Caspase-11 activation requires lysis of pathogen-containing vacuoles by IFN-induced GTPases

E Meunier, MS Dick, RF Dreier, N Schürmann, DK Broz… - Nature, 2014 - nature.com
E Meunier, MS Dick, RF Dreier, N Schürmann, DK Broz, S Warming, M Roose-Girma…
Nature, 2014nature.com
Lipopolysaccharide from Gram-negative bacteria is sensed in the host cell cytoplasm by a
non-canonical inflammasome pathway that ultimately results in caspase-11 activation and
cell death,,. In mouse macrophages, activation of this pathway requires the production of
type-I interferons,, indicating that interferon-induced genes have a critical role in initiating
this pathway. Here we report that a cluster of small interferon-inducible GTPases, the so-
called guanylate-binding proteins, is required for the full activity of the non-canonical …
Abstract
Lipopolysaccharide from Gram-negative bacteria is sensed in the host cell cytoplasm by a non-canonical inflammasome pathway that ultimately results in caspase-11 activation and cell death,,. In mouse macrophages, activation of this pathway requires the production of type-I interferons,, indicating that interferon-induced genes have a critical role in initiating this pathway. Here we report that a cluster of small interferon-inducible GTPases, the so-called guanylate-binding proteins, is required for the full activity of the non-canonical caspase-11 inflammasome during infections with vacuolar Gram-negative bacteria. We show that guanylate-binding proteins are recruited to intracellular bacterial pathogens and are necessary to induce the lysis of the pathogen-containing vacuole. Lysis of the vacuole releases bacteria into the cytosol, thus allowing the detection of their lipopolysaccharide by a yet unknown lipopolysaccharide sensor. Moreover, recognition of the lysed vacuole by the danger sensor galectin-8 initiates the uptake of bacteria into autophagosomes, which results in a reduction of caspase-11 activation. These results indicate that host-mediated lysis of pathogen-containing vacuoles is an essential immune function and is necessary for efficient recognition of pathogens by inflammasome complexes in the cytosol.
nature.com