Inhibition of nuclear factor-kappa B activation decreases survival of Mycobacterium tuberculosis in human macrophages.

ABSTRACT: Nuclear factor-kappa B (NF?B) is a ubiquitous transcription factor that mediates pro-inflammatory responses required for host control of many microbial pathogens; on the other hand, NF?B has been implicated in the pathogenesis of other inflammatory and infectious diseases. Mice with genetic disruption of the p50 subunit of NF?B are more likely to succumb to Mycobacterium tuberculosis (MTB). However, the role of NF?B in host defense in humans is not fully understood. We sought to examine the role of NF?B activation in the immune response of human macrophages to MTB. Targeted pharmacologic inhibition of NF?B activation using BAY 11-7082 (BAY, an inhibitor of I?B? kinase) or an adenovirus construct with a dominant-negative I?B? significantly decreased the number of viable intracellular mycobacteria recovered from THP-1 macrophages four and eight days after infection. The results with BAY were confirmed in primary human monocyte-derived macrophages and alveolar macrophages. NF?B inhibition was associated with increased macrophage apoptosis and autophagy, which are well-established killing mechanisms of intracellular MTB. Inhibition of the executioner protease caspase-3 or of the autophagic pathway significantly abrogated the effects of BAY. We conclude that NF?B inhibition decreases viability of intracellular MTB in human macrophages via induction of apoptosis and autophagy.

SUBMITTER: Bai X 

PROVIDER: S-EPMC3636238 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature