Hic-5 deficiency attenuates the activation of hepatic stellate cells and liver fibrosis through upregulation of Smad7 in mice.

Hydrogen peroxide-inducible clone-5 (Hic-5), also named as transforming growth factor beta-1-induced transcript 1 protein (Tgfb1i1), was found to be induced by TGF-β. Previous studies have shown that TGF-β is a principal mediator of hepatic stellate cell (HSC) activation in liver fibrosis. However, this process remains elusive. In this study, we aimed to define the role of Hic-5 in HSC activation and liver fibrosis. We examined the expression levels of Hic-5 during HSCs activation and in fibrotic liver tissues by quantitative real-time reverse transcriptase polymerase chain reaction, Western blot and immunohistochemistry. Hic-5 knockout (KO) and wild-type (WT) mice were subjected to bile duct ligation (BDL) or carbon tetrachloride (CCl4) injection to induce liver fibrosis. Hic-5 expression was strongly upregulated in activated HSCs of the human fibrotic liver tissue and BDL or CCl4-induced mouse liver fibrosis. Hic-5 deficiency significantly attenuated mouse liver fibrosis and HSC activation. Furthermore, Hic-5 knockdown by siRNA in vivo repressed CCl4-induced liver fibrosis in mice. Mechanistically, the absence of Hic-5 significantly inhibited the TGF-β/Smad2 signaling pathway, proved by increasing Smad7 expression, resulting in reduced collagen production and α-smooth muscle actin expression in the activated HSCs. Hic-5 deficiency attenuates the activation of HSCs and liver fibrosis though reducing the TGF-β/Smad2 signaling by upregulation of Smad7. Thus, Hic-5 can be regarded as a potential therapeutic target for liver fibrosis.

Lei XF ，Fu W ，Kim-Kaneyama JR ，Omoto T ，Miyazaki T ，Li B ，Miyazaki A ... -  《-》

Physalin D attenuates hepatic stellate cell activation and liver fibrosis by blocking TGF-β/Smad and YAP signaling.

Hepatic fibrosis is considered integral to the progression of chronic liver diseases, as it leads to the development of cirrhosis and hepatocellular carcinoma. The activation of hepatic stellate cells (HSCs) is the dominant event in hepatic fibrogenesis. The transforming growth factor-β1 (TGF-β1) and Yes-associated protein (YAP) pathways play a pivotal role in HSC activation, hepatic fibrosis and cirrhosis progression. Therefore, targeting the TGF-β/Smad and YAP signaling pathways is a promising strategy for antifibrotic therapy. The present study investigated the protective effects of Physalin D (PD), a withanolide isolated from Physalis species (Solanaceae), against liver fibrosis and further elucidated the mechanisms involved in vitro and in vivo. We conducted a series of experiments using carbon tetrachloride (CCl4)- and bile duct ligation (BDL)-induced fibrotic mice and cultured LX-2 cells. Serum markers of liver injury, and the morphology, histology and fibrosis of liver tissue were investigated. Western blot assays and quantitative real-time PCR were used to investigate the mechanisms underlying the antifibrotic effects of PD. PD decreased TGF-β1-induced COL1A1 promoter activity. PD inhibited TGF-β1-induced expression of Collagen I and α-smooth muscle actin (α-SMA) in human hepatic stellate LX-2 cells. PD significantly ameliorated hepatic injury, including transaminase activities, histology, collagen deposition and α-SMA, in CCl4- or BDL-induced mice. Moreover, PD markedly decreased the expression of phosphorylated Smad2/3 in vitro and in vivo. Furthermore, PD significantly decreased YAP protein levels, and YAP knockdown did not further enhance the effects of PD, namely α-SMA inhibition, Collagen I expression and YAP target gene expression in LX-2 cells. These results clearly show that PD ameliorated experimental liver fibrosis by inhibiting the TGF-β/Smad and YAP signaling pathways, indicating that PD has the potential to effectively treat liver fibrosis.

Xiang D ，Zou J ，Zhu X ，Chen X ，Luo J ，Kong L ，Zhang H ... -  《-》

MicroRNA-30 Protects Against Carbon Tetrachloride-induced Liver Fibrosis by Attenuating Transforming Growth Factor Beta Signaling in Hepatic Stellate Cells.

