Genetically diverse Mycobacterium tuberculosis isolates manipulate inflammasome activation and IL-1β secretion independently of macrophage metabolic rewiring.

Abstract

The diversity of Mycobacterium tuberculosis (Mtb) impacts the outcome of tuberculosis. We previously showed that Mtb isolates obtained from patients with severe disease induced low inflammasome activation and IL-1β production by infected macrophages. Here we questioned whether this differential modulation of macrophages by Mtb isolates depended on distinct metabolic reprogramming. We found that the macrophage metabolic landscape was similar regardless of the infecting Mtb isolate. Paralleling single-TLR activated macrophages, glycolysis inhibition during infection impaired IL-1β secretion. However, departing from TLR based models, in infected macrophages, IL-1β secretion was independent of mitochondrial metabolic changes and HIF-1α. Additionally, we found an unappreciated impact of a host metabolic inhibitor on the pathogen, and show that inflammasome activation and IL-1β production by macrophages require metabolically active bacteria. Our study highlights the potential confounding effect of host metabolic inhibitors on the pathogen and uncouples Mtb-inflammasome modulation from the host metabolic reprogramming.