Development of a three-dimensional airway organoid-pillar dish (3D AO-PD) platform for particulate matter-induced airway toxicity analysis.

Particulate matter (PM) is a major component of air pollution and is associated with respiratory diseases and lung dysfunction. Physiologically relevant models are essential for studying PM-induced airway responses in vitro. Conventional two-dimensional (2D) monolayer models comprising only bronchial epithelial cells are limited in their ability to mimic the complex structure of airway tissue. In contrast, three-dimensional (3D) airway organoids contain basal, ciliated, and goblet cells, which better reflect airway architecture. However, the standardization of 3D cultures has been a major challenge. In the present study, to address this, we developed the 3D Airway Organoid-Pillar Dish (AO-PD) model, a platform that enables reproducible formation of standardized 3D airway. We compared this model with a 2D monolayer model under PM exposure. The 3D AO-PD model showed higher cell viability and significant inflammatory and epithelial-mesenchymal transition responses than that of the 2D model. These results indicate that the 3D AO-PD model more accurately reflects PM-induced airway damage and provides greater resistance to environmental insults owing to its pseudostratified epithelial structure and enhanced cell-cell interactions. Thus, the 3D AO-PD model serves as a robust in vitro platform for investigating PM-induced airway toxicity and inflammation-related responses.