Transcriptional regulation of β-defensin-2 by lipopolysaccharide in cultured human cervical carcinoma (HeLa) cells

Abstract

Human β-defensin-2 (hBD-2) is an antimicrobial peptide with a broad spectrum of antimicrobial activity against bacteria, yeast and fungi. Here, we analyzed the transcriptional regulation of hBD-2 in cultured human cervical carcinoma (HeLa) cells with or without lipopolysaccharide (LPS). DNA from position −329 to −39 in the hBD-2 promoter region contained the consensus binding sites for transcription factors, one site for nuclear factor for IL-6 expression (NF-IL6) and two sites for nuclear factor-κB (NF-κB). Reporter gene assays for promoter activity revealed that the region had the highest level of responsiveness to LPS. Furthermore, mutations in both of the NF-κB binding sites caused a significant reduction of the responsiveness to LPS, whereas mutation in the NF-IL6 binding site resulted in an elevation of the basal promoter activity. Electrophoretic mobility shift assays demonstrated that LPS induced the binding of HeLa nuclear factors to 60-bp probe containing the two NF-κB binding sites, suggesting that the sites were essential for the binding. Our results suggest that the two NF-κB binding sites contribute to LPS-mediated hBD-2 transcription while the NF-IL6 binding site represses LPS-independent hBD-2 transcription in the HeLa cells.