A group of novel polyfluoroether substances affects lipid metabolism in human hepatocyte HepaRG cells less than classic perfluoroalkyl compounds

Per- and polyfluoroalkyl substances (PFAS) are used for numerous industrial applications including the production of fluorosurfactants. Some prominent PFAS, e.g., perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), are non-degradable and therefore persist in the environment. They display various toxic properties including dysregulation of hepatic lipid metabolism. At the molecular level, these effects are mainly based on a PFAS-mediated activation of the peroxisome proliferator-activated receptor alpha (PPARα). A group of novel, degradable polyfluoroether compounds has been designed as building blocks for the production of alternative, degradable fluorosurfactants. In the present study, we examined the capacity of four of these novel polyfluoroether compounds to induce PPARα activation, increase intracellular triglyceride accumulation, and produce a cytotoxic response. In contrast to some classic PFAS including PFOA and PFOS, the novel compounds neither activated PPARα in a transactivation assay, nor did they induce expression of selected PPARα-dependent target genes in differentiated HepaRG cells, a model for human hepatocytes. They also did not induce triglyceride accumulation in HepaRG cells. The in vitro data indicate that the polyfluoroether compounds tested in the present study are not PPARα agonists. Since PPARα agonist activity is often associated with toxic responses, it can be assumed that these substances are less toxic than classic PFAS such as PFOA and PFOS, at least with respect to PPARα-dependent toxicity mechanisms.