PLAC8 Expression Regulates Trophoblast Invasion and Conversion into an Endothelial Phenotype (eEVT)

PLAC8, expressed by interstitial extravillous trophoblasts (iEVTs), plays a crucial role in trophoblast invasion, differentiation, and immunotolerance. Its dysregulation may contribute to pregnancy complications, such as preeclampsia. This study investigates the role of PLAC8 in trophoblast invasiveness and endothelial-like differentiation under different oxygen tensions. Swan-71 cells were transiently transfected with PLAC8 overexpression or knockdown plasmids. Invasion was assessed using Matrigel-coated transwells, endothelial-like differentiation through tube formation assays, and vasculogenic marker expression (VEGF, PGF, ANGPT2) by RT-PCR. Hypoxia experiments were performed at different oxygen conditions. PLAC8 overexpression enhanced trophoblast invasion but reduced endothelial-like differentiation, downregulating VEGF and PGF while upregulating ANGPT2. Hypoxia increased PLAC8 expression, indicating oxygen tension as a regulatory factor. PLAC8 manipulation did not affect cell viability. PLAC8 modulates trophoblast behavior by promoting invasion while inhibiting endothelial-like differentiation. Its regulation of vasculogenic and angiogenic factors suggests a critical role in placental homeostasis and potential relevance to pregnancy disorders, such as preeclampsia.