Effect of cytokines and growth factors on the secretion of inhibin A, activin A and follistatin by term placental villous trophoblasts in culture.
OBJECTIVE
Maternal serum inhibin A and activin A are higher in pre-eclampsia than in normal pregnancy. The placenta is a source of these proteins in pregnancy. The aim of this study was to investigate the effect of growth factors and proinflammatory cytokines that are raised in pre-eclampsia on the secretion of dimeric inhibin A, activin A and follistatin by villous cytotrophoblasts in culture.


METHODS
Villous cytotrophoblasts were prepared from term placentae and cultured in serum-free media. Cells were treated with increasing concentrations of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, transforming growth factor (TGF)-beta1, granulocyte and monocyte colony-stimulating factor (GMCSF), inhibin A, activin A and follistatin for 2 days. Culture supernatants were assayed for human chorionic gonadotrophin (hCG), inhibin A, activin A and follistatin as appropriate. Experiments were repeated at least three times with each cytokine or growth factor and the data pooled.


RESULTS
Cytotrophoblasts syncytialise and spontaneously secrete hCG, inhibin A and activin A in culture. Follistatin levels were <20 pg/ml in most experiments. Activin A secretion was increased in culture in a dose-dependent manner by IL-1beta (approximately 150%, P<0.05), TNF-alpha (approximately 35%, P=0.02) and GMCSF (approximately 100%, P<0.01). hCG secretion was inhibited in a dose-dependent manner by TNF-alpha (50%, P<0.05). Inhibin A was stimulated by IL-1beta ( approximately 30%, P=0.05). Inhibin A, activin A, follistatin or TGF-beta1 did not have a significant effect on any measured parameters.


CONCLUSIONS
These data show that inflammatory cytokines increase the secretion of activin A by trophoblasts in culture. The presence of very low levels, or no follistatin (<20 pg/ml) in the culture media suggests 'free' activin A could have autocrine/paracrine effects on cytotrophoblasts. Inhibin A secretion was stimulated by IL-1beta. However, absence of an effect by the other cytokines investigated on inhibin A in this study suggests that the mechanism(s) involved in increasing maternal circulating levels of inhibin A and activin A in pre-eclampsia are controlled differentially.
Mohan
A
A
Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
Asselin
J
J
Sargent
I L
IL
Groome
N P
NP
Muttukrishna
S
S
D028341:Activins / Q000378:metabolism*; D002478:Cells, Cultured; D002824:Chorionic Villi / Q000378:metabolism*; D016207:Cytokines / Q000494:pharmacology*; D005260:Female; D038681:Follistatin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D028322:Inhibin-beta Subunits / Q000378:metabolism*; D007265:Inhibins / Q000378:metabolism*; D007375:Interleukin-1 / Q000494:pharmacology; D010920:Placenta / Q000166:cytology; D011247:Pregnancy; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014327:Trophoblasts / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D016207:Cytokines; D038681:Follistatin; D006133:Growth Substances; D007375:Interleukin-1; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; C422405:activin A; C422362:inhibin A; D028341:Activins; D007265:Inhibins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D028322:Inhibin-beta Subunits