Comparative sensitivity of in vitro acute and chronic apical and transcriptomic points of departure for perfluorooctanoic acid in human vascular endothelial cells

In vitro human cell models and new approach methodologies offer valuable alternatives to animal testing, providing human-relevant data for chemical risk assessment. However, the impact of exposure duration and biological levels on the sensitivity of responses in human cells in vitro remains underexplored. In this study, we employed benchmark concentration modeling to derive and compare points of departure (PODs) for apical (A-POD) and transcriptomic (T-POD) changes in human vascular endothelial cells EA.hy926 following short-term (48 h) and long-term (6 and 12 weeks) exposure to 1, 10, and 100 {micro}M and 1, 10, and 100 nM perfluorooctanoic acid (PFOA), respectively. We found that A-POD could not be calculated for short-term exposure; however, A-PODs after 6 and 12 weeks were determined to be 3.7 nM and 5.4 nM, respectively. mRNA sequencing revealed a significant number of differentially expressed genes in PFOA-exposed EA.hy926 cells across all time points. T-POD values after 6 and 12 weeks (4.1 nM and 22.1 nM, respectively) demonstrated greater sensitivity than the acute T-POD (6.3 {micro}M) and were comparable to the chronic A-POD. Functional gene analysis revealed that transcription was a sensitive, yet general molecular pathway affected by acute exposure, while the IL-17 pathway and extracellular matrix and cytokine-cytokine interactions were implicated after 6 and 12 weeks of exposure to PFOA, respectively. In conclusion, chronic PODs proved to be more informative than acute PODs for chemical risk assessment in PFOA-exposed human endothelial cells. Furthermore, transcriptomics data from long-term exposure can elucidate early molecular pathways associated with chemical exposure, highlighting their potential to connect toxicity effects across different biological levels.