Smoking is strongly associated with the onset and progression of chronic obstructive pulmonary disease (COPD). Cigarette smoke (CS) contains more than 4500 highly reactive chemicals that drive inflammation and tissue damage in the alveoli and understanding the complex interaction with human lung cells could lead to development of better targeted therapies.

Our setup includes a continuous flow smoking chamber (CFAX12; Vitrocell) seamlessly integrated with the breathing ^AXLung-on-chip System (AlveoliX). In addition, human lung alveolar epithelial cells (^AXiAECs; Sengupta, A. et al., 2022) cultured on-chip were subjected to breathing-like cyclic stretch (BR) and air-liquid interface (ALI) culture conditions. To mimic heavy smokers (>20 pack years), the tight alveolar barrier (Transepithelial barrier resistance; TER> 2000?cm2) on-chip was exposed to acute CS regimen. Next, traditionally used cigarette smoke extract (CSE) was generated fresh and the toxic effects were compared with whole CS exposure on-chip.

Significant barrier disruption on-chip (with TER<100 ?cm2) was established starting early at 4 hours after CS exposure. Moreover, increased expression of pro-inflammatory markers (like IL6, IFN?) along with decreased gene levels of epithelial-specific markers (like cadherin, occludin) signified an active inflammation. Cells in ALI+BR conditions indicated (4-folds) better response in terms of inflammation and ROS generation compared to cells in ALI. Our results also indicate that CS exposure was more physiological in comparison to CSE treatments that incited higher cytotoxicity.

Collectively, our model offers reproducible conditions for CS-induced toxicity and advocates use of inhalation tool in pre-clinical studies.