Preventive effects of ME3738 on hepatic fibrosis induced by bile duct ligation in rats

Newly Invented Micellized Vitamin K2 Recovered Prolonged Prothrombin Time under Obstructive Jaundice in Rats with Bile Duct Ligation

In cholestatic liver diseases, coagulopathy is induced by malabsorption of vitamin K. Supplementation of vitamin K has previously been shown to prevent coagulopathy. In this study, we tested the efficacy of a newly invented micellized vitamin K2 (m-vitK2) in treating coagulopathy, using a rat bile duct ligation (BDL) model. Experiment 1: m-vitK2 (0.3 mg/kg) or m-vitK2 (0.3 mg/kg) mixed with taurocholic acid (TA) (10 mg/body) was orally administrated every day for 7 d from the fourth day after BDL (n=6 for each). Experiment 2: To evaluate absorption, m-vitK2 (0.3 mg/kg) with or without TA (10 mg/body) was orally administered on the fourth day after BDL and compared with the untreated control BDL (n=2 for each). These data were compared with sham-operated (n=6) and untreated control BDL rats (n=6). The m-vitK2 recovered prothrombin time (PT) in Experiment 1 (control 42.7±5.7 s vs. m-vitK2 24.0±9.3 s, p<0.05). Experiment 2 demonstrated that the mixture of m-vitK2 and TA enhanced absorption compared to m-vitK2 alone. Moreover, in Experiment 1, m-vitK2 mixed with TA completely recovered PT (control 42.7±5.7 s vs. m-vitK2+TA 14.9±1.2 s, p<0.01). Micelle sizes decreased with the m-vitK2 and TA treatment (m-vitK2 86.3±5.6 nm vs. m-vitK2+TA 71.9±4.7 nm, p<0.05). Orally administered, newly invented m-vitK2 recovered coagulopathy even under obstructive jaundice. TA decreased the mean micelle size and improved m-vitK2 absorption.

A novel role of glutathione S-transferase A3 in inhibiting hepatic stellate cell activation and rat hepatic fibrosis

Background and aims

Glutathione S-transferase A3 (GSTA3) is known as an antioxidative protease, however, the crucial role of GSTA3 in liver fibrosis remains unclear. As a recently we developed water-soluble pyridone agent with antifibrotic features, fluorofenidone (AKF-PD) can attenuate liver fibrosis, present studies were designed to explore the role of GSTA3 in liver fibrosis and its modulation by AKF-PD in vivo and in vitro.

Methods

Rats liver fibrosis models were induced by dimethylnitrosamine (DMN) or carbon tetrachloride (CCl4). The two activated hepatic stellate cells (HSCs) lines, rat CFSC-2G and human LX2 were treated with AKF-PD respectively. The lipid peroxidation byproduct malondialdehyde (MDA) in rat serum was determined by ELISA. The accumulation of reactive oxygen species (ROS) was measured by dichlorodihydrofluorescein fluorescence analysis. The expression of α-smooth muscle actin (α-SMA), fibronectin (FN), and phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2), p38 mitogen-activated protein kinase (p38 MAPK), c-Jun N-terminal kinase (JNK) and glycogen synthase kinase 3 beta (GSK-3β) were detected by western blotting (WB).

Results

GSTA3 was substantially reduced in the experimental fibrotic livers and transdifferentiated HSCs. AKF-PD alleviated rat hepatic fibrosis and potently inhibited HSCs activation correlated with restoring GSTA3. Moreover, GSTA3 overexpression prevented HSCs activation and fibrogenesis, while GSTA3 knockdown enhanced HSCs activation and fibrogenesis resulted from increasing accumulation of ROS and subsequent amplified MAPK signaling and GSK-3β phosphorylation.

Conclusions

We demonstrated firstly that GSTA3 inhibited HSCs activation and liver fibrosis through suppression of the MAPK and GSK-3β signaling pathways. GSTA3 may represent a promising target for potential therapeutic intervention in liver fibrotic diseases.

