transforming-growth-factor-beta and Non-alcoholic-Fatty-Liver-Disease

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis with insulin resistance, oxidative stress, lipotoxicity, adipokine secretion by fat cells, endotoxins (lipopolysaccharides) released by gut microbiota, and endoplasmic reticulum stress. Together, these factors promote NAFLD progression from steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, and eventually end-stage liver diseases in a proportion of cases. Hepatic fibrosis and carcinogenesis often progress together, sharing inflammatory pathways. However, NASH can lead to hepatocarcinogenesis with minimal inflammation or fibrosis. In such instances, insulin resistance, oxidative stress, and lipotoxicity can directly lead to liver carcinogenesis through genetic and epigenetic alterations. Transforming growth factor (TGF)-β signaling is implicated in hepatic fibrogenesis and carcinogenesis. TGF-β type I receptor (TβRI) and activated-Ras/c-Jun-N-terminal kinase (JNK) differentially phosphorylate the mediator Smad3 to create two phospho-isoforms: C-terminally phosphorylated Smad3 (pSmad3C) and linker-phosphorylated Smad3 (pSmad3L). TβRI/pSmad3C signaling terminates cell proliferation, while constitutive Ras activation and JNK-mediated pSmad3L promote hepatocyte proliferation and carcinogenesis. The pSmad3L signaling pathway also antagonizes cytostatic pSmad3C signaling. This review addresses TGF-β/Smad signaling in hepatic carcinogenesis complicating NASH. We also discuss Smad phospho-isoforms as biomarkers predicting HCC in NASH patients with or without cirrhosis.

Topics: Carcinogenesis; Carcinoma, Hepatocellular; Humans; Insulin Resistance; Liver Cirrhosis; Liver Neoplasms; Non-alcoholic Fatty Liver Disease; Protein Isoforms; Signal Transduction; Smad3 Protein; Transforming Growth Factor beta

Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disease that encompasses a spectrum of pathological conditions, ranging from simple steatosis (NAFL), nonalcoholic steatohepatitis (NASH), fibrosis/cirrhosis which can further progress to hepatocellular carcinoma and liver failure. The progression of NAFL to NASH and liver fibrosis is closely associated with a series of liver injury resulting from lipotoxicity, oxidative stress, redox imbalance (excessive nitric oxide), ER stress, inflammation and apoptosis that occur sequentially in different liver cells which ultimately leads to the activation of liver regeneration and fibrogenesis, augmenting collagen and extracellular matrix deposition and promoting liver fibrosis and cirrhosis. Type 2 diabetes is a significant risk factor in NAFLD development by accelerating liver damage. Here, we overview recent findings from human study and animal models on the pathophysiological communication among hepatocytes (HCs), Kupffer cells (KCs), hepatic stellate cells (HSCs) and liver sinusoidal endothelial cells (LSECs) during the disease development. The mechanisms of crucial signaling pathways, including Toll-like receptor, TGFβ and hedgehog mediated hepatic injury are also discussed. We further highlight the potentials of precisely targeting hepatic individual cell-type using nanotechnology as therapeutic strategy for the treatment of NASH and liver fibrosis.

Topics: Animals; Cell Communication; Endoplasmic Reticulum Stress; Hedgehog Proteins; Hepatocytes; Humans; Insulin Resistance; Liver Cirrhosis; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Toll-Like Receptors; Transforming Growth Factor beta

Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease and a risk factor for cirrhosis and hepatocellular carcinoma. The pathological features of NASH include steatosis, hepatocyte injury, inflammation, and various degrees of fibrosis. Steatosis reflects disordered lipid metabolism. Insulin resistance and excessive fatty acid influx to the liver are two important contributing factors. Steatosis is also likely associated with lipotoxicity and cellular stresses such as oxidative stress and endoplasmic reticulum stress, which result in hepatocyte injury. Inflammation and fibrosis are frequently triggered by various signals such as proinflammatory cytokines and chemokines, released by injuried hepatocytes and activated Kupffer cells. Although much progress has been made, the pathogenesis of NASH is not fully elucidated. The purpose of this review is to discuss the current understanding of NASH pathogenesis, mainly focusing on factors contributing to steatosis, hepatocyte injury, inflammation, and fibrosis.

Topics: Adipose Tissue; Animals; Apoptosis; Autophagy; Carcinoma, Hepatocellular; Chemokines; Cytokines; Fatty Acids; Fibrosis; Gastrointestinal Microbiome; Genetic Predisposition to Disease; Hepatic Stellate Cells; Hepatocytes; Humans; Inflammation; Insulin Resistance; Kupffer Cells; Lipid Metabolism; Lipopolysaccharides; Liver; Liver Neoplasms; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Risk Factors; Signal Transduction; Transforming Growth Factor beta

Alcohol consumption exacerbates liver abnormalities in animal models, but whether it increases the severity of liver disease in early diabetic or prediabetic rats is unclear. To investigate the molecular mechanisms underlying alcohol-induced liver steatosis or hepatitis, we used a prediabetic animal model. Otsuka Long-Evans Tokushima Fatty (OLETF) and Long-Evans Tokushima Fatty (LETO) rats were pair-fed with an ethanol-containing liquid diet for 6 weeks. Compared with controls, OLETF and LETO rats displayed more pronounced liver steatosis and higher plasma levels of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamate pyruvate transaminase (SPGT), indicating liver injury. Ethanol-fed LETO (Pd-L-E) rats showed mild liver steatosis and no inflammation compared with ethanol-fed OLETF (Pd-O-E) rats. Although precursor and active SREBP-1 levels in the liver of ethanol-fed OLETF rats significantly increased compared with control diet-fed OLETF rats (Pd-O-C), those of Pd-L-E rats did not. Bone morphogenetic protein (BMP) and TGF-β1 balance in Pd-O-E rats was significantly altered because BMP signaling was upregulated by inducing BMP2, BMP4, BMP7, BMP9, Smad1, and Smad4, whereas TGF-β1, Smad3, and Erk were downregulated. Activation of TGF-β/Smad signaling inhibited BMP2 and BMP9 expression and increased epithelial-mesenchymal transition (EMT) marker levels (Hepcidin, Snail, and Twist) in the liver of LETO rats. Livers of ethanol-fed OLETF rats showed increased levels of vimentin, FSP-1, α-SMA, MMP1, MMP13, and collagen III compared with rats of other groups, whereas EMT marker levels did not change. Thus, BMP exerted anti- and/or pro-fibrotic effects in ethanol-fed rats. Therefore, BMP and TGF-β, two key members of the TGF-β superfamily, play important but diverse roles in liver steatosis in young LETO and OLETF rats.

Topics: Animals; Diabetes Mellitus, Type 2; Disease Models, Animal; Ethanol; Male; Non-alcoholic Fatty Liver Disease; Prediabetic State; Rats; Rats, Inbred OLETF; Transforming Growth Factor beta; Transforming Growth Factor beta1

Liver fibrosis is a leading indicator for increased mortality and long-term comorbidity in NASH. Activation of HSCs and excessive extracellular matrix production are the hallmarks of liver fibrogenesis. Tyrosine kinase receptor (TrkB) is a multifunctional receptor that participates in neurodegenerative disorders. However, paucity of literature is available about TrkB function in liver fibrosis. Herein, the regulatory network and therapeutic potential of TrkB were explored in the progression of hepatic fibrosis.. The protein level of TrkB was decreased in mouse models of CDAHFD feeding or carbon tetrachloride-induced hepatic fibrosis. TrkB suppressed TGF-β-stimulated proliferation and activation of HSCs in 3-dimensional liver spheroids and significantly repressed TGF-β/SMAD signaling pathway either in HSCs or in hepatocytes. The cytokine, TGF-β, boosted Nedd4 family interacting protein-1 (Ndfip1) expression, promoting the ubiquitination and degradation of TrkB through E3 ligase Nedd4-2. Moreover, carbon tetrachloride intoxication-induced hepatic fibrosis in mouse models was reduced by adeno-associated virus vector serotype 6 (AAV6)-mediated TrkB overexpression in HSCs. In addition, in murine models of CDAHFD feeding and Gubra-Amylin NASH (GAN), fibrogenesis was reduced by adeno-associated virus vector serotype 8 (AAV8)-mediated TrkB overexpression in hepatocytes.. TGF-β stimulated TrkB degradation through E3 ligase Nedd4-2 in HSCs. TrkB overexpression inhibited the activation of TGF-β/SMAD signaling and alleviated the hepatic fibrosis both in vitro and in vivo . These findings demonstrate that TrkB could be a significant suppressor of hepatic fibrosis and confer a potential therapeutic target in hepatic fibrosis.

Topics: Animals; Carbon Tetrachloride; Hepatic Stellate Cells; Liver; Liver Cirrhosis; Mice; Non-alcoholic Fatty Liver Disease; Receptor Protein-Tyrosine Kinases; Signal Transduction; Smad Proteins; Transforming Growth Factor beta; Transforming Growth Factor beta1; Ubiquitin-Protein Ligases

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. Aberrant lipid metabolism and accumulation of extracellular matrix proteins are hallmarks of the disease, but the underlying mechanisms are largely unknown. This study aims to elucidate the key role of sine oculis homeobox homologue 1 (SIX1) in the development of NAFLD.. Alb-Cre mice were administered the AAV9 vector for SIX1 liver-specific overexpression or knockdown. Metabolic disorders, hepatic steatosis, and inflammation were monitored in mice fed with HFHC or MCD diet. High throughput CUT&Tag analysis was employed to investigate the mechanism of SIX1 in diet-induced steatohepatitis.. Here, we found increased SIX1 expression in the livers of NAFLD patients and animal models. Liver-specific overexpression of SIX1 using adeno-associated virus serotype 9 (AAV9) provoked more severe inflammation, metabolic disorders, and hepatic steatosis in the HFHC or MCD-induced mice model. Mechanistically, we demonstrated that SIX1 directly activated the expression of liver X receptor α (LXRα) and liver X receptor β (LXRβ), thus inducing de novo lipogenesis (DNL). In addition, our results also illustrated a critical role of SIX1 in regulating the TGF-β pathway by increasing the levels of type I and II TGF-β receptor (TGFβRI/TGFβRII) in hepatic stellate cells (HSCs). Finally, we found that liver-specific SIX1 deficiency could ameliorate diet-induced NAFLD pathogenesis.. Our findings suggest a detrimental function of SIX1 in the progression of NAFLD. The direct regulation of LXRα/β and TGF-β signalling by SIX1 provides a new regulatory mechanism in hepatic steatosis and fibrosis.

Topics: Animals; Diet, High-Fat; Fibrosis; Inflammation; Lipogenesis; Liver; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Transforming Growth Factor beta

Curcumin 2005-8 (Cur5-8), a derivative of curcumin, improves fatty liver disease via AMP-activated protein kinase activation and autophagy regulation. EW-7197 (vactosertib) is a small molecule inhibitor of transforming growth factor β (TGF-β) receptor I and may scavenge reactive oxygen species and ameliorate fibrosis through the SMAD2/3 canonical pathway. This study aimed to determine whether co-administering these two drugs having different mechanisms is beneficial.. Hepatocellular fibrosis was induced in mouse hepatocytes (alpha mouse liver 12 [AML12]) and human hepatic stellate cells (LX-2) using TGF-β (2 ng/mL). The cells were then treated with Cur5-8 (1 μM), EW-7197 (0.5 μM), or both. In animal experiments were also conducted during which, methionine-choline deficient diet, Cur5-8 (100 mg/kg), and EW-7197 (20 mg/kg) were administered orally to 8-week-old C57BL/6J mice for 6 weeks.. TGF-β-induced cell morphological changes were improved by EW-7197, and lipid accumulation was restored on the administration of EW-7197 in combination with Cur5-8. In a nonalcoholic steatohepatitis (NASH)-induced mouse model, 6 weeks of EW-7197 and Cur5-8 co-administration alleviated liver fibrosis and improved the nonalcoholic fatty liver disease (NAFLD) activity score.. Co-administering Cur5-8 and EW-7197 to NASH-induced mice and fibrotic hepatocytes reduced liver fibrosis and steatohepatitis while maintaining the advantages of both drugs. This is the first study to show the effect of the drug combination against NASH and NAFLD. Similar effects in other animal models will confirm its potential as a new therapeutic agent.

Topics: Animals; Curcumin; Fibrosis; Humans; Liver Cirrhosis; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Transforming Growth Factor beta; Transforming Growth Factors

Activation of hepatic stellate cells (HSCs), the central event of fibrosis, indicates the severe stage of non-alcoholic fatty liver disease (NAFLD). MicroRNAs (miRNAs) participate in this process. Treatment with a sodium-glucose cotransporter 2 inhibitor (SGLT2i) alleviates liver fibrosis in patients with type 2 diabetes and NAFLD; however, the role of SGLT2i in ameliorating liver fibrosis in NAFLD by regulating miRNAs remains unclear.. We monitored the expression of NAFLD-associated miRNAs in the livers of two NAFLD models and observed high expression of miR-34a-5p. miR-34a-5p was highly expressed in mouse primary liver non-parenchymal cells and LX-2 HSCs, and this miRNA was positively correlated with alanine transaminase levels in NAFLD models. Overexpression of miR-34a-5p enhanced LX-2 activation, whereas its inhibition prevented HSCs activation by regulating the TGFβ signaling pathway. The SGLT2i empagliflozin significantly downregulated miR-34a-5p, inhibited the TGFβ signaling pathway, and ameliorated hepatic fibrosis in NAFLD models. Subsequently, GREM2 was identified as a direct target of miR-34a-5p through database prediction and a dual-luciferase reporter assay. In LX-2 HSCs, the miR-34a-5p mimic and inhibitor directly downregulated and upregulated GREM2, respectively. Overexpressing GREM2 inactivated the TGFβ pathway whereas GREM2 knockdown activated it. Additionally, empagliflozin upregulated Grem2 expression in NAFLD models. In methionine- and choline-deficient diet-fed ob/ob mice, a fibrosis model, empagliflozin downregulated miR-34a-5p and upregulated Grem2 to improve liver fibrosis.. Empagliflozin ameliorates NAFLD-associated fibrosis by downregulating miR-34a-5p and targeting GREM2 to inhibit the TGFβ pathway in HSCs.

Topics: Animals; Diabetes Mellitus, Type 2; Fibrosis; Hepatic Stellate Cells; Liver; Liver Cirrhosis; Mice; MicroRNAs; Non-alcoholic Fatty Liver Disease; Sodium-Glucose Transporter 2 Inhibitors; Transforming Growth Factor beta

Nonalcoholic steatohepatitis (NASH) is a complex disease involving both genetic and environmental factors in its onset and progression. We analyzed NASH phenotypes in a genetically diverse cohort of mice, the Hybrid Mouse Diversity Panel, to identify genes contributing to disease susceptibility.. A "systems genetics" approach, involving integration of genetic, transcriptomic, and phenotypic data, was used to identify candidate genes and pathways in a mouse model of NASH. The causal role of Matrix Gla Protein (MGP) was validated using heterozygous MGP knockout (Mgp. Local cis-acting regulation of MGP was correlated with fibrosis, suggesting a causal role in NASH, and this was validated using loss of function experiments in 2 models of diet-induced NASH. Using single-cell RNA sequencing, Mgp was found to be primarily expressed in hepatic stellate cells and dendritic cells in mice. Knockdown of MGP expression in stellate LX-2 cells led to a blunted response to TGF-β stimulation. This was associated with reduced regulatory SMAD phosphorylation and TGF-β receptor ALK1 expression as well as increased expression of inhibitory SMAD6. Hepatic MGP expression was found to be significantly correlated with the severity of fibrosis in livers of patients with NASH, suggesting relevance to human disease.. MGP regulates liver fibrosis and TGF-β signaling in hepatic stellate cells and contributes to NASH pathogenesis.

