Wortmannin blocks Yersinia invasin-triggered internalization, but not interleukin-8 production by epithelial cells.
In response to bacterial infection epithelial cells up-regulate expression and secretion of proinflammatory cytokines. Previous work from our laboratory showed that basolateral infection of polarized T84 cells with Yersinia enterocolitica induces interleukin-8 (IL-8) secretion in the absence of significant invasion. Here we studied Y. enterocolitica-induced IL-8 secretion by epithelial HeLa cells as a function of Yersinia invasion or adhesion. For this purpose we tried to separated induction of IL-8 secretion from invasion by treating HeLa cells with signal transduction inhibitors prior to infection. While staurosporin and genistein inhibited both Yersinia invasion and Yersinia-triggered IL-8 secretion, wortmannin, an inhibitor of the phosphatidylinositol-3-phosphate kinase (PI3-K), blocked invasion of Y. enterocolitica into HeLa cells but did not show any effect on IL-8 secretion. These results suggest that Yersinia adhesion might be sufficient to induce IL-8 secretion by epithelial cells. Further analysis demonstrated the requirement of the Yersinia invasion locus inv for adhesion-mediated induction of IL-8 secretion. Thus, HeLa cells infected with an E. coli strain expressing the Y. enterocolitica inv locus induced IL-8 secretion in the presence and absence of wortmannin. Reverse transcription-polymerase chain reaction analysis revealed that adhesion of inv-expressing Y. enterocolitica or E. coli results in the transcriptional activation of the IL-8 gene. These results suggest that Y. enterocolitica adhesion to host cells via Inv activates de novo synthesis and secretion of IL-8.
Schulte
R
R
Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität München, Germany. schulte@m3401.mpk.med.uni-muenchen.de
Zumbihl
R
R
Kampik
D
D
Fauconnier
A
A
Autenrieth
I B
IB
D018829:Adhesins, Bacterial; D000730:Androstadienes / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D001425:Bacterial Outer Membrane Proteins / Q000502:physiology*; D001426:Bacterial Proteins / Q000502:physiology*; D018938:Caco-2 Cells; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D019833:Genistein / Q000494:pharmacology; D006367:HeLa Cells / Q000187:drug effects; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D016133:Polymerase Chain Reaction; D019311:Staurosporine / Q000494:pharmacology; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D000077191:Wortmannin; D015008:Yersinia enterocolitica / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology
D018829:Adhesins, Bacterial; D000730:Androstadienes; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D016209:Interleukin-8; D000081082:Phosphoinositide-3 Kinase Inhibitors; C053476:invasin, Yersinia; D019833:Genistein; D019311:Staurosporine; D000077191:Wortmannin