Sulforaphane attenuates pulmonary fibrosis by inhibiting the epithelial-mesenchymal transition

BMC Pharmacol Toxicol. 2018 Apr 2;19(1):13. doi: 10.1186/s40360-018-0204-7.

Abstract

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disease with no effective treatment. The epithelial-mesenchymal transition (EMT) is a critical stage during the development of fibrosis. To assess the effect of sulforaphane (SFN) on the EMT and fibrosis using an in vitro transforming growth factor (TGF)-β1-induced model and an in vivo bleomycin (BLM)-induced model.

Methods: In vitro studies, cell viability, and cytotoxicity were measured using a Cell Counting Kit-8. The functional TGF-β1-induced EMT and fibrosis were assessed using western blotting and a quantitative real-time polymerase chain reaction. The lungs were analyzed histopathologically in vivo using hematoxylin and eosin and Masson's trichrome staining. The BLM-induced fibrosis was characterized by western blotting and immunohistochemical analyses for fibronectin, TGF-β1, E-cadherin (E-cad), and α-smooth muscle actin (SMA) in lung tissues.

Results: SFN reversed mesenchymal-like changes induced by TGF-β1 and restored cells to their epithelial-like morphology. The results confirmed that the expression of the epithelial marker, E-cadherin, increased after SFN treatment, while expression of the mesenchymal markers, N-cadherin, vimentin, and α-SMA decreased in A549 cells after SFN treatment. In addition, SFN inhibited TGF-β1-induced mRNA expression of the EMT-related transcription factors, Slug, Snail, and Twist. The SFN treatment attenuated TGF-β1-induced expression of fibrosis-related proteins, such as fibronection, collagen I, collagen IV, and α-SMA in MRC-5 cells. Furthermore, SFN reduced the TGF-β1-induced phosphorylation of SMAD2/3 protein in A549 cells and MRC-5 cells. BLM induced fibrosis in mouse lungs that was also attenuated by SFN treatment, and SFN treatment decreased BLM-induced fibronectin expression, TGF-β1 expression, and the levels of collagen I in the lungs of mice.

Conclusions: SFN showed a significant anti-fibrotic effect in TGF-β-treated cell lines and BLM-induced fibrosis in mice. These findings showed that SFN has anti-fibrotic activity that may be considered in the treatment of IPF.

Keywords: Bleomycin; Epithelial-mesenchymal transition; Idiopathic pulmonary fibrosis; Sulforaphane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bleomycin
  • Cell Line
  • Collagen Type I / metabolism
  • Collagen Type IV / metabolism
  • Epithelial-Mesenchymal Transition / drug effects*
  • Humans
  • Isothiocyanates / pharmacology
  • Isothiocyanates / therapeutic use*
  • Lung / drug effects
  • Lung / metabolism
  • Lung / pathology
  • Male
  • Mice, Inbred C57BL
  • Pulmonary Fibrosis / chemically induced
  • Pulmonary Fibrosis / drug therapy*
  • Pulmonary Fibrosis / metabolism
  • Pulmonary Fibrosis / pathology
  • Smad2 Protein / metabolism
  • Smad3 Protein / metabolism
  • Sulfoxides
  • Transforming Growth Factor beta / metabolism

Substances

  • Collagen Type I
  • Collagen Type IV
  • Isothiocyanates
  • SMAD2 protein, human
  • SMAD3 protein, human
  • Smad2 Protein
  • Smad3 Protein
  • Sulfoxides
  • Transforming Growth Factor beta
  • Bleomycin
  • sulforaphane