The role of the miR-31/FIH1 pathway in TGF-β-induced liver fibrosis.
The miRNAs are small, non-coding RNAs that regulate various biological processes, including liver fibrosis. Hepatic stellate cells (HSCs) play a central role in the pathogenesis of liver fibrosis. By microarray profiling and real-time PCR, we noted that miR-31 expression in HSCs from rats, mice and humans was significantly increased during HSC activation in culture. Overall, miR-31 expression levels were unchanged in the whole-liver RNA extracts from fibrotic rat and human samples. Nevertheless, we found that miR-31 was particularly up-regulated in HSCs but not in hepatocytes during fibrogenesis. Thus, we hypothesized that miR-31 may mediate liver fibrosis. In the present study, we found that inhibition of miR-31 expression significantly inhibited HSC activation, whereas its over-expression obviously promoted HSC activation. Moreover, over-expression of miR-31 promoted HSC migration by enhancing matrix metalloproteinase (MMP)-2 expression whereas inhibition of miR-31 has an opposite effect. The biological function of miR-31 during HSC activation might be through targeting FIH1, a suppressor of hypoxia-inducible factor (HIF-1), because a knockdown of FIH1 by shRNA could mimic the effects of miR-31. In addition, primary rat HSCs were isolated and treated with different cytokines, such as transforming growth factor β (TGF-β), vascular endothelial growth factor and platelet-derived growth factor-BB, to evaluate upstream regulators of miR-31. We found that only TGF-β, a pivotal regulator in liver fibrosis, remarkably increased miR-31 expression in HSCs. And the effects of TGF-β on HSCs can be partially counteracted by inhibition of miR-31. In addition, chromatin immunoprecipitation experiments and the luciferase reporter assay demonstrated that Smad3, a major TGF-β-downstream transcription factor, stimulated the transcription activity of miR-31 by binding directly to miR-31's promoter. In conclusion, the miR-31/FIH1 pathway associates with liver fibrosis, perhaps by participation in the TGF-β/Smad3 signalling of HSCs.
*Department of Gastroenterology, Changzheng Hospital, Second Military Medical University, Shanghai, China.
Jiangfeng
J
Hu
‡‡Department of Pathology, Changzheng Hospital, Second Military Medical University, Shanghai, China.
Chao
C
Chen
§Clinical and Translational Research Centre of Shanghai First Maternity and Infant Health Hospital, Shanghai Key Laboratory of Signalling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai, China.
Qidong
Q
Liu
║Office of Medical Education, Training Department, Second Military Medical University, Shanghai, China.
Baohai
B
Liu
¶German Cancer Research Centre, Heidelberg, Germany.
Chenlin
C
Song
§Clinical and Translational Research Centre of Shanghai First Maternity and Infant Health Hospital, Shanghai Key Laboratory of Signalling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai, China.
Songchen
S
Zhu
**Genetics Institute, Fudan University, Shanghai, China.
Chaoqun
C
Wu
††Department of Gastroenterology, Central Hospital of Zhabei District, Changzheng Hospital, Second Military Medical University, Shanghai, China.
Su
S
Liu
‡‡Department of Pathology, Changzheng Hospital, Second Military Medical University, Shanghai, China.
Hongyu
H
Yu
*Department of Gastroenterology, Changzheng Hospital, Second Military Medical University, Shanghai, China.
Dingkang
D
Yao
§Clinical and Translational Research Centre of Shanghai First Maternity and Infant Health Hospital, Shanghai Key Laboratory of Signalling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai, China.
Jiuhong
J
Kang
*Department of Gastroenterology, Changzheng Hospital, Second Military Medical University, Shanghai, China.
Liang
L
Zhu
D020413:3' Untranslated Regions; D000818:Animals; D001665:Binding Sites; D002465:Cell Movement; D049109:Cell Proliferation; D017930:Genes, Reporter; D057809:HEK293 Cells; D055166:Hepatic Stellate Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008106:Liver Cirrhosis, Experimental / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D051900:Smad3 Protein / Q000378:metabolism; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D015854:Up-Regulation
D020413:3' Untranslated Regions; C534612:MIRN31 microRNA, human; C570112:MIRN31 microRNA, rat; D035683:MicroRNAs; C539917:Mirn31 microRNA, mouse; D012097:Repressor Proteins; D051900:Smad3 Protein; D053773:Transforming Growth Factor beta1; D006899:Mixed Function Oxygenases; C551240:factor inhibiting hypoxia-inducible factor 1, mouse; C439790:HIF1AN protein, human; D020778:Matrix Metalloproteinase 2