Effects of PFOA, PFBA, PFHxA, PFOS, PFBS, PFHxS on gene expression in monolayer and non-neuroectoderm cells differentiated from H1

Per- and polyfluoroalkyl substances (PFAS) are a group of organic chemicals that contain multiple carbon-fluorine bonds, which make them highly stable and widespread in our environment, even in the human body. They have been detected in cord blood and showed correlation with neonatal health abnormalities such as weight loss. Here, we utilized human embryonic stem cell-based model to assess the early developmental toxicity of six PFAS (PFOA, PFHxA, PFBA, PFOS, PFHxS, and PFBS) and their skin developmental toxicity. We employed global monolayer differentiated model to mimic the early embryonic development and performed non-neural ectoderm (NNE) differentiation which can give rise to keratinocytes to imitate early skin development. Transcriptomic analysis revealed that PFOS caused the most differentially expressed genes (DEGs) both in day 16 global monolayer samples and NNE samples to making it the most toxic of the six PFAS. Further validation of gene expression levels showed that the TGF-β signaling pathways were involved in the early global developmental toxicity and in the early skin developmental toxicity of PFOS. Interestingly, our results showed that PFOS inhibited the ciliogenesis of NNE cells, which may interfere with the transduction of TGF-β, Notch, Hedgehog, and Hippo signaling pathways, ultimately inhibiting early embryonic skin development and posing a potential threat to the occurrence of congenital skin diseases. Overall, our study suggests a potential toxicity mechanism by which PFAS inhibit ciliogenesis to interfere with the transduction of important signaling pathways, leading to early global developmental toxicity as well as early embryonic skin developmental toxicity and potential congenital skin diseases. To assess the early global developmental toxicity and the early skin developmental toxicity of the six PFAS (PFOA, PFHxA, PFBA, PFOS, PFHxS, and PFBS), we employed human embryonic stem cells (hESCs)-based global monolayer differentiation model and non-neural ectoderm (NNE) differentiation model to mimic early embryonic development and early skin development respectively. We then performed transcriptome analysis based on RNA-seq to evaluate the toxic effect of the six PFAS on gene expression level. Samples were treated with 10 μM PFAS respectively for 8 days and 16 days during global monolayer differentiation while 8 days for NNE differentiation.