Network Pharmacology-Based Approaches of Rheum undulatum Linne and Glycyrriza uralensis Fischer Imply their Regulation of Liver Failure with Hepatic Encephalopathy in Mice.

Rheum undulatum and Glycyrrhiza uralensis have been used as supplementary ingredients in various herbal medicines. They have been reported to have anti-inflammatory and antioxidant effects and, therefore, have potential in the treatment and prevention of various liver diseases. Considering that hepatic encephalopathy (HE) is often associated with chronic liver failure, we investigated whether an R. undulatum and G. uralensis extract mixture (RG) could reduce HE. We applied systems-based pharmacological tools to identify the active ingredients in RG and the pharmacological targets of RG by examining mechanism-of-action profiles. A CCl4-induced HE mouse model was used to investigate the therapeutic mechanisms of RG on HE. We successfully identified seven bioactive ingredients in RG with 40 potential targets. Based on an integrated target-disease network, RG was predicted to be effective in treating neurological diseases. In animal models, RG consistently relieved HE symptoms by protecting blood-brain barrier permeability via downregulation of matrix metalloproteinase-9 (MMP-9) and upregulation of claudin-5. In addition, RG inhibited mRNA expression levels of both interleukin (IL)-1ß and transforming growth factor (TGF)-ß1. Based on our results, RG is expected to function various biochemical processes involving neuroinflammation, suggesting that RG may be considered a therapeutic agent for treating not only chronic liver disease but also HE.

Liquiritigenin inhibits hepatic fibrogenesis and TGF-ß1/Smad with Hippo/YAP signal.

BACKGROUND: Recent reports highlighted the possibility that Yes-associated protein (YAP) and transforming growth factor-ß1 (TGF-ß1) can act as critical regulators of hepatic stellate cells (HSCs) activation; therefore, it is natural for compounds targeting Hippo/YAP and TGF-ß1/Smad signaling pathways to be identified as potential anti-fibrotic candidates. PURPOSE: Liquiritigenin (LQ) is an aglycone of liquiritin and has been reported to protect the liver from injury. However, its effects on the Hippo/YAP and TGF-ß1/Smad pathways have not been identified to date. METHODS: We conducted a series of experiments using CCl4-induced fibrotic mice and cultured LX-2 cells. RESULT: LQ significantly inhibited liver fibrosis, as indicated by decreases in regions of hepatic degeneration, inflammatory cell infiltration, and the intensity of α-smooth muscle actin (α-SMA) staining in mice. Moreover, LQ blocked the TGF-ß1-induced phosphorylation of Smad 3, and the transcript levels of plasminogen activator inhibitor-1 (PAI-1) and matrix metalloproteinase-2 (MMP-2) in LX-2 cells, which is similar with resveratrol and oxyresveratrol (positive controls). Furthermore, LQ increased activation of large tumor suppressor kinase 1 (LATS1) with the induction of YAP phosphorylation, thereby preventing YAP transcriptional activity and suppressing the expression of exacerbated TGF-ß1/Smad signaling molecules. CONCLUSION: These results clearly show that LQ ameliorated experimental liver fibrosis by acting on the TGF-ß1/Smad and Hippo/YAP pathways, indicating that LQ has the potential for effective treatment of liver fibrosis.

Deoxypodophyllotoxin in Anthriscus sylvestris alleviates fat accumulation in the liver via AMP-activated protein kinase, impeding SREBP-1c signal.

Deoxypodophyllotoxin (DPT) is a naturally occurring flavolignan in Anthriscus sylvestris known as cow parsley or wild chervil, and has been reported to have inhibitory effects against several pathological processes including cancer, inflammation and infection. Here, we report the effects of DPT in the fatty liver induced by high fat diet in vivo as well as its regulatory mechanism related with the transcription factor for lipogenic genes such as sterol regulatory element binding protein-1c (SREBP-1c) in vitro. C57BL/6 mice were fed high fat diet for 10 weeks and also orally administrated with DPT for additional 4 weeks. 5 and 10 mg/kg of DPT decreased lipid accumulation in the liver induced by high fat diet, as indicated by histological parameters such as Oil Red O staining and hematoxylin & eosin as well as the contents of hepatic triglyceride and cholesterol. In hepatocytes, DPT inhibited the liver X receptor α-mediated SREBP-1c induction and expression of the lipogenic genes, including fatty acid synthase, acetyl-CoA carboxylase and stearoyl-CoA desaturase-1. Moreover, DPT induced AMP-activated protein kinase (AMPK) activation, which has been known to inhibit the expression of SREBP-1c in hepatocyte. Also this compound restored the dysregulation of AMPK and SREBP-1c induced by high fat diet in mice. In conclusion, we demonstrated that DPT significantly inhibited fatty liver by adjusting lipid metabolism coordinated with AMPK activation and SREBP-1c inhibition.

Oxyresveratrol ameliorates nonalcoholic fatty liver disease by regulating hepatic lipogenesis and fatty acid oxidation through liver kinase B1 and AMP-activated protein kinase.

