Coronavirus activates a stem cell-mediated defense mechanism that reactivates dormant tuberculosis: implications in COVID-19 pandemic

We postulate that similar to bacteria, adult stem cells may also exhibit an innate defense mechanism to protect their niche. Here, we provide preliminary data on stem cell based innate defense against a mouse model of coronavirus, murine hepatitis virus-1 (MHV-1) infection. In a mouse model of mesenchymal stem cell (MSC) mediatedMycobacterium tuberculosis(Mtb) dormancy, MHV-1 infection in the lung exhibited 20 fold lower viral loads than the healthy control mice, suggesting the potential enhancement of an anti-MHV-1 defense byMtb. This defense mechanism involves thein vivoexpansion and reprogramming of CD271+MSCs in the lung to an enhanced stemness phenotype. The reprogrammed MSCs facilitate the activation of stemness genes, intracellular Mtb replication, and extracellular release ofMtb. The conditioned media of the reprogrammed MSCs exhibit direct anti-viral activity in anin vitromodel of MHV-1 induced toxicity to type II alveolar epithelial cells. Thus, our data suggest that reprogrammed MSCs exert a unique innate defense against MHV-1 by activating dormantMtb.The molecular details of this anti-viral defense mechanism against coronavirus could be further studied to develop a vaccine against COVID-19.