Topics: Animals; Humans; Liver Cirrhosis; Matrix Gla Protein; Mice; Non-alcoholic Fatty Liver Disease; Transforming Growth Factor beta; Transforming Growth Factors

The antidiabetic drug pioglitazone ameliorates insulin resistance by activating the transcription factor PPARγ. In addition to its blood glucose-lowering action, pioglitazone exerts pleiotropic effects including amelioration of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH). The mechanism by which pioglitazone achieves this latter effect has remained unclear, however. We here show that pioglitazone administration increases the amount of linoleic acid (LA) metabolites in adipose tissue of KK-Ay mice. These metabolites are produced by lactic acid bacteria in the gut, and pioglitazone also increased the fraction of Lactobacillus in the gut microbiota. Administration of the LA metabolite HYA (10-hydroxy-cis-12-octadecenoic acid) to C57BL/6 J mice fed a high-fat diet improved liver histology including steatosis, inflammatory cell infiltration, and fibrosis. Gene ontology analysis of RNA-sequencing data for the liver revealed that the top category for genes downregulated by HYA treatment was related to extracellular matrix, and the expression of individual genes related to fibrosis was confirmed to be attenuated by HYA treatment. Mechanistically, HYA suppressed TGF-β-induced Smad3 phosphorylation and fibrosis-related gene expression in human hepatic stellate cells (LX-2). Our results implicate LA metabolites in the mechanism by which pioglitazone ameliorates liver fibrosis, and they suggest that HYA is a potential therapeutic for NAFLD/NASH.

Topics: Animals; Diet, High-Fat; Fibrosis; Gastrointestinal Microbiome; Hepatic Stellate Cells; Humans; Linoleic Acid; Liver; Liver Cirrhosis; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Pioglitazone; Transforming Growth Factor beta

Nonalcoholic Steatohepatitis (NASH) is the most severe type of non-alcoholic fatty liver disease (NAFLD) and one of the most common chronic liver diseases, leading to the increased risk of liver failure, cirrhosis and hepatocellular carcinoma. Trans-anethole was reported to have anti-inflammatory, anti-obesity and anti-diabetic activities. However, its role in NASH remains unknown. Therefore, we aimed to explore the effect of Trans-anethole on NASH.. Eight-week-old C57BL/6 mice were fed on a methionine- and choline-deficient (MCD) diet for 8 weeks to induce NASH in mice, and on the meanwhile, mice were also orally administrated with or without 100 mg/kg Trans-anethole daily to evaluate the effect of Trans-anethole on NASH.. Trans-anethole dose-dependently ameliorated liver injury in MCD diet-fed mice, then the most effective dose of Trans-anethole 100 mg/kg was chosen. Trans-anethole significantly attenuated hepatic steatosis, inflammation and hepatic fibrosis in MCD diet-induced NASH mice. Moreover, Trans-anethole reduced hepatic fibrosis by inhibiting transforming growth factor-beta signaling pathway both in vivo and in vitro.. Trans-anethole effectively ameliorated NASH in MCD diet-fed mice, which suggested that Trans-anethole might serve as a therapeutic strategy for NASH.

Topics: Allylbenzene Derivatives; Animals; Anisoles; Choline; Diet; Liver; Liver Cirrhosis; Methionine; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Transforming Growth Factor beta

Obesity-induced inflamed visceral adipose tissue (VAT) secretes pro-inflammatory cytokines thereby promoting systemic inflammation and insulin resistance which further exacerbate obesity-associated nonalcoholic fatty liver disease (NAFLD). Transforming growth factor (TGF)-β /Smad3 signaling plays a crucial role in the inflammatory events within the VAT. Here, we investigate whether SP-1154, a novel synthetic verbenone derivative, can inhibit TGF-β/Smad3 signaling thereby exhibiting a therapeutic effect against obesity-induced inflamed VAT and subsequent NAFLD in high-fat diet-induced mice.. NAFLD was induced by a high-fat diet (60% fat) for 20 weeks using the male C57BL/6 mice. SP-1154 (50 mg/kg) was orally given daily for 20 weeks. In vivo VAT- and systemic inflammation were measured by using. SP-1154 inhibited TGF-β/Smad3 signaling pathway and remarkably suppressed high-fat diet-induced VAT inflammation and its related systemic inflammation. Furthermore, SP-1154 significantly improved insulin sensitivity with glucose homeostasis and reduced hepatic steatosis. SP-1154 significantly improves VAT inflammation and obesity-related NAFLD.. Our novel findings support the potential use of SP-1154 as a therapeutic drug for obesity and its related NAFLD by targeting the inflamed VAT.

Topics: Animals; Diet, High-Fat; Glucose Tolerance Test; Inflammation; Insulin Resistance; Intra-Abdominal Fat; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Obesity; Positron-Emission Tomography; Smad3 Protein; Transforming Growth Factor beta

Transforming growth factor beta (TGF-β) signaling in hepatocytes promotes steatosis and body weight gain. However, processes that TGF-β signaling in hepatocytes promote pathological body weight gain in nonalcoholic fatty liver disease (NAFLD) are incompletely understood. Obesity and NAFLD were induced by 16 weeks of feeding a high-fat diet (HFD) in hepatocyte-specific TGF-β receptor II-deficient (Tgfbr2

Topics: Adipose Tissue, White; Animals; Hepatocytes; Mice; MicroRNAs; Non-alcoholic Fatty Liver Disease; Obesity; Receptor, Transforming Growth Factor-beta Type II; Transforming Growth Factor beta; Weight Gain

Nonalcoholic steatohepatitis (NASH) is a disease with a high incidence worldwide, but its diagnosis and treatment are poorly managed. In this study, NASH pathophysiology and DNA damage biomarkers were investigated in mice with NASH treated and untreated with melatonin (MLT). C57BL/6 mice were fed a methionine- and choline-deficient (MCD) diet for 4 weeks to develop NASH. Melatonin was administered at 20 mg/kg during the last 2 weeks. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured, and hepatic tissue was dissected for histological analysis, evaluation of lipoperoxidation, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), as well as nuclear factor-erythroid 2 (Nrf2), tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), and transforming growth factor beta (TGF-β) expression by immunohistochemistry. DNA damage was evaluated using Comet assay, while a micronucleus test in bone marrow was performed to assess the genomic instability associated with the disease. Melatonin decreased AST and ALT, liver inflammatory processes, balloonization, and fibrosis in mice with NASH, decreasing TNF-α, iNOS, and TGF-β, as well as oxidative stress, shown by reducing lipoperoxidation and intensifying Nrf2 expression. The SOD and GPx activities were increased, while CAT was decreased by treatment with MLT. Although the micronucleus frequency was not increased in mice with NASH, a protective effect on DNA was observed with MLT treatment in blood and liver tissues using Comet assay. As conclusions, MLT slows down the progression of NASH, reducing hepatic oxidative stress and inflammatory processes, inhibiting DNA damage via anti-inflammatory and antioxidant actions.

Topics: Alanine Transaminase; Animals; Anti-Inflammatory Agents; Antioxidants; Aspartate Aminotransferases; Biomarkers; Catalase; Choline; Choline Deficiency; Diet; DNA Damage; Glutathione Peroxidase; Inflammation; Liver; Melatonin; Methionine; Mice; Mice, Inbred C57BL; NF-E2-Related Factor 2; Nitric Oxide Synthase Type II; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Superoxide Dismutase; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Danhe granule (DHG) is used by Chinese doctors to treat blood stasis, phlegm and dampness. Its lipid-lowering ability has been investigated in our previous research. However, the anti-liver inflammatory and fibrotic effects and mechanism of action of DHG in non-alcoholic steatohepatitis (NASH) have not been explored.. To evaluate the ameliorative effects of DHG on liver inflammation and fibrosis in a methionine/choline-deficient (MCD) diet-induced NASH rat model, and its underlying mechanism.. Sprague-Dawley rats were fed an MCD diet for two weeks and then treated with or without DHG by oral gavage for eight weeks. Their body weight and liver index were measured. The serum alanine aminotransferase (ALT) and aspartate transaminase (AST) activities as well as the liver triglyceride (TG) and free fatty acid (FFA) levels were tested using reagent kits. Inflammatory cytokines, including Tnf-α, Il-β and Il-6, and fibrosis genes, including Acta2, Col1a1, Col1a2 and Tgf-β were examined by real-time quantitative PCR (RT-qPCR). Hematoxylin-eosin (H&E), Oil Red O, Masson's and Sirius Red staining were used to observe liver changes. The plasma and liver ceramide levels were analyzed using HPLC-QQQ-MS/MS. The expression of serine palmitoyl-CoA transferase (Spt), ceramide synthase 6 (Cers6), dihydroceramide desaturase 1 (Des1), glucosylceramide synthase (Gcs), and ceramide kinase (Cerk) mRNA was assayed by RT-qPCR, while the protein expression of CerS6, DES1, GCS, CerK, and casein kinase 2α (CK2α) was tested by western blotting (WB). CerS6 degradation was evaluated using a cycloheximide (CHX) assay in vitro.. The liver index decreased by 20% in DHG groups and the serum ALT and AST decreased by approximately 50% and 30%, respectively in the DHG-H group. The liver Oil Red O staining, TG, and FFA changes showed that DHG reduced hepatic lipid accumulation by approximately 30% in NASH rats. H&E, Masson's and Sirius Red staining and the mRNA levels of Tnf-α, Il-β, Il-6, Acta2, Col1a1, Col1a2 and Tgf-β revealed that DHG alleviated liver inflammation and fibrosis in NASH rats. The ceramide (Cer 16:0), and hexosylceramide (HexCer 16:0, HexCer 18:0, HexCer 22:0, HexCer 24:0 and HexCer 24:1) levels decreased by approximately 17-56% in the plasma of the DHG-M and H rats. The Cer 16:0 content in the liver decreased by 20%, 50%, and 70% with the DHG-L, M, and H treatments; additionally, the dhCer 16:0, Cer 18:0, HexCer 18:0, HexCer 20:0 Cer 22:0-1P, Cer 24:0-1p, Cer 24:1-1p, and Cer 26:1-1p levels decreased in the DHG groups. The mRNA and protein expression levels of DES1, GCS, Cerk, CerS6, and CHX assay indicated that DHG decreased the mRNA and protein expression levels of CerK and reduced CerS6 protein expression by promoting its degradation. Additionally, DHG attenuated the protein expression of CK2α which could increase CerS6 enzymatic activity by phosphorylating its C-terminal region.. DHG ameliorated the levels of liver FFA and TG and inflammation and fibrosis in MCD-induced rats, which were associated with decreasing ceramide species in the plasma and liver by reducing the expression levels of CerS6 and CerK.

Topics: Animals; Anti-Inflammatory Agents; Ceramides; Fibrosis; Interleukin-6; Liver; Liver Cirrhosis; Methionine; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Phosphotransferases (Alcohol Group Acceptor); Rats; Rats, Sprague-Dawley; RNA, Messenger; Sphingosine N-Acyltransferase; Tandem Mass Spectrometry; Transforming Growth Factor beta; Triglycerides; Tumor Necrosis Factor-alpha

NAFLD and NASH are emerging as primary causes of chronic liver disease, indicating a need for an effective treatment. Mutaflor® probiotic, a microbial treatment of interest, was effective in sustaining remission in ulcerative colitis patients.. To construct a genetic-epigenetic network linked to HSC signaling as a modulator of NAFLD/NASH pathogenesis, then assess the effects of Mutaflor. First, in silico analysis was used to construct a genetic-epigenetic network linked to HSC signaling. Second, an investigation using rats, including HFHSD induced NASH and Mutaflor

Topics: Animals; Hepatic Stellate Cells; Interleukin-6; Liver; Liver Cirrhosis; MicroRNAs; Non-alcoholic Fatty Liver Disease; Probiotics; Rats; RNA, Long Noncoding; RNA, Messenger; Transforming Growth Factor beta

Non-alcoholic fatty liver disease (NAFLD)-related liver fibrosis results in the encapsulation of injured liver parenchyma by a collagenous scar mainly imputable to hepatic stellate cells' activation. Approved pharmacological treatments against NAFLD-related fibrosis are still lacking, but natural compounds such as hydroxytyrosol (HXT) and vitamin E (VitE), are emerging as promising therapeutic opportunities. In this study, the potential anti-fibrotic effect of HXT + VitE combination therapy was investigated in vitro and in vivo. In particular, tumor growth factor (TGF)-β-activated LX-2 cells as an in vitro model, and carbon tetrachloride plus a Western diet as a mice model were employed. The effect of HXT + VitE on fibrosis was also investigated in children with biopsy-proven NAFLD. Our results demonstrated that HXT + VitE caused a reduction of proliferation, migration, contractility, and expression of pro-fibrogenic genes in TGF-β-activated LX-2 cells. HXT + VitE treatment also antagonized TGF-β-dependent upregulation of pro-oxidant NOX2 by interfering with nuclear translocation/activation of SMAD2/3 transcription factors. The mouse model of NAFLD-related fibrosis treated with HXT + VitE showed a marked reduction of fibrosis pattern by histology and gene expression. Accordingly, in children with NAFLD, HXT + VitE treatment caused a decrease of circulating levels of PIIINP and NOX2 that was supported over time. Our study suggests that HXT + VitE supplementation may improve NAFLD-related fibrosis.

Topics: Animals; Carbon Tetrachloride; Fibrosis; Liver; Liver Cirrhosis; Mice; Non-alcoholic Fatty Liver Disease; Phenylethyl Alcohol; Reactive Oxygen Species; Transcription Factors; Transforming Growth Factor beta; Vitamin E

Non-alcoholic fatty liver disease affects one-fourth of the world's population. Central to the disease progression is lipid accumulation in the liver, followed by inflammation, fibrosis and cirrhosis. The underlying mechanism behind the early stages of the disease is poorly understood. We have exposed human hepatic HepG2/C3A cells-based spheroids to 65 μM oleic acid and 45 μM palmitic acid and employed proteomics and lipidomics analysis to investigate their effect on hepatocytes. The treatment successfully induced in vivo hallmarks of NAFLD, as evidenced by intracellular lipid accumulation and increased ATP levels. Quantitative lipidome analysis revealed an increase in ceramides, LPC and saturated triglycerides and a decrease in the ratio of PC/PE, similar to the changes observed in patients' liver biopsies. The proteomics analysis combined with qPCR showed increased epithelial to mesenchymal transition (EMT) signalling. Activation of EMT was further validated by transcriptomics in TGF-β treated spheroids, where an increase in mesenchymal cell markers (N-cadherin and collagen expression) was found. Our study demonstrates that this model system thus closely echoes several of the clinical features of non-alcoholic fatty liver disease and can be used to investigate the underlying molecular changes occurring in the condition.

