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Tumor necrosis factor α-mediated induction of interleukin 17C in human keratinocytes is controlled by nuclear factor κB

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IL-17C is a member of the IL-17 family of cytokines. The expression of IL-17C has been demonstrated to be strongly induced by TNFα in human keratinocytes, and recently the level of IL-17C was found to be increased in the inflammatory skin disease psoriasis. However, little is known about the molecular mechanisms involved in the regulation of IL-17C. Here, we show that pretreatment of cultured human keratinocytes with the inhibitor of κB kinase 2 inhibitor, SC-514, resulted in a significant reduction in both IL-17C mRNA and protein expression, indicating the significance of this pathway in the regulation of IL-17C. NF-κB binding sites were identified upstream from the IL-17C gene, and by electrophoretic mobility shift assay NF-κB was shown to bind to all three identified binding sites. Moreover, NF-κB binding to these sites was inducible by TNFα. Supershift analysis revealed binding of the NF-κB subunits p65 and p50 to all three NF-κB binding sites. To determine the contribution of NF-κB in IL-17C expression, we conducted luciferase gene reporter experiments and demonstrated that a 3204-bp promoter fragment of IL-17C containing three putative NF-κB binding sites was strongly activated by TNFα. Interestingly, mutations of the three NF-κB binding sites revealed that one specific NF-κB binding site was crucial for the TNFα-mediated IL-17C induction because mutation of this specific site completely abolished TNFα-induced IL-17C promoter activation. We conclude that the activation of NF-κB (p65/p50) is crucial for the TNFα-induced stimulation of IL-17C expression in human keratinocytes.
Original languageEnglish
JournalJournal of Biological Chemistry
Pages (from-to)25487-94
Number of pages8
Publication statusPublished - 22 Jul 2011

    Research areas

  • Adult, Base Sequence, Binding Sites, Cells, Cultured, DNA, Humans, Interleukin-17, Keratinocytes, NF-kappa B p50 Subunit, Oligodeoxyribonucleotides, Promoter Regions, Genetic, Signal Transduction, Thiophenes, Transcription Factor RelA, Transcriptional Activation, Tumor Necrosis Factor-alpha

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