Methionine- And Choline-deficient Research Articles

Si-Wei-Qing-Gan-Tang Improves Non-Alcoholic Steatohepatitis by Modulating the Nuclear Factor-κB Signal Pathway and Autophagy in Methionine and Choline Deficient Diet-Fed Rats.

Si-Wei-Qing-Gan-Tang (SWQGT) is a Chinese medicine formula that is widely used as a folk remedy of herbal tea for the treatment of chronic hepatitis, like non-alcoholic steatohepatitis (NASH), around Ganzhou City (Jiangxi province, China). However, the underlying mechanisms of this formula against NASH are still unknown. This study aimed to explore the effect and mechanisms of SWQGT against NASH. A network pharmacology approach was used to predict the potential mechanisms of SWQGT against NASH. Then a rat model of NASH established by feeding the methionine and choline deficient (MCD) diet was used to verify the effect and mechanisms of SWQGT on NASH in vivo. SWQGT (1 g/kg/d and 3 g/kg/d) were given by intragastric administration. Body weight, liver weight, serum biochemical indicators, liver triglyceride and total cholesterol were all measured. Tumor necrosis factor-α (TNF-α), Interleukin (IL)-1β, IL-6 levels in the livers were evaluated using ELISA. Hematoxylin and eosin (HE) and Oil Red O staining were used to determine histology, while western blot was used to assess the relative expression levels of the nuclear factor-κB (NF-κB) pathway- and autophagy-related proteins. Functional and pathway enrichment analyses revealed that SWQGT obviously influenced inflammation-related signal pathways in NASH. Furthermore, in vivo experiment showed that SWQGT caused a reduction in liver weight and liver index of MCD diet-fed rats. The formula also helped to reduce hepatomegaly and improve pathological liver changes and hepatic steatosis. SWQGT likewise reduced liver TNF-α, IL-1β, and IL-6 levels and down-regulated p-NF-κB p65, p-p38 MAPK, p-MEK1/2, p-ERK1/2, p-mTOR, and p62, while up-regulating p-ULK1 and LC3II protein expression levels. SWQGT could improve NASH in MCD diet-fed rats, and this effect may be associated with its down-regulation of NF-κB and activation of autophagy.

Loss of Hepatocyte-Specific PPARγ Expression Ameliorates Early Events of Steatohepatitis in Mice Fed the Methionine and Choline-Deficient Diet.

The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing worldwide. To date, there is not a specific and approved treatment for NAFLD yet, and therefore, it is important to understand the molecular mechanisms that lead to the progression of NAFLD. Methionine- and choline-deficient (MCD) diets are used to reproduce some features of NAFLD in mice. MCD diets increase the expression of hepatic peroxisome proliferator-activated receptor gamma (PPARγ, Pparg) and the fatty acid translocase (CD36, Cd36) which could increase hepatic fatty acid uptake and promote the progression of NAFLD in mice and humans. In this study, we assessed the contribution of hepatocyte-specific PPARγ and CD36 expression to the development of early events induced by the MCD diet. Specifically, mice with adult-onset, hepatocyte-specific PPARγ knockout with and without hepatocyte CD36 overexpression were fed a MCD diet for three weeks. Hepatocyte PPARγ and/or CD36 expression did not contribute to the development of steatosis induced by the MCD diet. However, the expression of inflammatory and fibrogenic genes seems to be dependent on the expression of hepatocyte PPARγ and CD36. The expression of PPARγ and CD36 in hepatocytes may be relevant in the regulation of some features of NAFLD and steatohepatitis.

L-Selectin/CD62L is a Key Driver of Non-Alcoholic Steatohepatitis in Mice and Men.

CD62L (L-Selectin) dependent lymphocyte infiltration is known to induce inflammatory bowel disease (IBD), while its function in the liver, especially in non-alcoholic steatohepatitis (NASH), remains unclear. We here investigated the functional role of CD62L in NASH in humans as well as in two mouse models of steatohepatitis. Hepatic expression of a soluble form of CD62L (sCD62L) was measured in patients with steatosis and NASH. Furthermore, CD62L−/− mice were fed with a methionine and choline deficient (MCD) diet for 4 weeks or with a high fat diet (HFD) for 24 weeks. Patients with NASH displayed increased serum levels of sCD62L. Hepatic CD62L expression was higher in patients with steatosis and increased dramatically in NASH patients. Interestingly, compared to wild type (WT) mice, MCD and HFD-treated CD62L−/− mice were protected from diet-induced steatohepatitis. This was reflected by less fat accumulation in hepatocytes and a dampened manifestation of the metabolic syndrome with an improved insulin resistance and decreased cholesterol and triglyceride levels. Consistent with ameliorated disease, CD62L−/− animals exhibited an enhanced hepatic infiltration of Treg cells and a strong activation of an anti-oxidative stress response. Those changes finally resulted in less fibrosis in CD62L−/− mice. Additionally, this effect could be reproduced in a therapeutic setting by administrating an anti-CD62L blocking antibody. CD62L expression in humans and mice correlates with disease activity of steatohepatitis. CD62L knockout and anti-CD62L-treated mice are protected from diet-induced steatohepatitis suggesting that CD62L is a promising target for therapeutic interventions in NASH.