Topics: Adenosine Triphosphate; Cadherins; Ceramides; Epithelial-Mesenchymal Transition; Hep G2 Cells; Humans; Lipidomics; Non-alcoholic Fatty Liver Disease; Oleic Acid; Palmitic Acid; Proteome; Transforming Growth Factor beta; Triglycerides

The study employed a rat model to examine the effects of taurine (Tau) on prevention and therapy of non-alcoholic fatty liver disease (NAFLD). In model rats maintained on a high-fat diet (HFD), the serum levels of ALT, AST, triglycerides, cholesterol, and LDL were higher than the corresponding levels in normal control and NP groups (p<0.05). In Tau-prevention and Tau-treatment groups, the serum levels of AST and triglycerides were lower than in HFD rats (p<0.05). In HFD rats, diffuse fatty degeneration and infiltration with inflammatory cells was observed in the liver; in the ileal mucosa, the villi were fractured or absent, the epithelium was exfoliated and infiltrated with inflammatory cells. The levels of TGF-β, IL-9, and their mRNA in the liver and ileal mucosa of HFD rats were significantly higher than in normal control and NP groups (p<0.05). In Tau-prevention and Tau-treatment groups, these levels were significantly lower than in HFD rats (p<0.05). Thus, TGF-β and IL-9 can be implicated in NAFLD genesis, while Tau can preventively or therapeutically diminish the damage to the liver and ileal mucosa in rats with this disease by down-regulating the expression of TGF-β and IL-9.

Topics: Animals; Disease Models, Animal; Down-Regulation; Interleukin-9; Intestinal Mucosa; Liver; Liver Cirrhosis; Male; Non-alcoholic Fatty Liver Disease; Rats; Rats, Wistar; Taurine; Transforming Growth Factor beta

Non-alcoholic steatohepatitis (NASH) results, in part, from the interaction of metabolic derangements with predisposing genetic variants, leading to liver-related complications and mortality. The strongest genetic determinant is a highly prevalent missense variant in patatin-like phospholipase domain-containing protein 3 (PNPLA3 p.I148M). In human liver hepatocytes PNPLA3 localizes to the surface of lipid droplets where the mutant form is believed to enhance lipid accumulation and release of pro-inflammatory cytokines. Less is known about the role of PNPLA3 in hepatic stellate cells (HSCs). Here we characterized HSC obtained from patients carrying the wild type (n = 8 C/C) and the heterozygous (n = 6, C/G) or homozygous (n = 6, G/G) PNPLA3 I148M and investigated the effect of genotype and PNPLA3 downregulation on baseline and TGF-β-stimulated fibrotic gene expression. HSCs from all genotypes showed comparable baseline levels of PNPLA3 and expression of the fibrotic genes α-SMA, COL1A1, TIMP1 and SMAD7. Treatment with TGF-β increased PNPLA3 expression in all 3 genotypes (~2-fold) and resulted in similar stimulation of the expression of several fibrogenic genes. In primary human HSCs carrying wild-type (WT) PNPLA3, siRNA treatment reduced PNPLA3 mRNA by 79% resulting in increased expression of α-SMA, Col1a1, TIMP1, and SMAD7 in cells stimulated with TGF-β. Similarly, knock-down of PNPLA3 in HSCs carrying either C/G or G/G genotypes resulted in potentiation of TGF-β induced expression of fibrotic genes. Knockdown of PNPLA3 did not impact fibrotic gene expression in the absence of TGF-β treatment. Together, these data indicate that the presence of the I148M PNPLA3 mutation in HSC has no effect on baseline activation and that downregulation of PNPLA3 exacerbates the fibrotic response irrespective of the genotype.

Topics: Adult; Aged; Cells, Cultured; Down-Regulation; Female; Gene Expression Regulation; Hepatic Stellate Cells; Humans; Lipase; Lipid Droplets; Male; Membrane Proteins; Middle Aged; Mutation, Missense; Non-alcoholic Fatty Liver Disease; Polymorphism, Single Nucleotide; Primary Cell Culture; Transforming Growth Factor beta

Interleukin (IL)-19, a member of the IL-10 family, is an anti-inflammatory cytokine produced primarily by macrophages. Nonalcoholic steatohepatitis (NASH) is a disease that has progressed from nonalcoholic fatty liver disease (NAFLD) and is characterized by inflammation and fibrosis. We evaluated the functions of IL-19 in a NAFLD/NASH mouse model using a 60% high fat diet with 0.1% methionine, without choline, and with 2% cholesterol (CDAHFD). Wild-type (WT) and IL-19 gene-deficient (KO) mice were fed a CDAHFD or standard diet for 9 weeks. Liver injury, inflammation, and fibrosis induced by CDAHFD were significantly worse in IL-19 KO mice than in WT mice. IL-6, TNF-α, and TGF-β were significantly higher in IL-19 KO mice than in WT mice. As a mechanism using an in vitro experiment, palmitate-induced triglyceride and cholesterol contents were decreased by the addition of IL-19 in HepG2 cells. Furthermore, addition of IL-19 decreased the expression of fatty acid synthesis-related enzymes and increased ATP content in HepG2 cells. The action of IL-19 in vitro suppressed lipid metabolism. In conclusion, IL-19 may play an important role in the development of steatosis and fibrosis by directly regulating liver metabolism and may be a potential target for the treatment of liver diseases.

Topics: Adenosine Triphosphate; Animals; Cholesterol; Diet, High-Fat; Disease Models, Animal; Fatty Acids; Hep G2 Cells; Humans; Inflammation; Interleukin-6; Interleukins; Lipid Metabolism; Liver; Mice; Mice, Knockout; Non-alcoholic Fatty Liver Disease; Palmitates; Transforming Growth Factor beta; Triglycerides; Tumor Necrosis Factor-alpha

Topics: Computational Biology; Hep G2 Cells; Humans; MicroRNAs; Non-alcoholic Fatty Liver Disease; RNA, Messenger; Transforming Growth Factor beta

Non‑alcoholic steatohepatitis (NASH) may progress via liver fibrosis along with hepatic stellate cell (HSC) activation. A single nucleotide polymorphism (SNP; rs58542926) located in transmembrane 6 superfamily 2 (

Topics: Actins; Cell Line; Gene Expression Regulation; Gene Knockdown Techniques; Hepatic Stellate Cells; Humans; Membrane Proteins; Models, Biological; Non-alcoholic Fatty Liver Disease; Polymorphism, Single Nucleotide; Transforming Growth Factor beta

Nonalcoholic fatty liver disease is defined as the accumulation of excessive fat in the liver in the absence of excessive alcohol consumption or any secondary cause. Although the disease generally remains asymptomatic, chronic liver inflammation leads to fibrosis, liver cirrhosis, and even to the development of hepatocellular carcinoma (HCC). Fibrosis results from epithelial-mesenchymal transition (EMT), which leads to dedifferentiation of epithelial cells into cells with a mesenchymal-like phenotype. During EMT, epithelial cells with high expression of E-cadherin, influenced by growth factors, cytokines, and inflammatory processes, undergo morphological changes via enhanced expression of, e.g., vimentin, fibronectin, and N-cadherin. An inducer of EMT and, consequently, of fibrosis development is transforming growth factor beta (TGFβ), a pleiotropic cytokine associated with the progression of hepatocarcinogenesis. However, the understanding of the molecular events that direct the development of steatosis into steatohepatitis and liver fibrosis remains incomplete. Our study revealed that both prolonged exposure of hepatocarcinoma cells to fatty acids in vitro and high-fat diet in mice (20 weeks) result in inflammation. Prolonged treatment with fatty acids increased the levels of TGFβ, MMP9, and β-catenin, important EMT inducers. Moreover, the livers of mice fed a high-fat diet exhibited features of liver fibrosis with increased TGFβ and IL-1 levels. Increased expression of IL-1 correlated with a decrease in monocyte chemoattractant protein-induced protein 1 (MCPIP1), a negative regulator of the inflammatory response that regulates the stability of proinflammatory transcripts encoding IL-1. Our study showed that a high-fat diet induced EMT by increasing the levels of EMT-activating transcription factors, including Zeb1, Zeb2, and Snail and changed the protein profile to a profile characteristic of the mesenchymal phenotype.

Topics: Animals; beta Catenin; Cadherins; Cell Line, Tumor; Diet, High-Fat; Disease Models, Animal; Epithelial-Mesenchymal Transition; Fibronectins; Gene Expression Regulation; Hepatocytes; Humans; Interleukin-1; Liver; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Oleic Acid; Ribonucleases; Signal Transduction; Transforming Growth Factor beta; Vimentin; Zinc Finger E-box Binding Homeobox 2; Zinc Finger E-box-Binding Homeobox 1

Accurate evaluation of liver steatosis is required from brain-dead donors (BDDs) with nonalcoholic fatty liver disease (NAFLD). Our purposes were to investigate expression and regulation of connective tissue growth factor (CTGF) expression in livers from human and rat after brain death, and further evaluate its potential application. NAFLD and brain death models were established in rats. LX2 cells were cultured under hypoxia/reoxygenation. CTGF protein and mRNA levels were measured in liver samples from BDDs of human and rat by immunohistochemistry and reverse transcription-quantitative polymerase chain reaction. YAP-regulated CTGF expression was investigated in LX2 cells via YAP small interfering RNA and Verteporfin treatment. Blood CTGF level from BDDs was measured by enzyme-linked immunosorbent assay. After brain death, CTGF, transforming growth factor-β and YAP were overexpressed in non-alcoholic steatotic liver, whereas CTGF was downregulated in non-steatotic liver. Time-series analysis revealed that CTGF and YAP expression was comparable, as confirmed by inhibited YAP expression in LX2 cells. CTGF level and NAFLD activity were linearly correlated. CTGF expression and regulation differ between non-steatosis and nonalcoholic steatosis livers from BDDs. CTGF may be an important factor to evaluate graft quality from BDDs with NAFLD.

Topics: Animals; Biomarkers; Brain Death; Connective Tissue Growth Factor; Humans; Liver; Male; Non-alcoholic Fatty Liver Disease; Rats, Inbred Lew; Transforming Growth Factor beta; YAP-Signaling Proteins

Nonalcoholic fatty liver disease is a rapidly rising problem in the 21st century and is a leading cause of chronic liver disease that can lead to end-stage liver diseases, including cirrhosis and hepatocellular cancer. Despite this rising epidemic, no pharmacological treatment has yet been established to treat this disease. The rapidly increasing prevalence of nonalcoholic fatty liver disease and its aggressive form, nonalcoholic steatohepatitis (NASH), requires novel therapeutic approaches to prevent disease progression. Alterations in microbiome dynamics and dysbiosis play an important role in liver disease and may represent targetable pathways to treat liver disorders. Improving microbiome properties or restoring normal bile acid metabolism may prevent or slow the progression of liver diseases such as NASH. Importantly, aberrant systemic circulation of bile acids can greatly disrupt metabolic homeostasis. Bile acid sequestrants are orally administered polymers that bind bile acids in the intestine, forming nonabsorbable complexes. Bile acid sequestrants interrupt intestinal reabsorption of bile acids, decreasing their circulating levels. We determined that treatment with the bile acid sequestrant sevelamer reversed the liver injury and prevented the progression of NASH, including steatosis, inflammation, and fibrosis in a Western diet-induced NASH mouse model. Metabolomics and microbiome analysis revealed that this beneficial effect is associated with changes in the microbiota population and bile acid composition, including reversing microbiota complexity in cecum by increasing

Topics: Animals; Bile Acids and Salts; Cecum; Chemokine CCL2; Cholesterol; Collagen Type I; Collagen Type I, alpha 1 Chain; Diet, Western; Disease Models, Animal; Feces; Gastrointestinal Microbiome; Lactobacillus; Lipid Metabolism; Liver; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Sevelamer; Severity of Illness Index; Transforming Growth Factor beta

Hepatocellular carcinoma (HCC) is the strongest independent predictor of mortality in non-alcoholic steatohepatitis (NASH)-related cirrhosis. The effects and mechanisms of combination of sodium-dependent glucose cotransporter inhibitor and canagliflozin (CA) and dipeptidyl peptidase-4 inhibitor and teneligliptin (TE) on non-diabetic NASH progression were examined. CA and TE suppressed choline-deficient, L-amino acid-defined diet-induced hepatic fibrogenesis and carcinogenesis. CA alone or with TE significantly decreased proinflammatory cytokine expression. CA and TE significantly attenuated hepatic lipid peroxidation. In vitro studies showed that TE alone or with CA inhibited cell proliferation and TGF-β1 and α1 (I)-procollagen mRNA expression in Ac-HSCs. CA+TE inhibited liver fibrogenesis by attenuating hepatic lipid peroxidation and inflammation and by inhibiting Ac-HSC proliferation with concomitant attenuation of hepatic lipid peroxidation. Moreover, CA+TE suppressed in vivo angiogenesis and oxidative DNA damage. CA or CA+TE inhibited HCC cells and human umbilical vein endothelial cell (HUVEC) proliferation. CA+TE suppressed vascular endothelial growth factor expression and promoted increased E-cadherin expression in HUVECs. CA+TE potentially exerts synergistic effects on hepatocarcinogenesis prevention by suppressing HCC cell proliferation and angiogenesis and concomitantly reducing oxidative stress and by inhibiting angiogenesis with attenuation of oxidative stress. CA+TE showed chemopreventive effects on NASH progression compared with single agent in non-diabetic rat model of NASH, concurrent with Ac-HSC and HCC cell proliferation, angiogenesis oxidative stress, and inflammation. Both agents are widely, safely used in clinical practice; combined treatment may represent a potential strategy against NASH.

Topics: Animals; Cadherins; Canagliflozin; Carcinogenesis; Carcinoma, Hepatocellular; Cell Proliferation; Collagen Type I; Collagen Type I, alpha 1 Chain; Cytokines; Disease Progression; DNA Damage; Drug Synergism; Hepatic Stellate Cells; Human Umbilical Vein Endothelial Cells; Humans; Lipid Peroxidation; Liver Cirrhosis; Liver Neoplasms; Male; Neovascularization, Pathologic; Non-alcoholic Fatty Liver Disease; Pyrazoles; Rats; Rats, Inbred Strains; Thiazolidines; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A

Non-alcoholic fatty liver disease (NAFLD) is gaining in importance and is linked to obesity. Especially, the development of fibrosis and portal hypertension in NAFLD patients requires treatment. Transgenic TGR(mREN2)27 rats overexpressing mouse renin spontaneously develop NAFLD with portal hypertension but without obesity. This study investigated the additional role of obesity in this model on the development of portal hypertension and fibrosis. Obesity was induced in twelve-week old TGR(mREN2)27 rats after receiving Western diet (WD) for two or four weeks. Liver fibrosis was assessed using standard techniques. Hepatic expression of transforming growth factor-β1 (TGF-β1), collagen type Iα1, α-smooth muscle actin, and the macrophage markers Emr1, as well as the chemoattractant Ccl2, interleukin-1β (IL1β) and tumor necrosis factor-α (TNFα) were analyzed. Assessment of portal and systemic hemodynamics was performed using the colored microsphere technique. As expected, WD induced obesity and liver fibrosis as confirmed by Sirius Red and Oil Red O staining. The expression of the monocyte-macrophage markers, Emr1, Ccl2, IL1β and TNFα were increased during feeding of WD, indicating infiltration of macrophages into the liver, even though this increase was statistically not significant for the EGF module-containing mucin-like receptor (Emr1) mRNA expression levels. Of note, portal pressure increased with the duration of WD compared to animals that received a normal chow. Besides obesity, WD feeding increased systemic vascular resistance reflecting systemic endothelial and splanchnic vascular dysfunction. We conclude that transgenic TGR(mREN2)27 rats are a suitable model to investigate NAFLD development with liver fibrosis and portal hypertension. Tendency towards elevated expression of Emr1 is associated with macrophage activity point to a significant role of macrophages in NAFLD pathogenesis, probably due to a shift of the renin-angiotensin system towards a higher activation of the classical pathway. The hepatic injury induced by WD in TGR(mREN2)27 rats is suitable to evaluate different stages of fibrosis and portal hypertension in NAFLD with obesity.

