HNF4A and cholestasis: Thus, PFOA/PFOS-mediated inhibition of HNF4α either at the protein level and/or at the level of gene transcription may be the key event that finally leads to the observed effects in HepaRG cells in the present study that may account for the onset of cholestasis and that may also be related to the elevated blood serum cholesterol levels observed in humans in vivo.