Analysis of transcriptomic alterations induced by 33 different per- and polyfluoroalkyl substances (PFAS) in differentiated HepaRG cells

Due to their high persistence and adverse health effects in humans the use of a number of per- and polyfluoroalkyl substances (PFAS) has been restricted. As a consequence, novel PFAS are increasingly being introduced for industrial applications, although toxicological data are still limited or lacking for many of these compounds. This study examined the molecular mechanisms of action of novel PFAS with a focus on mono- and polyether PFAS with linear or branched structures and either carboxylic acid or sulfonic acid functional groups. Differentiated HepaRG cells, a model of human hepatocytes, were exposed for 24 h to different PFAS congeners at three non-cytotoxic concentrations each. Total RNA was isolated and subjected to whole transcriptome analysis. The study provides transcriptomic data for in total 33 PFAS congeners, for 13 of them for the first time. For most PFAS, the number of differentially expressed genes (DEG) increased in a concentration-dependent manner, whereas five PFAS induced only minor transcriptional changes even at the highest test concentration. Ingenuity Pathway Analysis (IPA) revealed broadly comparable transcriptional responses across all 33 PFAS, indicating convergent molecular effects in HepaRG cells despite marked structural differences among the PFAS congeners. The tested PFAS consistently activated canonical pathways related to fatty acid and lipid metabolism, mainly regulated by the nuclear receptor PPAR alpha, and also affected pathways related to xenobiotic metabolism, partially linked to PXR and CAR signaling. In addition, several PFAS inhibited cholesterol and bile acid biosynthesis pathways. IPA further predicted effects on hepatocyte-relevant upstream regulators such as HNF4A, HNF1A, and FOXA2. Finally, IPA tox-function analysis indicated associations between PFAS-induced transcriptional changes and liver diseases related to cholestasis.