Topics: Animals; Chemokine CCL2; Diet, Western; Disease Models, Animal; Gene Expression Regulation; Hypertension, Portal; Mice; Non-alcoholic Fatty Liver Disease; Obesity; Peptidyl-Dipeptidase A; Rats; Rats, Transgenic; Receptor, Angiotensin, Type 1; Receptors, Cell Surface; Renin; Transforming Growth Factor beta

The primary focus of this study was to explore the effects of cyclic AMP response element-binding protein H (CREBH) on the development of nonalcoholic fatty liver disease (NAFLD).. CREBH knockout (KO) and wildtype (WT) mice were averagely divided into a methionine and choline-deficient (MCD) or high fat (HF) diet group and respective chow diet (CD) groups. Mice were sacrificed after 4-week treatment for MCD model and 24-week treatment for HF model.. Characteristics of nonalcoholic steatohepatitis-related liver fibrosis in KO-MCD/HF group were verified by hepatic histological analyses. Compared with WT-MCD/HF group, levels of plasma ALT and hepatic hydroxyproline increased in KO-MCD/HF group. Significantly higher levels of MCP-1, αSMA, Desmin, COL-1, TIMP-1, TGF-β1, TGF-β2 were found while MMP-9 and FGF21 mRNA levels decreased in KO-MCD/HF group. There was also a distinct difference of mRNA levels of TNFα, CTGF and CCND1 in KO-HF group compared with controls. Protein levels of MCP-1, BAX, αSMA, COL-1, TGF-β1 and SMAD2/3 significantly increased in KO-MCD/HF group and CCND1 was also upregulated in KO-HF group compared to their counterparts.. CREBH knockout may primarily regulate the TGF-β1 signaling pathway via TGF-β2 and FGF21 resulting in more severe inflammation and fibrosis in NAFLD.

Topics: Alanine Transaminase; Animals; Choline Deficiency; Cyclic AMP Response Element-Binding Protein; Diet, High-Fat; Fibroblast Growth Factors; Hydroxyproline; Lipids; Liver Cirrhosis; Male; Methionine; Mice; Mice, Knockout; Non-alcoholic Fatty Liver Disease; Signal Transduction; Transforming Growth Factor beta

Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease characterized by fat accumulation and inflammation in liver. Yet, the mechanistic insight and diagnostic and therapeutic options of NASH remain incompletely understood. This study tested the roles of cysteine protease cathepsin B (CatB) in mouse NASH development. Immunoblot revealed increased liver CatB expression in NASH mice. Fructose-palmitate-cholesterol diet increased body weight gain, liver to body weight ratio, blood fasting glucose, plasma total cholesterol and alanine transaminase levels, and liver triglyceride, but decreased plasma high-density lipoprotein in wild-type mice. All these changes were blunted in CatB-deficient (Ctsb

Topics: Animals; Cadherins; Cathepsin B; Cell Polarity; Diet, High-Fat; Inflammation; Lipid Metabolism; Liver; Liver Cirrhosis; Macrophages; Male; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Signal Transduction; Smad Proteins; Transforming Growth Factor beta; Weight Gain

Persistent inflammation is one of the main reasons that nonalcoholic fatty liver disease develops into cirrhosis and liver cancer, and reducing the expression of inflammatory factors may be an effective strategy to alleviate the development of nonalcoholic steatohepatitis (NASH). SIGIRR, a member of the interleukin-1 receptor family, has been shown to inhibit the production of inflammatory cytokines, and its down-regulation or deletion has been suggested to be an important cause of inflammatory damage to organs. In this study, we identified that resveratrol efficiently induced the transcriptional activity of the SIGIRR promoter and also increased SIGIRR mRNA levels in human hepatocytes and mouse livers. Furthermore, the potential effects of resveratrol on a methionine/choline-deficient diet-induced NASH mouse model were investigated. Resveratrol maintained the expression level of SIGIRR in the mouse liver. Resveratrol intervention alleviated NASH progression; decreased the levels of alanine aminotransferase and aspartate aminotransferase; and down-regulated tumor necrosis factor-α, interleukin (IL)-6, IL-1β and transforming growth factor-β mRNA and protein levels. Additionally, increased SIGIRR potentially blocked the activity of the Toll-like receptor/nuclear factor-κB signaling pathway both in vivo and in vitro. In vitro, resveratrol pretreatment protected against hepatocyte injury caused by foamy macrophage-released inflammatory cytokines, which are involved in the development of NASH. However, resveratrol did not effectively induce hepatocyte SIGIRR gene transcription in the inflammatory cytokine microenvironment. In conclusion, resveratrol is practical and acts as an agonist of the SIGIRR protein to negatively regulate the expression of inflammatory factors in liver, suggesting that appropriate intake may be a potential way to prevent the occurrence and development of NASH.

Topics: Alanine Transaminase; Animals; Antioxidants; Choline Deficiency; Disease Models, Animal; Hepatocytes; Humans; Interleukin-1beta; Interleukin-6; Liver; Male; Methionine; Mice; Mice, Inbred C57BL; NF-kappa B; Non-alcoholic Fatty Liver Disease; Receptors, Interleukin-1; Resveratrol; Toll-Like Receptors; Transcription, Genetic; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Non-alcoholic steatohepatitis (NASH) is characterized by lipotoxicity, inflammation and fibrosis, ultimately leading to end-stage liver disease. The molecular mechanisms promoting NASH are poorly understood, and treatment options are limited. Here, we demonstrate that hepatic expression of bone morphogenetic protein 8B (BMP8B), a member of the transforming growth factor beta (TGFβ)-BMP superfamily, increases proportionally to disease stage in people and animal models with NASH. BMP8B signals via both SMAD2/3 and SMAD1/5/9 branches of the TGFβ-BMP pathway in hepatic stellate cells (HSCs), promoting their proinflammatory phenotype. In vivo, the absence of BMP8B prevents HSC activation, reduces inflammation and affects the wound-healing responses, thereby limiting NASH progression. Evidence is featured in primary human 3D microtissues modelling NASH, when challenged with recombinant BMP8. Our data show that BMP8B is a major contributor to NASH progression. Owing to the near absence of BMP8B in healthy livers, inhibition of BMP8B may represent a promising new therapeutic avenue for NASH treatment.

Topics: Animals; Bone Morphogenetic Proteins; Carbon Tetrachloride Poisoning; Diet, High-Fat; Diet, Western; Hepatic Stellate Cells; Humans; Inflammation; Liver Regeneration; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Recombinant Proteins; Smad Proteins; Transforming Growth Factor beta; Wound Healing

Ginsenosides have offered a wide array of beneficial roles in the pharmacological regulation of hepatic metabolic syndromes, including non-alcoholic steatohepatitis (NASH), non-alcoholic fatty liver disease (NAFLD), and obesity. Of the numerous ginsenosides, Rg3 has been widely investigated, but there have been few studies of gypenosides (Gyp). Particularly, no study on Gyp LXXV has been reported to date. Here, to firstly explore the pharmacological effects of Gyp LXXV against NASH and the related mechanism, methionine- and choline-deficient (MCD) diet-induced NASH mice and hepatic cells (stellate cells, hepatic macrophages, and hepatocytes) were selected. Gyp LXXV exhibited markedly alleviated MCD diet-induced hepatic injury, inflammation, and fibrosis by down-regulating hepatic fibrosis markers such as α-smooth muscle actin(α-SMA), collagen1, transforming growth factors-β (TGF-β1), tumor necrosis factor-α (TNF-α), MCP-1, interleukin (IL)-1β, nuclear factor κB (NFκB), and GRP78. Remarkably, histopathological studies confirmed that 15 mg/kg of Gyp LXXV administration to MCD diet-induced mice led to effective prevention of liver injury, lipid accumulation, and activation of hepatic macrophages, indicating that Gyp LXXV might be a potential anti-NASH drug.

Topics: Animals; Cells, Cultured; Diet, High-Fat; Endoplasmic Reticulum Chaperone BiP; Ginsenosides; Gynostemma; Hep G2 Cells; Hepatocytes; Humans; Lipid Metabolism; Liver; Liver Cirrhosis; Macrophages; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Plant Extracts; Saponins; Signal Transduction; THP-1 Cells; Transforming Growth Factor beta; Treatment Outcome; Triterpenes

Sestrin 3 (Sesn3) belongs to the three-member sestrin protein family. Sestrins have been implicated in antioxidative stress, adenosine monophosphate-activated protein kinase and mammalian target of rapamycin signal transduction, and metabolic homeostasis. However, the role of Sesn3 in the development of nonalcoholic steatohepatitis (NASH) has not been previously studied. In this work, we generated Sesn3 whole-body knockout and liver-specific transgenic mice to investigate the hepatic function of Sesn3 in diet-induced NASH. With only 4 weeks of dietary treatment, Sesn3 knockout mice developed severe NASH phenotype as characterized by hepatic steatosis, inflammation, and fibrosis. Strikingly, after 8-week feeding with a NASH-inducing diet, Sesn3 transgenic mice were largely protected against NASH development. Transcriptomic analysis revealed that multiple extracellular matrix-related processes were up-regulated, including transforming growth factor β (TGF-β) signaling and collagen production. Further biochemical and cell biological analyses have illustrated a critical control of the TGF-β-mothers against decapentaplegic homolog (Smad) pathway by Sesn3 at the TGF-β receptor and Smad3 levels. First, Sesn3 inhibits the TGF-β receptor through an interaction with Smad7; second, Sesn3 directly inhibits the Smad3 function through protein-protein interaction and cytosolic retention. Conclusion: Sesn3 is a critical regulator of the extracellular matrix and hepatic fibrosis by suppression of TGF-β-Smad3 signaling.

Topics: Animals; Diet; Female; Heat-Shock Proteins; Male; Mice; Mice, Knockout; Mice, Transgenic; Non-alcoholic Fatty Liver Disease; Signal Transduction; Transforming Growth Factor beta

Non-alcoholic steatohepatitis (NASH) is a common disease and feeding mice a methionine-choline-deficient (MCD) diet is a frequently used model to study its pathophysiology. Genetic and environmental factors influence NASH development and liver lipid content, which was studied herein using C57BL/6 J mice bred in two different animal facilities.. Age-matched male C57BL/6 J mice bred in two different animal facilities (later on referred to as WT1 and WT2) at the University Hospital of Regensburg were fed identical MCD or control chows for 2 weeks. Hepatic gene and protein expression and lipid composition were determined.. NASH was associated with increased hepatic triglycerides, which were actually higher in WT1 than WT2 liver in both dietary groups. Cholesterol contributes to hepatic injury but was only elevated in WT2 NASH liver. Ceramides account for insulin resistance and cell death, and ceramide species d18:1/16:0 and d18:1/18:0 were higher in the NASH liver of both groups. Saturated sphingomyelins only declined in WT1 NASH liver. Lysophosphatidylcholine concentrations were quite normal in NASH and only one of the 12 altered phosphatidylcholine species declined in NASH liver of both groups. Very few phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol species were comparably regulated in NASH liver of both animal groups. Seven of these lipid species declined and two increased in NASH. Notably, hepatic mRNA expression of proinflammatory (F4/80, CD68, IL-6, TNF and chemerin) and profibrotic genes (TGF beta and alpha SMA) was comparable in WT1 and WT2 mice.. Mice housed and bred in different animal facilities had comparable disease severity of NASH whereas liver lipids varied among the groups. Thus, there was no specific lipid signature for NASH in the MCD model.

Topics: Actins; Animal Experimentation; Animals; Calcium-Binding Proteins; Ceramides; Cholesterol; Choline Deficiency; Diet; Disease Models, Animal; Gene Expression Regulation; Interleukin-6; Liver; Lysophosphatidylcholines; Male; Methionine; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Phosphatidylethanolamines; Phosphatidylinositols; Phosphatidylserines; Receptors, G-Protein-Coupled; Sphingomyelins; Transforming Growth Factor beta; Triglycerides

Non-alcoholic steatohepatitis (NASH) is predicted to become the most common cause of cirrhosis and liver failure. Risk factors include obesity, insulin resistance and diabetes. Macrophages and other myeloid cells play crucial roles in initiating and driving inflammation. Aryl hydrocarbon Receptor Nuclear Translocator (ARNT) is a transcription factor which binds to a range of partners to mediate responses to environmental signals, including the diet. In people with diabetes it is decreased in liver. We hypothesised that myeloid cell ARNT activity may contribute to the development of liver pathology.. Floxed-ARNT mice were bred with LysM-Cre mice to generate mice with reduced ARNT in myeloid cells. Animals were fed a high fat diet (HFD) and liver pathology was assessed. Histology, mRNA, fat accumulation and metabolism were studied.. Animals with reduced myeloid ARNT developed steatohepatitis on a HFD, with additional alterations of metabolism and fat deposition. Steatohepatitis was accompanied by hepatic macrophage infiltration and expression of both M1 and M2 markers. Expression of mRNAs for Cxcl1, Mcp-1, Tnf-α and Tgf-β1 were increased. Human livers from controls and people with NASH were tested; ARNT mRNA was decreased by 80% (p = 0.0004).. Decreased myeloid ARNT may play a role in the conversion from non-alcoholic fatty liver to steatohepatitis. Increasing ARNT may be a therapeutic strategy to reduce NASH.

Topics: Adult; Animals; Aryl Hydrocarbon Receptor Nuclear Translocator; Cells, Cultured; Chemokine CCL2; Chemokine CXCL1; Diet, High-Fat; Female; Gene Deletion; Humans; Lipid Metabolism; Male; Mice; Mice, Inbred C57BL; Middle Aged; Myeloid Cells; Non-alcoholic Fatty Liver Disease; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

We sought to explore the interplay of multiple serum biomarkers of fibrosis and extracellular matrix remodeling with the results of liver histology in patients with nonalcoholic fatty liver disease (NAFLD).. Venous blood samples were collected from 80 patients with biopsy-proven NAFLD and 59 age-matched and sex-matched healthy controls. Serum levels of transforming growth factor (TGF)-β1, TGF-β2, matrix metalloproteinases (MMP)-1, MMP-2, MMP-7, MMP-9, MMP-10, tissue inhibitors of metalloproteinase (TIMP)-1, and TIMP-2 were determined by using the Luminex MagPix technology on a MAGPIX analyzer.. We documented significant differences in the levels of TGF-β1, TGF-β2, MMP-2, MMP-7, MMP-9, TIMP-1, and TIMP-2 between NAFLD patients and controls. However, none of these biomarkers was able to distinguish between nonalcoholic steatohepatitis and nonalcoholic fatty liver. TIMP-1 levels were significantly higher in patients with significant fibrosis (fibrosis stage ≥2; 2624±1261 pg/ml) than in those without (fibrosis stage 0-1; 2096±906 pg/ml; P=0.03). Moreover, serum levels of TIMP-1 were identified as the only independent predictor of histological fibrosis (β=0.298, t=2.7, P=0.007).. Our study provides insights into the association of multiple serum biomarkers of fibrosis and extracellular matrix remodeling with NAFLD histology. Notably, serum levels of TIMP-1 were identified as a clinically useful marker for distinguishing NAFLD patients with and without significant fibrosis.

