Advances in an In Vitro Tuberculosis Infection Model Using Human Lung Organoids for Host-Directed Therapies

The emergence of drug-resistant Mycobacterium tuberculosis ( M . tb ) has led to the development of novel anti-tuberculosis (anti-TB) drugs. Common methods for testing the efficacy of new drugs, including two-dimensional cell culture models or animal models, have several limitations. Therefore, an appropriate model representative of the human organism is required. Here, we developed an M . tb infection model using human lung organoids (hLOs) and demonstrated that M . tb H37Rv can infect lung epithelial cells and human macrophages (hMφs) in hLOs. This novel M . tb infection model can be cultured long-term and split several times while maintaining a similar number of M . tb H37Rv inside the hLOs. Anti-TB drugs reduced the intracellular survival of M . tb in hLOs. Notably, M . tb growth in hLOs was effectively suppressed at each passage by rifampicin and bedaquiline. Furthermore, a reduction in inflammatory cytokine production and intracellular survival of M . tb were observed upon knockdown of MFN2 and HERPUD1 (host-directed therapeutic targets for TB) in our M . tb H37Rv-infected hLO model. Thus, the incorporation of hMφs and M . tb into hLOs provides a powerful strategy for generating an M . tb infection model. This model can effectively reflect host-pathogen interactions and be utilized to test the efficacy of anti-TB drugs and host-directed therapies.