The Effect of Leukemia Inhibitory Factor in Decidualizing Human Endometrial Stromal Cells

Joo, Myung Hee; Bae, Eun Kyung; Hwang, Jung Hye; Lee, Jung Han; Kim, Seung Ryong; Hwang, Youn Young

Abstract

OBJECTIVE
Decidualization of endometrial stromal cells is essential for a successful implantation of the embryo. The process of decidualization can be modulated by sex steroids, growth factors and cytokines. Leukemia inhibitory factor (LIF) is a pleiotropic cytokine of the interleukin-6 family and has different biological actions in various tissue systems. Recently, LIF has been reported as an important factor for adequate decidualization of endometrium. However, the effect on production of prolactin (PRL), known as the decidualization marker, are not clearly understood. The objective of this study was to determine whether LIF is capable of modulating prolactin production during 8-bromo (Br)-cAMP induced decidualization in vitro.
METHODS
Human endometrial stromal cells were cultured and decidualization was induced by 0.5 mM 8-Br-cAMP. Phase contrast microscopy was used to verify morphological changes associated with differentiation in vitro in response to 8-Br-cAMP. Both stromal cells exposed to 8-Br-cAMP and cells not exposed to 8-Br-cAMP were also incubated with LIF (10 ng/mL). PRL levels in each supernatant were measured by a commercial PRL ELISA kit. Immunostaining and reverse transcription-polymerase chain reaction (RT-PCR) for PRL were performed.
RESULTS
The concentration of PRL in the supernatant increased significantly in the cells treated with 8-Br-cAMP plus LIF (10 ng/mL) at culture day 6 compared with the others. The results of immunohistochemical staining reflected that of immunoassay. The PRL genes are expressed in the decidualized stromal cells treated with 8-Br-cAMP. No PRL mRNA was detectable in the absence of the 8-Br-cAMP. The intensity of the PCR band measured by densitometry is stronger in the cells treated with 8-Br-cAMP plus LIF than that with the others.
CONCLUSION
These results suggested that LIF increased the production of PRL in decidualizing human endometrial stromal cells and may play a role in preparing the human endometrium for implantation through the promotion of PRL production.