Lemon Balm and Its Constituent, Rosmarinic Acid, Alleviate Liver Damage in an Animal Model of Nonalcoholic Steatohepatitis.

Nonalcoholic fatty liver disease (NAFLD) ranges in severity from hepatic steatosis to cirrhosis. Lemon balm and its major constituent, rosmarinic acid (RA), effectively improve the liver injury and obesity; however, their therapeutic effects on nonalcoholic steatohepatitis (NASH) are unknown. In this study, we investigated the effects of RA and a lemon balm extract (LBE) on NAFLD and liver fibrosis and elucidated their mechanisms. Palmitic acid (PA)-exposed HepG2 cells and db/db mice fed a methionine- and choline-deficient (MCD) diet were utilized to exhibit symptoms of human NASH. LBE and RA treatments alleviated the oxidative stress by increasing antioxidant enzymes and modulated lipid metabolism-related gene expression by the activation of adenosine monophosphate-activated protein kinase (AMPK) in vitro and in vivo. LBE and RA treatments inhibited the expression of genes involved in hepatic fibrosis and inflammation in vitro and in vivo. Together, LBE and RA could improve liver damage by non-alcoholic lipid accumulation and may be promising medications to treat NASH.

Analysis of piRNA expression spectra in a non-alcoholic fatty liver disease mouse model induced by a methionine- and choline-deficient diet.

Non-alcoholic fatty liver disease (NAFLD) has become a common health issue worldwide, and P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) have been shown to be differentially expressed in a variety of diseases. The aim of the present study was to investigate the potential relationship between piRNA and NAFLD. A NAFLD mouse model was established using a methionine- and choline-deficient (MCD) diet and methionine- and choline-sufficient (MCS) diet. Following this, mouse liver tissues were removed and stained with hematoxylin and eosin, and the levels of alanine aminotransferase, aspartate aminotransferase, total cholesterol and triglyceride were measured. Moreover, the liver tissues of the control and model groups were selected for piRNA gene chip analysis to identify piRNAs with differential expression in NAFLD. In addition, the differentially expressed piRNAs screened from the microarray were assessed by reverse transcription-quantitative PCR (RT-qPCR). piRNAs with potential research value were also selected for further analysis of target genes, using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. The present study identified a total of 1,285 piRNAs with differential expression levels. The results indicated that in the model group, 641 piRNAs were upregulated, while 644 piRNAs were downregulated. Furthermore, piRNAs were enriched in ‘cancer’, ‘Hippo signaling’, ‘Wnt signaling’ and ‘Mitogen-activated protein kinase signaling’ pathways. The RT-qPCR results demonstrated that piRNA DQ566704 and piRNA DQ723301 were significantly upregulated in the model group, which was largely consistent with the analysis results of the piRNA arrays. Therefore, the results of the piRNA arrays and the further analyses in the present study were considered reliable. Collectively, the present results suggest that differentially expressed piRNAs exist in NAFLD and may affect the development of NAFLD via related pathways.

Altered Cisplatin Pharmacokinetics during Nonalcoholic Steatohepatitis Contributes to Reduced Nephrotoxicity

