NEISSERIA-GONORRHOEAE EPITHELIAL-CELL INTERACTION LEADS TO THE ACTIVATION OF THE TRANSCRIPTION FACTORS NUCLEAR FACTOR KAPPA-B AND ACTIVATORPROTEIN-1 AND THE INDUCTION OF INFLAMMATORY CYTOKINES

We have studied the effect of human bacterial pathogen Neisseria gonor rhoeae (Ngo) on the activation of nuclear factor (NF)-kappa B and the transcriptional activation of inflammatory cytokine genes upon infecti on of epithelial cells. During the course of infection, Ngo, the etiol ogic agent of gonorrhea, adheres to and penetrates mucosal epithelial cells. In vivo, localized gonococcal infections are often associated w ith a massive inflammatory response. We observed upregulation of sever al inflammatory cytokine messenger RNAs (mRNAs) and the release of the proteins in Ngo-infected epithelial cells. Moreover, infection with N go induced the formation of a NF-kappa B DNA-protein complex and, with a delay in time, the activation of activator protein 1, whereas basic leucine zipper transcription factors binding to the cAMP-responsive e lement or CAAT/enhancer-binding protein DNA-binding sites were not act ivated. In supershift assays using NF-kappa B-specife antibodies, we i dentified a NF-kappa B p50/p65 heterodimer. The NF-kappa B complex was formed within 10 min after infection and decreased 90 min after infec tion. Synthesis of tumor necrosis factor alpha and interleukin (IL)-1 beta occurred at later times and therefore did not account for NF-kapp a B activation. An analysis of transiently transfected IL-6 promoter d eletion constructs suggests that NF-kappa B plays a crucial role for t he transcriptional activation of the IL-6 promoter upon Ngo infection. Inactivation of NF-kappa B conferred by the protease inhibitor N-tosy l-L-phenylalanine chloromethyl ketone inhibited mRNA upregulation of m ost, but not all, studied cyctokine genes. Activation of NF-kappa B an d cytokine mRNA upregulation also occur in Ngo-infected epithelial cel ls that were treated with cytochalasin D, indicating an extracellular signaling induced before invasion.