Smad3 specific inhibitor, naringenin, decreases the expression of extracellular matrix induced by TGF-beta1 in cultured rat hepatic stellate cells.
OBJECTIVE
During the process of liver fibrogenesis, transforming growth factor-beta (TGF-beta) plays an essential role in modulating extracellular matrix (ECM) gene expression, and a growing body of evidence suggests that this is a Smad3-dependent process in the activated hepatic stellate cells (HSCs). Naringenin showed a significantly protective effect on experimental rat liver fibrosis, in our efforts to elucidate its antifibrosis molecular mechanisms and to find a novel target based on Smad3 signaling for challenging fibrosis diseases.


METHODS
In this study, reverse transcription-polymerase chain reaction and Western blot assays were used to investigate the inhibitory effect of naringenin on ECM formation induced by TGF-beta1 in the HSC-T6 cells.


RESULTS
Naringenin reduced not only the accumulation of ECM, including collagen Ialpha1 (Col Ialpha1), fibronectin (FN), and plasminogen activator inhibitor-1 (PAI-1), but also the production of Smad3 induced by TGF-beta1 in both mRNA and protein levels in a dose-dependent manner. Moreover, naringenin selectively inhibited the transcription of Smad3, but not other Smads involved in TGF-beta1 signaling pathways.


CONCLUSIONS
Our data demonstrate that naringenin can exert antifibrogenic effects by directly or indirectly down-regulating Smad3 protein expression and phosphorylation through TGF-beta signaling.
Liu
Xingjun
X
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China.
Wang
Wei
W
Hu
Han
H
Tang
Ning
N
Zhang
Chunling
C
Liang
Wei
W
Wang
Minwei
M
D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000096:biosynthesis; D004965:Estrogen Antagonists / Q000494:pharmacology*; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism*; D005353:Fibronectins / Q000096:biosynthesis; D044950:Flavanones / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051900:Smad3 Protein / Q000037:antagonists & inhibitors*; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
D024042:Collagen Type I; D004965:Estrogen Antagonists; D005353:Fibronectins; D044950:Flavanones; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D051900:Smad3 Protein; C497787:Smad3 protein, rat; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D012313:RNA; C005273:naringenin