The Inhibitory Effects Of Hint1on Liver Fibrosis

Background:TGF-β signaling pathway play a key role in the process of liver fibrosis. Recently, emerging evidences suggested that sustained Wnt/β-catenin pathway reactivation was linked to the pathogenesis of liver fibrosis. Hintl, the histidine triad nucleotide-binding protein1, is a newly discovered tumor suppressor. Several studies have demonstrated that Hintl can inhibit TGF-β and Wnt/β-catenin pathways at the transcriptional level. However, there are few data regarding the effects of Hintl on liver fibrosis. Therefore, we suppose that Hintl could inhibit TGF-β and β-catenin signaling pathways on liver fibrosis, and might be a promising therapeutic strategy.Objective:To investigate the effects of Hintl on HSC-T6cells treated with recombinant Wnt3a, and the effects of Hintl on experimental rat hepatic fibrosis.Methods:Due to the lentivirus can express an exogenous gene stably, a Hintl-expression plasmid mediated by lentivirus (pGC-FU-Hintl-EGFP-3FLAG) was constructed, and the Hintl recombinant lentivirus (Lentivirus-Hintl) and blank vector lentivirus (Lentivirus-EGFP) were packaged. Then, the HSC-T6cells were infected with Hintl recombinant lentivirus. After treated with recombinant Wnt3a, the protein expression of a-SMA, COLIA1, TGF-β1, Smad3, Smad7, β-catenin and CyclinDl were investigated by Western Blot analysis. The gene expression of MMP-2and TIMP-lwere investigated by Real-time PCR. Meanwhile, Hintl recombinant lentivirus was induced into the rats by tail intravenous injection, and hepatic fibrosis model was established by subcutaneous injection of CCl4. After8weeks treatment, HE and Masson staining were used to observe the pathological changes in liver tissues, the hydroxyproline in liver tissues were detected, the protein expression of a-SMA, TGF-β1and Vimentin were observed by immunohistochemical analysis, and Real-Time PCR was used to investigate the mRNA expression of fibrosis-related genes.Results:Our study results indicated that overexpression of Hintl in vitro can restrain recombinant Wnt3a induced activation of HSC-T6cells, and decrease the protein expression of TGF-β1, Smad3, β-catenin and CyclinD1, whereas increase the expression of Smad7. At the same time, Hintl enhanced the degradation of extracellular matrix by increasing the expression of MMP-2and reducing the expression of TTMP-1, and the differences had statistical significance (P<0.05). In vivo, Hintl recombinant lentivirus treament group could significantly suppress the progression of liver fibrosis than model group, and the hydroxyproline content decreased significantly, the protein expression of a-SMA, TGF-β1and Vimentin were decreased. The liver fibrosis-related genes expression of TGF-β1, Smad3and β-catenin, CyclinDl were down-regulated, whereas the Smad7up-regulated, and the difference had statistical significance (P<0.05), while the data between the blank vector group and model group had no obvious change, there was no statistically significant difference between the blank vector group and model group (P>0.05).Conclusion:Hintl exhibited inhibitory effects in vivo and in vitro. It might be developed as a new treatment for liver fibrosis.