Using a Human Induced Pluripotent Stem Cell Differentiation Model to Assess Developmental Effects of PFOS, PFOA, and GenX

Polyfluoroalkyl substances (PFASs) such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are persistent organic pollutants commonly found in human blood samples. PFAS exposure has been linked to a number of health issues, including impaired vaccination response in children, increased blood cholesterol levels, and decreased birth weight. However, the molecular basis of these effects remain elusive. Substitutes such as ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate (GenX), with largely unknown toxicological potential, are now being used in response to restrictions. Here, we sought to better understand the potential effects of old- and new-generation PFASs on human embryonic development. Human induced pluripotent stem cells (hiPSCs) offer new ways for screening chemicals for developmental effects in humans. Using a hiPSC-cardiomyocyte assay, named PluriBeat, we studied the effects of PFASs on early human development. In our assay, hiPSCs are prompted to form embryoid bodies (EBs) before they go through the early stages of embryonic development, leading to the formation of beating cardiomyocytes after seven days. Both PFOS and PFOA elicited a strong effect on cardiomyocyte differentiation at non-cytotoxic concentrations, with PFOS being more potent than PFOA. Both compounds also reduced the EB size at the highest tested concentrations. GenX did not initially affect differentiation in the first cell line tested, but induced a weak dose-dependent effect when tested in a second hiPS cell line. Gene expression analysis of the cardiomyocytes at experiment termination showed that PFOS increased expression of the early cardiac marker ISL1, while PFOA decreased expression of the cardiomyocyte marker MYH7. This suggest that PFOS, PFOA and potentially GenX disturb cardiomyocyte differentiation. However, GenX did not affect expression of any of the analyzed genes. Our study shows that PFOS, PFOA and GenX have the potential to disrupt the early development of the embryo.