Topics: Adult; Biomarkers; Biopsy; Case-Control Studies; Extracellular Matrix; Female; Humans; Liver; Liver Cirrhosis; Male; Matrix Metalloproteinases; Middle Aged; Non-alcoholic Fatty Liver Disease; Predictive Value of Tests; Tissue Inhibitor of Metalloproteinase-1; Transforming Growth Factor beta; Up-Regulation

There is an inadequacy of relevant animal models to study non-alcoholic steatohepatitis (NASH) and fibrosis. Here, we co-administered thioacetamide (TH) along with fast food diet (FFD) to C57BL/6 J mice for eight weeks. The treatments were: a) standard chow, SC b) FFD c) FFD + TH [75 mg/kg], FTH d) SC + TH [150 mg/kg], STH for 8 weeks. In in-vitro model, Hep3B cells were exposed to palmitic acid (PA) and TH viz. PA (0.25 mM) + TH (25 mM), PA (0.5 mM) alone and TH (50 mM) alone for 12 h, later supernatant media was transferred to LX-2 cells, for another 12 h. Molecular and cellular events related to inflammation, fibrosis, collagen deposition were studied. The FTH mice featured hepatic inflammation, severe diffuse fibrosis, and collagen deposition, which were less severe in FF & STH groups. In FTH group the protein expressions of α-SMA, TGF-ß, Col1 A1, CYP2E1, were up-regulated as compared to the FF group. The in-vivo findings were complemented in the LX-2 and Hep3B cells. The protein expressions of inflammatory and cellular injury markers were significantly higher in PA + TH exposed LX-2 cells. This novel model manifested hepatic inflammation and fibrosis in just eight weeks, which may be exploited for rapid screening of novel anti-NAFLD and liver anti-fibrotic agents.

Topics: Actins; Animals; Cell Line, Tumor; Cholesterol, Dietary; Collagen; Collagen Type I; Collagen Type I, alpha 1 Chain; Cytochrome P-450 CYP2E1; Diet, High-Fat; Hepatic Stellate Cells; Hepatocytes; Humans; Liver; Liver Cirrhosis, Experimental; Male; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Thioacetamide; Time Factors; Transforming Growth Factor beta

Postmenopausal women have a higher risk of nonalcoholic steatohepatitis (NASH) along with an increase in age, and vitamin D deficiency occurs in some patients with NASH.. We performed ovariectomy (OVX) surgery on female mice to mimic menopause, fed them a choline-deficient high-fat (CDHF) diet to induce NASH, and then investigated the effects of treatment with 1,25(OH). Supplementation of 1,25(OH)

Topics: Actins; Alanine Transaminase; Animals; Aspartate Aminotransferases; Calcitriol; Choline; Collagen Type I; Collagen Type I, alpha 1 Chain; Diet, High-Fat; Female; Gene Expression; Interleukin-6; Mice; Non-alcoholic Fatty Liver Disease; Ovariectomy; Receptors, Calcitriol; RNA, Messenger; Smad2 Protein; Smad3 Protein; Tissue Inhibitor of Metalloproteinase-1; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Vitamins

MicroRNA-29 (miR-29) has been found to reduce liver inflammation and fibrosis following a liver injury. Meanwhile, DNA methyltransferase has been reported to participate in the development of non-alcoholic steatohepatitis (NASH). The aim of this study is to investigate the miR-29a regulation of methyltransferase signaling and epigenetic program in NASH progression. Methods: miR-29a transgenic mice (miR-29aTg mice) and wild-type littermates were subjected to the methionine-choline-deficient (MCD) diet-induced animal model of NASH. Primary hepatic stellate cells were transfected with a miR-29a mimic and antisense inhibitor. We then analyzed gene expressions with qRT-PCR, immunohistochemical stain, Western blot, and luciferase reporter assay. The results demonstrated that increased miR-29a alleviated the MCD diet-induced body weight loss and steatosis and decreased aspartate aminotransferase (AST) levels in mice. Furthermore, hepatic tissue in miR-29aTg mice displayed a weak fibrotic matrix, as shown with Sirius Red staining concomitant with low fibrotic α-SMA expression within affected tissues compared to the wild-type mice fed the MCD diet. Forced miR-29a expression reduced the MCD diet exaggeration of reactive oxygen species (ROS) production by immunohistochemically staining 8-OHdG. Increased miR-29a signaling also resulted in the downregulation of DNMT3b, TGF-β, IL-6, heme oxygenase-1 (HO-1), p-SMAD3, PI3K, and L3BII expression within the liver tissue. An in vitro luciferase reporter assay further confirmed that miR-29a mimic transfection reduced DNMT3b expression in primary HSCs. Our data provide new insights that miR-29a improves MCD diet-induced liver inflammation, steatosis and fibrosis, and highlight the potential of miR-29a targeted therapy for treating NASH.

Topics: Animals; Cells, Cultured; Choline Deficiency; DNA (Cytosine-5-)-Methyltransferases; DNA Methyltransferase 3B; Hepatocytes; Interleukin-6; Male; Methionine; Mice; Mice, Inbred C57BL; MicroRNAs; Non-alcoholic Fatty Liver Disease; Phosphatidylinositol 3-Kinases; Reactive Oxygen Species; Smad3 Protein; Transforming Growth Factor beta

TGFβ superfamily member Activin-A is a multifunctional hormone/cytokine expressed in multiple tissues and cells, where it regulates cellular differentiation, proliferation, inflammation and tissue architecture. High activin-A levels have been reported in alcoholic cirrhosis and non-alcoholic steatohepatitis (NASH). Our aim was to identify the cell types involved in the fibrotic processes induced by activin-A in liver and verify the liver diseases that this molecule can be found increased.. We studied the effect of activin-A on mouse primary Kupffer cells (KCs) and Hepatic Stellate cells (HSCs) and the levels of activin-A and its inhibitor follistatin in the serum of patients from a large panel of liver diseases.. Activin-A is expressed by mouse hepatocytes, HSCs and Liver Sinusoid Endothelial cells but not KCs. Each cell type expresses different activin receptor combinations. HSCs are unresponsive to activin-A due to downregulation/desensitization of type-II activin receptors, while KCs respond by increasing the expression/production of TNFα και TGFβ1. In the presence of KCs or conditioned medium from activin-A treated KCs, HSCs switch to a profibrogenic phenotype, including increased collagen and αSMA expression and migratory capacity. Incubation of activin-A treated KC conditioned medium with antibodies against TNFα and TGFβ1 partially blocks its capacity to activate HSCs. Only patients with alcoholic liver diseases and NASH cirrhosis have significantly higher activin-A levels and activin-A/follistatin ratio.. Activin-A may induce fibrosis in NASH and alcoholic cirrhosis via activation of KCs to express pro-inflammatory molecules that promote HSC-dependent fibrogenesis and could be a target for future anti-fibrotic therapies.

Topics: Activins; Aged; Animals; Case-Control Studies; Fibrosis; Hepatic Stellate Cells; Humans; Kupffer Cells; Liver; Liver Cirrhosis; Male; Mice; Mice, Inbred BALB C; Middle Aged; Non-alcoholic Fatty Liver Disease; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Nonalcoholic steatohepatitis (NASH), in which there is steatosis and fibrosis in the liver, is linked to metabolic syndrome and progresses to hepatic cirrhosis. In this study, a novel hamster NASH model derived from metabolic syndrome was made using hamsters. Hamsters were fed a normal or a high-fat and high-cholesterol (HFC) diet for 12 weeks. Body weight and the ratio of liver weight to body weight were significantly greater in HFC diet-fed hamsters than in normal diet-fed hamsters. Triglyceride, low-density lipoprotein cholesterol, and glucose levels in blood were significantly increased in HFC diet-fed hamsters, and blood pressure also tended to be high, suggesting that the HFC diet-fed hamsters developed metabolic syndrome. Hepatic steatosis and fibrosis were observed in liver sections of HFC diet-fed hamsters, as in patients with NASH, but they were not seen in normal diet-fed hamsters. Chymase generates angiotensin II and transforming growth factor (TGF)-β, both of which are related to hepatic steatosis and fibrosis, and a significant augmentation of chymase activity was observed in livers from HFC diet-fed hamsters. Both angiotensin II and TGF-β were also significantly increased in livers of HFC diet-fed hamsters. Thus, HFC diet-fed hamsters might develop metabolic syndrome-derived NASH that clinically resembles that in NASH patients.

Topics: Angiotensin II; Animals; Body Weight; Cholesterol, Dietary; Chymases; Cricetinae; Diet, High-Fat; Disease Models, Animal; Liver; Liver Cirrhosis; Male; Metabolic Syndrome; Non-alcoholic Fatty Liver Disease; Organ Size; Transforming Growth Factor beta

We previously demonstrated that lansoprazole provided hepatoprotection in a drug-induced hepatitis animal model partially through the Nrf2/HO-1 pathway. Here, we examined whether lansoprazole could also provide hepatoprotection in a rat model of non-alcoholic steatohepatitis (NASH).. Six-week-old rats were fed a normal chow or a choline-deficient amino acid-defined (CDAA) diet to establish a rat model of NASH. The groups fed a CDAA diet for 5 weeks were subcutaneously administered either a vehicle or a lansoprazole suspension for 4 weeks beginning the second week of the experiment.. Bridging fibrosis was observed in the livers of almost all the NASH model rats (six of seven), but it was not always observed in NASH model rats (one of seven) continuously administered lansoprazole. The serum aspartate aminotransferase level elevated by the CDAA diet was significantly decreased following lansoprazole administration. Lansoprazole also increased the expression of Nrf2, but not HO-1, in the liver of NASH model rats. Lansoprazole decreased the level of activated TGF-β protein. Furthermore, interleukin-6 gene and protein expression were decreased.. Lansoprazole inhibits hepatic fibrogenesis, at least during the early stages, in CDAA diet-induced NASH model rats. The mechanisms might be associated with cytokine suppression but not the inhibition of reactive oxygen species.

Topics: Animals; Aspartate Aminotransferases; Diet; Disease Models, Animal; Disease Progression; Heme Oxygenase (Decyclizing); Interleukin-6; Lansoprazole; Liver Cirrhosis; Male; NF-E2-Related Factor 2; Non-alcoholic Fatty Liver Disease; Rats; Transforming Growth Factor beta

Accumulating evidence suggests that activated hepatocytes are involved in the deposition of the excess extracellular matrix during liver fibrosis via the epithelial to mesenchymal transition. Lipid accumulation in hepatocytes are implicated in the pathogenesis of chronic liver injury. CD36 is known to mediate long-chain fatty acid (LCFA) uptake and lipid metabolism. However, it is unclear whether LCFA directly promotes hepatocyte activation and the involved mechanisms have not been fully clarified.. Mice were fed with a high fat diet (HFD) and normal hepatocyte cells (Chang liver cells) were treated with palmitic acid (PA) in vivo and in vitro. Real-time polymerase chain reaction (RT-PCR) and western blotting were used to examine the gene and protein expression of molecules involved in hepatic fibrogenesis and hepatocyte activation. CD36 was knocked down by transfecting CD36 siRNA into hepatocyte cells. Hydrogen peroxide (H. HFD induced a profibrogenic response and up-regulated CD36 expression in vivo. Analogously, PA increased lipid accumulation and induced human hepatocyte activation in vitro, which was also accompanied by increased CD36 expression. Interestingly, knockdown of CD36 resulted in a reduction of hepatocyte lipid deposition and decreased expression of Acta2 (34% decrease), Vimentin (29% decrease), Desmin (60% decrease), and TGF-β signaling pathway related genes. In addition, HFD and PA increased the production of H. Our study demonstrated that LCFA facilitates hepatocyte activation by up-regulating oxidative stress through CD36, which could be an important mechanism in the development of hepatic fibrosis.

Topics: Actins; Animals; CD36 Antigens; Cell Line; Desmin; Diet, High-Fat; Gene Expression Regulation; Hepatocytes; Humans; Hydrogen Peroxide; Liver; Liver Cirrhosis; Mice; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Palmitic Acid; RNA, Small Interfering; Signal Transduction; Transforming Growth Factor beta; Vimentin

Liver disease is a leading cause of high mortality and morbidity worldwide. The aim of the present study is to investigate the regulatory role of prolyl hydroxylase-2 (PHD2)-hypoxia-inducible factor-2a (HIF-2α) axis on nonalcoholic fatty liver disease (NAFLD) and to explore the potential mechanisms by which endothelial (EC)-specific PHD2 deficiency regulates hepatic steatosis and fibrosis.. In the endothelial-specific PHD2 knockout (PHD2ECKO) mouse fed with normal diet or high fat diet (HFD), liver lipid accumulation and fibrosis were measured by Oil Red O and Masson trichrome staining. The fat and body weight (FW/BW) ratio and glucose tolerance were measured. The expression of HIF-2α, atrial natriuretic peptide (ANP), angiopoietin-2 (Ang-2), and transforming growth factor-b (TGF-β) were analyzed by western blot analysis.. The steatosis and fibrosis were significantly increased in the PHD2ECKO mice. FW/BW ratio was significantly increased in the PHD2ECKO mice. Moreover, knockout of endothelial PHD2 resulted in an impairment of glucose tolerance in mice. Western blot analysis showed that the expression of HIF-2α in liver tissues was not significantly increased. Interestingly, the expression of ANP was decreased, and Ang-2 and TGF-β levels were significantly increased in the liver of PHD2ECKO mice. The FW/BW ratio was also significantly increased in the PHD2ECKO mice fed with HFD for 16 weeks. Feeding HFD resulted in a significant increase in hepatic steatosis in the control PHD2f/f mice, but did not further enhance hepatic steatosis in the PHD2ECKO mice.. We concluded that the endothelial PHD2 plays a critical role in hepatic steatosis and fibrosis, which may be involved in the regulation of ANP and Ang-2/TGF-β signaling pathway, but not the HIF-2α expression.

Topics: Animals; Atrial Natriuretic Factor; Basic Helix-Loop-Helix Transcription Factors; Diet, High-Fat; Endothelium; Glucose Tolerance Test; Hypoxia-Inducible Factor-Proline Dioxygenases; Liver; Mice; Mice, Knockout; Non-alcoholic Fatty Liver Disease; Phosphofructokinase-2; Proto-Oncogene Proteins c-akt; Ribonuclease, Pancreatic; Signal Transduction; Transforming Growth Factor beta

Isoquercetin (IQ), a glucoside derivative of quercetin, has been reported to have beneficial effects in nonalcoholic fatty liver disease (NAFLD). In this study, we investigated the potential improvement of IQ in liver lipid accumulation, inflammation, oxidative condition, and activation in Kupffer cells (KCs) on a high-fat diet (HFD) induced NAFLD models. Male Sprague-Dawley (SD) rats were induced by HFD, lipopolysaccharides/free fatty acids (LPS/FFA) induced co-culture cells model between primary hepatocytes and Kupffer cells was used to test the effects and the underlying mechanism of IQ. Molecular docking was performed to predict the potential target of IQ. Significant effects of IQ were found on reduced lipid accumulation, inflammation, and oxidative stress. In addition, AMP-activated protein kinase (AMPK) pathway was activated by IQ, and is plays an important role in lipid regulation. Meanwhile, IQ reversed the increase of activated KCs which caused by lipid overload, and also suppression of Transforming growth factor beta (TGF-β) signaling by TGF-β Recptor-1 and SMAD2/3 signaling. Finally, TGF-βR1 and TGF-βR2 were both found may involve in the mechanism of IQ. IQ can improve hepatic lipid accumulation and decrease inflammation and oxidative stress by its activating AMPK pathway and suppressing TGF-β signaling to alleviate NAFLD.