Antiproliferative effect of ME3738, a derivative of soyasapogenol, on hepatocellular carcinoma cell lines in vitro and in vivo

Soyasapogenol, an aglycon of soyasaponin, ameliorates liver injury induced by concanavalin A in mice. A derivative of soyasapogenol, 22β-methoxyolean-12-ene-3β, 24(4β)-diol (ME3738), was reported to induce the gene expression of interferon (IFN)-β in hepatitis C virus replicon cells. The effect of ME3738 on hepatocellular carcinoma (HCC) cell lines was investigated in the present study. A total of 11 HCC cell lines were cultured in medium containing 0-10 µM ME3738, and after 24, 48, or 72 h of culture, morphological observation and MTT cell growth assays were performed. Furthermore, the effects of ME3738 with or without PEG-IFN-α-2b on cell lines were investigated. Induction of apoptosis was examined on cells treated with 1 µM of ME3738 using an Annexin V assay. The effect of ME3738 (0.63 and 2.5 µM) on cell cycle progression was analyzed on two cell lines. The mice with subcutaneous tumors were divided into four groups: i) Control; ii) ME3738 alone; iii) PEG-IFN-α-2b alone and iv) ME3738+PEG-IFN-α-2b (combination). ME3738 was mixed with food (1.5 mg/g) and was taken orally for 15 days. PEG-IFN-α-2b (1,920 IU/mouse) was subcutaneously injected twice a week for two consecutive weeks. On day 15, the mice were sacrificed and the tumors were resected. A dose-dependent anti-proliferative effect was observed to various degrees in all the HCC cell lines in vitro. This inhibitory effect reached its maximal level 24 h after the treatment and the 50% inhibitory dose was between 0.8 and 2.4 µM. The combination treatment did not show a synergistic effect. Induction of apoptosis was not observed. Cell cycle arrest at S-phase was observed in two of the examined cell lines. On day 15, the tumor volume of mice receiving ME3738, PEG-IFN-α-2b, and ME3738+PEG-IFN-α-2b was 69, 30, and 33%, respectively, of the control tumor volume. ME3738 induced antiproliferative effects on the HCC cells in vitro and in vivo. The data suggested potential clinical application of ME3738.

Curcumin upregulates Nrf2 nuclear translocation and protects rat hepatic stellate cells against oxidative stress

The present study aimed to investigate the protective role of curcumin against oxidative stress in rat hepatic stellate cells (HSCs)-T6, and to determine the possible underlying mechanisms. HSC-T6 cells were divided into three groups: Negative control group, oxidant-treated group and curcumin-treated group. Flow cytometry and spectrophotometry were used to measure the production of reactive oxygen species (ROS), and the levels of malondialdehyde (MDA) and glutathione (GSH). Immunocytochemistry and a radioimmunoassay were used to determine the expression of smooth muscle α-actin (α-SMA) and the secretion of extracellular matrix (ECM) molecules. In addition, western blotting and immunocytochemistry were used to determine the expression levels of nuclear factor-erythroid 2-related factor (Nrf2). Treatment with glucose oxidase (GO) significantly stimulated the formation of ROS and increased the production of MDA, as compared with the control cells; however, the production of GSH was only slightly increased. In addition, treatment with GO significantly promoted the expression of α-SMA and the secretion of ECM molecules. Conversely, treatment with curcumin significantly decreased the levels of ROS and MDA, and significantly increased the levels of GSH. Curcumin significantly inhibited the expression of α-SMA and decreased the secretion of ECM molecules. Furthermore, treatment with curcumin significantly increased the nuclear expression levels of Nrf2. These results indicated that curcumin may protect rat HSCs against oxidative stress and inhibit the GO-induced activation and secretion of ECM molecules in vitro. These effects were mediated by the upregulation of Nrf2 nuclear translocation.

