Oxidant-Mediated Increases in Redox Factor-1 Nuclear Protein and Activator Protein-1 DNA Binding in Asbestos-Treated Macrophages

• Published in: The Journal of immunology (1950) Vol. 168; no. 11; pp. 5675 - 5681
• Main Authors: Flaherty, Dawn M, Monick, Martha M, Carter, A. Brent, Peterson, Michael W, Hunninghake, Gary W
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 01.06.2002
• Subjects: Animals; Asbestos, Crocidolite - toxicity; Carbon-Oxygen Lyases - biosynthesis; Cell Line; DNA - metabolism; DNA-(Apurinic or Apyrimidinic Site) Lyase; Humans; Iron - pharmacology; Macrophages, Alveolar - drug effects; Macrophages, Alveolar - metabolism; Mice; NADPH Oxidases - antagonists & inhibitors; Reactive Oxygen Species; Transcription Factor AP-1 - metabolism
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.168.11.5675

Alveolar macrophages have been implicated in the pathogenesis of a number of acute and chronic lung disorders. We have previously shown that normal human alveolar macrophages exhibit decreased DNA binding activity of the transcription factor, AP-1, compared with monocytes. Furthermore, this decrease in AP-1 DNA binding appears to be due to a decrease in the redox active protein, redox factor (Ref)-1. Ref-1 is an important redox regulator of a number of transcription factors, including NF-kappaB and AP-1. In this study we evaluated the role of asbestos, a prototypic model of chronic fibrotic lung disease, in Ref-1 expression and activity. We found that incubation with low concentrations of crocidolite asbestos (0.5-1.25 microg/cm(2)) resulted in an increase in nuclear Ref-1 protein after 5 min, with a persistent elevation in protein up to 24 h. Additionally, an increase in nuclear Ref-1 could be induced by treating the cells with an oxidant-generating stimulus (iron loading plus PMA) and inhibited by diphenyleneiodonium chloride, an inhibitor of NADPH oxidase. The asbestos-induced accumulation of nuclear Ref-1 was associated with an increase in AP-1 DNA binding activity. These findings suggest that an exposure associated with fibrotic lung disease, i.e., asbestos, modulates accumulation of nuclear Ref-1 in macrophages, and that this effect is mediated by an oxidant stimulus.