Bcl-xL mediates RIPK3-dependent necrosis in M. tuberculosis-infected macrophages

Mucosal Immunol. 2017 Nov;10(6):1553-1568. doi: 10.1038/mi.2017.12. Epub 2017 Apr 12.

Abstract

Virulent Mycobacterium tuberculosis (Mtb) triggers necrosis in host Mϕ, which is essential for successful pathogenesis in tuberculosis. Here we demonstrate that necrosis of Mtb-infected Mϕ is dependent on the action of the cytosolic Receptor Interacting Protein Kinase 3 (RIPK3) and the mitochondrial Bcl-2 family member protein B-cell lymphoma-extra large (Bcl-xL). RIPK3-deficient Mϕ are able to better control bacterial growth in vitro and in vivo. Mechanistically, cytosolic RIPK3 translocates to the mitochondria where it promotes necrosis and blocks caspase 8-activation and apoptosis via Bcl-xL. Furthermore, necrosis is associated with stabilization of hexokinase II on the mitochondria as well as cyclophilin D-dependent mitochondrial permeability transition. Collectively, these events upregulate the level of reactive oxygen species to induce necrosis. Thus, in Mtb-infected Mϕ, mitochondria are an essential platform for induction of necrosis by activating RIPK3 function and preventing caspase 8-activation.

MeSH terms

  • Animals
  • Bacterial Load
  • Caspase 8 / metabolism*
  • Cell Membrane Permeability
  • Cells, Cultured
  • Cyclophilins / metabolism
  • Disease Models, Animal
  • Hexokinase
  • Humans
  • Macrophages / microbiology
  • Macrophages / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Mitochondria / metabolism*
  • Mycobacterium tuberculosis / physiology*
  • Necrosis
  • Peptidyl-Prolyl Isomerase F
  • Receptor-Interacting Protein Serine-Threonine Kinases / genetics
  • Receptor-Interacting Protein Serine-Threonine Kinases / metabolism*
  • Tuberculosis / immunology*
  • bcl-X Protein / genetics
  • bcl-X Protein / metabolism*

Substances

  • Bcl2l1 protein, mouse
  • Peptidyl-Prolyl Isomerase F
  • PPIF protein, mouse
  • bcl-X Protein
  • Hexokinase
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Ripk3 protein, mouse
  • Caspase 8
  • Cyclophilins