Topics: AMP-Activated Protein Kinases; Animals; Biomarkers; Coculture Techniques; Cytokines; Diet, High-Fat; Disease Models, Animal; Down-Regulation; Inflammation; Kupffer Cells; Lipid Metabolism; Liver; Male; Molecular Docking Simulation; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Phosphorylation; Protein Serine-Threonine Kinases; Quercetin; Rats, Sprague-Dawley; Signal Transduction; Transforming Growth Factor beta

Nonalcoholic fibrosing steatohepatitis is a uniform process that occurs throughout nonalcoholic fatty liver disease (NAFLD). MicroRNAs (miRNAs) have been shown to be involved in the biological processes, but the role and molecular mechanism of miRNAs in NAFLD are not entirely clear. In this study, we observed a significant reduction in the expression of miR-130a-3p in livers of a mouse model with fibrosis induced by a methionine-choline-deficient diet, of NAFLD patients, and in activated hepatic stellate cells (HSCs). A dual-luciferase activity assay confirmed that transforming growth factor-beta receptors (TGFBRs) 1 and 2 were both the target genes of miR-130a-3p. The hepatic expression of TGFBR1 and TGFBR2 was significantly increased. Moreover, the overexpression of miR-130a-3p in HSCs inhibited HSC activation and proliferation, concomitant with the decreased expression of TGFBR1, TGFBR2, Smad2, Smad3, matrix metalloproteinase-2 (MMP-2), MMP-9, type I collagen (Col-1), and Col-4. In addition, the overexpression of miR-130a-3p promoted HSC apoptosis by inducing the expression of caspase-dependent apoptosis genes. Transfection with si-TGFBR1 and si-TGFBR2 revealed effects on HSC function that were consistent with those of miR-130a-3p. TGFBR1 and TGFBR2 rescued the miR-130a-3p-mediated reductions in the mRNA and protein expression levels of Smad2, Smad3, Col-1, and Col-4. In conclusion, our findings suggest that miR-130a-3p might play a critical role in negatively regulating HSC activation and proliferation in the progression of nonalcoholic fibrosing steatohepatitis by directly targeting TGFBR1 and TGFBR2 via the TGF-β/SMAD signaling pathway.

Topics: 3' Untranslated Regions; Adult; Animals; Apoptosis; Cell Proliferation; Collagen; Disease Models, Animal; Down-Regulation; Female; Gene Knockdown Techniques; Gene Ontology; Hepatic Stellate Cells; Humans; Male; Mice, Inbred C57BL; MicroRNAs; Middle Aged; Non-alcoholic Fatty Liver Disease; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type I; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Reproducibility of Results; Transforming Growth Factor beta

Chemokine (CC-motif) receptor-like 2 (CCRL2) is a decoy receptor and regulates the local responses of the chemokine chemerin. Recently our group has shown that the functional chemerin receptor, chemokine-like receptor 1 (CMKLR1), correlates with fibrosis and non-alcoholic steatohepatitis (NASH) score in males only. In our current study, we wanted to know whether CCRL2 shows similar correlations as CMKLR1. Therefore, we analyzed the hepatic expression of CCRL2 in murine NASH and in liver tissues obtained from 85 patients with non-alcoholic fatty liver disease (NAFLD) and 33 controls. CCRL2 mRNA was not significantly changed in murine and human NASH liver. CCRL2 mRNA levels were positively correlated with inflammation, fibrosis and NASH scores in the patients. Concordantly, CCRL2 was related to the mRNA levels of F4/80, transforming growth factor beta and alpha smooth muscle actin in murine NASH. In the human cohort, CCRL2 mRNA correlated with fibrosis score and CMKLR1 mRNA in both gender. CCRL2 mRNA was induced in the liver of type 2 diabetes and hypercholesterolemic patients, but still positively correlated with fibrosis score when these patients were excluded from calculations. Human hepatic stellate cells (HSC), hepatic sinusoidal endothelial cells and Kupffer cells (KC) express CCRL2 mRNA. TNF induces CCRL2 expression in HSC and lipopolysaccharide in KC suggesting that correlations identified in NAFLD patients are partly related to the activation of these cells.

Topics: Adult; Aged; Aged, 80 and over; Animals; Body Mass Index; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Gene Expression Regulation; Hepatic Stellate Cells; Humans; Hypercholesterolemia; Kupffer Cells; Liver; Male; Mice; Middle Aged; Non-alcoholic Fatty Liver Disease; Receptors, CCR; Receptors, Chemokine; Receptors, G-Protein-Coupled; RNA, Messenger; Transforming Growth Factor beta; Young Adult

Nonalcoholic fatty liver disease (NAFLD) is now the most common progressive liver disease in developed countries and is the second leading indication for liver transplantation due to the extensive fibrosis it causes. NAFLD progression is thought to be tied to chronic low-level type 1 inflammation originating in the adipose tissue during obesity; however, the specific immunological mechanisms regulating the progression of NAFLD-associated fibrosis in the liver are unclear. To investigate the immunopathogenesis of NAFLD more completely, we investigated adipose dysfunction, nonalcoholic steatohepatitis (NASH), and fibrosis in mice that develop polarized type 1 or type 2 immune responses. Unexpectedly, obese interleukin-10 (IL-10)/IL-4-deficient mice (type 1-polarized) were highly resistant to NASH. This protection was associated with an increased hepatic interferon-γ (IFN-γ) signature. Conversely, IFN-γ-deficient mice progressed rapidly to NASH with evidence of fibrosis dependent on transforming growth factor-β (TGF-β) and IL-13 signaling. Unlike increasing type 1 inflammation and the marked loss of eosinophils seen in expanding adipose tissue, progression of NASH was associated with increasing eosinophilic type 2 liver inflammation in mice and human patient biopsies. Finally, simultaneous inhibition of TGF-β and IL-13 signaling attenuated the fibrotic machinery more completely than TGF-β alone in NAFLD-associated fibrosis. Thus, although type 2 immunity maintains healthy metabolic signaling in adipose tissues, it exacerbates the progression of NAFLD collaboratively with TGF-β in the liver.

Topics: Adipose Tissue; Animals; Diet, High-Fat; Disease Progression; Eosinophils; Humans; Immunity; Inflammation; Interferon-gamma; Liver Cirrhosis; Male; Metabolic Diseases; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Obesity; Transforming Growth Factor beta

Topics: Humans; Liver; Metabolic Diseases; Non-alcoholic Fatty Liver Disease; Transforming Growth Factor beta

Topics: Disease Progression; Humans; Metabolic Diseases; Non-alcoholic Fatty Liver Disease; Transforming Growth Factor beta

Non-alcoholic fatty liver disease (NAFLD) is a major cause of liver morbidity and mortality, and there is still no proven effective therapy. The endocannabinoid system plays an important role in various liver diseases. Activin A is a member of the transforming growth factor beta (TGF-β) superfamily and inhibits hepatocyte growth. Follistatin antagonizes the biological actions of activin A. This study was designed to investigate the effect of rimonabant (a potent cannabinoid receptor1 (CB1) antagonist) on NAFLD induced with a choline-deficient (CD) diet in rats, as well as to detect whether it can alter the hepatic expression of activin A and follistatin. Forty rats were distributed among 4 groups: the control group, the rimonabant treatment group (normal rats that received rimonabant); the CD diet group (NAFLD induced with a CD diet); and the CD diet + rimonabant group (NAFLD treated with rimonabant). It was found that the CD diet caused significant increase in liver index, serum levels of liver enzymes, malondialdehyde (MDA), TGF-β1, activin A, and CB1 expression in liver tissue, with a significant decrease in glutathione peroxidase (GSH-Px) and follistatin mRNA expression in liver tissues. The administration of rimonabant significantly improved all of the studied parameters compared with the group fed the CD diet alone. Histopathological examination supported these results. We concluded that rimonabant significantly counteracted NAFLD induced with the CD diet by decreasing oxidative stress and hepatic expression of TGF-β1, and modulating the hepatic expression of activin A and follistatin.

Topics: Activins; Animals; Biomarkers; Cannabinoid Receptor Antagonists; Cytoprotection; Disease Models, Animal; Follistatin; Gene Expression Regulation; Liver; Male; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Rimonabant; RNA, Messenger; Transforming Growth Factor beta

Growth arrest and DNA damage-inducible 45 α (Gadd45α) is a stress-inducible protein that plays an important role in cell survival/death and DNA repair, but its contribution to the development of nonalcoholic steatohepatitis (NASH) has not been investigated. C57BL/6 Gadd45a-null and wild-type (WT) mice were treated with a methionine and choline-deficient diet (MCD) for eight weeks and phenotypic changes examined. Gadd45a-null mice had more severe hepatic inflammation and fibrosis, higher levels of mRNAs encoding pro-inflammatory, pro-fibrotic, and pro-apoptotic proteins, and greater oxidative and endoplasmic reticulum (ER) stress compared with WT mice. Indeed, Gadd45a mRNA was induced in response to ER stress in primary hepatocytes. Lipidomic analysis of NASH livers demonstrated decreased triacylglycerol (TG) in MCD-treated Gadd45a-null mice, which was associated with increased mRNAs encoding phospholipase D (Pld1/2), phosphatidic acid phosphatase type 2A, and choline/ethanolamine phosphotransferase 1 (Cept1), involved in the phosphatidylcholine-phosphatidic acid-diacylglycerol cycle, and decreased mRNAs encoding fatty acid (FA)-binding protein 1 (Fabp1) and FA transport protein 5. Treatment of cultured primary hepatocytes with tumor necrosis factor α, transforming growth factor β, and hydrogen peroxide led to the corresponding induction of Fabp1, Pld1/2, and Cept1 mRNAs. Collectively, Gadd45α plays protective roles against MCD-induced NASH likely due to attenuating cellular stress and ensuing inflammatory signaling. These results also suggest an interconnection between hepatocyte injury, inflammation and disrupted glycerophospholipid/FA metabolism that yields a possible mechanism for decreased TG accumulation with NASH progression (i.e., "burned-out" NASH).

Topics: Animals; Cell Cycle Proteins; Choline Deficiency; Diet; Endoplasmic Reticulum Stress; Fatty Acid Transport Proteins; Fatty Acid-Binding Proteins; Fatty Acids; Glycerophospholipids; Hepatocytes; Male; Methionine; Mice, Inbred C57BL; Mice, Knockout; Non-alcoholic Fatty Liver Disease; Nuclear Proteins; Phosphatidate Phosphatase; Phospholipase D; RNA, Messenger; Transferases (Other Substituted Phosphate Groups); Transforming Growth Factor beta; Triglycerides; Tumor Necrosis Factor-alpha

The effects of pomegranate juice (PJ) on the risk factors of non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) have been reported previously; however, the effects on NAFLD and its prevention have not yet been clarified. The present study aimed to evaluate the effects of PJ consumption with respect to the prevention of NAFLD/NASH development. Sprague-Dawley rats were fed either a high-fat, high sugar diet (model group); a high-fat, high sugar diet plus PJ (model+PJ); or a chow diet ad libitum for 7 weeks. Serum levels of fasting glucose, triglyceride, cholesterol, liver enzymes, insulin and hepatic tumor necrosis factor-α and tissue growth factor-β gene expression were determined. Hepatic histology was examined by hemotoxylin and eosin staining.. The model+PJ group had significantly lower hepatic steatosis, ballooning, lobular inflammation and portal inflammation (P < 0.001); lower hepatic pro-inflammatory and pro-fibrotic gene expression (P < 0.001); and lower plasma levels of alanine aminotransferase (P = 0.026), aspartate aminotransferase (P = 0.041), insulin (P < 0.001), triglycerides (P = 0.041) and glucose (P = 0.009) compared to the model group; however, weight gain, food intake and plasma high-density lipoprotein levels were not significantly different between these two groups.. The data obtained in the present study indicate that the regular consumption of PJ can prevent NAFLD even in the presence of the other risk factors such as obesity, hypercholesterolemia, and high energy, fat and sugar intakes. © 2016 Society of Chemical Industry.

Topics: Animals; Blood Glucose; Cholesterol; Diet, High-Fat; Dietary Carbohydrates; Fruit and Vegetable Juices; Inflammation; Insulin; Liver; Lythraceae; Male; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Rats, Sprague-Dawley; Transforming Growth Factor beta; Triglycerides

The role of invariant natural killer T cells in the development of nonalcoholic steatohepatitis (NASH) has not yet been fully understood. Here, the effect of the invariant natural killer T-cell activator alpha-galactosylceramide (αGalCer) on the development of nonalcoholic fatty liver disease and intestinal barrier function was assessed in a mouse model of early Western-style diet (WSD) induced NASH.. Female C57BL/6J mice were either fed a liquid control diet or a liquid fructose-enriched WSD for 6 wk while being treated three times weekly with αGalCer (2 μg intraperitoneal) or vehicle. Indices of liver damage, glucose metabolism, and intestinal permeability were measured. Treatment with αGalCer markedly suppressed hepatic fat accumulation and inflammation while not affecting fasting glucose. The protective effects of αGalCer were associated with a protection against the increased translocation of bacterial endotoxins and the decreased protein levels of tight junction proteins occludin and zonula occludens 1 found in vehicle-treated mice while being fed a WSD.. Taken together, our data suggest that the protective effects of αGalCer against the development of a diet-induced NASH in mice are associated with a protection against the increased translocation of intestinal bacterial endotoxins associated with the development of NASH.

Topics: Actins; Alanine Transaminase; Animals; Aspartate Aminotransferases; Diet, Western; Disease Models, Animal; Endotoxins; Female; Galactosylceramides; Interferon-gamma; Intestines; Mice; Mice, Inbred C57BL; Natural Killer T-Cells; Non-alcoholic Fatty Liver Disease; Occludin; Protective Agents; Tight Junction Proteins; Transforming Growth Factor beta; Triglycerides; Zonula Occludens-1 Protein

Topics: Female; Hepatic Stellate Cells; Humans; Male; Non-alcoholic Fatty Liver Disease; Receptors, Calcitriol; Transforming Growth Factor beta; Vitamin D

Obesity and nonalcoholic fatty liver disease (NAFLD) are associated with the development and progression of chronic kidney disease. We recently showed that NAFLD induces liver-specific cytochrome P-450 (CYP)2E1-mediated metabolic oxidative stress after administration of the CYP2E1 substrate bromodichloromethane (BDCM) (Seth RK, Das S, Kumar A, Chanda A, Kadiiska MB, Michelotti G, Manautou J, Diehl AM, Chatterjee S. Toxicol Appl Pharmacol 274: 42-54, 2014; Seth RK, Kumar A, Das S, Kadiiska MB, Michelotti G, Diehl AM, Chatterjee S. Toxicol Sci 134:291-303, 2013). The present study examined the effects of CYP2E1-mediated oxidative stress in NAFLD leading to kidney toxicity. Mice were fed a high-fat diet for 12 wk to induce NAFLD. NAFLD mice were exposed to BDCM, a CYP2E1 substrate, for 4 wk. NAFLD + BDCM increased CYP2E1-mediated lipid peroxidation in proximal tubular cells compared with mice with NAFLD alone or BDCM-treated lean mice, thus ruling out the exclusive role of BDCM. Lipid peroxidation increased IL-1β, TNF-α, and interferon-γ. In parallel, mesangial cell activation was observed by increased α-smooth muscle actin and transforming growth factor-β, which was blocked by the CYP2E1 inhibitor diallyl sulphide both in vivo and in vitro. Mice lacking natural killer T cells (CD1d knockout mice) showed elevated (>4-fold) proinflammatory mediator release, increased Toll-like receptor (TLR)4 and PDGF2 mRNA, and mesangial cell activation in the kidney. Finally, NAFLD CD1D knockout mice treated with BDCM exhibited increased high mobility group box 1 and Fas ligand levels and TUNEL-positive nuclei, indicating that higher cell death was attenuated in TLR4 knockout mice. Tubular cells showed increased cell death and cytokine release when incubated with activated mesangial cells. In summary, an underlying condition of progressive NAFLD causes renal immunotoxicity and aberrant glomerular function possibly through high mobility group box 1-dependent TLR4 signaling and mesangial cell activation, which, in turn, is modulated by intrinsic CD1D-dependent natural killer T cells.