Cisplatin is an alkylating antineoplastic agent that is indicated for the treatment of solid malignancies. Cisplatin is preferentially eliminated from systemic circulation via tubular secretion, whereby it exhibits dose‐limiting nephrotoxicity. Interindividual variability in xenobiotic transporter expression is a known contributor to differential cisplatin toxicity and efficacy, and may be the result of genetic, environmental, and pathological contributions. In this study, we aimed to determine if nonalcoholic steatohepatitis (NASH) alters cisplatin pharmacokinetics and if this change elicits differential nephrotoxicity. Sprague Dawley rats fed a control or methionine and choline deficient (MCD) diet to model NASH were given a single bolus dose of cisplatin and sacrificed after 72 h. The MCD diet resulted in a NASH hepatic phenotype that remained unchanged following cisplatin exposure. Drug‐naïve NASH rats also displayed no evidence of differential renal pathology relative to control rats. However, renal necrosis and inflammation were reduced in NASH by 40 and 63% following cisplatin treatment, respectively, relative to healthy controls. Furthermore, kidney weights of cisplatin‐treated control rats were increased by 31%, compared to an 18% increase in NASH. Plasma cisplatin clearance was reduced from 6.78 (control) to 4.04 mL/min in NASH, and cisplatin plasma AUC was significantly increased by 44% in NASH, relative to control. Cumulative urinary elimination of cisplatin was decreased from 73 to 34% of total dose and renal clearance was reduced from 4.64 to 1.49 mL/min in NASH, compared to control. Subsequently, renal intracellular accumulation of cisplatin after 6 h was reduced by 34% in NASH, relative to control. Supporting these findings, expression of proximal tubule cisplatin uptake transporters, Ctr1 and Ctr2, were reduced by 24 and 64%, respectively compared to healthy control rats, whereas expression of Oct1, Oct2, and Oct3 were unchanged. Interestingly, expression of cisplatin efflux transporters Mate1 and Atp7a were reduced by 52 and 31%, respectively, in NASH compared to control. Taken together, these data suggest that NASH alters renal uptake and efflux transporter expression, thereby attenuating cisplatin uptake and clearance in the kidney with a corresponding reduction in renal cell exposure and nephrotoxicity during NASH. As such, this study demonstrates that NASH can influence pharmacokinetics of drugs cleared by renal elimination, which may contribute to adverse drug reactions.Support or Funding InformationThis work is supported by a NIH grant [R01 ES028668] and the Southwest Environmental Health Sciences Center [P30 ES006694]. JLJ is supported by an institutional training grant [T32 ES007091].

Impact of global PTP1B deficiency on the gut barrier permeability during NASH in mice

ObjectiveNon-alcoholic steatohepatitis (NASH) is characterized by a robust pro-inflammatory component at both hepatic and systemic levels together with a disease-specific gut microbiome signature. Protein tyrosine phosphatase 1 B (PTP1B) plays distinct roles in non-immune and immune cells, in the latter inhibiting pro-inflammatory signaling cascades. In this study, we have explored the role of PTP1B in the composition of gut microbiota and gut barrier dynamics in methionine and choline-deficient (MCD) diet-induced NASH in mice. MethodsGut features and barrier permeability were characterized in wild-type (PTP1B WT) and PTP1B-deficient knockout (PTP1B KO) mice fed a chow or methionine/choline-deficient (MCD) diet for 4 weeks. The impact of inflammation was studied in intestinal epithelial and enteroendocrine cells. The secretion of GLP-1 was evaluated in primary colonic cultures and plasma of mice. ResultsWe found that a shift in the gut microbiota shape, disruption of gut barrier function, higher levels of serum bile acids, and decreased circulating glucagon-like peptide (GLP)-1 are features during NASH. Surprisingly, despite the pro-inflammatory phenotype of global PTP1B-deficient mice, they were partly protected against the alterations in gut microbiota composition during NASH and presented better gut barrier integrity and less permeability under this pathological condition. These effects concurred with higher colonic mucosal inflammation, decreased serum bile acids, and protection against the decrease in circulating GLP-1 levels during NASH compared with their WT counterparts together with increased expression of GLP-2-sensitive genes in the gut. At the molecular level, stimulation of enteroendocrine STC-1 cells with a pro-inflammatory conditioned medium (CM) from lipopolysaccharide (LPS)-stimulated macrophages triggered pro-inflammatory signaling cascades that were further exacerbated by a PTP1B inhibitor. Likewise, the pro-inflammatory CM induced GLP-1 secretion in primary colonic cultures, an effect augmented by PTP1B inhibition. ConclusionAltogether our results have unraveled a potential role of PTP1B in the gut–liver axis during NASH, likely mediated by increased sensitivity to GLPs, with potential therapeutic value.

Placental extract ameliorates liver fibrosis in a methionine- and choline-deficient diet-induced mouse model of non-alcoholic steatohepatitis.

