E and F), data shown as mean ± s.e.m., ****P < 0.001 and **P < 0.01, ns denotes not significant.

Figure 3

Effect of normal RI and high RI rDSC CM on SGHPL-4 cell motility, apoptosis and proliferation. The effect of re-decidualised (rDSC) CM from normal RI and high RI pregnancies on SGHPL-4 motility trophoblast motility (A: <10-week gestation, B: >10-week gestation), apoptosis (C: <10-week gestation, D: >10-week gestation) or proliferation (E: <10-week gestation, F: >10-week gestation) was assessed over 24 h. Dec control is media with the decidualisation factors added (cAMP and MPA). No difference in motility, apoptosis or proliferation was observed when incubated with normal or high RI rDSC CM from <10 weeks and >10 weeks gestation (n = 6). ANOVA, data shown as mean + s.e.m.

Figure 4

Effect of rDSC CM from normal and high RI pregnancies on chemotaxis of SGHPL-4 cells. SGHPL-4 cells were cultured in chemotaxis chambers to analyse chemotactic capacity of normal and high RI rDSC CM. Non-directional movement of cells gives expected chemotaxis of 50%. (A) Normal RI rDSC CM from pregnancies <10 weeks gestation is significantly more chemotactic to SGHPL-4 cells than high RI rDSC CM from pregnancies at <10 weeks gestation. (B) Normal and high RI rDSC CM from pregnancies >10 weeks gestation have no chemotactic effect on SGHPL-4 cells (n = 6). Paired t-test, data shown as mean ± s.e.m., *P < 0.05.