An assessment of serum-dependent impacts on intracellular accumulation and genomic response of per- and polyfluoroalkyl substances in a placenta trophoblast model

Per- and polyfluoroalkyl substances (PFAS) are a family of environmental contaminants that have been detected in human placenta and cord blood. The mechanisms driving PFAS-induced adverse pregnancy outcomes and effects on the placenta are not well understood. We investigated the impact of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and a replacement PFAS known as hexafluoropropylene oxide dimer acid (HFPO-DA, tradename GenX) on placental trophoblasts in vitro . First, we assessed factors that can influence data quality including quantification of PFAS in common cell culture reagents. Second, we investigated the role of supplemental media serum in intracellular accumulation of PFAS in a human trophoblast (JEG3) cell line. Finally, we evaluated the impact of PFAS on mRNA expression of 96 genes involved in proper placental function in JEG3 cells. Analytical results revealed that, at baseline, serum-free media (SFM) contained no detectable PFAS. Fetal bovine serum-supplemented media (SSM) contained PFNA, PFUdA, PFTrDA, and 6:2 FTS, but these PFAS were not detected internally in cells. Intracellular accumulation following 24 hr treatments was significantly higher when cultured in SFM compared to SSM for PFOS and PFOA, but not HFPO-DA. Finally, PFAS exposure was associated with modest gene expression changes in pathways vital to placental function, including viability, syncytialization, inflammation, transport, and invasion/mesenchymal transition. Among the most robust PFAS-associated changes were those observed in BAD and BAX , apoptosis-related genes. These results suggest a complex relationship between PFAS and culture conditions in vitro, and that PFAS alter key genes necessary for trophoblast involvement in placentation.