EXPRESSION OF LEUKEMIA INHIBITORY FACTOR (LIF) RECEPTOR IN HUMAN PLACENTA - A POSSIBLE ROLE FOR LIF IN THE GROWTH AND DIFFERENTIATION OF TROPHOBLASTS

Leukaemia inhibitory factor (LIF) is a cytokine that displays multiple activities in various tissues and is essential for blastocyst implant ation in mice. In the human uterus, LIF is expressed in endometrial ti ssue and the decidua. To elucidate the role it plays, the mRNA levels for two LIF receptor (R) subunits, LIF-R and gp130, were examined in h uman endometrium, placenta and decidua by Northern blot hybridization. The expression of LIF-R gene was detected in the chorionic villus dur ing the first trimester, in term placenta, and at lower levels in the decidua. The expression of LIF-R gene was not detectable in non-pregna nt endometrium. The expression of the gp130 gene was detected in all t issues examined. During pregnancy, there was no significant change in the mRNA concentration of LIF-R in the placenta, while that of gp130 i ncreased after the second trimester. The human choriocarcinoma cell li ne, BeWo, was found to express LIF-R and gp130. LIF inhibited forskoli n-induced human chorionic gonadotrophin (HCG)-beta production by BeWo in a dose-dependent manner, and it ameliorated forskolin-induced growt h suppression. These findings suggest that LIF plays a regulatory role in trophoblast growth and differentiation during pregnancy in human p lacenta.