An EG-VEGF-Dependent Decrease in Homeobox Gene Contributes to Cytotrophoblast Dysfunction: A Possible Mechanism in Human Fetal Growth Restriction

Idiopathic fetal growth restriction (FGR) is frequently associated with placental insufficiency. Previous reports have provided evidence that endocrine gland-derived vascular endothelial growth factor (EG-VEGF), a placental secreted protein, is expressed during the first trimester of pregnancy, controls both trophoblast proliferation and invasion, and its increased expression is associated with human FGR. In this study, we hypothesize that EG-VEGF-dependent changes in placental homeobox gene expressions contribute to trophoblast dysfunction in idiopathic FGR. The changes in EG-VEGF-dependent homeobox gene expressions were determined using a homeobox gene cDNA array on placental explants of 8-12 wks gestation after stimulation with EG-VEGF for 24 h. The homeobox gene array identified a greater-than-five-fold increase in , , , , , and , while showed a greater-than-two-fold decrease in mRNA expression compared with untreated controls. Homeobox gene was selected as a candidate because it is a downstream target of EG-VEGF and its expression and functional roles are largely unknown in control and idiopathic FGR-affected placentae. Real-time PCR and immunoblotting showed a significant decrease in mRNA and protein levels, respectively, in placentae from FGR compared with control pregnancies. Gene inactivation using short-interference RNA specific for demonstrated an increase in BeWo cell differentiation and a decrease in HTR-8/SVneo proliferation. We conclude that the decreased expression of homeobox gene downstream of EG-VEGF may contribute to the trophoblast dysfunction associated with idiopathic FGR pregnancies.