Transforming growth factor beta (TGF-β) is crucial for transdifferentiation of hepatic stellate cells (HSCs) and the blunting of TGF-β signaling in HSCs can effectively prevent liver fibrosis. Krüppel-like factor 11 (KLF11) is an early response transcription factor that potentiates TGF-β/Smad signaling by suppressing the transcription of inhibitory Smad7. Using a mouse model of carbon tetrachloride (CCl4)-induced liver fibrosis, we observed significant upregulation of KLF11 in the activated HSCs during liver fibrogenesis. Meanwhile, the downregulation of miR-30 was observed in the HSCs isolated from fibrotic liver. Adenovirus-mediated ectopic expression of miR-30 was under the control of smooth muscle α-actin promoter, showing that the increase in miR-30 in HSC greatly reduced CCl4-induced liver fibrosis. Subsequent investigations showed that miR-30 suppressed KLF11 expression in HSC and led to a significant upregulation of Smad7 in vivo. Mechanistic studies further confirmed that KLF11 was the direct target of miR-30, and revealed that miR-30 blunted the profibrogenic TGF-β signaling in HSC by suppressing KLF11 expression and thus enhanced the negative feedback loop of TGF-β signaling imposed by Smad7. Finally, we demonstrated that miR-30 facilitated the reversal of activated HSC to a quiescent state as indicated by the inhibition of proliferation and migration, the loss of activation markers, and the gain of quiescent HSC markers. In conclusion, our results define miR-30 as a crucial suppressor of TGF-β signaling in HSCs activation and provide useful insights into the mechanisms underlying liver fibrosis.

Tu X ，Zheng X ，Li H ，Cao Z ，Chang H ，Luan S ，Zhu J ，Chen J ，Zang Y ，Zhang J ... -  《-》

Sauchinone attenuates liver fibrosis and hepatic stellate cell activation through TGF-β/Smad signaling pathway.

Hepatic stellate cells (HSCs) are key mediators of fibrogenesis, and the regulation of their activation is now viewed as an attractive target for the treatment of liver fibrosis. Here, the authors investigated the ability of sauchinone, an active lignan found in Saururus chinensis, to regulate the activation of HSCs, to prevent liver fibrosis, and to inhibit oxidative stress in vivo and in vitro. Blood biochemistry and histopathology were assessed in CCl4-induced mouse model of liver fibrosis to investigate the effects of sauchinone. In addition, transforming growth factor-β1 (TGF-β1)-activated LX-2 cells (a human HSC line) were used to investigate the in vitro effects of sauchinone. Sauchinone significantly inhibited liver fibrosis, as indicated by decreases in regions of hepatic degeneration, inflammatory cell infiltration, and the intensity of α-smooth muscle actin staining in mice. Sauchinone blocked the TGF-β1-induced phosphorylation of Smad 2/3 and the transcript levels of plasminogen activator inhibitor-1 and matrix metalloproteinase-2 as well as autophagy in HSCs. Furthermore, sauchinone inhibited oxidative stress, as assessed by stainings of 4-hydroxynonenal and nitrotyrosine: these events may have a role in its inhibitory effects on HSCs activation. Sauchinone attenuated CCl4-induced liver fibrosis and TGF-β1-induced HSCs activation, which might be, at least in part, mediated by suppressing autophagy and oxidative stress in HSCs.

Lee JH ，Jang EJ ，Seo HL ，Ku SK ，Lee JR ，Shin SS ，Park SD ，Kim SC ，Kim YW ... -  《-》

MicroRNA-212 activates hepatic stellate cells and promotes liver fibrosis via targeting SMAD7.

There has been an increasing number of researches about microRNAs (miRNAs) in the progression of liver fibrosis from the point of their comprehensive functions in regulating the activation of hepatic stellate cells (HSCs). Among them, it has been reported that miR-212 is up-regulated in activated rat primary HSCs. However, its mechanism has not been determined yet. Here, we confirmed that the level of miR-212-3p was up-regulated in livers of carbon tetrachloride (CCl4)-treated mice compared with the normal control, which is a classical model of chronically damaged fibrotic liver. In vitro, we demonstrated that TGF-β, a master fibrogenic cytokine, could induce the level of miR-212. In turn, overexpression of miR-212 could induce the activation marker of HSC including α-smooth muscle actin (α-SMA) and collagens by activating TGF-β signaling pathway. Furthermore, SMAD7, a dominant suppressor of TGF-β pathway, was identified as a direct target of miR-212-3p. Our results indicate that miR-212-3p facilitates the activation of HSCs and TGF-β pathway by targeting SMAD7, highlighting that it can be served as a novel biomarker or therapeutic target for liver fibrosis.

Zhu J ，Zhang Z ，Zhang Y ，Li W ，Zheng W ，Yu J ，Wang B ，Chen L ，Zhuo Q ，Chen L ，Zhang J ，Liu J ... -  《-》