Oxyresveratrol (OXY) is a naturally occurring polyhydroxylated stilbene that is abundant in mulberry wood (Morus alba L.), which has frequently been supplied as a herbal medicine. It has been shown that OXY has regulatory effects on inflammation and oxidative stress, and may have potential in preventing or curing nonalcoholic fatty liver disease (NAFLD). This study examined the effects of OXY on in vitro model of NAFLD in hepatocyte by the liver X receptor α (LXRα)-mediated induction of lipogenic genes and in vivo model in mice along with its molecular mechanism. OXY inhibited the LXRα agonists-mediated sterol regulatory element binding protein-1c (SREBP-1c) induction and expression of the lipogenic genes and upregulated the mRNA of fatty acid ß-oxidation-related genes in hepatocytes, which is more potent than genistein and daidzein. OXY also induced AMP-activated protein kinase (AMPK) activation in a time-dependent manner. Moreover, AMPK activation by the OXY treatment helped inhibit SREBP-1c using compound C as an AMPK antagonist. Oral administration of OXY decreased the Oil Red O stained-positive areas significantly, indicating lipid droplets and hepatic steatosis regions, as well as the serum parameters, such as fasting glucose, total cholesterol, and low density lipoprotein-cholesterol in high fat diet fed-mice, as similar with orally treatment of atorvastatin. Overall, this result suggests that OXY has the potency to inhibit hepatic lipogenesis through the AMPK/SREBP-1c pathway and can be used in the development of pharmaceuticals to prevent a fatty liver.

Fucoxanthin, the constituent of Laminaria japonica, triggers AMPK-mediated cytoprotection and autophagy in hepatocytes under oxidative stress.

BACKGROUND: Laminaria japonica has frequently been used as a food supplement and drug in traditional oriental medicine. Among the major active constituents responsible for the bioactivities of L. japonica, fucoxanthin (FX) has been considered as a potential antioxidant. This study was conducted to examine the effects of L. japonica extract (LJE) or FX against oxidative stress on hepatocytes and to elucidate the overall their cellular mechanisms of the effects. METHODS: We constructed an in vitro model with the treatment of arachidonic acid (AA) + iron in HepG2 cells to stimulate the oxidative damage. The cells were pre-treated with LJE or FX for 1 h, and incubated with AA + iron. The effect on oxidative damage and cellular mechanisms of LJE or FX were assessed by cytological examination and several biochemical assays under conditions with or without kinase inhibitiors. RESULTS: LJE or FX pretreatment effectively blocked the pathological changes caused by AA + iron treatment, such as cell death, altered expression of apoptosis-related proteins such as procaspase-3 and poly (ADP-ribose) polymerase, and mitochondria dysfunction. Moreover, FX induced AMPK activation and AMPK inhibitor, compound C, partially reduced the protective effect of FX on mitochondria dysfunction. Consistent with AMPK activation, FX increased the protein levels of autophagic markers (LC3II and beclin-1) and the number of acridine orange stained cells, and decreased the phosphorylation of mTOR and simultaneously increased the phosphorylation of ULK1. And the inhibition of autophagy by 3-methylanine or bafilomycin A1 partially inhibited the protective effect of FX on mitochondria dysfunction. CONCLUSION: These findings suggest that FX have the function of being a hepatic protectant against oxidative damages through the AMPK pathway for the control of autophagy.

Moutan Cortex Protects Hepatocytes against Oxidative Injury through AMP-Activated Protein Kinase Pathway.

Moutan Cortex, the root bark of Paeonia suffruticosa ANDREWS in Ranunculaceae, has widely demonstrated analgesic, anti-spasmodic, and anti-inflammatory effects in various cancer and immune cell lines. Oxidative stress is associated with development of several diseases, including liver disease. We prepared the water extract of Moutan Cortex (MCE) to investigate the cytoprotective activities and its mechanism. MCE protected hepatocytes from arachidonic acid (AA)+iron induced oxidative stress, as indicated by reactive oxygen species (ROS) production and cell viability analysis. MCE also suppressed mitochondrial dysfunction in AA+iron-treated human hepatocyte-derived hepatocellular carcinoma cell line, HepG2 cells. In addition, MCE treatment induces AMP-activated protein kinase (AMPK) and liver kinase B1 phosphorylation, which play a role in inhibition of oxidative stress induced cell death. Moreover, one of the MCE compounds, chlorogenic acid, exerted protective effects against oxidative stress and apoptosis. Taken together, MCE protected hepatocytes against AA+iron-induced oxidative stress through AMPK activation, and may be a candidate for the treatment of liver disease.

Liqustri lucidi Fructus inhibits hepatic injury and functions as an antioxidant by activation of AMP-activated protein kinase in vivo and in vitro.

Medicinal herbs are used to treat or prevent various diseases, and function to regulate protective mechanisms as nutraceuticals. Fructus Ligustri lucidi is the fruit of Ligustrum lucidum and has been used for its tonic effects on the liver. This study was designed to examine the effects of Fructus Ligustri lucidi water extract (FLL) against severe oxidative stress and mitochondrial impairment in vivo and in vitro and to elucidate its cellular mechanisms of action. Treatment of HepG2 cells with arachidonic acid (AA) + iron successfully induced oxidative stress and apoptosis, as indicated by depletion of glutathione, formation of ROS, decreses in mitochondrial membrane potential (Δψm), and altered expression of apoptosis-related proteins, such as procaspase-3 and Bcl-xL. FLL treatment significantly blocked these pathological changes and the mitochondrial dysfunction caused by AA + iron, which were similar with the effect of aminoimidazole-carboxamide-ß-d-ribofuranoside (AICAR). Moreover, FLL induced the activation of AMP-activated protein kinase (AMPK), which was mediated by its upstream kinase LKB1. Inhibition or activation of AMPK revealed the role of AMPK in cellular protection conferred by FLL in LKB1-deficient cells. In mice, oral administration of 100 mg/kg FLL activated AMPK in the liver, and protected against oxidative stress and liver injury induced by CCl4 injection. Among the components of FLL, chlorogenic acid was found to be responsible for the protection of hepatocytes against AA + iron-induced cellular damage. Overall, our results confirmed that FLL has the ability to protect hepatocytes against oxidative injury through regulation of the AMPK signaling pathway.