Hepatotoxicity of 8:2 Polyfluoroalkyl Phosphate Diesters Exposure via JAK2/STAT3 Pathway Activation and M1 Macrophage Polarization in Mice

Polyfluoroalkyl phosphate esters (PAPs) are widely used as substitutes for legacy perfluoroalkyl and polyfluoroalkyl substances (PFAS), contributing a non-negligible environmental burden. However, their in vivo hepatotoxicity and underlying mechanisms remain poorly understood. We developed a mouse model to assess the hepatotoxic effects and mechanisms of 8:2 polyfluoroalkyl phosphate diesters (8:2 diPAP). Exposure to 8:2 diPAP at doses of 0.5, 5, and 50 mg/kg resulted in hepatocyte damage and elevated serum levels of total bilirubin. Albumin, alanine transaminase, and aspartate aminotransferase were significantly elevated in the 50 mg/kg 8:2 diPAP group. Expressions of M1-type macrophage markers and the proportion of M1 macrophages were significantly increased in the liver under 8:2 diPAP exposure. Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling were significantly enriched under 8:2 diPAP exposure. Molecular docking revealed direct 8:2 diPAP-JAK2 binding, and Western blot analysis showed decreased hepatic Jak2 expression in exposed mice. Increased Stat3 phosphorylation and reduced Socs3 expression in the exposed livers suggested that 8:2 diPAP activates the Stat3 pathway by inhibiting Socs3, thereby promoting M1 macrophage polarization. Our findings demonstrate that 8:2 diPAP exposure induces liver injury by driving M1 macrophage polarization in mice, providing further insight into the health effects and risk assessment of PAPs.