Tumour necrosis factor alpha binding to human and mouse trophoblast

Tumour necrosis factor alpha (TNF-alpha) is a cytokine with pleiotropic effects, modulating cell growth, differentiation, and synthesis of various substances. Recent demonstration of TNF-alpha mRNA and protein in the uteroplacental unit suggests that this cytokine may be involved in the development of the embryo. To determine whether the embryo itself binds TNF-alpha, mouse blastocyst outgrowths and human first trimester villous trophoblast were analysed for TNF-alpha binding. Our experiments revealed that binding of TNF-alpha could be specifically detected on the trophectoderm of the outgrowing mouse embryos. They also show a complete disappearance of the colony-stimulating factor 1 (CSF-1) receptor that occurs shortly after the binding of TNF-alpha by the trophectoderm. In human first trimester villous trophoblast, TNF-alpha binding was found to be predominantly detectable on the syncytiotrophoblast and to a lesser extent on the cytotrophoblastic cells. Binding was not observed on adjacent embryonic or maternal cells. Our results further support the idea that TNF-alpha as well as other cytokines may modulate early embryonic development and implantation.