Pet serine protease from enteroaggregative Escherichia coli stimulates the inflammatory response activating human macrophages

Abstract

BackgroundPet is a toxin from the family of Serine Protease Autotransporters of Enterobacteriaceae which was initially identified in Enteroaggregative Escherichia coli strains. This protease exhibits enterotoxin properties, damages the cell cytoskeleton and induces intestinal epithelium alterations, which are associated with a severe inflammatory process. An in-vitro study was conducted to evaluate the effect of Pet on the migration of human peripheral blood monocytes-derived macrophages and its participation in the activation of the early inflammatory response and cytokine expression.ResultsIn the macrophage migration activation assay, Pet produced a similar effect to that induced by opsonized zymosan (ZAS). Regarding the cytokine expression, an increase of IL-8, TNF-α (pro-inflammatory) and IL-10 (anti-inflammatory) was identified. In addition to the above results, the nuclear translocation of NF-kB pp65 was also identified. These events are probably related to the inflammatory response identified in the histological examination of intestine rat samples inoculated with Pet during a ligated loop assay.ConclusionThe results showed that Pet participates as an immunostimulant molecule for macrophages, which activates both their mobility and cytokine expression. These observations suggest that the toxin participates in the inflammatory process that is observed during the host infection by EAEC Pet producing.

Alteraciones en el tracto urinario durante la infección con Proteus mirabilis que expresa la toxina codificada en plásmido (Pet)

“…Many in vitro an in vivo assays have been performed to understand the mechanism of action of Pet from EAEC 042. Pet induces cytotoxic and cytopathic effects on different cell lines, in rat ileal loop and in the intestine of mice infected with EAEC 042, modifying the morphological conformation of enterocytes from cuboidal to a rounded shape, this modification is due to the proteolysis of α-fodrin scaffolding protein of the cytoskeleton, resulting in reorganization of actin filaments (Navarro-García et al, 1998;Navarro-García, Sears, Eslava, Cravioto & Nataro, 1999;Navarro-García, Sonnested & Tetter, 2010); Canizalez-Roman & Navarro-García, 2003;Capello et al, 2011;Henderson et al, 1999;Villaseca et al, 2000;Betancourt-Sánchez & Navarro-García, 2009;Sainz et al, 2002;Sui, Dutta & Nataro, 2003;Rocha-Ramírez et al, 2016). Previous histological analysis of the ileal loop and the intestine of mice inoculated with purified Pet and EAEC 042 revealed the hypersecretion of mucus and the presence of abundant exfoliated rounded cells belonging to the intestinal mucosa (Navarro-García et al, 1998;Sainz et al, 2002; Rocha-Ramírez et al., 2016).…”

“…The morphological changes of intestinal cells due to Pet from EAEC have been widely studied in several cell lines and in the ligated loops of intestine model (Navarro-García et al, 1998;Navarro-García, Sears, Eslava, Cravioto & Nataro,1999;Navarro-García, Sonnested & Tetter, 2010;Canizalez-Roman & Navarro-García, 2003;Capello et al, 2011;Henderson et al, 1999;Villaseca et al 2000;Betancourt-Sánchez & Navarro-García, 2009;Sainz et al, 2002;Sui, Dutta & Nataro, 2003;Rocha-Ramírez et al, 2016). However, there are not studies on the effect of Pet produced by P. mirabilis (Pet+) during UTI.…”

ProbioticLactobacillusStrains Stimulate the Inflammatory Response and Activate Human Macrophages

“…Mononuclear cells were separated using gradient centrifugation, as previously described [22]. Briefly, the interface mononuclear cells were washed twice with sterile physiological saline solution and then collected in Falcon tubes.…”

Intracellular Persistence of Enteroaggregative Escherichia Coli Induces a Proinflammatory Cytokines Secretion in Intestinal Epithelial T84 Cells

“…The diarrhea caused by EAEC is the result of a complex interaction pathogen-host. In different clinical settings, the diseases induced by EAEC is accompanied by activation of an inflammatory response (23) . The pathogenicity of bacteria frequently includes colonizing, adhesion of the intestinal tract and the ability to invade and persist within enterocytes (9) .…”