The Salvia miltiorrhiza monomer IH764-3 induces apoptosis of hepatic stellate cells in vivo in a bile duct ligation-induced model of liver fibrosis

During the process of liver fibrosis, hepatic stellate cells (HSCs) play a critical role in the excessive production of extracellular matrix (ECM). Previous studies have indicated that the monomer IH764-3, one of the major bioactive components of Salvia miltiorrhiza, is able to inhibit HSC proliferation and induce the apoptosis of activated HSCs in vitro. In the current study, we used a rat model of liver fibrosis induced by bile duct ligation (BDL) to investigate the effect of the monomer IH764-3 on the induction of apoptosis in HSCs in vivo. The rat model of liver fibrosis was established by BDL. Immunohistochemical staining of α-smooth muscle actin (α-SMA) was performed to detect HSC activation and proliferation and HSC apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and α-SMA immunohistochemical double staining. In addition, the protein expression levels of focal adhesion kinase (FAK), p-FAK (Tyr397), extracellular signal-regulated kinase (ERK) and p-ERK and the mRNA expression levels of FAK and ERK were measured by western blotting and reverse transcription-polymerase chain reaction (RT-PCR), respectively. The monomer IH764-3 was associated with a significant decrease in intrahepatic fibrogenesis and collagen deposition and attenuated the liver fibrosis induced by BDL. Immunohistochemical staining revealed that the expression of α-SMA in the IH764-3 group was significantly decreased compared with that in the model group (12.92±2.45 vs. 22.65±2.16%, P<0.01). TUNEL and α-SMA immunohistochemical double staining also confirmed that IH764-3 increased the apoptotic rate of the activated HSCs (34.8±4.5 vs. 4.72±0.37%, P<0.01). Moreover, the results revealed that IH764-3 downregulated the expression levels of FAK, p-FAK (Tyr397), ERK and p-ERK in the liver tissue of rats with liver fibrosis. The monomer IH764-3 ameliorates experimental liver fibrosis by inhibiting HSC proliferation and inducing HSC apoptosis, warranting its use as a potential therapeutic agent in the treatment of liver fibrosis.

Hydroxysafflor Yellow A Attenuates Carbon Tetrachloride-Induced Hepatic Fibrosis in Rats by Inhibiting Erk5 Signaling

Hepatic stellate cells (HSCs) undergo activation during the development of liver fibrosis. Transcription factor myocyte enhancer factor (MEF2) 2C plays a key role in this process. In the present study, we investigated the effect of hydroxysafflor yellow A (HSYA) on hepatic fibrosis and further investigated potential mechanisms in vivo. Sprague-Dawley rats were administered with CCl4 together with or without HYSA for 12 weeks. The effect of HYSA on hepatic fibrosis was evaluated using hematoxylin-eosin and Van Gieson staining. Messenger RNA expression was quantified by real-time polymerase chain reaction, and protein was quantified by Western blot or immunohistochemistry. Our results revealed that CCl4 treatment induced micronodular hepatic fibrosis with a pronounced deposition of collagen fibers. Treatment with HYSA resulted in a significant decrease in fibrosis, protein expression of α-SMA, and MEF-2C gene expression. This was accompanied by a decreased expression of Tβ-RI, Tβ-RII, MEKK3, MEK5, and phosphorylation of ERk5. HYSA alone had no effect on the measured parameters. Our findings demonstrate that HSYA protected, at least in part, the rat liver from CCl 4-caused fibrogenesis through inhibition of hepatic stellate cell (HSC) activation, attenuation of transforming growth factor beta (TGF-β) signaling. HSYA may become a novel and promising agent for the inhibition of hepatic fibrosis.

ME3738 enhances the effect of interferon and inhibits hepatitis C virus replication both in vitro and in vivo

BACKGROUND & AIMS

ME3738 (22β-methoxyolean-12-ene-3β, 24-diol), a derivative of soyasapogenol B, attenuates liver disease in several animal models of acute and chronic liver injury. ME3738 is thought to inhibit replication of hepatitis C virus (HCV) by enhancing interferon (IFN)-β production, as determined using the HCV full-length binary expression system. We examined the effect of ME3738 combined with IFN-α on HCV replication using the genotype 1b subgenomic replicon system and an in vivo mouse HCV model.

METHODS

HCV replicon cells (ORN/3-5B/KE cells and Con1 cells) were incubated with ME3738 and/or IFN-α, and then intracellular IFN-stimulated genes (ISGs) and HCV RNA replication were analyzed by reverse-transcription-real time polymerase chain reaction and luciferase reporter assay. HCV-infected human hepatocyte chimeric mice were also treated with ME3738 and/or IFN-α for 4 weeks. Mouse serum HCV RNA titer, HCV core antigen, and ISGs expression in the liver were measured.

