Uptake-independent killing of macrophages by extracellular Mycobacterium tuberculosis aggregates

ABSTRACT: Mycobacterium tuberculosis (Mtb) infection is initiated by inhalation of bacteria into lung alveoli, where they are phagocytosed by resident macrophages. Intracellular Mtb replication induces death of the infected macrophages and release of bacterial aggregates. Here, we show that these aggregates can evade phagocytosis by killing macrophages in a contact-dependent but uptake-independent manner. We use time-lapse fluorescence microscopy to show that contact with extracellular Mtb aggregates triggers macrophage plasma membrane perturbation, cytosolic calcium accumulation, and pyroptotic cell death. These effects depend on the Mtb ESX-1 secretion system, however, this system alone cannot induce calcium accumulation and macrophage death in the absence of the Mtb surface-exposed lipid phthioce

SUBMITTER: Dr. Chiara Toniolo 

PROVIDER: S-SCDT-10_15252-EMBJ_2023113490 | biostudies-other |

REPOSITORIES: biostudies-other