Perfluorooctanesulfonate (PFOS) Precursor Biotransformation Drives Shared Lipidomic Remodeling in HepaRG Cells

Perfluorooctanesulfonate (PFOS) is a persistent legacy per- and polyfluoroalkyl substance (PFAS) associated with hepatic metabolic disruption, whereas PFOS precursors remain less characterized despite their potential to generate PFOS through biotransformation. This study investigated whether PFOS precursors induce PFOS-like or precursor-specific metabolic perturbations in HepaRG cells. Cells were exposed to PFOS, perfluorooctanesulfonamide (PFOSA), or N-methylperfluorooctanesulfonamidoethanol (N-MeFOSE-M) for 48 h, followed by paired intracellular and extracellular metabolomics and lipidomics analyses. Intracellular PFOS-related signals were detected after PFOSA and N-MeFOSE-M exposure, particularly at the highest exposure concentration, consistent with potential precursor biotransformation. Intracellular samples showed broader differential feature distributions than extracellular samples. Overlapping responses across PFOS and precursor exposures were dominated by putatively annotated lipid-related classes, while pathway-associated features mapped to fatty acid transport and metabolism, SREBP-related lipid regulation, glucose homeostasis, urea cycle-related metabolism, and amino acid transport. Paired intracellular and extracellular profiling unraveled divergent changes in glutamine and phenylalanine between compartments, suggesting altered amino acid handling following PFAS exposure. These findings indicate that PFOS precursors could undergo intracellular biotransformation while producing both overlapping and compound-specific hepatometabolic perturbations. Complementary intracellular and extracellular profiling provides a useful strategy to capture intracellular metabolic remodeling and extracellular metabolite or lipid redistribution.