Non-alcoholic steatohepatitis (NASH) is a severe form of fatty liver disease that is defined by the presence of inflammation and fibrosis, which ultimately leads to cirrhosis and hepatocellular carcinoma. We previously showed that human placental extract (hPE) was intramuscularly injected to ameliorates liver injury in a methionine- and choline-deficient (MCD) diet-induced NASH model. In the present study, we investigated the effects of hPE using dB/dB mice which exhibit obesity and insulin resistance and are thought to reproduce the pathological background of NASH. The MCD-diet induced liver atrophy accompanied by fibrosis around the liver sinusoids. hPE dose-dependently reduced the perivascular fibrosis. Moreover, αSMA-positive activated hepatic stellate cells increased in number in mice on the MCD diet, with this effect reversed by hPE treatment. hPE significantly decreased expression of Acta2, Col1a1, and Tgfb1 genes in hepatic stellate cells, and inhibited Smad phosphorylation. Moreover, hPE treatment increased the expression of the anti-oxidative genes Hmox1, Nqo1, Cat, and Sod1, and significantly enhanced nuclear factor erythroid 2-related factor 2 activity. Furthermore, hPE decreased the expression of Nox4 and attenuated the levels of intracellular reactive oxygen species. These results, along with our previous study, suggest that hPE effectively ameliorates liver fibrosis in NASH. This beneficial effect may, in part, be due to suppression of hepatic stellate cell activation.

Antagonizing circRNA_002581\u2013miR-122\u2013CPEB1 axis alleviates NASH through restoring PTEN\u2013AMPK\u2013mTOR pathway regulated autophagy

Circular RNAs (circRNAs) have been shown to play critical roles in cancer biology, but their functions in nonalcoholic steatohepatitis (NASH) remain unexplored. Full length of circRNA_002581 was amplified and sequenced, followed by RNA immunoprecipitation, RNA-Fluorescence in Situ Hybridization and dual luciferase reporter gene analysis to confirm the existence of the circRNA_002581–miR-122–CPEB1 regulatory axis in vitro. CircRNA_002581 knockdown was used to study its roles in high concentration of free fatty acids-induced NASH-like cell model and a methionine and choline deficiency (MCD) diet-induced NASH mice model. Autophagy flux and related potential PTEN–AMPK–mTOR pathway were tested by western blot. CircRNA_002581 overexpression significantly relieved the inhibitory role of miR-122 on its target CPEB1 by sponging miR-122. CircRNA_002581 knockdown markedly attenuated lipid droplet accumulation, reduced the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), pro-inflammatory cytokines, apoptosis, H2O2, and increased ATP level in both mice and cellular models of NASH. Mechanistically, circRNA_002581 interference significantly rescue the defective autophagy evidenced by increased autophagosome number, upregulated LC3-II/I level, and decreased p62 level. Further chloroquine-mediated total autophagy inhibition antagonizes the protective effect of circRNA_002581 knockdown. Finally, CPEB1–PTEN–AMPK–mTOR pathway is shown to link the autophagy and circRNA_002581 knockdown-mediated NASH alleviation. CircRNA_002581–miR-122–CPEB1 axis actively participates in the pathogenesis of NASH through PTEN–AMPK–mTOR pathway-related autophagy suppression. Targeting circRNA_002581 is a potential therapeutic strategy for NASH through partial autophagy restoration.

Mapping of fatty acid composition with free-breathing MR spectroscopic imaging and compressed sensing.

Nonalcoholic fatty liver disease (NAFLD) is a growing health problem, and a major challenge in NAFLD management is identifying which patients are at risk of progression to more serious disease. Simple measurements of liver fat content are not strong predictors of clinical outcome, but biomarkers related to fatty acid composition (ie, saturated vs. unsaturated fat) may be more effective. MR spectroscopic imaging (MRSI) methods allow spatially resolved, whole‐liver measurements of chemical composition but are traditionally limited by slow acquisition times. In this work we present an accelerated MRSI acquisition based on spin echo single point imaging (SE‐SPI), which, using appropriate sampling and compressed sensing reconstruction, allows free‐breathing acquisition in a mouse model of fatty liver disease. After validating the technique's performance in oil/water phantoms, we imaged mice that had received a normal diet or a methionine and choline deficient (MCD) diet, some of which also received supplemental injections of iron to mimic hepatic iron overload. SE‐SPI was more resistant to the line‐broadening effects of iron than single‐voxel spectroscopy measurements, and was consistently able to measure the amplitudes of low‐intensity spectral peaks that are important to characterizing fatty acid composition. In particular, in the mice receiving the MCD diet, SE‐SPI showed a significant decrease in a metric associated with unsaturated fat, which is consistent with the literature. This or other related metrics may therefore offer more a specific biomarker of liver health than fat content alone. This preclinical study is an important precursor to clinical testing of the proposed method.MR‐based quantification of fatty acid composition may allow for improved characterization of non‐alcoholic fatty liver disease. A spectroscopic imaging method with appropriate sampling strategy allows whole‐liver mapping of fat composition metrics in a free‐breathing mouse model. Changes in metrics like the surrogate unsaturation index (UIs) are visible in mice receiving a diet which induces fat accumulation in the liver, as compared to a normal diet; such metrics may prove useful in future clinical studies of liver disease.

