Human airway submucosal gland organoids to study respiratory inflammation and infection.

The human airway lining consists of two physiologically distinct compartments: the surface airway epithelium (SAE) and the submucosal glands (SMGs). Despite their critical role, the SMGs have remained largely overlooked in airway in vitro modeling of respiratory inflammation and infection. In this study, we leverage long-term cultured organoids derived separately from SAE and SMGs to investigate their unique physiological characteristics. Single-cell RNA sequencing (scRNA-seq) analysis confirms that these organoid models accurately replicate the cellular heterogeneity inherent to each tissue type. Specifically, SMG organoids are enriched in MUC5B-producing mucous cells and also generate alpha-smooth muscle actin (αSMA)-expressing myoepithelial cells. ANPEP/CD13 specifically marks SMG secretory cells. Exposure to cytokines elicits distinct inflammatory transcriptomic responses in SMG secretory cells. Infection assays with human alpha-coronavirus 229E (HCoV-229E) reveal the selective vulnerability of CD13-positive secretory cells, triggering an unfolded protein response. These findings broaden the utility of airway organoids for modeling respiratory (patho-)physiology.