Topics: Animals; Antigens, CD1d; Cell Death; Cell Line; Cell Proliferation; Cellular Microenvironment; Cytochrome P-450 CYP2E1; Diet, High-Fat; Disease Models, Animal; Fibrosis; HMGB1 Protein; Inflammation Mediators; Kidney Diseases; Kidney Tubules, Proximal; Lipid Peroxidation; Liver; Male; Mesangial Cells; Mice, Inbred C57BL; Mice, Knockout; Natural Killer T-Cells; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Toll-Like Receptor 4; Transforming Growth Factor beta; Trihalomethanes

Nonalcoholic steatohepatitis (NASH) affects 3%-5% of the U.S. population, having severe clinical complications to the development of fibrosis and end-stage liver diseases, such as cirrhosis and hepatocellular carcinoma. A critical cause of NASH is chronic systemic inflammation promoted by innate immune cells, such as liver macrophages (Mϕ) and natural killer (NK) cells. However, little is known about how the crosstalk between Mϕ and NK cells contributes to regulate NASH progression to fibrosis. In this report, we demonstrate that NKp46(+) cells play an important role in preventing NASH progression to fibrosis by regulating M1/M2 polarization of liver Mϕ. Using a murine model of NASH, we demonstrate that DX5(+)NKp46(+) NK cells are increased during disease and play a role in polarizing Mϕ toward M1-like phenotypes. This NK's immunoregulatory function depends on the production of interferon-gamma (IFN-γ), but not by granzyme-mediated cytolytic activity. Notably, depletion of NKp46(+) cells promotes the development of fibrosis with increased expression of profibrogenic genes as well as skewed M2 Mϕ phenotypes in hepatic tissues.. NK cell-derived IFN-γ may be essential for maintaining a balanced inflammatory environment that promotes tissue integrity and limiting NASH progression to fibrosis.

Topics: Animals; Cell Death; Collagen; Disease Progression; Female; Fibrosis; Hepatic Stellate Cells; Immunity, Innate; Interferon-gamma; Killer Cells, Natural; Liver; Macrophage Activation; Macrophages; Mice, Inbred C57BL; Natural Cytotoxicity Triggering Receptor 1; Non-alcoholic Fatty Liver Disease; Phenotype; Receptor Cross-Talk; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

nonalcoholic fatty liver disease (NAFLD), an obesity and insulin resistance associated clinical condition - ranges from simple steatosis to nonalcoholic steatohepatitis. To model the human condition, a high-fat Western diet that includes liquid sugar consumption has been used in mice. Even though liver pathophysiology has been well characterized in the model, little is known about the metabolic phenotype (e.g., energy expenditure, activity, or food intake). Furthermore, whether the consumption of liquid sugar exacerbates the development of glucose intolerance, insulin resistance, and adipose tissue dysfunction in the model is currently in question. In our study, a high-fat Western diet (HFWD) with liquid sugar [fructose and sucrose (F/S)] induced acute hyperphagia above that observed in HFWD-fed mice, yet without changes in energy expenditure. Liquid sugar (F/S) exacerbated HFWD-induced glucose intolerance and insulin resistance and impaired the storage capacity of epididymal white adipose tissue (eWAT). Hepatic TG, plasma alanine aminotransferase, and normalized liver weight were significantly increased only in HFWD+F/S-fed mice. HFWD+F/S also resulted in increased hepatic fibrosis and elevated collagen 1a2, collagen 3a1, and TGFβ gene expression. Furthermore, HWFD+F/S-fed mice developed more profound eWAT inflammation characterized by adipocyte hypertrophy, macrophage infiltration, a dramatic increase in crown-like structures, and upregulated proinflammatory gene expression. An early hypoxia response in the eWAT led to reduced vascularization and increased fibrosis gene expression in the HFWD+F/S-fed mice. Our results demonstrate that sugary water consumption induces acute hyperphagia, limits adipose tissue expansion, and exacerbates glucose intolerance and insulin resistance, which are associated with NAFLD progression.

Topics: Adipocytes, White; Adipose Tissue, White; Alanine Transaminase; Animals; Collagen Type I; Collagen Type III; Diet, High-Fat; Diet, Western; Dietary Sucrose; Disease Models, Animal; Fibrosis; Fructose; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Hyperphagia; Immunoblotting; Insulin Resistance; Liver; Macrophages; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Obesity; Organ Size; Phenotype; Proto-Oncogene Proteins c-akt; Transcriptome; Transforming Growth Factor beta; Triglycerides

Phosphatidylethanolamine N-methyltransferase (PEMT) is an important enzyme in hepatic phosphatidylcholine (PC) biosynthesis. Pemt(-/-) mice are protected against high-fat diet (HFD)-induced obesity and insulin resistance; however, these mice develop nonalcoholic fatty liver disease (NAFLD). We hypothesized that peroxisomal proliferator-activated receptor-γ (PPARγ) activation by pioglitazone might stimulate adipocyte proliferation, thereby directing lipids from the liver toward white adipose tissue. Pioglitazone might also act directly on PPARγ in the liver to improve NAFLD. Pemt(+/+) and Pemt(-/-) mice were fed a HFD with or without pioglitazone (20 mg·kg(-1)·day(-1)) for 10 wk. Pemt(-/-) mice were protected from HFD-induced obesity but developed NAFLD. Treatment with pioglitazone caused an increase in body weight gain in Pemt(-/-) mice that was mainly due to increased adiposity. Moreover, pioglitazone improved NAFLD in Pemt(-/-) mice, as indicated by a 35% reduction in liver weight and a 57% decrease in plasma alanine transaminase levels. Livers from HFD-fed Pemt(-/-) mice were steatotic, inflamed, and fibrotic. Hepatic steatosis was still evident in pioglitazone-treated Pemt(-/-) mice; however, treatment with pioglitazone reduced hepatic fibrosis, as evidenced by reduced Sirius red staining and lowered mRNA levels of collagen type Iα1 (Col1a1), tissue inhibitor of metalloproteinases 1 (Timp1), α-smooth muscle actin (Acta2), and transforming growth factor-β (Tgf-β). Similarly, oxidative stress and inflammation were reduced in livers from Pemt(-/-) mice upon treatment with pioglitazone. Together, these data show that activation of PPARγ in HFD-fed Pemt(-/-) mice improved liver function, while these mice were still protected against diet-induced obesity and insulin resistance.

Topics: Actins; Adipocytes, White; Adipose Tissue, White; Adiposity; Animals; Anti-Infective Agents; Cell Proliferation; Collagen Type I; Collagen Type I, alpha 1 Chain; Diet, High-Fat; Genetic Predisposition to Disease; Hepatitis; Insulin Resistance; Liver; Liver Cirrhosis, Experimental; Mice, Inbred C57BL; Mice, Knockout; Non-alcoholic Fatty Liver Disease; Obesity; Oxidative Stress; Phenotype; Phosphatidylethanolamine N-Methyltransferase; Pioglitazone; PPAR gamma; Signal Transduction; Thiazolidinediones; Time Factors; Tissue Inhibitor of Metalloproteinase-1; Transforming Growth Factor beta

Although animal studies demonstrated that Smad7 induction ameliorates TGF-β/SMAD-mediated fibrogenesis, its role in human hepatic diseases is rather obscure. Our study explored the activation status of TGF-β/activin pathway in patients with chronic liver diseases, and how it is affected by successful antiviral treatment in chronic HBV hepatitis (CHB).. Thirty-seven CHB patients (19 with active disease, 14 completely remitted on long-term antiviral treatment and 4 with relapse after treatment withdrawal), 18 patients with chronic HCV hepatitis, 12 with non-alcoholic fatty liver disease (NAFLD), and 3 controls were enrolled in the study. Liver mRNA levels of CTGF, all TGF-β/activin isoforms, their receptors and intracellular mediators (SMADs) were evaluated using qRT-PCR and were correlated with the grade of liver inflammation and fibrosis staging. The expression and localization of pSMAD2 and pSMAD3 were assessed by immunohistochemistry.. TGF-β signalling is activated in CHB patients with active disease, while SMAD7 is up-regulated during the resolution of inflammation after successful treatment. SMAD7 overexpression was also observed in NAFLD patients exhibiting no or minimal fibrosis, despite the activation of TGF-β/activin signaling.. SMAD7 overexpression might represent a mechanism limiting TGF-β-mediated fibrogenesis in human hepatic diseases; therefore, SMAD7 induction likely represents a candidate for novel therapeutic approaches.

Topics: Adult; Aged; Antiviral Agents; Chronic Disease; Female; Fibrosis; Hepatitis B; Hepatitis C; Humans; Liver; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; RNA, Messenger; Signal Transduction; Smad7 Protein; Transforming Growth Factor beta; Young Adult

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide and there is an urgent need to identify effective pharmacological strategies to treat NAFLD. For this purpose, in the present study, we examined the the possible molecular mechanisms responsible for the effects of MgIG and the protective effects of MgIG in a model of NAFLD. The human hepatic L02 cell line and oleic acid were employed to establish an in vitro model of NAFLD. The CCK-8 assay, Hoechst 33258 staining and Annexin V-PI staining were performed in order to evaluate cell viability and apoptosis. Oil red O staining was used to detect lipid accumulation within the L02 cells. We found that MgIG significantly inhibited lipid accumulation and protected the L02 cells against lipid accumulation-induced apoptosis. Key molecules involved in unfolded protein response (UPR) signaling were upregulated in lipid-overloaded hepatic cells whereas MgIG suppressed the activation of the UPR. Furthermore, MgIG significantly inhibited the expression of the downstream inflammatory cytokines which had been induced by lipid accumulation. Taken together, these findings suggest that the activation of UPR signaling induces the expression of inflammatory cytokines through the activation of nuclear factor-κB (NF-κB) in lipid-overloaded hepatic cells. In addition, MgIG may suppress the activation of UPR signaling thereby protecting hepatic cells from NAFLD‑induced injury.

Topics: Apoptosis; Cell Line; Cell Survival; Fibroblast Growth Factor 2; Humans; Interleukin-6; Lipid Droplets; NF-kappa B; Non-alcoholic Fatty Liver Disease; Oleic Acid; Protective Agents; RNA, Messenger; Saponins; Signal Transduction; Transforming Growth Factor beta; Triterpenes; Unfolded Protein Response

Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease and is increasing with the rising rate of obesity in the developed world. Signaling pathways known to influence the rate of lipid deposition in liver, known as hepatic steatosis, include the transforming growth factor (TGF) superfamily, which function through the SMAD second messengers. The kielin/chordin-like protein (KCP) is a large secreted protein that can enhance bone morphogenetic protein signaling while suppressing TGF-β signaling in cells and in genetically modified mice. In this report, we show that aging KCP mutant (Kcp

Topics: Aging; Animals; Carrier Proteins; Diet, High-Fat; Disease Models, Animal; Gene Expression Profiling; Liver; Mice; Mice, Knockout; Non-alcoholic Fatty Liver Disease; Phosphorylation; Signal Transduction; Smad3 Protein; Transforming Growth Factor beta

Non-alcoholic fatty liver disease (NAFLD) is closely linked to obesity and constitutes part of the metabolic syndrome, which have been associated with low serum vitamin D (VD). Due to known crosstalk between VD and transforming growth factor (TGF)-β signalling, VD has been proposed as an antifibrotic treatment.. We evaluated the association between VD, the vitamin D receptor (VDR) and liver fibrosis in primary human hepatic stellate cells (phHSC) and 106 morbidly obese patients with NAFLD.. Treating phHSC with VD ameliorated TGF-β-induced fibrogenesis via both VDR-dependent and VDR-independent mechanisms. Reduction of fibrogenic response was abolished in cells homozygous for GG at the A1012G single nucleotide polymorphisms within the VDR gene. Compared with healthy livers, NAFLD livers expressed higher levels of VDR mRNA and VDR fragments. VDR mRNA was lower in patients homozygous for GG at A1012G and expression of pro-fibrogenic genes was higher in patients carrying the G allele.. VD may be an antifibrotic treatment option early in the onset of fibrosis in specific genotypes for VDR. Known polymorphisms of the VDR may influence the response to VD treatment.

Topics: Adult; Cells, Cultured; Drug Evaluation, Preclinical; Female; Gene Expression Regulation; Gene Knockdown Techniques; Hepatic Stellate Cells; Humans; Liver; Liver Cirrhosis; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Obesity, Morbid; Polymorphism, Single Nucleotide; Receptors, Calcitriol; RNA, Messenger; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta; Vitamin D; Young Adult

Topics: Female; Hepatic Stellate Cells; Humans; Male; Non-alcoholic Fatty Liver Disease; Receptors, Calcitriol; Transforming Growth Factor beta; Vitamin D

Hepatic fibrosis in nonalcoholic steatohepatitis (NASH) is the common pathophysiological process resulting from chronic liver inflammation and oxidative stress. Although significant research has been carried out on the role of leptin-induced NADPH oxidase in fibrogenesis, the molecular mechanisms that connect the leptin-NADPH oxidase axis in upregulation of transforming growth factor (TGF)-β signaling have been unclear. We aimed to investigate the role of leptin-mediated upregulation of NADPH oxidase and its subsequent induction of micro-RNA 21 (miR21) in fibrogenesis. Human NASH livers and a high-fat (60% kcal) diet-fed chronic mouse model, where hepatotoxin bromodichloromethane was used to induce NASH, were used for this study. To prove the role of the leptin-NADPH oxidase-miR21 axis, mice deficient in genes for leptin, p47phox, and miR21 were used. Results showed that wild-type mice and human livers with NASH had increased oxidative stress, increased p47phox expression, augmented NF-κB activation, and increased miR21 levels. These mice and human livers showed increased TGF-β, SMAD2/3-SMAD4 colocalizations in the nucleus, increased immunoreactivity against Col1α, and α-SMA with a concomitant decrease in protein levels of SMAD7. Mice that were deficient in leptin or p47phox had decreased activated NF-κB and miR21 levels, suggesting the role of leptin and NADPH oxidase in inducing NF-κB-mediated miR21 expression. Further miR21 knockout mice had decreased colocalization events of SMAD2/3-SMAD4 in the nucleus, increased SMAD7 levels, and decreased fibrogenesis. Taken together, the studies show the novel role of leptin-NADPH oxidase induction of miR21 as a key regulator of TGF-β signaling and fibrogenesis in experimental and human NASH.

