Mechanism of the inhibitory effect of atorvastatin on endoglin expression induced by transforming growth factor-beta1 in cultured cardiac fibroblasts.
OBJECTIVE
Transforming growth factor-beta1 (TGF-beta1) and endoglin play a causal role in promoting cardiac fibrosis. Atorvastatin has been shown to have an inhibitory effect on cardiac fibroblasts in vitro. However, the effects of statins on TGF-beta1 and endoglin are poorly understood. We therefore sought to investigate the molecular mechanisms of atorvastatin on endoglin expression after TGF-beta1 stimulation in cardiac fibroblasts.


RESULTS
Cultured cardiac fibroblasts were obtained from adult male Sprague-Dawley rat hearts. TGF-beta1 stimulation increased endoglin and collagen I expression and atorvastatin inhibited the induction of endoglin and collagen I by TGF-beta1. Phosphatidylinositol-3 kinase (PI-3) and Akt inhibitors (wortmannin and Akt inhibitor X) completely attenuated the endoglin protein expression induced by TGF-beta1. TGF-beta1 induced phosphorylation of PI-3 kinase and Akt, while atorvastatin and wortmannin and Akt inhibitor X inhibited the phosphorylation of PI-3 kinase and Akt induced by TGF-beta1. The gel shift and promoter activity assay showed that TGF-beta1 increased Smad3/4-binding activity and endoglin promoter activity, while wortmannin and atorvastatin inhibited the Smad3/4-binding activity and endoglin promoter activity induced by TGF-beta1. TGF-beta1 increased collagen I protein expression, while endoglin siRNA attenuated collagen I protein expression induced by TGF-beta1. Atorvastatin decreased left ventricular TGF-beta1, endoglin, and collagen I protein expression and fibrotic area in a rat model of volume overload heart failure.


CONCLUSIONS
Atorvastatin inhibits endoglin expression through the inhibition of PI-3 kinase, Akt, and Smad3 phosphorylation, and reduced Smad3/4 binding activity and endoglin promoter activity in cardiac fibroblasts.
Division of Cardiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
Kou-Gi
KG
Shyu
Bao-Wei
BW
Wang
Wei-Jan
WJ
Chen
Peiliang
P
Kuan
Chi-Ren
CR
Hung
D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors; D000704:Analysis of Variance; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis* / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000037:antagonists & inhibitors; D000069059:Atorvastatin; D002478:Cells, Cultured; D024042:Collagen Type I / Q000096:biosynthesis / Q000187:drug effects; D000071063:Endoglin; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D006538:Heptanoic Acids / Q000494:pharmacology*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000187:drug effects; D011758:Pyrroles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D051900:Smad3 Protein / Q000037:antagonists & inhibitors / Q000187:drug effects; D053773:Transforming Growth Factor beta1 / Q000037:antagonists & inhibitors* / Q000187:drug effects; D000077191:Wortmannin
C486377:AKTIP protein, human; D048868:Adaptor Proteins, Signal Transducing; D000730:Androstadienes; D015703:Antigens, CD; D051017:Apoptosis Regulatory Proteins; D024042:Collagen Type I; C064206:ENG protein, human; D000071063:Endoglin; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011758:Pyrroles; D011956:Receptors, Cell Surface; D051900:Smad3 Protein; D053773:Transforming Growth Factor beta1; D000069059:Atorvastatin; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D000077191:Wortmannin