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|Title:||Caspase-1 mediates resistance in murine melioidosis|
Guang Wen Sun
Yunn Hwen Gan
National University of Singapore
DSO National Laboratories
|Keywords:||Immunology and Microbiology;Medicine|
|Citation:||Infection and Immunity. Vol.77, No.4 (2009), 1589-1595|
|Abstract:||The gram-negative rod Burkholderia pseudomallei is the causative agent of melioidosis, a potentially fatal disease which is endemic in tropical and subtropical areas. The bacterium multiplies intracellularly within the cytosol, induces the formation of actin tails, and can spread directly from cell to cell. Recently, it has been shown that B. pseudomallei can induce caspase-1-dependent cell death in macrophages. The aim of the present study was to further elucidate the role of caspase-1 during B. pseudomallei infection. In vivo experiments with caspase-1-/- mice revealed a high susceptibility to B. pseudomallei challenge. This phenotype was associated with a significantly higher bacterial burden 2 days after infection and decreased gamma interferon (IFN-γ) and interleukin-18 cytokine levels 24 h after infection compared to control animals. caspase-1-/- bone marrow- derived macrophages (BMM) exhibited strong caspase-3 expression and reduced cell damage compared to wild-type (WT) cells during early B. pseudomallei infection, indicating "classical" apoptosis, whereas WT BMM showed signs of rapid caspase-1-dependent cell death. Moreover, we found that caspase-1-/- BMM had a strongly increased bacterial burden compared to WT cells 3 h after infection under conditions where no difference in cell death could be observed between both cell populations at this time point. We therefore suggest that caspase-1-dependent rapid cell death might contribute to resistance by reducing the intracellular niche for B. pseudomallei, but, in addition, caspase-1 might also have a role in controlling intracellular replication of B. pseudomallei in macrophages. Moreover, caspase-1-dependent IFN-γ production is likely to contribute to resistance in murine melioidosis. Copyright © 2009, American Society for Microbiology, All Rights Reserved.|
|Appears in Collections:||Scopus 2006-2010|
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