Hepatocyte growth factor antagonizes the profibrotic action of TGF-beta1 in mesangial cells by stabilizing Smad transcriptional corepressor TGIF

Chunsun Dai, Youhua Liu
Journal of the American Society of Nephrology: JASN 2004, 15 (6): 1402-12
Mesangial cell activation is a predominant pathologic feature of diabetic nephropathy that precedes the accumulation of extracellular matrix leading to glomerulosclerosis. For understanding the potential mechanism by which hepatocyte growth factor (HGF) ameliorates diabetic nephropathy, the effects of HGF on mesangial cell activation induced by TGF-beta1 were investigated. Western blot analysis and immunostaining revealed that HGF suppressed alpha-smooth muscle actin expression induced by TGF-beta1 in cultured rat and human mesangial cells. HGF also inhibited TGF-beta1-mediated fibronectin and type I collagen expression. Such action of HGF was dependent on the activation of extracellular signal-regulated kinase-1 and -2 but not on Akt and p38 mitogen-activated protein kinase. HGF did not affect TGF-beta1-mediated Smad2 phosphorylation and its nuclear translocation. However, it rapidly upregulated Smad transcriptional corepressor TG-interacting factor (TGIF) abundance in mesangial cells, which was primarily mediated by stabilizing its protein from degradation. Ectopic expression of TGIF markedly suppressed Smad-mediated activation of TGF-beta1-responsive promoter activity and completely blocked TGF-beta1-induced alpha-smooth muscle actin expression. In vivo, TGIF expression was dramatically downregulated in the glomeruli of diabetic kidneys, and delivery of exogenous HGF induced TGIF expression. These results suggest that HGF specifically antagonizes the profibrotic action of TGF-beta1 in mesangial cells by stabilizing Smad transcriptional corepressor TGIF.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"