P25-19 Unravelling Respiratory Toxicity of PFAS: One Cell at a Time

Per- and polyfluoroalkyl substances (PFAS) represent a critical group of persistent environmental contaminants, widely recognised for their bioaccumulation potential and adverse effects on human health. Their interaction with the respiratory system, particularly through inhalation exposure, remains understudied. Here, we aim to elucidate the respiratory toxicity and cellular responses induced by selected PFAS compounds using ALIsens, an advanced human-relevant in vitro model. The ALIsens model is a sophisticated 3-dimensional co-culture model cultivated at the air-liquid interface, combining epithelial cells (A549), PMA-differentiated macrophages (THP-1), endothelial cells (EA.hy926), and naïve THP-1 cells. This configuration accurately replicates key anatomical and functional features of the human respiratory tract, facilitating physiologically relevant exposure scenarios. We exposed the ALIsens model to seven environmentally relevant PFAS. Single-cell transcriptomics (scRNA-seq) was applied to dissect cell-type specific molecular responses and identify sensitive biomarkers of PFAS-induced cellular stress, inflammation, and barrier dysfunction. Additional functional endpoints were assessed to link transcriptional changes with altered tissue-level outcomes. Initial results are expected to shed light on critical mechanistic pathways influenced by PFAS exposure in human respiratory tissues, including immune modulation and inflammatory responses. Ultimately, this research will enhance our understanding of PFAS toxicity at the respiratory interface, guiding the development of predictive assays and regulatory strategies to safeguard human health. This work highlights the importance of advanced in vitro methodologies, such as ALIsens, as valuable tools within next-generation toxicological assessments, aligning with the ongoing transition towards human-relevant and animal-free research models. The results are expected to inform on potential apical effects that can be measured in high throughput assays, and so contributing to a testing toolbox to improve and address the hazard of PFAS exposure to human health and ultimately, facilitate read-across actions between legacy and poor-data congeners.