Simvastatin impairs smad-3 phosphorylation and modulates transforming growth factor beta1-mediated activation of intestinal fibroblasts.
BACKGROUND
Transforming growth factor (TGF) beta1, acting through the smad pathway, is critical to fibroblast-mediated intestinal fibrosis. Simvastatin exhibits antifibrotic properties. This study assessed the effects of simvastatin on TGF-beta1-mediated intestinal fibroblast activation.


METHODS
Human intestinal fibroblasts were activated with TGF-beta1 with or without simvastatin or the cholesterol pathway intermediates farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). Collagen-Ialpha2 expression was assessed by reverse transcriptase-polymerase chain reaction. Connective tissue growth factor (CTGF) and smad phosphorylation were evaluated by western blot, and plasminogen activator inhibitor (PAI) 1 activity by enzyme-linked immunosorbent assay. Fibroblast filamentous (F)-actin accumulation was assessed by confocal microscopy and contraction by a fibroblast-populated collagen lattice (FPCL) model.


RESULTS
TGF-beta1 treatment of fibroblasts induced smad-2/3 phosphorylation, CTGF and collagen-Ialpha2 production, F-actin bundling, FPCL contraction and PAI-1 activation. Pretreatment with simvastatin inhibited the induction of CTGF and collagen-Ialpha2, PAI-1 activation, F-actin bundling and FPCL contraction. The inhibitory effect of simvastatin on PAI-1 activation was reversed by GGPP and FPP. Simvastatin pretreatment inhibited TGF-beta1-mediated phosphorylation of smad-3.


CONCLUSIONS
Simvastatin abrogates TGF-beta1-mediated intestinal fibroblast activation by inhibition of smad-3 phosphorylation. These findings offer a mechanism for the antifibrotic effects of simvastatin and a therapeutic entry point in the treatment of intestinal fibrosis.
Burke
J P
JP
Department of Surgery, Mater Misericordiae University Hospital, Dublin, Ireland.
Watson
R W G
RW
Murphy
M
M
Docherty
N G
NG
Coffey
J C
JC
O'Connell
P R
PR
D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D002450:Cell Communication; D002478:Cells, Cultured; D003106:Colon / Q000166:cytology*; D055513:Connective Tissue Growth Factor / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D018613:Microscopy, Confocal; D010766:Phosphorylation / Q000187:drug effects; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019821:Simvastatin / Q000494:pharmacology*; D051900:Smad3 Protein / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000187:drug effects* / Q000502:physiology
D000199:Actins; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D017395:Plasminogen Activator Inhibitor 1; D051900:Smad3 Protein; D053773:Transforming Growth Factor beta1; D055513:Connective Tissue Growth Factor; D019821:Simvastatin