Benzene-extracted components are important for the major activity of diesel exhaust particles: effect on interleukin-8 gene expression in human bronchial epithelial cells

Am J Respir Cell Mol Biol. 2001 Apr;24(4):419-26. doi: 10.1165/ajrcmb.24.4.4085.


Epidemiologic and experimental studies suggest that diesel exhaust particles (DEPs) may be related to increasing respiratory mortality and morbidity. We have shown that DEPs augmented the production of inflammatory cytokines by human airway epithelial cells in vitro. To better understand the mechanisms of their proinflammatory activities, we studied the effects of several components extracted from DEPs on interleukin (IL)-8 expression in human bronchial epithelial cell line BEAS-2B and normal human airway epithelial cells obtained from very peripheral airways by an ultrathin bronchoscope. We used several agents active on signal transduction pathways in cytokine expression, such as the protein kinase C inhibitor staurosporin, antioxidant agents including N-acetyl cysteine (NAC) and pyrrolidine dithiocarbamate (PDTC), and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. Benzene-extracted components showed effects mimicking DEPs on IL-8 gene expression, release of several cytokines (IL-8; granulocyte macrophage colony-stimulating factor; and regulated on activation, normal T cells expressed and secreted) and nuclear factor (NF)-kappa B activation. We also found that NAC, PDTC, and SB203580 suppressed the activities of DEPs and their benzene extracts, suggesting the roles of oxidants-mediated NF-kappa B activation and p38MAPK pathways. Finally, benzo[a]pyrene, one of the important compounds included in the benzene component, replicated the activities shown by DEPs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcysteine / pharmacology
  • Antioxidants / pharmacology
  • Benzene*
  • Bronchi / cytology*
  • Cell Line
  • Chemokine CCL5 / metabolism
  • Enzyme Inhibitors / pharmacology
  • Epithelial Cells / cytology
  • Epithelial Cells / enzymology
  • Epithelial Cells / immunology
  • Free Radical Scavengers / pharmacology
  • Gene Expression / drug effects
  • Gene Expression / immunology
  • Granulocyte-Macrophage Colony-Stimulating Factor / metabolism
  • Humans
  • Imidazoles / pharmacology
  • In Vitro Techniques
  • Interleukin-8 / immunology*
  • Mitogen-Activated Protein Kinases / metabolism
  • NF-kappa B / metabolism
  • Pyridines / pharmacology
  • Pyrrolidines / pharmacology
  • RNA, Messenger / analysis
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism
  • Thiocarbamates / pharmacology
  • Vehicle Emissions / toxicity*
  • p38 Mitogen-Activated Protein Kinases


  • Antioxidants
  • Chemokine CCL5
  • Enzyme Inhibitors
  • Free Radical Scavengers
  • Imidazoles
  • Interleukin-8
  • NF-kappa B
  • Pyridines
  • Pyrrolidines
  • RNA, Messenger
  • Thiocarbamates
  • Vehicle Emissions
  • pyrrolidine dithiocarbamic acid
  • Granulocyte-Macrophage Colony-Stimulating Factor
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases
  • Benzene
  • SB 203580
  • Acetylcysteine