Si‐Wu‐Tang Alleviates Nonalcoholic Fatty Liver Disease via Blocking TLR4‐JNK and Caspase‐8‐GSDMD Signaling Pathways

Background Nonalcoholic fatty liver disease (NAFLD) has high global prevalence; however, the treatments of NAFLD are limited due to lack of approved drugs. Methods Mice were randomly assigned into three groups: Control group, NAFLD group, NAFLD plus Si-Wu-Tang group. A NAFLD mice model was established by feeding with a methionine- and choline-deficient (MCD) diet for four weeks. Si-Wu-Tang was given orally by gastric gavage at the beginning of 3rd week, and it lasted for two weeks. The treatment effects of Si-Wu-Tang were confirmed by examining the change of body weight, serum alanine aminotransferase (ALT) and aspartate transaminase (AST) levels, Oil Red O staining, and hematoxylin and eosin (H&E) staining of the liver samples and accompanied by steatosis grade scores. The expression and activation of the possible signaling proteins involved in the pathogenesis of NAFLD were determined by western blotting. Results Mice fed with four weeks of MCD diet displayed elevated serum levels of ALT and AST, while there was decreased body weight. The hepatic Oil Red O staining and H&E staining showed severe liver steatosis with high steatosis grade scores. All these can be improved by treating with Si-Wu-Tang for two weeks. Mechanistically, the increased hepatic TLR4 expression and its downstream JNK phosphorylation induced by MCD diet were suppressed by Si-Wu-Tang. Moreover, the upregulations of Caspase-8, gasdermin D (GSDMD), and cleaved-GSDMD in liver mediated by MCD diet were all inhibited by Si-Wu-Tang. Conclusions Treatment with Si-Wu-Tang improves MCD diet-induced NAFLD in part via blocking TLR4-JNK and Caspase-8-GSDMD signaling pathways, suggesting that Si-Wu-Tang has potential for clinical application in treating NAFLD.

Interaction of Oatp1b2 expression and nonalcoholic steatohepatitis on pravastatin plasma clearance

The downregulation of hepatic uptake transporters, including those of the OATP family, are a well known consequence of nonalcoholic steatohepatitis (NASH). Prior studies have shown that the combination of NASH and Oatp1b2 knockout synergistically reduces the clearance of pravastatin (PRAV) in the methionine and choline deficient (MCD) mouse model of NASH, and the current study therefore aimed to determine the impact of NASH and genetic heterozygosity of Oatp1b2 on PRAV clearance, modeling the overlap between the 24% of the human population who are heterozygous for non-functioning OATP1B1, and the ~15% with NASH, potentially placing these people at higher risk of statin-induced myopathy. Therefore, male C57BL/6 wild-type (WT), Oatp1b2+/− (HET), and Oatp1b2−/− (KO) mice were fed either a control (methionine and choline sufficient) or methionine and choline-deficient (MCD) diet to induce NASH. After six weeks of feeding, pravastatin was administered via the carotid artery. Blood and bile samples were collected throughout 90 min after PRAV administration. The concentration of PRAV in plasma, bile, liver, kidney, and muscle was determined by liquid chromatography-tandem mass spectrometry. MCD diet did not alter the plasma AUC values of PRAV in either WT or HET mice. However, the MCD diet increased plasma AUC by 4.4-fold in KO mice. MCD diet and nonfunctional Oatp1b2 synergistically increased not only plasma AUC but also the extrahepatic tissue concentration of pravastatin, whereas the partially decreased function of Oatp1b2 and NASH together were insufficient in significantly altering PRAV pharmacokinetics. These data suggest that a single copy of fully functional OATP1B1 in NASH patients may be sufficient to avoid the increase of pravastatin toxicity.

Acupuncture on ST36, CV4 and KI1 Suppresses the Progression of Methionine- and Choline-Deficient Diet-Induced Nonalcoholic Fatty Liver Disease in Mice.

