Ricin toxin activates the NALP3 inflammasome

Meghan Lindauer, John Wong, Bruce Magun

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Ricin exhibits well characterized ribotoxic actions that lead to the inhibition of protein synthesis and the phosphorylation of stress activated protein kinases (SAPKs). Proinflammatory effects of ricin are thought to be caused by upregulation of genes encoding proinflammatory transcripts as a result of the activation of c-Jun N-terminal kinase (JNK) and p38 MAPK. We reported previously that macrophages and interleukin-1 β (IL-1β) signaling are required for murine host immune responses to ricin delivered to the lungs. Here we report that ricin-mediated IL-1βrelease from bone-marrow derived macrophages is dependent on the NALP3 inflammasome, a scaffolding complex that mediates pro-IL-1β cleavage to active IL-1β by caspase-1. Release of IL-1β from macrophages was suppressed by the reactive oxygen species (ROS) scavenger N-acetyl cysteine (NAC) and high extracellular K +, which are two agents known to inhibit NALP3/cryopyrin/CIAS1 inflammasome formation. By employing inhibitors of p38 MAPK and JNK, we demonstrated that ricin-mediated release of IL-1β was enhanced, rather than suppressed, by inhibition of SAPK phosphorylation. In contrast, proteasomal inhibitors bortezomib and MG-132 completely suppressed ricin-induced IL-1β release from macrophages. These data suggest that ricin-mediated translational inhibition itself, by fostering the disappearance of labile protein(s) that normally suppress inflammasome formation, may constitute the mechanism underlying IL-1-dependent inflammatory signaling by ricin.

Original languageEnglish (US)
Pages (from-to)1500-1514
Number of pages15
JournalToxins
Volume2
Issue number6
DOIs
StatePublished - Jun 2010

Fingerprint

Inflammasomes
Ricin
Interleukin-1
Macrophages
Phosphorylation
p38 Mitogen-Activated Protein Kinases
Heat-Shock Proteins
Protein Kinases
Acetylcysteine
Caspase 1
Gene encoding
Foster Home Care
JNK Mitogen-Activated Protein Kinases
Cysteine
Reactive Oxygen Species
Bone
Proteins
Phosphotransferases
Up-Regulation
Chemical activation

Keywords

  • IL-1
  • Inflammasome
  • NALP3
  • Ricin

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis

Cite this

Lindauer, M., Wong, J., & Magun, B. (2010). Ricin toxin activates the NALP3 inflammasome. Toxins, 2(6), 1500-1514. https://doi.org/10.3390/toxins2061500

Ricin toxin activates the NALP3 inflammasome. / Lindauer, Meghan; Wong, John; Magun, Bruce.

In: Toxins, Vol. 2, No. 6, 06.2010, p. 1500-1514.

Research output: Contribution to journalArticle

Lindauer, M, Wong, J & Magun, B 2010, 'Ricin toxin activates the NALP3 inflammasome', Toxins, vol. 2, no. 6, pp. 1500-1514. https://doi.org/10.3390/toxins2061500
Lindauer M, Wong J, Magun B. Ricin toxin activates the NALP3 inflammasome. Toxins. 2010 Jun;2(6):1500-1514. https://doi.org/10.3390/toxins2061500
Lindauer, Meghan ; Wong, John ; Magun, Bruce. / Ricin toxin activates the NALP3 inflammasome. In: Toxins. 2010 ; Vol. 2, No. 6. pp. 1500-1514.
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