Dimethylfumarate attenuates renal fibrosis via NF-E2-related factor 2-mediated inhibition of transforming growth factor-β/Smad signaling

PLoS One. 2012;7(10):e45870. doi: 10.1371/journal.pone.0045870. Epub 2012 Oct 8.

Abstract

TGF-β plays a key role in the development of renal fibrosis. Suppressing the TGF-β signaling pathway is a possible therapeutic approach for preventing this disease, and reports have suggested that Nrf2 protects against renal fibrosis by inhibiting TGF-β signaling. This study examines whether dimethylfumarate (DMF), which stimulates Nrf2, prevents renal fibrosis via the Nrf2-mediated suppression of TGF-β signaling. Results showed that DMF increased nuclear levels of Nrf2, and both DMF and adenovirus-mediated overexpression of Nrf2 (Ad-Nrf2) decreased PAI-1, alpha-smooth muscle actin (α-SMA), fibronectin and type 1 collagen expression in TGF-β-treated rat mesangial cells (RMCs) and renal fibroblast cells (NRK-49F). Additionally, DMF and Ad-Nrf2 repressed TGF-β-stimulated Smad3 activity by inhibiting Smad3 phosphorylation, which was restored by siRNA-mediated knockdown of Nrf2 expression. However, downregulation of the antioxidant response element (ARE)-driven Nrf2 target genes such as NQO1, HO-1 and glutathione S-transferase (GST) did not reverse the inhibitory effect of DMF on TGF-β-induced upregulation of profibrotic genes or extracellular matrix proteins, suggesting an ARE-independent anti-fibrotic activity of DMF. Finally, DMF suppressed unilateral ureteral obstruction (UUO)-induced renal fibrosis and α-SMA, fibronectin and type 1 collagen expression in the obstructed kidneys from UUO mice, along with increased and decreased expression of Nrf2 and phospho-Smad3, respectively. In summary, DMF attenuated renal fibrosis via the Nrf2-mediated inhibition of TGF-β/Smad3 signaling in an ARE-independent manner, suggesting that DMF could be used to treat renal fibrosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / genetics
  • Actins / metabolism
  • Animals
  • Blotting, Western
  • Cell Line
  • Collagen Type I / genetics
  • Collagen Type I / metabolism
  • Dimethyl Fumarate
  • Fibronectins / genetics
  • Fibronectins / metabolism
  • Fibrosis
  • Fumarates / pharmacology*
  • HEK293 Cells
  • Humans
  • Immunosuppressive Agents / pharmacology
  • Kidney / drug effects*
  • Kidney / metabolism
  • Kidney / pathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Muscle, Smooth / metabolism
  • NF-E2-Related Factor 2 / genetics
  • NF-E2-Related Factor 2 / metabolism*
  • Phosphorylation / drug effects
  • Plasminogen Activator Inhibitor 1 / genetics
  • Plasminogen Activator Inhibitor 1 / metabolism
  • RNA Interference
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / drug effects
  • Smad3 Protein / genetics
  • Smad3 Protein / metabolism*
  • Transforming Growth Factor beta / pharmacology*

Substances

  • Actins
  • Collagen Type I
  • Fibronectins
  • Fumarates
  • Immunosuppressive Agents
  • NF-E2-Related Factor 2
  • Nfe2l2 protein, mouse
  • Plasminogen Activator Inhibitor 1
  • Smad3 Protein
  • Transforming Growth Factor beta
  • Dimethyl Fumarate

Grant support

This work was supported by grants from the National Research Foundation (2011-0028659; WCU Program, R32-10064; Future-based Technology Development Program Bio Field, 2011-0019229; and Basic Science Research Program, 2012-0006798 to J-YK and 2012-0001350 to H-JK), funded by the Korean Ministry of Education, Science and Technology. The funders had no role in study design, data collection and analysis, decision publish, or preparation of the manuscript.