• BMB Reports
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• v.53 no.2
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• pp.100-105
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• 2020

While liver histopathology is heterogeneous in diabetes, the underlying mechanisms remain unclear. We investigated whether glycemic variation resulting from differential diets can induce heterogeneity in diabetic liver and the underlying molecular mechanisms. We generated end-stage non-obese diabetic model rats by subtotal-pancreatectomy in male Sprague-Dawley rats and ad libitum diet for 7 weeks (n = 33). The rats were then divided into three groups, and fed a standard- or a low-protein diet (18 or 6 kcal%, respectively), for another 7 weeks: to maintain hyperglycemia, 11 rats were fed ad libitum (18AL group); to achieve euglycemia, 11 were calorie-restricted (18R group), and 11 were both calorie- and protein-restricted with the low-protein diet (6R group). Overnight-fasted liver samples were collected after the differential diets together with sham-control (18S group), and histology and molecular changes were compared. Hyperglycemic-18AL showed glycogenic hepatopathy (GH) without steatosis, with the highest GSK-3β inactivation because of Akt activation during hyperglycemia; mitochondrial function was not impaired, compared to the 18S group. Euglycemic-18R showed neither GH nor steatosis, with intermediate GSK-3β activation and mitochondrial dysfunction. However, euglycemic-6R showed both GH and steatosis despite the highest GSK-3β activity and no molecular evidence of increased lipogenesis or decreased ApoB expression, where mitochondrial dysfunction was highest among the groups. In conclusion, heterogeneous liver histopathology developed in end-stage non-obese diabetic rats as the glycemic levels varied with differential diets, in which protein content in the diets as well as glycemic levels differentially influenced GSK-3β activity and mitochondrial function in insulin-deficient state.

• Biomolecules & Therapeutics
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• v.29 no.4
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• pp.419-426
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• 2021

In this study, we aimed to investigate the effects of 8 weeks of treatment with a combination of evogliptin and leucine, a branched-chain amino acid, in mice with high-fat diet (HFD)-induced diabetes. Treatment with evogliptin alone or in combination with leucine reduced the body weight of the mice, compared to the case for those from the HFD control group. Long-term treatment with evogliptin alone or in combination with leucine resulted in a significant reduction in glucose intolerance; however, leucine alone did not affect postprandial glucose control, compared to the case for the mice from the HFD control group. Furthermore, the combination of evogliptin and leucine prevented HFD-induced insulin resistance, which was associated with improved homeostasis model assessment for insulin resistance, accompanied by markedly reduced liver fat deposition, hepatic triglyceride content, and plasma alanine aminotransferase levels. The combination of evogliptin and leucine increased the gene expression levels of hepatic peroxisome proliferator-activated receptor alpha, whereas those of the sterol regulatory element-binding protein 1 and stearoyl-CoA desaturase 1 were not altered, compared to the case in the HFD-fed mice (p<0.05). Thus, our results suggest that the combination of evogliptin and leucine may be beneficial for treating patients with type 2 diabetes and hepatic steatosis; however, further studies are needed to delineate the molecular mechanisms underlying the action of this combination.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.11a
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• pp.134-134
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• 2004

• Experimental and Molecular Medicine
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• v.50 no.12
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• pp.2.1-2.12
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• 2018

Glucagon-like peptide-1 (GLP-1) has a broad spectrum of biological activity by regulating metabolic processes via both the direct activation of the class B family of G protein-coupled receptors and indirect nonreceptor-mediated pathways. GLP-1 receptor (GLP-1R) agonists have significant therapeutic effects on non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) in animal models. However, clinical studies indicated that GLP-1 treatment had little effect on hepatic steatosis in some NAFLD patients, suggesting that GLP-1 resistance may occur in these patients. It is well-known that the gut metabolite sodium butyrate (NaB) could promote GLP-1 secretion from intestinal L cells. However, it is unclear whether NaB improves hepatic GLP-1 responsiveness in NAFLD. In the current study, we showed that the serum GLP-1 levels of NAFLD patients were similar to those of normal controls, but hepatic GLP-1R expression was significantly downregulated in NAFLD patients. Similarly, in the NAFLD mouse model, mice fed with a high-fat diet showed reduced hepatic GLP-1R expression, which was reversed by NaB treatment and accompanied by markedly alleviated liver steatosis. In addition, NaB treatment also upregulated the hepatic p-AMPK/p-ACC and insulin receptor/insulin receptor substrate-1 expression levels. Furthermore, NaB-enhanced GLP-1R expression in HepG2 cells by inhibiting histone deacetylase-2 independent of GPR43/GPR109a. These results indicate that NaB is able to prevent the progression of NAFL to NASH via promoting hepatic GLP-1R expression. NaB is a GLP-1 sensitizer and represents a potential therapeutic adjuvant to prevent NAFL progression to NASH.

