Early-life 6:2 diPAP exposure induces SQSTM1/p62-associated NAFLD-like liver injury in juvenile zebrafish

Per- and polyfluoroalkyl substances (PFASs) are persistent environmental contaminants closely linked to metabolic liver disease; however, the transgenerational hepatotoxicity and underlying mechanisms of emerging PFAS substitutes remain poorly understood. Herein, we focused on 6:2 polyfluoroalkyl phosphate diester (6:2 diPAP), a prominent PFAS substitute, to evaluate its developmental hepatotoxicity. By integrating zebrafish phenotyping, transcriptomic feature selection, virtual gene knockout, and experimental validation, we characterized the candidate molecular events through which 6:2 diPAP triggers non-alcoholic fatty liver disease (NAFLD)-like injury in offspring. Early-life exposure to environmentally relevant concentrations of 6:2 diPAP from 0 to 5 dpf, particularly 500 ng/L, induced persistent hepatic lipid accumulation, hepatic vacuolation, and metabolic disturbances in zebrafish at 28 dpf. Integrated network and transcriptomic analyses identified sequestosome 1 (SQSTM1) as a key stress-responsive hub associated with pathological hepatocyte remodeling. Quantitative real-time polymerase chain reaction (RT-qPCR) and immunofluorescence analyses further demonstrated exposure-responsive increases in sqstm1 expression and SQSTM1/p62 protein fluorescence intensity, with the strongest changes observed in the 500 ng/L group. Human single-nucleus RNA-seq and pseudotime analyses revealed that SQSTM1-high hepatocytes were enriched in injury-associated and senescence-associated states during NAFLD progression, suggesting a link between SQSTM1 activation and hepatocyte-state deterioration. Furthermore, virtual SQSTM1 knockout in NASH hepatocytes predicted oxidative stress, xenobiotic metabolic, and inflammatory rewiring. Molecular docking predicted a feasible 6:2 diPAP-SQSTM1 interaction with a binding affinity of -6.0 kcal/mol, and 200 ns molecular dynamics simulation supported the structural plausibility of the ligand-protein complex. Collectively, this study proposes a 6:2 diPAP-SQSTM1-hepatocyte remodeling axis and provides a comprehensive framework linking early-life PFAS exposure with hepatocyte-state transition and NAFLD-like metabolic dysfunction.