NF-kappa B-mediated transcriptional regulation of human beta-defensin-2 gene following lipopolysaccharide stimulation.
beta-Defensins are cationic peptides with broad-spectrum antimicrobial activities that contribute to innate host defense. Among human beta-defensins (hBDs), hBD-2 is up-regulated in epithelial tissues and mononuclear phagocytes in response to bacterial infection and proinflammatory cytokines. However, little is known about the molecular mechanism of hBD-2 gene regulation. Here, we investigated lipopolysaccharide (LPS)-mediated transcriptional regulation of the hBD-2 gene by focusing on the roles of NF-kappa B, STAT, and NF-IL-6 sites in mononuclear phagocytes using RAW264.7 cells, which are sensitive to LPS. Luciferase reporter analyses demonstrated that two NF-kappa B sites were essential for full LPS responsiveness of the hBD-2 gene. Further, both NF-kappa B sites were also crucial for basal transcriptional activity. In contrast, neither the NF-IL-6 nor STAT binding site was required for LPS-induced hBD-2 transcription. Electrophoretic mobility shift assay indicated that in unstimulated cells, NF-kappa B p50 homodimer bound to both NF-kappa B sites, whereas the p65-p50 heterodimer formed complexes with these sites following LPS stimulation. Together, these observations indicate that NF-kappa B plays an important role in the regulation of hBD-2 gene expression in response to LPS.
Tsutsumi-Ishii
Yuko
Y
Department of Biochemistry, Juntendo University, School of Medicine, Tokyo, Japan.
Nagaoka
Isao
I
D000818:Animals; D000890:Anti-Infective Agents; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics; D002460:Cell Line; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D016328:NF-kappa B / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics; D015533:Transcriptional Activation / Q000187:drug effects*; D014162:Transfection; D023083:beta-Defensins / Q000235:genetics*
D000890:Anti-Infective Agents; D022782:CCAAT-Enhancer-Binding Protein-beta; C106641:DEFB4A protein, human; D008070:Lipopolysaccharides; D016328:NF-kappa B; D015534:Trans-Activators; D023083:beta-Defensins