Glomerular activin A overexpression is linked to fibrosis in anti-Thy1 glomerulonephritis

Nephrol Dial Transplant. 2005 Feb;20(2):319-28. doi: 10.1093/ndt/gfh653.


Background: Activin A, a member of the transforming growth factor-beta (TGF-beta) superfamily of proteins, shares many biological features with the pro-fibrotic cytokine TGF-beta1, which is primarily responsible for the accumulation of extracellular matrix proteins in renal disease. This study was designed to identify regulators of activin A production in glomerular mesangial cells and test if activin A acts as a pro-fibrotic cytokine in mesangial cells.

Methods: The effect of inflammatory cytokines on activin A production and the effect of exogenous activin A on mediators of fibrosis were analysed in cultured rat mesangial cells. Expression of activin A and of established mediators of fibrosis was analysed in a rat model of glomerular fibrosis (anti-Thy1 glomerulonephritis).

Results: In cultured mesangial cells, interleukin-1 and basic fibroblast growth factor, both mediators of glomerular inflammatory injury, dose-dependently increased activin A expression. Incubation with activin A significantly stimulated TGF-beta1, PAI-1 and connective tissue growth factor RNA expression and increased production of extracellular matrix proteins in mesangial cells. In rats with anti-Thy1 glomerulonephritis, expression of glomerular activin A mRNA and protein paralled the expression of TGF-beta and other indices of fibrosis, showing little change from normal on day 1, a marked, 70-fold increase of activin protein production on day 6, and a subsequent decrease at day 12. Antifibrotic therapy with the angiotensin-converting enzyme inhibitor enalapril significantly reduced glomerular activin A production.

Conclusion: Taken together, the results of this study link overexpression of activin A to glomerular matrix protein expansion in vivo and in vitro, suggesting that activin A acts as pro-fibrotic cytokine in renal disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activins / genetics*
  • Animals
  • Cells, Cultured
  • Disease Models, Animal
  • Enalapril / pharmacology
  • Fibroblast Growth Factor 2 / pharmacology
  • Gene Expression Regulation / drug effects
  • Glomerular Mesangium / physiopathology*
  • Inflammation
  • Inhibin-beta Subunits / genetics*
  • Interleukin-1 / pharmacology
  • Male
  • Rats
  • Rats, Sprague-Dawley
  • Reference Values
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription, Genetic / drug effects
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta1


  • Interleukin-1
  • Tgfb1 protein, rat
  • Transforming Growth Factor beta
  • Transforming Growth Factor beta1
  • activin A
  • Fibroblast Growth Factor 2
  • Activins
  • Enalapril
  • Inhibin-beta Subunits