title: Pathogenic Lifestyles ofE. coliPathotypes in a Standardized Epithelial Cell Model Influence Inflammatory Signaling Pathways and Cytokines Secretion.
abstract: Inflammatory response is key for the host defense against diarrheagenicEscherichia coliand contributes to the pathogenesis of the disease but there is not a comparative study among different diarrheagenic pathotypes. We analyzed the inflammatory response induced by five diarrheagenic pathotypes in a HT-29 cell infection model. The model was unified to reproduce the pathogenesis of each pathotype. To compare the inflammatory responses we evaluated: (i) nuclear NF-κB and ERK1/2 translocation by confocal microscopy; (ii) kinetics of activation by each pathway detecting p65 and ERK1/2 phosphorylation by Western blotting; (iii) pathways modulation through bacterial infections with or without co-stimulation with TNF-α or EGF; (iv) cytokine profile induced by each pathotype with and without inhibitors of each pathway. EHEC but mainly EPEC inhibited translocation and activation of p65 and ERK1/2 pathways, as well as cytokines secretion; inhibition of p65 and ERK1/2 phosphorylation prevailed in the presence of TNF-α and EGF, respectively. Intracellular strains, EIEC/Shigella flexneri, caused a strong translocation, activation, and cytokines secretion but they could not inhibit TNF-α and EGF stimulation. ETEC and mainly EAEC caused a moderate translocation, but a differential activation, and high cytokines secretion; interestingly TNF-α and EGF stimulation did no modify p65 and ERK1/2 activation. The use of inhibitors of NF-κB and/or ERK1/2 showed that NF-κB is crucial for cytokine induction by the different pathotypes; only partially depended on ERK1/2 activation. Thus, in spite of their differences, the pathotypes can also be divided in three groups according to their inflammatory response as those (i) that inject effectors to cause A/E lesion, which are able to inhibit NF-κB and ERK1/2 pathways, and cytokine secretion; (ii) with fimbrial adherence and toxin secretion with a moderate inhibition of both pathways but high cytokines secretion through autocrine cytokine regulation; and (iii) the intracellular bacteria that induce the highest pathways activation and cytokines secretion by using different activation mechanisms. This study provides a comprehensive analysis of how the different pathogenesis schemes ofE. colipathotypes manipulate inflammatory signaling pathways, which leads to a specific proinflammatory cytokine secretion in a cell model infection that reproduce the hallmarks of infection of each pathotype.
authors: Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional México City, Mexico.
authors: Javier
authors: J
authors: Sanchez-Villamil
authors: Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional México City, Mexico.
authors: Gabriela
authors: G
authors: Tapia-Pastrana
authors: Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional México City, Mexico.
authors: Fernando
authors: F
authors: Navarro-Garcia
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D016207:Cytokines / Q000378:metabolism*; D004847:Epithelial Cells / Q000382:microbiology*; D004926:Escherichia coli / Q000472:pathogenicity*; D054884:Host-Pathogen Interactions; D006801:Humans; D018613:Microscopy, Confocal; D008954:Models, Biological; D015398:Signal Transduction
chemical_list: D016207:Cytokines
keywords: ERK1/2; IL-8; NF-κB; TNF-α; inflammatory response; pathogenic E. coli