Regulation and Role of Aryl Hydrocarbon Receptor in Human Embryonic Stem Cells and Their Differentiating Counterparts [ChIP-Seq]

Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, which mediates the effects of various environmental contaminants, like polycyclic and halogenated aromatic hydrocarbons, including the most potent agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), in multiple tissues. Recent advances in AHR biology have underlined its importance in cells with high developmental potency, including pluripotent stem cells. Nonetheless, there is little data on AHR expression and its role during the initial stages of stem cell differentiation. The purpose of this study was to investigate the temporal pattern of AHR expression during directed differentiation of human embryonic stem cells (hESC) into neural progenitor, early mesoderm and definitive endoderm cells. Additionally, we studied the effect of AHR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on gene expression profile in hESCs and differentiated cells by RNA-seq, accompanied by identification of AHR binding sites by ChIP-seq and epigenetic landscape analysis by ATAC-seq. . We show that AHR is differentially regulated in distinct lineages, provide evidence that TCDD impairs differentiation of hESCs and identify novel potential AHR target genes which expand our understanding on the role of this protein in different cell types.