Neutrophil elastase induces MUC5AC gene expression in airway epithelium via a pathway involving reactive oxygen species.

Journal Article

Neutrophil-predominant airway inflammation and mucus obstruction of the airways are major pathologic features of chronic airway diseases, including cystic fibrosis and chronic bronchitis. Neutrophils release elastase, a serine protease that impairs mucociliary clearance and stimulates goblet cell metaplasia and mucin production. We previously reported that neutrophil elastase increases expression of a major respiratory mucin gene, MUC5AC, by enhancing mRNA stability. However, the molecular mechanisms of elastase-regulated MUC5AC expression are not known. We hypothesized that reactive oxygen species, generated by elastase treatment, mediate MUC5AC gene expression. To test this hypothesis, A549, a respiratory epithelial cell line, was treated with elastase in the presence or absence of the oxygen radical scavenger, dimethylthiourea, or the iron chelator, desferrioxamine. MUC5AC mRNA levels were assessed by Northern analysis. Both antioxidants significantly inhibited elastase-induced MUC5AC gene expression. Dimethylthiourea also inhibited the neutrophil elastase (NE)-induced increase in MUC5AC expression in normal human bronchial epithelial cells. To determine whether elastase treatment generated reactive oxygen species, A549 and normal human bronchial epithelial cells were loaded with dichlorodihydrofluorescein, a fluorescent indicator of oxidative stress. NE treatment increased cellular fluorescence in both cell types, indicating generation of intracellular reactive oxygen species. We conclude that NE treatment increases MUC5AC gene expression by an oxidant-dependent mechanism.

Full Text

Duke Authors

Cited Authors

  • Fischer, BM; Voynow, JA

Published Date

  • April 2002

Published In

Volume / Issue

  • 26 / 4

Start / End Page

  • 447 - 452

PubMed ID

  • 11919081

International Standard Serial Number (ISSN)

  • 1044-1549

Digital Object Identifier (DOI)

  • 10.1165/ajrcmb.26.4.4473

Language

  • eng

Conference Location

  • United States