Khader Lab

Macrophage metabolic reprogramming in multidrug-resistant Mtb-infection

The emergence of multidrug-resistant (MDR) Mtb that is resistant to the frontline anti-tubercular drugs rifampicin and isoniazid forces treatment with toxic second-line drugs. Currently, ~4% of new and ~21% of previously treated tuberculosis cases are either rifampicin-drug-resistant or MDR Mtb infections. The specific molecular host-pathogen interactions mediating the rapid worldwide spread of MDR Mtb strains remain poorly understood. W-Beijing Mtb strains are highly prevalent throughout the world and associated with increased drug resistance. The production of interleukin-1β (IL-1β) by macrophages coincides with the shift towards aerobic glycolysis, a metabolic process that mediates protection against drug-susceptible Mtb. Using a collection of MDR W-Mtb strains, we demonstrated that the overexpression of Mtb cell wall lipids, phthiocerol dimycocerosates, bypasses the interleukin 1 receptor, type I (IL-1R1) signaling pathway, instead driving the induction of interferon-β (IFN-β) to reprogram macrophage metabolism. Importantly, Mtb carrying a drug resistance-conferring single nucleotide polymorphism in rpoB (H445Y) can modulate host macrophage metabolic reprogramming (Howard et al. 2019). These findings transform our mechanistic understanding of how emerging MDR Mtb strains may acquire drug resistance single nucleotide polymorphisms, thereby altering Mtb surface lipid expression and modulating host macrophage metabolic reprogramming which needs to be thoroughly studied. This has implication in the efforts to successfully design new therapeutic targets and vaccines to prevent the spread of emerging MDR, as well as extensively and extremely drug resistant Mtb spread.

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