Integrative Proteomic and In Silico Analysis of Perfluorooctanoic Acid Exposures in Primary Human Placental Cytotrophoblasts

Perfluorooctanoic acid (PFOA), a major persistent per- and polyfluoroalkyl substance (PFAS), remains ubiquitous in humans, including pregnant women, despite regulatory actions to limit its production and use. The placenta has been proposed as a target of PFOA, however, the underlying mechanisms remain poorly defined. We exposed primary human placental cytotrophoblasts (CTBs) isolated from three second-trimester placentas to PFOA (0.1-25 μM) for 48 h. SWATH-MS identified 3,240 proteins, 274 of which were differentially expressed. Proteins involved in lipid and amino acid metabolism and innate immunity pathways were significantly enriched among these targets. Integration of protein and mRNA data sets revealed key molecules linking PFOA exposure to altered immune defense and placental dysfunction. Molecular docking and dynamic simulations predicted that PFOA and other PFAS directly interact with master regulators, including peroxisome proliferator-activated receptors α and γ (PPARα, PPARγ) and novel targets such as signal transducer and activator of transcription 1/2 (STAT1, STAT2) and interferon regulatory factor 1/3 (IRF1, IRF3). Benchmark modeling indicated that significant protein-level changes can occur at concentrations relative to reported serum concentrations and associated with placental toxicity in rodents. We propose that PFOA and other PFAS directly interact with these candidate regulators, contributing to placental dysfunction.