Abstract
Enteric pathogens represent a major cause of morbidity and mortality worldwide. Toll-like receptor (TLR) and inflammasome signaling are critical for host responses against these pathogens, but how these pathways are integrated remains unclear. Here, we show that TLR4 and the TLR adaptor TRIF are required for inflammasome activation in macrophages infected with the enteric pathogens Escherichia coli and Citrobacter rodentium. In contrast, TLR4 and TRIF were dispensable for Salmonella typhimurium-induced caspase-1 activation. TRIF regulated expression of caspase-11, a caspase-1-related protease that is critical for E. coli- and C. rodentium-induced inflammasome activation, but dispensable for inflammasome activation by S. typhimurium. Thus, TLR4- and TRIF-induced caspase-11 synthesis is critical for noncanonical Nlrp3 inflammasome activation in macrophages infected with enteric pathogens.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Vesicular Transport / genetics
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Adaptor Proteins, Vesicular Transport / immunology*
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Animals
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Carrier Proteins / genetics
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Carrier Proteins / immunology*
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Caspases / genetics
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Caspases / immunology*
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Caspases, Initiator
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Enterobacteriaceae / genetics
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Enterobacteriaceae / immunology*
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Enterobacteriaceae Infections / genetics
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Enterobacteriaceae Infections / immunology*
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Enterobacteriaceae Infections / microbiology
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Inflammasomes / genetics
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Inflammasomes / immunology*
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Macrophage Activation / genetics
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Macrophage Activation / immunology
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Macrophages / immunology*
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Mice
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Mice, Knockout
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NLR Family, Pyrin Domain-Containing 3 Protein
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Toll-Like Receptor 4 / genetics
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Toll-Like Receptor 4 / immunology*
Substances
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Adaptor Proteins, Vesicular Transport
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Carrier Proteins
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Inflammasomes
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NLR Family, Pyrin Domain-Containing 3 Protein
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Nlrp3 protein, mouse
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TICAM-1 protein, mouse
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Tlr4 protein, mouse
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Toll-Like Receptor 4
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Casp4 protein, mouse
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Caspases
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Caspases, Initiator