• Journal of Ginseng Research
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• v.43 no.2
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• pp.196-208
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• 2019

Background: Nonalcoholic steatohepatitis (NASH) is one of the chronic inflammatory liver diseases and a leading cause of advanced liver fibrosis, cirrhosis, and hepatocellular carcinoma. The main purpose of this study was to clarify the effects of GBCK25 fermented by Saccharomyces servazzii GB-07 and pectinase, on NASH severity in mice. Methods: Six-wk-old male mice were fed either a normal diet (ND) or a Western diet (WD) for 12 wks to induce NASH. Each group was orally administered with vehicle or GBCK25 once daily at a dose of 10 mg/kg, 20 mg/kg, 100 mg/kg, 200 mg/kg, or 400 mg/kg during that time. The effects of GBCK25 on cellular damage and inflammation were determined by in vitro experiments. Results: Histopathologic analysis and hepatic/serum biochemical levels revealed that WD-fed mice showed severe steatosis and liver injury compared to ND-fed mice. Such lesions were significantly decreased in the livers of WD-fed mice with GBCK25 administration. Consistently, mRNA expression levels of NASH-related inflammatory-, fibrogenic-, and lipid metabolism-related genes were decreased in the livers of WD-fed mice administered with GBCK25 compared to WD-fed mice. Western blot analysis revealed decreased protein levels of cytochrome P450 2E1 (CYP2E1) with concomitantly reduced activation of c-Jun N-terminal kinase (JNK) in the livers of WD-fed mice administered with GBCK25. Also, decreased cellular damage and inflammation were observed in alpha mouse liver 12 (AML12) cells and RAW264.7 cells, respectively. Conclusion: Administration of GBCK25 ameliorates NASH severity through the modulation of CYP2E1 and its associated JNK-mediated cellular damage. GBCK25 could be a potentially effective prophylactic strategy to prevent metabolic diseases including NASH.

• Biomedical Science Letters
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• v.16 no.1
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• pp.33-38
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• 2010

Culinary herbs and spices have received much attention since they contain high concentrations of bioactive ingredients for antioxidant and anti-inflammatory activities. Protection effect of the herb and spice against acute alcohol consumption has been investigated using zebrafish as a vertebrate model. During 30 days bathed in water containing 1% Et-OH and the designated herb or spice, the survival rate of the Et-OH group was decreased sharply (up to 20% at 10 days). The cinnamon-fed group showed the highest and longer survival rate up to 80% up to for 30 days under the presence of Et-OH, while clove-fed group showed 40% survival rate for 25 days. Et-OH group serum exhibited the weakest antioxidant ability from ferric ion removal ability (FRA) assay; FRA ability was increased in the cinnamon-fed group up to 414%, while the clove and laurel group increased 256% and 309%, respectively. Histologic observation and Oil-red O staining showed hepatic tissue damage was severe in the Et-OH group. The cinnamon- or clove-fed group showed much ameliorated hepatic tissue morphology with minimized steatosis. The cinnamon- or clove-fed group showed lower serum GOT and GPT levels than the Et-OH group. Among hepatic tissue extract, the clove-fed group exhibited the lowest level of GOT and GPT. These results suggest that consumption of cinnamon and clove might be beneficial to attenuate progress of acute fatty liver change by alcohol consumption.

• BMB Reports
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• v.51 no.5
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• pp.209-210
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• 2018

NAFLD induces the development of advanced liver diseases such as NASH and liver cancer. Therefore, understanding the mechanism of NAFLD development is critical for its prevention and treatment. Ablation of PTEN or Hippo pathway components induces liver cancer in a murine model by hyperactive AKT or YAP/TAZ, respectively. Although the regulation of these two pathways occurs in the same hepatocyte, the details of crosstalk between Hippo-YAP/TAZ and PTEN-AKT pathways in liver homeostasis and tumorigenesis still remain unclear. Here, we found that depletion of both PTEN and SAV1 in liver promotes spontaneous NAFLD and liver cancer through hyperactive AKT via YAP/TAZ-mediated up-regulation of IRS2 transcription. Conversely, NAFLD is rescued by both ablation of YAP/TAZ and activation of the Hippo pathway. Furthermore, human HCC patients with NAFLD showed strong correlation between YAP/TAZ and IRS2 or phospho-AKT expression. Finally, the inhibition of AKT by MK-2206 treatment attenuates NAFLD development and tumorigenesis. Our findings indicate that Hippo pathway interacts with AKT signaling during the intervention with IRS2 to prevent NAFLD and liver cancer.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.931-939
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• 2017

