Transient gene transfer and expression of Smad7 prevents bleomycin-induced lung fibrosis in mice

J Clin Invest. 1999 Jul;104(1):5-11. doi: 10.1172/JCI6094.


TGF-beta plays an important role in lung fibrosis, which is a major cause of suffering and death seen in pulmonary disease. Smad7 has been recently identified as an antagonist of TGF-beta signaling. To investigate whether this novel molecule can be exploited for therapy of lung fibrosis, we determined the effect of exogenous Smad7, introduced by a recombinant human type 5 adenovirus vector, on bleomycin-induced lung fibrosis in mice. C57BL/6 mice with bleomycin-induced lungs received an intratracheal injection of a recombinant adenovirus carrying mice Smad7 cDNA. These mice demonstrated suppression of type I precollagen mRNA, reduced hydroxyproline content, and no morphological fibrotic responses in the lungs when compared with mice administered adenovirus carrying Smad6 cDNA. In addition, we found that expression of Smad7 transgene blocked Smad2 phosphorylation induced by bleomycin in mouse lungs. These data indicated that gene transfer of Smad7 (but not Smad6) prevented bleomycin-induced lung fibrosis, suggesting that Smad7 may have applicability in the treatment of pulmonary fibrosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / genetics
  • Animals
  • Bleomycin / toxicity*
  • Bronchoalveolar Lavage Fluid / chemistry
  • Collagen / biosynthesis
  • Collagen / genetics
  • Cytomegalovirus / genetics
  • DNA, Complementary / genetics
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • Female
  • Gene Expression Regulation / drug effects
  • Genetic Therapy*
  • Genetic Vectors / genetics
  • Mice
  • Mice, Inbred C57BL
  • Pulmonary Fibrosis / prevention & control*
  • Recombinant Fusion Proteins / physiology
  • Smad6 Protein
  • Smad7 Protein
  • Trans-Activators / genetics
  • Trans-Activators / physiology*
  • Transfection*
  • Transforming Growth Factor beta / antagonists & inhibitors*
  • Transforming Growth Factor beta / physiology


  • DNA, Complementary
  • DNA-Binding Proteins
  • Recombinant Fusion Proteins
  • Smad6 Protein
  • Smad6 protein, mouse
  • Smad7 Protein
  • Smad7 protein, mouse
  • Trans-Activators
  • Transforming Growth Factor beta
  • Bleomycin
  • Collagen