Advancing non-animal respiratory toxicology: A TRPA1-based in vitro model for airway irritant detection

ESTIV Congress 2026 -- Environmental exposure to airway irritants can elicit sensory irritation and contribute to acute and chronic respiratory outcomes such as pain, cough, asthma and chronic obstructive pulmonary disease (COPD). Evaluation of respiratory irritation relies predominately on the in vivo RD50 or Alarie assay. Although the RD50 assay aligns well with human responses, various disadvantages, such as low throughput and interspecies differences in receptors responsible for detecting noxious stimuli, highlights the requirement for alternative, or complementary approaches. The transient receptor potential ankyrin 1 (TRPA1) ion channel, expressed in airway sensory neurons, is a key molecular sensor of such irritants. Its activation, leading to calcium influx and substance P release, has been identified as a key event leading to airway irritation. Here, we present the development of a human relevant in vitro model for airway irritant detection. Using human-relevant cell lines, we demonstrate endogenous TRPA1-driven substance P release following exposure to prototypical irritants. Furthermore, our model demonstrates concordance with in vivo RD50 data.