Malaria-induced NLRP12/NLRP3-dependent caspase-1 activation mediates inflammation and hypersensitivity to bacterial superinfection

PLoS Pathog. 2014 Jan;10(1):e1003885. doi: 10.1371/journal.ppat.1003885. Epub 2014 Jan 16.

Abstract

Cyclic paroxysm and high fever are hallmarks of malaria and are associated with high levels of pyrogenic cytokines, including IL-1β. In this report, we describe a signature for the expression of inflammasome-related genes and caspase-1 activation in malaria. Indeed, when we infected mice, Plasmodium infection was sufficient to promote MyD88-mediated caspase-1 activation, dependent on IFN-γ-priming and the expression of inflammasome components ASC, P2X7R, NLRP3 and/or NLRP12. Pro-IL-1β expression required a second stimulation with LPS and was also dependent on IFN-γ-priming and functional TNFR1. As a consequence of Plasmodium-induced caspase-1 activation, mice produced extremely high levels of IL-1β upon a second microbial stimulus, and became hypersensitive to septic shock. Therapeutic intervention with IL-1 receptor antagonist prevented bacterial-induced lethality in rodents. Similar to mice, we observed a significantly increased frequency of circulating CD14(+)CD16(-)Caspase-1(+) and CD14(dim)CD16(+)Caspase-1(+) monocytes in peripheral blood mononuclear cells from febrile malaria patients. These cells readily produced large amounts of IL-1β after stimulation with LPS. Furthermore, we observed the presence of inflammasome complexes in monocytes from malaria patients containing either NLRP3 or NLRP12 pyroptosomes. We conclude that NLRP12/NLRP3-dependent activation of caspase-1 is likely to be a key event in mediating systemic production of IL-1β and hypersensitivity to secondary bacterial infection during malaria.

Publication types

  • Clinical Trial

MeSH terms

  • Animals
  • Bacterial Infections / genetics
  • Bacterial Infections / immunology
  • Bacterial Infections / metabolism*
  • Carrier Proteins / genetics
  • Carrier Proteins / immunology
  • Carrier Proteins / metabolism*
  • Caspase 1 / genetics
  • Caspase 1 / immunology
  • Caspase 1 / metabolism*
  • Female
  • Humans
  • Inflammasomes / genetics
  • Inflammasomes / immunology
  • Inflammasomes / metabolism
  • Inflammation / genetics
  • Inflammation / immunology
  • Inflammation / metabolism
  • Inflammation / pathology
  • Interleukin-1beta / genetics
  • Interleukin-1beta / immunology
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / immunology
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Malaria, Vivax / immunology
  • Malaria, Vivax / metabolism
  • Malaria, Vivax / microbiology*
  • Malaria, Vivax / pathology
  • Male
  • Mice
  • Mice, Knockout
  • Monocytes / immunology
  • Monocytes / metabolism
  • Monocytes / pathology
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Plasmodium chabaudi / immunology
  • Plasmodium chabaudi / metabolism*
  • Plasmodium vivax / immunology
  • Plasmodium vivax / metabolism*
  • Shock, Septic / genetics
  • Shock, Septic / immunology
  • Shock, Septic / metabolism
  • Shock, Septic / pathology

Substances

  • Carrier Proteins
  • IL1B protein, human
  • Inflammasomes
  • Interleukin-1beta
  • Intracellular Signaling Peptides and Proteins
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • NLRP12 protein, human
  • NLRP12 protein, mouse
  • NLRP3 protein, human
  • Nlrp3 protein, mouse
  • Caspase 1