Epigenetically-Regulated MicroRNA-9-5p Suppresses the Activation of Hepatic Stellate Cells via TGFBR1 and TGFBR2.

Abstract

BACKGROUND/AIMS:

Recently, microRNAs (miRNAs) have been demonstrated to act as regulators of activation of hepatic stellate cells (HSCs). It is well known that the main profibrogenic inducer transforming growth factor-β1 (TGF-β1) contributes to HSC activation, which is a key event in liver fibrosis. Increasing studies show that miR-9-5p is down-regulated in liver fibrosis and restoration of miR-9-5p limits HSC activation. However, the role of miR-9-5p in TGF-β1-induced HSC activation is still not clear.

METHODS:

miR-9-5p expression was quantified using real-time PCR in chronic hepatitis B (CHB) patients and TGF-β1-treated LX-2 cells. In CHB patients, histological activity index (HAI) and fibrosis stages were assessed using the Ishak scoring system. Effects of miR-9-5p on liver fibrosis in vivo and in vitro were analyzed. Luciferase activity assays were performed to examine the binding of miR-9-5p to the 3'-untranslated region of type I TGF-β receptor (TGFBR1) as well as TGFBR2.

RESULTS:

Compared with healthy controls, miR-9-5p was reduced in CHB patients. There was a lower miR-9-5p expression in CHB patients with higher fibrosis scores or HAI scores. miR-9-5p was down-regulated by TGF-β1 in a dose-dependent manner. TGF-β1-induced HSC activation including cell proliferation, α-SMA and collagen expression was blocked down by miR-9-5p. Notably, miR-9-5p ameliorates carbon tetrachloride-induced liver fibrosis. As determined by luciferase activity assays, TGFBR1 and TGFBR2 were targets of miR-9-5p. Further studies demonstrated that miR-9-5p inhibited TGF-β1/Smads pathway via TGFBR1 and TGFBR2. Interestingly, promoter methylation was responsible for miR-9-5p down-regulation in liver fibrosis. The relationship between miR-9-5p expression and methylation was confirmed in CHB patients and TGF-β1-treated cells.

CONCLUSION:

Our results demonstrate that miR-9-5p could inhibit TGF-β1-induced HSC activation through TGFBR1 and TGFBR2. Loss of miR-9-5p is associated with its methylation status in liver fibrosis.

• Authors: Fujun Yu, BiCheng Chen, XuFei Fan, Guojun Li, Peihong Dong, Jianjian Zheng
• Journal: Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology (Cell Physiol Biochem) Vol. 43 Issue 6 Pg. 2242-2252 ( 2017) ISSN: 1421-9778 [Electronic] Germany
• PMID: 29073595 (Publication Type: Journal Article)
• Copyright: © 2017 The Author(s). Published by S. Karger AG, Basel.

Chemical References

• 3' Untranslated Regions
• ACTA2 protein, human
• Actins
• Antagomirs
• Collagen Type I
• MIRN92 microRNA, human
• MicroRNAs
• Receptors, Transforming Growth Factor beta
• Transforming Growth Factor beta1
• Carbon Tetrachloride
• Protein Serine-Threonine Kinases
• Receptor, Transforming Growth Factor-beta Type I
• Receptor, Transforming Growth Factor-beta Type II
• TGFBR1 protein, human
• Tgfbr1 protein, mouse

Topics

• 3' Untranslated Regions
• Actins (genetics, metabolism)
• Adult
• Animals
• Antagomirs (metabolism)
• Base Sequence
• Carbon Tetrachloride (toxicity)
• Cell Line
• Cell Proliferation (drug effects)
• Collagen Type I (genetics, metabolism)
• Down-Regulation (drug effects)
• Female
• Hepatic Stellate Cells (cytology, metabolism)
• Hepatitis B, Chronic (genetics, metabolism, pathology)
• Humans
• Liver (metabolism, pathology)
• Liver Cirrhosis (chemically induced, genetics, pathology)
• Male
• Mice
• Mice, Inbred C57BL
• MicroRNAs (antagonists & inhibitors, genetics, metabolism)
• Middle Aged
• Promoter Regions, Genetic
• Protein Serine-Threonine Kinases (antagonists & inhibitors, genetics, metabolism)
• Receptor, Transforming Growth Factor-beta Type I
• Receptor, Transforming Growth Factor-beta Type II
• Receptors, Transforming Growth Factor beta (antagonists & inhibitors, genetics, metabolism)
• Sequence Alignment
• Transforming Growth Factor beta1 (pharmacology)