Alcoholic liver disease (ALD) is a complex multifaceted disease that involves oxidative stress and inflammation as the key mediators. Despite decades of intensive research, there are no FDA-approved therapies, and/or no effective cure is yet available. Probiotics have received increasing attention in the past few years due to their well-documented gastrointestinal health-promoting effects. Interestingly, emerging studies have suggested that certain probiotics may offer benefits beyond the gut. Lactobacillus fermentum LA12 has been previously demonstrated to play a role in inflammatory-related disease. However, the possible protective effect of L. fermentum LA12 on ALD still remain to be explored. Thus, the aim of this study was to evaluate the possible protective effect of L. fermentum LA12 on alcohol-induced gut barrier dysfunction and liver damage in a rat model of alcoholic steatohepatitis (ASH). Daily oral administration of L. fermentum LA12 in rat model of ASH for four weeks was shown to significantly reduced intestinal nitric oxide production and hyperpermeability. Moreover, small intestinal histological- and qRT-PCR analysis further revealed that L. fermentum LA12 treatment was capable of up-regulating the mRNA expression levels of tight junction proteins, thereby stimulating the restitution of barrier structure and function. Serum and hepatic analyses also revealed that the restoration of epithelial barrier function may prevent the leakage of endotoxin into the blood, subsequently improve liver function and hepatic steatosis in the L. fermentum LA12-treated rats. Altogether, results in this study suggest that L. fermentum LA12 may be used as a dietary adjunct for the prevention and treatment of ASH.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.5
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• pp.385-394
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• 2020

Eupatilin is known to possess anti-apoptotic, anti-oxidative, and anti-inflammatory properties. We report here that eupatilin has a protective effect on the ethanol-induced injury in rats. Sprague-Dawley rats were divided into 6 groups: control, vehicle, silymarin, eupatilin 10 mg/kg, eupatilin 30 mg/kg, and eupatilin 100 mg/kg. Plasma levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were analyzed to determine the extent of liver damage. Total cholesterol (TC) and triglycerides (TG) were analyzed to determine the level of liver steatosis. Malondialdehyde level, superoxide dismutase (SOD) activity, and glutathione (GSH) level were analyzed to determine the extent of oxidative stress. Tumor necrosis factor (TNF)-α and interleukin (IL)-1β were quantified to verify the degree of inflammation. Based on our findings, chronic alcohol treatment significantly changed the serum indexes and liver indicators of the model rats, which were significantly improved by eupatilin treatment. Rats in the eupatilin-treatment group showed reduced levels of AST, ALT, TG, TC, TNF-α, and IL-1β, increased SOD activity and GSH levels, and improved overall physiology compared to the alcoholic liver disease model rats. H&E staining also verified the eupatilin-mediated improvement in liver injury. In conclusion, eupatilin inhibits alcohol-induced liver injury via its antioxidant and anti-inflammatory effects.

• The Journal of Internal Korean Medicine
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• v.33 no.4
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• pp.438-447
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• 2012

Objectives : In this study, we investigated the effect and the underlying mechanism of ethanol extract of Benincasa seeds on a cellular model of non-alcoholic fatty liver disease (NAFLD) established by treating HepG2 cells with palmitate. Methods : We evaluated ethanol extract of Benincasa seeds (EEBS) for its hepatic lipid-lowering potential in fatty acid overloaded HepG2 cells. After incubation in palmitate containing media with or without EEBS, intracellular neutral lipid accumulations were quantified by Nile red staining. We also investigated the effect of EEBS on lipogenesis and ${\beta}$-oxidation. $LXR{\alpha}$-dependent SREBP-1c activation, expression of lipogenic genes, and expression of ${\beta}$-oxidation related genes were determined with or without pretreatment of EEBS. Results : EEBS significantly attenuated palmitate-induced intracellular neutral lipid accumulation in HepG2 cells. EEBS suppressed fatty acid synthesis by inhibiting $LXR{\alpha}$-dependent SREBP-1c activation. EEBS also repressed SREBP-1c mediated induction of lipogenic genes, including ACC, FAS, and SCD-1. However, EEBS had no effect on ${\beta}$-oxidation related CPT-1 and $PPAR{\alpha}$ gene expression. Conclusions : Our results suggest that EEBS has an efficacy to decrease hepatic lipid accumulation, and this effect was mediated by inhibiting the $LXR{\alpha}$-SREBP-1c pathway that leads to expression of lipogenic genes and hepatic steatosis. Therefore, the Benincasa seeds may have a potential clinical application for treatment of this chronic liver disease.