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide, and its treatment remain a constant challenge. A number of clinical trials have shown that acupuncture treatment has beneficial effects for patients with NAFLD, but the molecular mechanisms underlying its action are still largely unknown. In this study, we established a mouse model of NAFLD by administering a methionine- and choline-deficient (MCD) diet and selected three acupoints (ST36, CV4, and KI1) or nonacupoints (sham) for needling. We then investigated the effects of acupuncture treatment on the progression of NAFLD and the underlying mechanisms. After two weeks of acupuncture treatment, the liver in the needling-nonapcupoint group (NG) mice appeared pale and yellowish in color, while that in the needling-acupoint group (AG) showed a bright red color. Histologically, fewer lipid droplets and inflammatory foci were observed in the AG liver than in the NG liver. Furthermore, the expression of proinflammatory signaling factors was significantly downregulated in the AG liver. A lipid analysis showed that the levels of triglyceride (TG) and free fatty acid (FFA) were lower in the AG liver than in the NG liver, with an altered expression of lipid metabolism-related factors as well. Moreover, the numbers of 8-hydroxy-2′-deoxyguanosine (8-OHdG)-positive hepatocytes and levels of hepatic thiobarbituric acid reactive substances (TBARS) were significantly lower in AG mice than in NG mice. In line with these results, a higher expressions of antioxidant factors was found in the AG liver than in the NG liver. Our results indicate that acupuncture repressed the progression of NAFLD by inhibiting inflammatory reactions, reducing oxidative stress, and promoting lipid metabolism of hepatocytes, suggesting that this approach might be an important complementary treatment for NAFLD.

Curcumin Ameliorates Nonalcoholic Fatty Liver Disease through Inhibition of O-GlcNAcylation.

The cause of progression to non-alcoholic fatty liver disease (NAFLD) is not fully understood. In the present study, we aimed to investigate how curcumin, a natural phytopolyphenol pigment, ameliorates NAFLD. Initially, we demonstrated that curcumin dramatically suppresses fat accumulation and hepatic injury induced in methionine and choline-deficient (MCD) diet mice. The severity of hepatic inflammation was alleviated by curcumin treatment. To identify the proteins involved in the pathogenesis of NAFLD, we also characterized the hepatic proteome in MCD diet mice. As a result of two-dimensional proteomic analysis, it was confirmed that thirteen proteins including antioxidant protein were differentially expressed in hepatic steatosis. However, the difference in expression was markedly improved by curcumin treatment. Interestingly, eight of the identified proteins are known to undergo O-GlcNAcylation modification. Thus, we further focused on elucidating how the regulation of O-linked β-N-acetylglucosamine (O-GlcNAc) modification is associated with the progression of hepatic steatosis leading to hepatitis in MCD diet mice. In parallel with lipid accumulation and inflammation, the MCD diet significantly up-regulated hexosamine biosynthetic pathway (HBP) and O-GlcNAc transferase (OGT) via ER stress. Curcumin treatment alleviates the severity of hepatic steatosis by relieving the dependence of O-GlcNAcylation on nuclear factor-κB (NF-κB) in inflammation signaling. Conversely, the expressions of superoxide dismutase 1 (SOD1) and SIRT1 were significantly upregulated by curcumin treatment. In conclusion, curcumin inhibits O-GlcNAcylation pathway, leading to antioxidant responses in non-alcoholic steatohepatitis (NASH) mice. Therefore, curcumin will be a promising therapeutic agent for diseases involving hyper-O-GlcNAcylation, including cancer.

Gynura procumbens aqueous extract alleviates nonalcoholic steatohepatitis through CFLAR-JNK pathway in vivo and in vitro

ObjectiveThe present work was to investigate the protective effects of the aqueous extract of Gynura procumbens (GPAE) against nonalcoholic steatohepatitis (NASH) in mice and NCTC-1469 cells. MethodsC57BL/6J mice were fed with methionine and choline-deficient (MCD) diet and administered simultaneously with GPAE (500 and 1000 mg/kg/d, respectively) by gavage for six weeks. The biomarkers of NASH in serum and liver were determined. NCTC-1469 cells were pretreated with 0.25 mmol/L palmitic acid (PA) plus 0.5 mmol/L oleic acid (OA) for 24 h or treated with adenovirus expressing short-hairpin RNA against CFLAR (Ad-shCFLAR) for 24 h and then treated with GPAE (80 and 160 µg/mL, respectively) for 24 h, and the content of cellular biomarkers of NASH was detected. ResultsIn mice treated with MCD, GPAE could decrease the levels of serum ALT, AST, the content of hepatic TG, TC and MDA, repress the activities and protein expression of CYP2E1 and CYP4A and the phosphorylation of JNK, increase the activities of HO-1, CAT and GSH-Px, up-regulate the mRNA expression of PPARα, FABP5, CPT1α, ACOX, SCD-1, mGPAT, MTTP and the protein expression of CFLAR and NRF2. In NCTC-1469 cells treated with PA and OA, GPAE could decrease the content of cellular TG and ROS, promote the uptake of 2-NBDG, up-regulate the protein expression of CFLAR and NRF2. In NCTC-1469 cells treated with Ad-shCFLAR, GPAE up-regulated the mRNA and protein expression of CFLAR, down-regulated the phosphorylation of JNK, and increased the protein expression of NRF2 and pIRS1. ConclusionThese results indicated that the activation on CFLAR-JNK pathway might be the main anti-NASH mechanism of GPAE, which on the one hand promote the β-oxidation and efflux of fatty acids in liver, and finally reduce hepatic lipid accumulation, on the other hand increase the activities of anti-oxidant enzymes and inhibit the activities of ROS generation enzymes by activating NRF2, and therefore attenuates hepatic oxidative stress damage.

