title: Effect of the protease inhibitor MG132 on the transforming growth factor-β/Smad signaling pathway in HSC-T6 cells.
abstract: The activation of hepatic stellate cells (HSCs) and their transformation to myofibroblasts are the key steps in the pathological progress of liver fibrosis. The transforming growth factor-β (TGFβ)/Smad pathway is involved in the proliferation and collagen synthesis of HSCs. This study aimed to examine the effect of the protease inhibitor MG132 on the signaling pathway of TGFβ/Smad in HSC-T6 cells and seek a novel therapeutic approach for liver fibrosis. The HSC-T6 cells were treated with MG132 at different concentrations (0-10 μmol/L). Cell proliferation was detected by MTT method. The mRNA and protein expression levels of TGFβ1, Smad3 and Smad7 were determined in HSC-T6 cells by real-time PCR and Western blotting, respectively, after treatment with MG132 at different concentrations (1, 2, 3 μmol/L) or RPMI1640 alone (serving as control). The results showed that MG132 could inhibit the proliferation of HSC-T6 cells in a dose-dependent manner, and the IC(50) of MG132 was 6.84 μmol/L. After treatment with MG132 at 1, 2 or 3 μmol/L for 24 h, the mRNA expression levels of TGF-β1 and Smad3 were significantly decreased (P<0.05), but the Smad7 mRNA expression had no significant change (P>0.05). There was also a significant decrease in the protein expression level of TGF-β1 and Smad3 (P<0.05). However, the expression of Smad7 protein was substantially increased when compared with the control group (P<0.05). It was concluded that the inhibition of TGFβ/Smad pathway in HSC-T6 cells by MG132 can reduce the production of profibrosis factors (TGFβ1, Smad3) and promote the expression of anti-fibrosis factor (Smad7), suggesting that MG132 may become a potential therapeutic alternative for liver fibrosis.
authors.affiliation: Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.|Department of Infectious Diseases, Xinxiang Center Hospital, Xinxiang, 453000, China.
authors.forename: Zhang-Peng
authors.initials: ZP
authors.lastname: Ren
authors.affiliation: Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Sun
authors.affiliation: Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
authors.forename: You-Chen
authors.initials: YC
authors.lastname: Xia
authors.affiliation: Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. tongqiaoxia@gmail.com.
authors.forename: Qiao-Xia
authors.initials: QX
authors.lastname: Tong
mesh_terms: D000818:Animals; D002460:Cell Line; D007976:Leupeptins / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology*; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects*; D051785:Smad Proteins / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: D007976:Leupeptins; D011480:Protease Inhibitors; D051785:Smad Proteins; D016212:Transforming Growth Factor beta; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde
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