Publications (45) View all
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Dataset: HB-suppl data-mmc1
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Dataset: HB-Suppl-Tables
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Article: Yersinia pseudotuberculosis disrupts intestinal barrier integrity through hematopoietic TLR-2 signaling.
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ABSTRACT: Intestinal barrier function requires intricate cooperation between intestinal epithelial cells and immune cells. Enteropathogens are able to invade the intestinal lymphoid tissue known as Peyer's patches (PPs) and disrupt the integrity of the intestinal barrier. However, the underlying molecular mechanisms of this process are poorly understood. In mice infected with Yersinia pseudotuberculosis, we found that PP barrier dysfunction is dependent on the Yersinia virulence plasmid and the expression of TLR-2 by hematopoietic cells, but not by intestinal epithelial cells. Upon TLR-2 stimulation, Y. pseudotuberculosis-infected monocytes activated caspase-1 and produced IL-1β. In turn, IL-1β increased NF-κB and myosin light chain kinase activation in intestinal epithelial cells, thus disrupting the intestinal barrier by opening the tight junctions. Therefore, Y. pseudotuberculosis subverts intestinal barrier function by altering the interplay between immune and epithelial cells during infection.The Journal of clinical investigation 05/2012; 122(6):2239-51. · 15.39 Impact Factor -
Article: Does the radiographic transition zone correlate with the level of aganglionosis on the specimen in Hirschsprung's disease?
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ABSTRACT: The correlation between radiographic transition zone on contrast enema in Hirschsprung's disease and the total length of aganglionosis is known to be inaccurate. The aim of our study was to analyse this correlation more precisely to improve preoperative planning of the corrective surgery. From 1998 to 2009, 79 patients were operated on for Hirschsprung's disease. All available preoperative contrast enemas (n = 61) had been single blind reviewed by the same radiologist who defined the radiographic transition zone when present in vertebral level. Four groups were determined (rectal, rectosigmoid, long segment, and absence of transition zone) and by Kappa coefficient of agreement correlated to the length of aganglionosis in the pathological report. Radiological findings were concordant with the specimen in pathology in 8 cases of 19 in rectal form (42 %), in 20 cases of 35 in rectosigmoid form (57 %), in all 6 cases of long-segment form (100 %), in the 2 cases of total colonic form (100 %) with a global agreement of 58.1 %, κ = 0.39 CI [0.24; 0.57]. Correlation between level of radiographic transition zone on contrast enema and length of aganglionosis remains low. Systematic preoperative biopsy by coelioscopy or ombilical incision is mandatory.Pediatric Surgery International 04/2012; 28(6):597-601. · 1.25 Impact Factor -
Article: Yersinia pseudotuberculosis effector YopJ subverts the Nod2/RICK/TAK1 pathway and activates caspase-1 to induce intestinal barrier dysfunction.
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ABSTRACT: Yersinia pseudotuberculosis is an enteropathogenic bacteria that disrupts the intestinal barrier and invades its host through gut-associated lymphoid tissue and Peyer's patches (PP). We show that the Y. pseudotuberculosis effector YopJ induces intestinal barrier dysfunction by subverting signaling of the innate immune receptor Nod2, a phenotype that can be reversed by pretreating with the Nod2 ligand muramyl-dipeptide. YopJ, but not the catalytically inactive mutant YopJ(C172A), acetylates critical sites in the activation loops of the RICK and TAK1 kinases, which are central mediators of Nod2 signaling, and decreases the affinity of Nod2 for RICK. Concomitantly, Nod2 interacts with and activates caspase-1, resulting in increased levels of IL-1β. Finally, IL-1β within PP plays an essential role in inducing intestinal barrier dysfunction. Thus, YopJ alters intestinal permeability and promotes the dissemination of Yersinia as well as commensal bacteria by exploiting the mucosal inflammatory response.Cell host & microbe 04/2012; 11(4):337-51. · 13.02 Impact Factor