Fermented black radish (Raphanus sativus L. var. niger) attenuates methionine and choline deficient diet-induced nonalcoholic fatty liver disease in mice.

As one of the wide‐ranging form of chronic liver disease, there are only limited therapeutic options for nonalcoholic fatty liver disease (NAFLD). We evaluated whether fermented black radish (Raphanus sativus L. var. niger; FBR) ameliorates lipid accumulation, inflammation, and hepatic fibrosis, which are characteristics of the pathogenesis of NAFLD. Fermented black radish treatment reduced lipid accumulation in 3T3‐L1 adipocytes, which appeared to be associated with the downregulation of adipogenic transcription factors, including sterol regulatory element‐binding protein 1c, CCAAT/enhancer‐binding protein α, peroxisome proliferator‐activated receptor γ, and lipid accumulation‐related genes including adipocyte protein‐2 and fatty acid synthase. Administration of FBR to C57BL/6J mice challenged with methionine and choline deficient (MCD) diet significantly attenuated the increased serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and triglyceride. In addition, treatment with FBR interestingly repressed the hepatic inflammation induced with MCD diet, by lowering the expression of inducible nitric oxide synthase and suppressing the inactivation of macrophages and Kupffer cells in the liver. Fermented black radish was also shown to mitigate liver fibrosis through the inhibition of alpha‐smooth muscle actin, transforming growth factor beta‐1, and collagen type I alpha 1 chain. Our results indicate that FBR ameliorates NAFLD and its related metabolic disease by regulating multiple pathways, suggesting that FBR may be an effective dietary supplement for ameliorating NAFLD.

Scoparone alleviates inflammation, apoptosis and fibrosis of non-alcoholic steatohepatitis by suppressing the TLR4/NF-κB signaling pathway in mice

Scoparone, a naturally-occurring, bioactive compound isolated from the Chinese herb Artemisia capillaria, has been shown to ameliorate hepatotoxicity and cholestasis in liver diseases. However, the pharmacological effect of scoparone in non-alcoholic steatohepatitis (NASH) has not been elucidated. In this study, we investigated the protective effects and mechanisms of scoparone in NASH. In vivo, the NASH model was established in mice fed a methionine and choline-deficient (MCD) diet for 4weeks, with or without simultaneous scoparone treatment. In vitro, RAW264.7 cells induced by lipopolysaccharide (LPS) were pretreated with or without different concentrations of scoparone. Hepatic triglycerides and serum AST and ALT levels were examined by biochemical assays. Hepatic histology was assessed by H&E, oil red O and Masson's trichrome staining methods, which were applied to analyze the protective effects of scoparone in NASH. To further explore the underlying mechanism of scoparone, immunohistochemistry, TUNEL, qRT-PCR, and Western blotting assays were applied to liver tissue or LPS-induced RAW264.7 cells. We found that scoparone can effectively improve hepatic steatosis, apoptosis, inflammation, and fibrosis in an MCD diet-induced NASH murine model. Mechanistically, we demonstrated that scoparone treatment alleviates NASH- and lipopolysaccharide (LPS)-induced immune responses in macrophages partly by blocking TLR-4/NF-κB signaling in a dose-dependent manner. Taken together, our results present the potential protective effects and mechanism of scoparone in NASH, suggesting a potentially beneficial drug treatment for NASH.

Sub-Chronic Microcystin-LR Liver Toxicity in Preexisting Diet-Induced Nonalcoholic Steatohepatitis in Rats.

Microcystin-LR (MCLR) is a hepatotoxic cyanotoxin reported to cause a phenotype similar to nonalcoholic steatohepatitis (NASH). NASH is a common progressive liver disease that advances in severity due to exogenous stressors such as poor diet and toxicant exposure. Our objective was to determine how sub-chronic MCLR toxicity affects preexisting diet-induced NASH. Sprague-Dawley rats were fed one of three diets for 10 weeks: control, methionine and choline deficient (MCD), or high fat/high cholesterol (HFHC). After six weeks of diet, animals received vehicle, 10 µg/kg, or 30 µg/kg MCLR via intraperitoneal injection every other day for the final 4 weeks. Incidence and severity scoring of histopathology endpoints suggested that MCLR toxicity drove NASH to a less fatty and more fibrotic state. In general, expression of genes involved in de novo lipogenesis and fatty acid esterification were altered in favor of decreased steatosis. The higher MCLR dose increased expression of genes involved in fibrosis and inflammation in the control and HFHC groups. These data suggest MCLR toxicity in the context of preexisting NASH may drive the liver to a more severe phenotype that resembles burnt-out NASH.

