Liver X receptors mediate inhibition of hCG secretion in a human placental trophoblast cell line

Liver X receptors (LXR) α and β are important regulators of lipid homeostasis in liver, adipose and other tissues. However, no such information is available for the human placenta. We determined expression of both LXR α and β in placental trophoblast cell lines, BeWo and JAR. Exposure of BeWo cells to a synthetic LXR agonist, T0901317, resulted in an increase in the amount of mRNA of LXR target genes, sterol regulatory element-binding protein-1 and fatty acid synthase. T0901317 also increased the synthesis of lipids. Moreover, T0901317 resulted in a reduced secretion of hCG during differentiation of these cells. Our data for the first time demonstrate a new role for LXRs in the human placenta.