A Role for Mitogen Activated Protein Kinase in Decidualization of Human Endometrial Stromal Cells

Presentation Number: SUN-0030
Date of Presentation: June 22nd, 2014

David Kulak*1, Andrea Wojtczuk2, Gerson Weiss3 and Laura T Goldsmith2
1Rutgers-New Jersey Medical School, United States, NJ, 2Rutgers-New Jersey Medical School, Newark, NJ, 3Rutgers - New Jersey Medical School, Newark, NJ

Abstract

Endometrial decidualization, the morphological and functional differentiation of endometrial stromal cells, is essential for successful blastocyst implantation and maintenance of pregnancy. Despite its functional significance, the biochemical mechanisms involved in decidualization are poorly understood.  Increased production of prolactin and IGFBP-1 are hallmarks of decidualization. Our prior data suggest that decidualization related changes in expression of vascular endothelial growth factor, interleukin 11, and interleukin 8 as well as alterations in cellular morphology are MAP kinase dependent.  We therefore hypothesized that decidual expression of prolactin and IGFBP-1 are MAP kinase dependent.  

A well characterized telomerase-immortalized line of human endometrial stromal cells which undergo characteristic decidualization response to increased intracellular cAMP was used as an in-vitro model. Replicate wells of cells were incubated for 14 days in phenol red-free media without (control) or with 8-br-cAMP (0.5mM) to decidualize the cells. To determine the role of MAP kinase in decidualization, cells were also incubated with 8-br-cAMP in the presence or absence of a selective MEK inhibitor (10uM UO126). Since PKA has been implicated in decidualization, cells were also incubated with 8-br-cAMP in the presence or absence of a PKA inhibitor (10uM Rp-cAMPs).  Medium was removed and replenished every 72 hours. Prolactin and IGFBP-1 concentrations in medium from each well were determined by specific human prolactin and human IGFBP-1 enzyme immunoassays. To determine the distribution of the data from all 4 experiments (each performed in triplicate), Kolmogorov- Smirnov tests were performed. Since the data were not normally distributed, differences between groups were assessed by non-parametric Mann-Whitney tests, and are herein expressed as median levels (pg/ml).

In medium from decidualized cells, median levels of prolactin were increased 45-fold compared to medium from the non-decidualized control group (p=0.001), and the median levels of IGFBP-1 were increased 350-fold (p=0.001). Inclusion of a MEK inhibitor reduced cAMP stimulated prolactin levels by 70% from median levels of 1,372 pg/ml (8-br-cAMP) to 465 pg/ml (8-br-cAMP+UO126) (p=0.002), and reduced IGFBP-1 levels by 60% from 115,820 pg/ml to 75,930 pg/ml (p=0.001). In distinct contrast, inhibition of PKA did not alter levels of prolactin (p=0.48) or IGFBP-1 (p=0.16).

These novel data demonstrate that the MAP kinase pathway plays an integral role in human endometrial stromal cell decidualization, including regulation of the hallmark indicators prolactin and IGFBP-1.

 

Nothing to Disclose: DK, AW, GW, LTG