Modulation of human beta-defensin-2 transcription in pulmonary epithelial cells by lipopolysaccharide-stimulated mononuclear phagocytes via proinflammatory cytokine production

J Immunol. 2003 Apr 15;170(8):4226-36. doi: 10.4049/jimmunol.170.8.4226.

Abstract

Human beta-defensin (hBD)-2, a cationic antimicrobial peptide primarily induced in epithelial cells in response to inflammatory stimuli, plays an important role in host defense. To elucidate the expression mechanism of hBD-2 in the lung, we investigated the modulation of hBD-2 transcription in pulmonary epithelial cells by mononuclear phagocytes stimulated with LPS. Coculture of A549 pulmonary epithelial cells with Mono-Mac-6 monocytic cells in the presence of Escherichia coli LPS markedly up-regulated hBD-2 promoter activity, whereas A549 alone did not respond to LPS to activate the hBD-2 promoter. Furthermore, IL-1beta and TNF-alpha in the culture supernatants from LPS-stimulated monocytic cells activated the hBD-2 promoter in A549 cells. Of note, IL-1beta was more potent than TNF-alpha in this effect. In addition, a mutation of the NF-kappaB site at -200 (pkappaB1 site) completely abolished this IL-1beta- and TNF-alpha-induced hBD-2 promoter activation, whereas NF-kappaB inhibitors (MG-132 and helenalin) strongly suppressed it. Moreover, electrophoretic mobility shift assay suggested that NF-kappaB, consisting of p65-p50 heterodimer, could bind to the pkappaB1 site in cytokine-stimulated A549 cells. Interestingly, flow cytometric analysis revealed that A549 cells expressed CD14 but lacked Toll-like receptor 4, which may account for the hyporesponsiveness of A549 cells to LPS. Taken together, these results suggest that hBD-2 expression in pulmonary epithelial cells is modulated by NF-kappaB via the actions of IL-1beta and TNF-alpha produced by LPS-stimulated mononuclear phagocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cytokines / biosynthesis*
  • Cytokines / physiology
  • Enzyme Inhibitors / pharmacology
  • Epithelial Cells / immunology*
  • Epithelial Cells / metabolism
  • Gene Expression Regulation / immunology*
  • Humans
  • Inflammation Mediators / pharmacology*
  • Interleukin-1 / antagonists & inhibitors
  • Interleukin-1 / biosynthesis
  • Interleukin-1 / physiology
  • Lipopolysaccharide Receptors / biosynthesis
  • Lipopolysaccharides / metabolism
  • Lipopolysaccharides / pharmacology*
  • Membrane Glycoproteins / biosynthesis
  • Monocytes / immunology*
  • Monocytes / metabolism
  • Multigene Family / immunology
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / metabolism
  • Promoter Regions, Genetic / immunology
  • Pulmonary Alveoli / cytology
  • Pulmonary Alveoli / immunology*
  • Pulmonary Alveoli / metabolism
  • Receptors, Cell Surface / biosynthesis
  • Response Elements / immunology
  • Toll-Like Receptor 4
  • Toll-Like Receptors
  • Transcription, Genetic / immunology
  • Tumor Necrosis Factor-alpha / antagonists & inhibitors
  • Tumor Necrosis Factor-alpha / biosynthesis
  • Tumor Necrosis Factor-alpha / physiology
  • U937 Cells
  • beta-Defensins / antagonists & inhibitors
  • beta-Defensins / genetics*
  • beta-Defensins / metabolism

Substances

  • Cytokines
  • DEFB4A protein, human
  • Enzyme Inhibitors
  • Inflammation Mediators
  • Interleukin-1
  • Lipopolysaccharide Receptors
  • Lipopolysaccharides
  • Membrane Glycoproteins
  • NF-kappa B
  • Receptors, Cell Surface
  • TLR4 protein, human
  • Toll-Like Receptor 4
  • Toll-Like Receptors
  • Tumor Necrosis Factor-alpha
  • beta-Defensins