Quantitative acetylomic analysis reveals a key role of acetylation site 1168K in carbamoyl-phosphate synthase 1 (CPS1) following exposure to PFOA and PFO4DA in mouse liver.

Hepatotoxicity induced by environmental pollutants can be regulated at the transcriptional, translational, and post-translational levels. However, few studies have investigated the changes in liver acetylomics caused by pollutant exposure. In the present study, we demonstrated that perfluorooctanoate (PFOA) and its potential alternative, perfluoro-(3,5,7,9-tetraoxadecanoic) acid (PFO4DA), modified the liver acetylation profile in male mice exposed to 10 mg/kg/d PFOA or PFO4DA for 28 days. Relative to the control group, liver proteins in the exposed mice exhibited altered acetylation patterns, with 1508 and 498 differentially acetylated sites identified in the PFOA- and PFO4DA-exposed groups, respectively. These modifications were not confined to lipid metabolism, but also extended to the urea cycle and hyperammonemia. Furthermore, in vitro and in silico experiments revealed that mutation of CPS1-1168K to CPS1-1168R restored enzymatic activity under PFOA/PFO4DA exposure, while mutation to CPS1-1168Kac reduced the adenosine triphosphate (ATP) binding capacity, suggesting that CPS1-1168K may be a key acetylation site for PFOA and PFO4DA disruption of the urea cycle. Additionally, both chemicals exhibited the potential to compete with ATP for the ATP-binding site, which is essential for CPS1 activity. These findings contribute to understanding the mechanisms underlying PFAS toxicity and support the establishment of an adverse outcome pathway framework.