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

ABSTRACT: Cyclic paroxysm and high fever are hallmarks of malaria and are associated with high levels of pyrogenic cytokines, including IL-1?. 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-?-priming and the expression of inflammasome components ASC, P2X7R, NLRP3 and/or NLRP12. Pro-IL-1? expression required a second stimulation with LPS and was also dependent on IFN-?-priming and functional TNFR1. As a consequence of Plasmodium-induced caspase-1 activation, mice produced extremely high levels of IL-1? 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-1? 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-1? and hypersensitivity to secondary bacterial infection during malaria.

SUBMITTER: Ataide MA 

PROVIDER: S-EPMC3894209 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature