Stress granule reporter system to assess perfluorooctanoic acid gastric toxicity in vitro

Perfluorooctanoic acid (PFOA) and its alternative compound, hexafluoropropylene oxide dimer acid (HFPO-DA), are commonly used in cookware and food packaging because they are structurally stable and have a long half-life. This allows them to enter the human body, where they accumulate and have potentially harmful effects on human health. While the ability of PFOA to induce various cytotoxicities, including endoplasmic reticulum (ER) stress, has been studied extensively, little is known about the effects of alternative compounds, such as HFPO-DA, on cells.

This study aimed to evaluate the gastrointestinal toxicity of PFOA and HFPO-DA in vitro using a gastrointestinal AGS cell line. We established a real-time stress granule reporter system in human gastrointestinal cell lines by inserting green fluorescent protein into the Ras-GTPase-activating protein SH3-domain-binding protein 1 gene using CRISPR/Cas9-mediated homologous recombination.

We found that PFOA induced the phosphorylation of PERK, which is activated by ER stress in AGS cells, and in contrast, the alternative compound HFPO-DA did not induce the phosphorylation of PKR-like endoplasmic reticulum kinase under the same conditions as PFOA.

Based on our results, we concluded that, unlike PFOA, HFPO-DA does not induce ER stress, suggesting that it is less toxic than PFOA. However, the risks of HFPO-DA cannot be dismissed completely, and further studies comprising different stress conditions are needed to accurately predict the potential risks of alternative compounds, such as HFPO-DA.