Role of reactive oxygen species in transforming growth factor-β1- inuduced fibronectin secretion and α-smooth muscle actin expression in human lung fibroblasts

Hunjoo Ha, Mi Ra Yu, Soo Taek Uh, Choon Sik Park, Hi Bahl Lee

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Background: The transforming growth factor-β1 (TGF-β1) plays a key role in lung fibrosis. However, the molecular mechanisms involved in TGF-β1-induced lung fibrosis are unclear. TGF-β1 is the key inducer of myofibroblast transdifferentiation via de novo synthesis of α-smooth muscle actin (α-SMA). Since TGF-β1 signals through reactive oxygen species (ROS) and ROS have been shown to induce accumulation of extracellular matrix (ECM) in various tissues, this study examined if ROS play a role in TGF-β1-induced fibronectin secretion and α-SMA expression in human lung fibroblasts, MRC-5 cells. Methods: Growth arrested and synchronized MRC-5 cells were stimulated with TGF-β1 (0.2-10 ng/ml) in the presence or absence of N-acetylcysteine (NAC) or diphenyleneiodonium (DPI) for up to 96 hours. Dichlorofluorescein (DCF)-sensitive cellular ROS were measured by FACScan and secreted fibronectin and cellular α-SMA by Western blot analysis. Results: TGF-β1 increased the level of fibronectin secretion and α-SMA expression in MRC-5 cells in a dose-dependent manner. Both NAC (20 and 30 mM) and DPI (1 and 5 μM) significantly inhibited TGF-β1-induced fibronectin and α-SMA upregulation. The TGF-β1-induced cellular ROS level was also significantly reduced by NAC and DPI. Conclusions: The results suggest that NADPH oxidase-dependent ROS play an important role in TGF-β1-induced fibronectin secretion and α-SMA expression in MRC-5 cells, which leads to myofibroblast transdifferentiation and progressive lung fibrosis.

Original languageEnglish
Pages (from-to)267-275
Number of pages9
JournalTuberculosis and Respiratory Diseases
Volume58
Issue number3
DOIs
StatePublished - Mar 2005

Keywords

  • Diphenyleneiodonium
  • Fibroblast
  • Fibronectin
  • Myofibroblast
  • N-acetylcysteine
  • Pulmonary fibrosis
  • Reactive oxygen species
  • Transforming growth factor-beta1
  • α-Smooth muscle actin

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