Attenuation of lung fibrosis in mice with a clinically relevant inhibitor of glutathione-S-transferase π
David H. McMillan, Jos L.J. van der Velden, Karolyn G. Lahue, Xi Qian, Robert W. Schneider, Martina S. Iberg, James D. Nolin, Sarah Abdalla, Dylan T. Casey, Kenneth D. Tew, Danyelle M. Townsend, Colin J. Henderson, C. Roland Wolf, Kelly J. Butnor, Douglas J. Taatjes, Ralph C. Budd, Charles G. Irvin, Albert van der Vliet, Stevenson Flemer, Vikas Anathy, Yvonne M.W. Janssen-Heininger
David H. McMillan, Jos L.J. van der Velden, Karolyn G. Lahue, Xi Qian, Robert W. Schneider, Martina S. Iberg, James D. Nolin, Sarah Abdalla, Dylan T. Casey, Kenneth D. Tew, Danyelle M. Townsend, Colin J. Henderson, C. Roland Wolf, Kelly J. Butnor, Douglas J. Taatjes, Ralph C. Budd, Charles G. Irvin, Albert van der Vliet, Stevenson Flemer, Vikas Anathy, Yvonne M.W. Janssen-Heininger
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Research Article Pulmonology Therapeutics

Attenuation of lung fibrosis in mice with a clinically relevant inhibitor of glutathione-S-transferase π

Abstract

Idiopathic pulmonary fibrosis (IPF) is a debilitating lung disease characterized by excessive collagen production and fibrogenesis. Apoptosis in lung epithelial cells is critical in IPF pathogenesis, as heightened loss of these cells promotes fibroblast activation and remodeling. Changes in glutathione redox status have been reported in IPF patients. S-glutathionylation, the conjugation of glutathione to reactive cysteines, is catalyzed in part by glutathione-S-transferase π (GSTP). To date, no published information exists linking GSTP and IPF to our knowledge. We hypothesized that GSTP mediates lung fibrogenesis in part through FAS S-glutathionylation, a critical event in epithelial cell apoptosis. Our results demonstrate that GSTP immunoreactivity is increased in the lungs of IPF patients, notably within type II epithelial cells. The FAS-GSTP interaction was also increased in IPF lungs. Bleomycin- and AdTGFβ-induced increases in collagen content, α-SMA, FAS S-glutathionylation, and total protein S-glutathionylation were strongly attenuated in Gstp–/– mice. Oropharyngeal administration of the GSTP inhibitor, TLK117, at a time when fibrosis was already apparent, attenuated bleomycin- and AdTGFβ-induced remodeling, α-SMA, caspase activation, FAS S-glutathionylation, and total protein S-glutathionylation. GSTP is an important driver of protein S-glutathionylation and lung fibrosis, and GSTP inhibition via the airways may be a novel therapeutic strategy for the treatment of IPF.

Authors

David H. McMillan, Jos L.J. van der Velden, Karolyn G. Lahue, Xi Qian, Robert W. Schneider, Martina S. Iberg, James D. Nolin, Sarah Abdalla, Dylan T. Casey, Kenneth D. Tew, Danyelle M. Townsend, Colin J. Henderson, C. Roland Wolf, Kelly J. Butnor, Douglas J. Taatjes, Ralph C. Budd, Charles G. Irvin, Albert van der Vliet, Stevenson Flemer, Vikas Anathy, Yvonne M.W. Janssen-Heininger

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Figure 2

GSTP deficiency attenuates bleomycin- and AdTGFβ-induced collagen content and fibrotic remodeling.

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GSTP deficiency attenuates bleomycin- and AdTGFβ-induced collagen conten...
Wild-type and Gstp–/– mice were treated with (A–D) bleomycin for 15 days or (E–H) AdTGFβ for 21 days. (A and B) Assessment of hydroxyproline and soluble collagen content in the lungs of wild-type or Gstp–/– mice 15 days after bleomycin administration. (C) Assessment of fibrotic remodeling by Masson’s trichrome staining 15 days after bleomycin administration. (D) Detection of α-SMA expression by immunohistochemistry (red, α-SMA; blue, hematoxylin). (E and F) Assessment of hydroxyproline and soluble collagen content in the lungs of wild-type or Gstp–/– mice 21 days after AdTGFβ treatment. (G) Assessment of fibrotic remodeling by Masson’s trichrome staining 21 days after infection. (H) Assessment of α-SMA immunoreactivity by immunohistochemistry (red, α-SMA; blue, hematoxylin). *P < 0.05 relative to PBS or AdCtrl group, †P < 0.05 relative to respective wild-type group by 2-way ANOVA with a Tukey post-test. Scale bar: 100 μm. Shown are pooled data from 2 independent experiments (n = 6–11 per group). GSTP, glutathione-S-transferase π; α-SMA, α smooth muscle actin; AdCtrl, control adenoviral vector; AdTGFβ, adenoviral vector expressing active TGF-β1.