Trifluoroacetic Acid Competitively Inhibits Lactate Dehydrogenase to Disrupt Endothelial Glycolysis and Impair Vascular Development.

Trifluoroacetic acid (TFA) is a two-carbon ultrashort-chain per- and polyfluoroalkyl substance (PFAS) and constitutes the most abundant PFAS in the environment. TFA has historically been regarded as a compound of relatively low acute lethality, yet its adverse effects on sensitive targets at environmentally relevant levels are largely unknown. Due to extreme hydrophilicity and anionic form in the aqueous phase of blood, TFA manifests high accessibility to the innermost layer of vasculature. In this study, we investigated the vascular toxicity of TFA using human umbilical vein endothelial cell and zebrafish embryo models at concentrations of 0.8-2000 μg/L. The results showed that TFA exposure reduced ATP content, lactate production, and glycolytic flux, concomitantly increasing pyruvate accumulation. The benchmark dose lower confidence limit (BMDL5) values ranged from 0.44 to 2.65 μg/L, falling within the range of environmental levels. Enzyme kinetics and molecular docking indicated that TFA competitively inhibited lactate dehydrogenase (LDH) at the pyruvate-binding site. In addition, TFA inhibited endothelial migration, induced cellular F-actin disruption, and impaired vascular development in zebrafish larvae. The AI-aided vascular phenomics revealed the most prominent defect in the subintestinal venous plexus. A quantitative adverse outcome pathway was subsequently established, and key-event relationships were robustly fitted, with R2 values exceeding 0.72. This study unravels a metabolic perturbation pathway of TFA-induced vascular toxicity and reinforces the need to reassess the health risks of TFA.