Browsing by Subject "Bacterial infection"

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    A human antithrombin isoform dampens inflammatory responses and protects from organ damage during bacterial infection
    (Nature Research, 2019) Papareddy, Praveen; Rossnagel, Madlen; Hollwedel, Femke; Kilic, Gülcan; Veerla, Srinivas; Naudin, Clément; Smeds, Emanuel; Westman, Johannes; Martínez-Martínez, Irene; Egesten, Arne; Morena-Barrio, María Eugenia de la; Corral, Javier; Linder, Adam; Artoni, Andrea; Abbattista, Maria; Novembrino, Cristina; Brakebusch, Cord Hebert; Martinelli, Ida; Kasetty, Gopinath; Herwarld, Heiko; Medicina
    Severe infectious diseases are often characterized by an overwhelming and unbalanced systemic immune response to microbial infections. Human antithrombin (hAT) is a crucial coagulation inhibitor with anti-inflammatory activities. Here we identify three hAT-binding proteins (CD13, CD300f and LRP-1) on human monocytes that are involved in blocking the activity of nuclear factor-κB. We found that the modulating effect is primarily restricted to the less abundant β-isoform (hβAT) of hAT that lacks N-glycosylation at position 135. Individuals with a mutation at this position have increased production of hβAT and analysis of their blood, which was stimulated ex vivo with lipopolysaccharide, showed a decreased inflammatory response. Similar findings were recorded when heterozygotic mice expressing hAT or hβAT were challenged with lipopolysaccharide or infected with Escherichia coli bacteria. Our results finally demonstrate that in a lethal E. coli infection model, survival rates increased when mice were treated with hβAT one hour and five hours after infection. The treatment also resulted in a reduction of the inflammatory response and less severe organ damage.
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    Neutrophils mediate Salmonella Typhimurium clearance through the GBP4 inflammasome-dependent production of prostaglandins
    (Nature Research, 2016-07-01) Martín Sánchez, María Rosario Fátima; Tyrkalska, Sylwia D.; Candel Camacho, Sergio; Angosto, Diego; Gómez Abellán, Victoria; García Moreno, Diana; Zapata Pérez, Rubén; Sánchez Ferrer, Álvaro; Pelegrín Vivancos, Pablo; Mulero Méndez, Victoriano Francisco; Sepulcre Cortés, María Pilar; Farmacología
    Inflammasomes are cytosolic molecular platforms that alert the immune system about thepresence of infection. Here we report that zebrafish guanylate-binding protein 4 (Gbp4),an IFNg-inducible GTPase protein harbouring a C-terminal CARD domain, is required for theinflammasome-dependent clearance of Salmonella Typhimurium (ST) by neutrophils in vivo.Despite the presence of the CARD domain, Gbp4 requires the universal inflammasomeadaptor Asc for mediating its antibacterial function. In addition, the GTPase activity of Gbp4is indispensable for inflammasome activation and ST clearance. Mechanistically, neutrophilsare recruited to the infection site through the inflammasome-independent production of thechemokine (CXC motif) ligand 8 and leukotriene B4, and then mediate bacterial clearancethrough the Gbp4 inflammasome-dependent biosynthesis of prostaglandin D2. Our resultspoint to GBPs as key inflammasome adaptors required for prostaglandin biosynthesis andbacterial clearance by neutrophils and suggest that transient activation of the inflammasomemay be used to treat bacterial infections.