Wnt/β-catenin signaling reduces Bacillus Calmette-Guerin-induced macrophage necrosis through a ROS -mediated PARP/AIF-dependent pathway

BMC Immunol. 2015 Mar 18:16:16. doi: 10.1186/s12865-015-0080-5.


Background: Necrosis of alveolar macrophages following Mycobacterium tuberculosis infection has been demonstrated to play a vital role in the pathogenesis of tuberculosis. Our previous study demonstrated that Wnt/β-catenin signaling was able to promote mycobacteria-infected cell apoptosis by a caspase-dependent pathway. However, the functionality of this signaling in the necrosis of macrophage following mycobacterial infection remains largely unknown.

Methods: Murine macrophage RAW264.7 cells were infected with Bacillus Calmette-Guerin (BCG) in the presence of Wnt/β-catenin signaling. The necrotic cell death was determined by cytometric assay and electronic microscopy; the productions of reactive oxygen species (ROS) and reduced glutathione (GSH) were measured by a cytometric analysis and an enzyme-linked immunosorbent assay, respectively; and the activity of poly (ADP-ribose) polymerase 1 (PARP-1)/apoptosis inhibition factor (AIF) signaling was examined by an immunoblotting assay.

Results: The BCG can induce RAW264.7 macrophage cells necrosis in a dose- and time-dependent manner along with an accumulation of reactive oxygen species (ROS). Intriguingly, an enhancement of Wnt/β-catenin signaling shows an ability to reduce the mycobacteria-induced macrophage necrosis. Mechanistically, the activation of Wnt/β-catenin signaling is capable of inhibiting the necrotic cell death in BCG-infected RAW264.7 cells through a mechanism by which the Wnt signaling scavenges intracellular ROS accumulation and increases cellular GSH concentration. In addition, immunoblotting analysis further reveals that Wnt/β-catenin signaling is capable of inhibiting the ROS-mediated cell necrosis in part through a PARP-1/AIF- dependent pathway.

Conclusions: An activation of Wnt/β-catenin signaling can inhibit BCG-induced macrophage necrosis by increasing the production of GSH and scavenging ROS in part through a mechanism of repression of PARP-1/AIF signaling pathway. This finding may thus provide an insight into the underlying mechanism of alveolar macrophage cell death in response to mycobacterial infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis Inducing Factor / metabolism*
  • BCG Vaccine / immunology*
  • Cell Line
  • Enzyme Repression
  • Glutathione / metabolism
  • Humans
  • Macrophages / immunology*
  • Macrophages / microbiology
  • Macrophages / pathology
  • Mice
  • Necrosis
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerases / metabolism*
  • Reactive Oxygen Species / metabolism
  • Wnt Signaling Pathway / immunology
  • beta Catenin / metabolism*


  • AIFM1 protein, human
  • Apoptosis Inducing Factor
  • BCG Vaccine
  • Reactive Oxygen Species
  • beta Catenin
  • PARP1 protein, human
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerases
  • Glutathione