Requirements for two proximal NF-kappaB binding sites and IkappaB-zeta in IL-17A-induced human beta-defensin 2 expression by conducting airway epithelium.
Among a panel of 21 cytokines (IL-1alpha, -1beta, -2-13, and -15-18; interferon-gamma; granulocyte-macrophage colony-stimulating factor; and tumor necrosis factor alpha), we have recently observed that IL-17A is the most potent inducer for human beta-defensin 2 (hBD-2) in conducting airway epithelial cells (Kao, C. Y., Chen, Y., Thai, P., Wachi, S., Huang, F., Kim, C., Harper, R. W., and Wu, R. (2004) J. Immunol. 173, 3482-3491). The molecular basis of this regulation is not known. In this study, we demonstrated a coordinated degradation of inhibitory kappaB(IkappaB)-alpha followed by a nuclear translocation of p50 and p65 NF-kappaB subunits and their binding to NF-kappaB sites of hBD-2 promoter region. With site-directed mutagenesis, we demonstrated the requirement of two proximal NF-kappaB binding sites (pkappaB1, -205 to -186; pkappaB2, -596 to -572) but not the distal site (dkappaB, -2193 to -2182) in supporting IL-17A-induced hBD-2 promoter activity. These results are consistent with the data of the chromatin immunoprecipitation assay, which showed enhanced p50 binding to these pkappaB sites but not the dkappaB site in cells after IL-17A treatment. We also found that the NF-kappaB binding cofactor, IkappaB-zeta, was up-regulated by IL-17A, and the knockdown of IkappaB-zeta significantly diminished the IL-17A-induced hBD-2 expression. This is the first demonstration of the involvement of two proximal NF-kappaB sites and IkappaB-zeta in the regulation of hBD-2 by IL-17A, two important genes responsible for host defense.
Kao
Cheng-Yuan
CY
Center for Comparative Respiratory Biology and Medicine, University of California-Davis, 451 Health Science Drive, Davis, CA 95616, USA.
Kim
Christy
C
Huang
Fei
F
Wu
Reen
R
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology; D048868:Adaptor Proteins, Signal Transducing; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020672:I-kappa B Proteins; D020381:Interleukin-17 / Q000378:metabolism* / Q000494:pharmacology; D052002:NF-kappa B p50 Subunit / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000166:cytology / Q000378:metabolism*; D020218:Response Elements / Q000502:physiology*; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D023083:beta-Defensins / Q000096:biosynthesis* / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; C106641:DEFB4A protein, human; D020672:I-kappa B Proteins; C508717:IL17A protein, human; D020381:Interleukin-17; D052002:NF-kappa B p50 Subunit; C417234:NFKBIZ protein, human; D009687:Nuclear Proteins; D051996:Transcription Factor RelA; D023083:beta-Defensins