Enterohemorrhagic Escherichia coli infection induces interleukin-8 production via activation of mitogen-activated protein kinases and the transcription factors NF-kappaB and AP-1 in T84 cells.
Enterohemorrhagic Escherichia coli (EHEC) infections are associated with hemorrhagic colitis and the hemolytic-uremic syndrome (HUS). In vivo, elevated plasma levels of the proinflammatory cytokine interleukin-8 (IL-8) in EHEC-infected children are correlated with a high risk of developing HUS. As IL-8 gene transcription is regulated by the transcription factors NF-kappaB and AP-1, we analyzed the role of these factors in the regulation of IL-8 production after infection of the epithelial intestinal T84 cell line by EHEC. By 6 h of infection, EHEC had induced significant secretion of IL-8 (35.84 +/- 6.76 ng/ml versus 0.44 +/- 0.04 ng/ml in control cells). EHEC induced AP-1 and NF-kappaB activation by 3 h of infection. Moreover, the three mitogen-activated protein kinases (MAPK) (ERK1/2, p38, and JNK) were phosphorylated in EHEC-infected T84 cells concomitant with induction of AP-1 DNA binding activity, and IkappaB-alpha was phosphorylated and then degraded concomitant with induction of NF-kappaB DNA binding activity. Pretreatment of cells with the highly specific MEK1/2 inhibitor U0126, the p38 inhibitor SB203580, and/or the proteasome inhibitor ALLN led to inhibition of the IL-8 secretion induced in EHEC-infected T84 cells. These findings demonstrate that (i) EHEC can induce in vitro a potent proinflammatory response by secretion of IL-8 and (ii) the secretion of IL-8 is due to the involvement of MAPK, AP-1, and NF-kappaB signaling pathways.
Dahan
Stephanie
S
Laboratoire de Gastroenterologie et Nutrition, Faculte de Medecine, Universite de Nice-Sophia Antipolis, 06107 Nice cedex 2, France.
Busuttil
Valere
V
Imbert
Veronique
V
Peyron
Jean-Francois
JF
Rampal
Patrick
P
Czerucka
Dorota
D
D002460:Cell Line; D004789:Enzyme Activation; D004927:Escherichia coli Infections / Q000276:immunology*; D019453:Escherichia coli O157; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000633:toxicity; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation; D018808:Transcription Factor AP-1 / Q000378:metabolism*
D016209:Interleukin-8; D008070:Lipopolysaccharides; D016328:NF-kappa B; D018808:Transcription Factor AP-1; D020928:Mitogen-Activated Protein Kinases