Human lung organoids model for assessing host response to <i>Mycobacterium tuberculosis</i> infection

Introduction Airway and alveolar epithelial cells serve as the primary defense in the lower respiratory tract, yet their exact role in Mycobacterium tuberculosis (Mtb) infection is incompletely understood. Given that Mtb is a human-restricted pathogen, a representative human model is required. Lung organoids (LOs), which are composed of various epithelial cells, mesenchymal cells, and extracellular matrix, facilitate the investigation of bacterial infections. Methods In this study, we established an Mtb infection model using human induced pluripotent stem cells (iPSCs)-derived LOs. Results Prolonged infection led to the gradual invasion of Mtb from the periphery to the interior of the organoid, leading to decreased viability and the induction of fibrotic responses. Transcriptomic and protein analyses suggest that Mtb infection triggered a TLR4/NF-κB-associated inflammatory response. Additionally, the elevation of antimicrobial peptides and the release of diverse pro-inflammatory cytokines and chemokines were noted in the infected LOs. Conclusion These findings emphasize the potential role of LOs in host defense and demonstrate that the Mtb -infected lung organoid model provides a novel platform for elucidating the role of pulmonary structural cells in tuberculosis pathogenesis. Furthermore, this model opens new avenues for the development of molecular therapeutic strategies.