RESULTS

ME3738 induced gene expression of oligoadenylate synthetase 1 and inhibited HCV replication in both HCV replicon cells. The drug enhanced the effect of IFN to significantly increase ISG expression levels, inhibit HCV replication in replicon cells, and reduce mouse serum HCV RNA and core antigen levels in mouse livers. The combination treatment was not hepatotoxic as evident histologically and did not reduce human serum albumin in mice.

CONCLUSIONS

ME3738 inhibited HCV replication, enhancing the effect of IFN-α to increase ISG expression both in vitro and in vivo, suggesting that the combination of ME3738 and IFN might be useful therapeutically for patients with chronic hepatitis C.

Oxidative stress is closely associated with tumor angiogenesis of hepatocellular carcinoma

BACKGROUND

Oxidative stress (OS) plays an important role in the progression of chronic liver disease and hepatocarcinogenesis. However, the role of OS in the progression of hepatocellular carcinoma (HCC) is unclear. The aim of this study was to assess whether OS promotes angiogenesis in HCC.

METHODS

The expressions of vascular endothelial growth factor (VEGF), VEGF receptor2 (VEGFR2), and phosphorylated Akt were assessed, and microvessel density (MVD) and the cancer-associated fibroblast (CAF) population were examined by immunohistological staining in 55 HCC samples. The OS level in these tissues was assessed using 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 4-hydroxy-2-nonenal (4-HNE) immunostaining, and an 8-OHdG enzyme-linked immunosorbent assay (ELISA). The expression and activation of angiogenic factors and the effect of growth stimulation of human umbilical vein endothelial cells (HUVECs) were also assessed in vitro, using HLE hepatoma-derived cells and conditioned medium with or without treatment with hydrogen peroxide (H₂O₂); a phosphoinositide 3-kinase (PI3K) inhibitor, wortmannin; and an anti-oxidative agent, N-acetyl-L-cysteine (NAC).

RESULTS

A higher OS grade was significantly associated with higher MVD, VEGF expression, Akt activity, and OS grade of CAFs, but not with the percentage of the CAF population in HCC tissues. Additionally, cancer cells constituted a major population of OS marker-positive cells in HCC tissues. In vitro, H₂O₂ treatment induced up-regulation of VEGF at both the mRNA and protein levels, activated Akt, and resulted in the proliferation of HUVECs; the addition of wortmannin and NAC counteracted the effects of OS.

CONCLUSIONS

OS enhances the malignant potential of HCC through the stimulation of angiogenesis by activation of the Akt-VEGF pathway.

PTEN expression is down-regulated in liver tissues of rats with hepatic fibrosis induced by biliary stenosis

The gene phosphatase and tensin homolog deleted on chromosome 10 (PTEN) codes for a tumor-suppressor phospholipid phosphatase. Deletion, mutation or abnormal expression of PTEN is commonly found in many kinds of malignant tumors. At the time of this study, though, the role of PTEN expression in the pathology of hepatic fibrosis remains unclear. In this study, we investigate the dynamic expression of PTEN in a rat model of hepatic fibrosis, with special emphasis on the activation and proliferation of hepatic stellate cells (HSC) in vivo. The rat model of hepatic fibrosis used in this study employed common bile duct ligation. At four time points, the expression of PTEN in hepatic tissues and activated HSC in rat liver tissues was measured by immunohistochemical staining, Western blotting, real-time fluorescent quantitative PCR and immunofluorescence confocal laser scanning microscopy, respectively. Further, alpha-smooth muscle actin (alpha-SMA), an activated HSC marker in rat liver tissues, was detected by immunohistochemical staining. This study showed that aggravation of hepatic fibrosis led to gradually decreasing expression of PTEN in the hepatic tissues. Further, as hepatic fibrosis worsens, PTEN-expressing activated HSC accounts for an increasingly smaller percentage of all activated HSC. In contrast, the percentage of alpha-SMA-expressing HSC cells increases significantly. In conclusion, expression of PTEN mRNA and protein is down-regulated in fibrogenic rat liver tissue, and its expression in HSC in vivo also decreases with progression of fibrosis. Thus, these results show that the dynamic expression of PTEN in hepatic tissues negatively correlates with activation and proliferation of HSC.