Lemon Balm Extract and Its Major Chemical Compound, Rosmarinic Acid, Alleviate Damages of Liver in an Animal Model of Nonalcoholic Steatohepatitis (NASH) (P06-093-19)

ObjectivesThe non-alcoholic fatty liver disease (NAFLD) comprises the broad histopathological states of liver, that ranging from asymptomatic hepatic steatosis to non-alcoholic steatohepatitis (NASH) and liver cirrhosis. In some studies, they suppose that almost 25–30% of world population is underlying NAFLD. Lemon balm (Melissa officinalis) is the herb that has some traditional medicinal usages. Also rosmarinic acid (RA; O-caffeoyl-3,4-dihydroxyphenyl lactic acid), the major chemical compound of lemon balm, already reported that it has the potency on anti-obesity and -inflammatory. Hence, we evaluate the whether lemon balm extract (LBE) and RA could suppress the pathogenesis of NASH using an in vitro and in vivo model. MethodsIn vitro model: The palmitic acid (PA) exposed HepG2 hepatocellular carcinoma cells can imitate the lipid accumulation in hepatocytes. PA exposed HepG2 cells were exposed with or without LBE or RA.In vivo model: The methionine- and choline-deficient (MCD) diet fed db/db C57BL/6 J mice model was used. This model is known as it can mimic well symptoms of human NAFLD. The LBE or RA were treated by oral gavage. ResultsWith the MCD diet only, the severe liver damage was caused by progression of NASH in animal model. LBE and RA treatments alleviated the oxidative stress in the MCD diet-fed db/db mice and PA-exposed HepG2 cells by increasing the expression of antioxidant enzymes (NRF2, SOD) and augmented lipolysis-related gene (PPARα, PGC-1α, CPT-1 L) expression. In addition, LBE and RA treatments inhibited the expression of genes involved in hepatic fibrosis (α-SMA, COL1A1) and fatty acid synthesis (SREBP-1c, CPT-1 L) and activated AMP-activated protein kinase in vitro and in vivo. Also, the histopathological results were ameliorated by treatment of LBE or RA. ConclusionsLBE and RA modulate lipid metabolism via AMPK activation and suppress inflammation via changes in NRF2 and NF-κB signalling. Importantly, the extract of lemon balm obtained with 20% EtOH showed effectiveness similar to that of RA at high concentrations. Therefore, LBE may be a good candidate for the treatment and prevention of NASH. Funding SourcesThis work was supported by the National Research Council of Science & Technology (NST) funded by the Korea Government (MSIP) (grant No. CRC-15-01-KIST). Supporting Tables, Images and/or Graphs▪

Interleukin-33 / Cyclin D1 imbalance in severe liver steatosis predicts susceptibility to ischemia reperfusion injury.

Transplanting donor livers with severe macrosteatosis is associated with increased risk of primary non-function (PNF). The purpose of this study was to identify steatosis-driven biomarkers as a predisposition to severe liver damage and delayed recovery following ischemia reperfusion injury. Wistar rats were fed a methionine- and choline-deficient (MCD) diet for up to three weeks to achieve severe macrosteatosis (>90%). Animals underwent diet withdrawal to control chow and/or underwent ischemia reperfusion and partial hepatectomy injury (I/R-PHx) and reperfused out to 7 days on control chow. For animals with severe macrosteatosis, hepatic levels of IL-33 decreased while Cyclin D1 levels increased in the absence of NF-κB p65 phosphorylation. Animals with high levels of nuclear Cyclin D1 prior to I/R-PHx either did not survive or had persistent macrosteatosis after 7 days on control chow. Survival 7 days after I/R-PHx fell to 57% which correlated with increased Cyclin D1 and decreased liver IL-33 levels. In the absence of I/R-PHx, withdrawing the MCD diet normalized IL-33, Cyclin D1 levels, and I/R-PHx survival back to baseline. In transplanted grafts with macrosteatosis, higher Cyclin D1 mRNA expression was observed. Shifts in Cyclin D1 and IL-33 expression may identify severely macrosteatotic livers with increased failure risk if subjected to I/R injury. Clinical validation of the panel in donor grafts with macrosteatosis revealed increased Cyclin D1 expression corresponding to delayed graft function. This pre-surgical biomarker panel may identify the subset of livers with increased susceptibility to PNF.