Topics: Animals; Case-Control Studies; Cell Nucleus; Diet, High-Fat; Disease Models, Animal; Humans; Leptin; Liver; Male; Membrane Glycoproteins; Mice, Inbred C57BL; Mice, Knockout; MicroRNAs; NADPH Oxidase 2; NADPH Oxidases; NF-kappa B; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Peroxynitrous Acid; RNA Interference; Signal Transduction; Smad Proteins, Receptor-Regulated; Smad4 Protein; Smad7 Protein; Transforming Growth Factor beta; Trihalomethanes

Pro-inflammatory mediators, glucocorticoids and transforming growth factor (TGF)-β are implicated in the pathogenesis of non-alcoholic steatohepatitis (NASH)-related insulin resistance. As physical activity is beneficial against NASH, we analyzed the voluntary physical activity (VPA) and endurance training (ET) (preventive and therapeutic strategies) effects on hepatic insulin, pro-inflammatory and glucocorticoid signaling regulators/mediators in high-fat (Lieber-DeCarli) diet (HFD)-induced NASH.. Adult male Sprague-Dawley rats were divided in standard diet (SD) or HFD, with sedentary, VPA and ET animals in both diet regimens. Plasma glucose and insulin concentrations were analyzed; plasma insulin sensitivity index (ISI) was calculated. Hepatic insulin, pro-inflammatory and glucocorticoid signaling regulators/mediators were evaluated by Western blot or reverse transcriptase-PCR.. ET improved ISI in both diet regimens. HFD-feeding increased interleukin-1β and induced a similar pattern on interleukin-6 and TGF-β, which were globally reduced by physical exercise. ET decreased HFD leukemia inhibitory factor level, SD+VPA animals presenting higher values than HFD+VPA animals. HFD increased the ratio of IRS-1(Ser307)/total IRS-1, which was completely mitigated by physical exercise. Physical exercise reduced total ERK and JNK (total and activated) expression in HFD. In SD vs. HFD, VPA presented higher activated JNK and ET presented higher total JNK. Generally, in HFD, the ratio (activated/total) of AKT, and each separately, decreased with exercise and also for activated AKT in SD. Overall, in both diets, exercise reduced 11β-hydroxysteroid dehydrogenase type 1. ET increased glucocorticoid receptor and reduced PTP1B in HFD.. Physical exercise mitigates the expression of pro-inflammatory mediators and positively modulates insulin and glucocorticoid signaling in NASH.

Topics: Animals; Blotting, Western; Diet, High-Fat; DNA Primers; Glucocorticoids; Inflammation Mediators; Insulin; Insulin Resistance; Male; Motor Activity; Non-alcoholic Fatty Liver Disease; Physical Conditioning, Animal; Physical Endurance; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Statistics, Nonparametric; Transforming Growth Factor beta

Non-alcoholic steatohepatitis (NASH) is a progressive liver disease more commonly diagnosed in obesity. Therapeutic options to treat NASH are limited. Liver inflammation is a hallmark of NASH, and here it was tested whether the lipid mediator resolvin E1 (RvE1) and chemerin derived C15 peptide, which both exert potent anti-inflammatory activities, ameliorate NASH pathology. Male mice fed an atherogenic diet for 12 weeks, well described to induce NASH, received intraperitoneal injections of RvE1, C15 peptide or PBS as control for four days. Both treatments did not affect body weight or serum ALT. Liver triglycerides were neither reduced by the lipid nor the peptide. Hepatic expression of the macrophage marker F4/80 and the inflammatory mediators TNF and CCL2 was not changed. Further, fibrotic genes including TGFbeta, alphaSMA and CTGF were not affected by RvE1 or C15 injections. Serum adiponectin was comparable in the three groups. RvE1 and C15 are ligands of CMKLR1 whose expression was not reduced upon feeding the NASH inducing diet. This excludes low receptor levels as reason for therapeutic failure. In summary, current data demonstrate that RvE1 and chemerin derived C15 peptide do not ameliorate murine NASH.

Topics: Actins; Adiponectin; Animals; Anti-Inflammatory Agents; Antigens, Differentiation; Chemokine CCL2; Chemokines; Chemotactic Factors; Connective Tissue Growth Factor; Eicosapentaenoic Acid; Intercellular Signaling Peptides and Proteins; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Peptides; Receptors, Chemokine; Receptors, G-Protein-Coupled; Transforming Growth Factor beta; Triglycerides; Tumor Necrosis Factor-alpha

Nonalcoholic fatty liver disease (NAFLD) and its progressive form, nonalcoholic steatohepatitis (NASH), are the most common causes of chronic liver disease. In this study, we evaluated the effects of Epigallocatechin gallate (EGCG) on methionine- and choline-deficient (MCD) diet-induced NASH. Our data showed that EGCG significantly prevented MCD diet-induced liver and body weight loss. Histological analysis showed that EGCG inhibited MCD diet-induced steatohepatitis including fat accumulation and inflammatory cells infiltration. Biochemical analysis data showed that EGCG significantly reduced the elevation of plasma ALT and AST levels but increased plasma triglyceride and cholesterol contents. However, EGCG significantly inhibited hepatic triglyceride and cholesterol content in MCD diet fed mice. Consistent with histology results, EGCG treatment significantly inhibited MCD diet-induced IL-1β, IL-6, TNF-α and MCP-1 mRNA expression. As an antioxidant, EGCG treatment significant inhibited hepatic MDA contents and increased hepatic SOD contents. In addition, transforming growth factor (TGF)-β, collagen I-α1, tissue inhibitor of metalloproteinase 1 (TIMP-1) and α-smooth muscle actin (SMA) mRNA expression, which are markers of hepatic fibrosis, were markedly inhibited by EGCG treatment. Western blot data showed that EGCG inhibited Smad2 and Smad3 phosphorylation in the liver and LX-2 cells which were involved in TGF-β-induced pathway. Taken together, EGCG attenuated NASH induced by MCD diet associated with ameliorating fibrosis, oxidative stress, and hepatic inflammation. Our results indicate that EGCG has beneficial roles in the development of MCD diet-induced NASH.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Biomarkers; Catechin; Choline Deficiency; Cytoprotection; Disease Models, Animal; Dose-Response Relationship, Drug; Hep G2 Cells; Humans; Inflammation Mediators; Lipids; Liver; Male; Methionine; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Signal Transduction; Transforming Growth Factor beta

Myeloperoxidase (MPO), a highly oxidative enzyme secreted by leukocytes has been implicated in human and experimental nonalcoholic steatohepatitis (NASH), but the underlying mechanisms remain unknown. In this study, we investigated how MPO contributes to progression from steatosis to NASH.. In C57Bl/6J mice fed a diet deficient in methionine and choline to induce NASH, neutrophils and to a lesser extent inflammatory monocytes are markedly increased compared with sham mice and secrete abundant amounts of MPO. Through generation of HOCl, MPO directly causes hepatocyte death in vivo. In vitro experiments demonstrate mitochondrial permeability transition pore induction via activation of SAPK/JNK and PARP. MPO also contributes to activation of hepatic stellate cells (HSCs), the most important source of collagen in the liver. In vitro MPO-activated HSCs have an activation signature (MAPK and PI3K-AKT phosphorylation) and upregulate COL1A1, α-SMA, and CXCL1. MPO-derived oxidative stress also activates transforming growth factor β (TGF-β) in vitro, and TGF-β signaling inhibition with SB-431542 decreased steatosis and fibrosis in vivo. Conversely, congenital absence of MPO results in reduced hepatocyte injury, decreased levels of TGF-β, fewer activated HSCs, and less severe fibrosis in vivo.. Cumulatively, these findings demonstrate important cross talk between inflammatory myeloid cells, hepatocytes, and HSCs via MPO and establish MPO as part of a proapoptotic and profibrotic pathway of progression in NASH, as well as a potential therapeutic target to ameliorate this disease.

Topics: Animals; Apoptosis; Cell Communication; Cell Membrane Permeability; Cytokines; Disease Models, Animal; Enzyme Activation; Gene Expression; Hepatic Stellate Cells; Hepatocytes; Intracellular Membranes; Liver Cirrhosis; Mice; Mice, Knockout; Mitochondria, Liver; Models, Biological; Myeloid Cells; Neutrophils; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Peroxidase; Signal Transduction; Transforming Growth Factor beta

DHA (22:6,ω3), but not EPA (20:5,ω3), attenuates Western diet (WD)-induced hepatic fibrosis in a Ldlr(-/-) mouse model of nonalcoholic steatohepatitis. We examined the molecular basis for the differential effect of dietary EPA and DHA on WD-induced hepatic fibrosis. DHA was more effective than EPA at preventing WD-induced effects on hepatic transcripts linked to fibrosis, including collagen 1A1 (Col1A1), transforming growth factor-β (TGFβ) signaling and proteins involved in remodeling the extracellular matrix, including metalloproteases, tissue inhibitors of metalloproteases, and lysyl oxidase subtypes. Examination of the TGFβ pathway showed that mice fed the WD supplemented with either olive oil or EPA had a significant (≥2.5-fold) increase in hepatic nuclear abundance of phospho-mothers against decapentaplegic homolog (Smad)3 when compared with mice fed the reference diet (RD); Smad3 is a key regulator of Col1A1 expression in stellate cells. In contrast, mice fed the WD supplemented with DHA had no increase in phospho-Smad3 when compared with mice fed the RD. Changes in hepatic phospho-Smad3 nuclear content correlated with proCol1A1 mRNA and protein abundance. Pretreatment of human LX2 stellate cells with DHA, but not other unsaturated fatty acids, blocked TGFβ1-mediated induction of Col1A1. In conclusion, DHA attenuates WD-induced fibrosis by targeting the TGFβ-Smad3-Col1A1 pathway in stellate cells.

Topics: Animals; Collagen Type I; Collagen Type I, alpha 1 Chain; Diet, Western; Dietary Supplements; Disease Models, Animal; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; Hepatic Stellate Cells; Liver Cirrhosis; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Non-alcoholic Fatty Liver Disease; Smad3 Protein; Transforming Growth Factor beta

Scavenger receptor, class B type I (SR-BI) is a physiologically relevant regulator of high density lipoprotein (HDL) metabolism. Low HDL is a common feature of patients with non-alcoholic fatty liver disease (NAFLD). Here, hepatic SR-BI expression was analyzed in human and murine NAFLD. In primary human hepatocytes NAFLD relevant factors like inflammatory cytokines, lipopolysaccharide and TGF-β did not affect SR-BI protein. Similarly, oleate and palmitate had no effect. The adipokines chemerin, adiponectin, leptin and omentin did not regulate SR-BI expression. Accordingly, hepatic SR-BI was not changed in human and murine fatty liver and non-alcoholic steatohepatits. SR-BI was higher in type 2 diabetes patients but not in those with hypercholesterolemia. The current study indicates a minor if any role of SR-BI in human and murine NAFLD.

Topics: Adiponectin; Adult; Aged; Aged, 80 and over; Animals; Chemokines; Cytokines; Diabetes Mellitus, Type 2; Female; Gene Expression Regulation; GPI-Linked Proteins; Hepatocytes; Humans; Intercellular Signaling Peptides and Proteins; Lectins; Leptin; Lipopolysaccharides; Lipoproteins, HDL; Liver; Male; Mice; Middle Aged; Non-alcoholic Fatty Liver Disease; Oleic Acid; Palmitic Acid; Primary Cell Culture; Scavenger Receptors, Class B; Signal Transduction; Transforming Growth Factor beta

n-3 polyunsaturated fatty acids (PUFA) ameliorate fatty liver in experimental models, but their effects on inflammation and fibrosis during steatohepatitis are either controversial or lacking. We compared the effects of supplementation with olive oil (OO) alone or OO and n-3 PUFA on the development and progression of experimental steatohepatitis.. Balb/C mice (≥5 mice/group) were fed a methionine- and choline-deficient (MCD) diet or a control diet for 4 or 8 weeks. At the same time, mice were supplemented with n-3 PUFA (eicosapentaenoic and docosahexahenoic acid, 25 mg together with 75 mg OO), or OO alone (100 mg), two times a week by intragastric gavage.. After 8 weeks, mice on MCD/n-3 had higher ALT levels compared to MCD/OO and more severe scores of inflammation, including a significant increase in the number of lipogranulomas (26.4 ± 8.4 vs. 5.1 ± 5 per field, P < 0.001). Intrahepatic expression of TNF-α and CCL2 was higher in MCD/n-3 mice at both time points. In addition, increased expression of the profibrogenic genes TIMP-1 and TGF-β, and more severe histological scores of fibrosis were evident in MCD/n-3 mice. After 8 week of MCD diet, portal pressure was higher in mice receiving n-3 than in those on OO alone (5.1 ± 1.4 vs. 7.0 ± 0.9 mmHg, P < 0.05). Analysis of hepatic fatty acid profile showed that supplementation resulted in effective incorporation of n-3 PUFA.. In a murine model of steatohepatitis, supplementation with n-3 PUFA and OO is associated with more severe necro-inflammation and fibrosis than in mice treated with OO only.

Topics: Animals; Biomarkers; Chemical and Drug Induced Liver Injury; Choline Deficiency; Dietary Supplements; Disease Models, Animal; Fatty Acids, Omega-6; Inflammation Mediators; Liver; Liver Cirrhosis; Male; Methionine; Mice, Inbred BALB C; Necrosis; Non-alcoholic Fatty Liver Disease; Olive Oil; Plant Oils; Time Factors; Tissue Inhibitor of Metalloproteinase-1; Transforming Growth Factor beta

Non-alcoholic fatty liver disease (NAFLD) affects 3-12% of the general pediatric population. HMGB1 protein is presently considered a potent inflammatory mediator in several liver diseases, even if its role in NAFLD is still unknown in clinical studies. Here we investigated the relationships between circulating HMGB1, TGF-β and MCP-1 and liver damage in pediatric NAFLD. HMGB1, TGF-β and MCP-1 plasma levels were measured in 110 obese children with biopsy-proven NAFLD and 40 age-matched obese controls. HMGB1, TGF-β and MCP-1, ALT, AST and cholesterol plasma levels were significantly higher in NAFLD than in control children. A significant association between increased levels of HMGB1, TGF-β and MCP-1 and high degrees of fibrosis was found. In this study, we showed for the first time that circulating levels of HMGB1 were raised in children with NAFLD and strongly correlated with fibrosis and systemic inflammation.

Topics: Biopsy; Case-Control Studies; Chemokine CCL2; Child; Child, Preschool; Cross-Sectional Studies; Female; HMGB1 Protein; Humans; Liver Cirrhosis; Male; Non-alcoholic Fatty Liver Disease; Transforming Growth Factor beta

The aim of the present study was to establish a progressive steatohepatitis mouse model because few reported animal models of non-alcoholic steatohepatitis (NASH) show the progression from fatty liver to steatohepatitis. C57BL/6N mice were fed a high-fat diet (HFD) to develop obesity and were either administered carbon tetrachloride (CCl4 ) eight times (0.05 mL/kg, s.c., once, followed by 0.1 mL/kg, s.c., seven times) or not. Serum parameters and hepatic histopathology were examined. In a separate experiment, CCl4 was administered subcutaneously from 0 to eight times to HFD-fed obese mice to investigate progressive changes. Markers of oxidative stress, inflammation and apoptosis, as well as histopathological changes in the liver, were analysed. The HFD-fed obese mice showed fatty liver but not steatohepatitis. In contrast, HFD-fed mice administered CCl4 eight times showed histopathological features of steatohepatitis (fatty liver, inflammation, hepatocellular ballooning and fibrosis) and increased serum alanine aminotransferase levels. However, the multiple administration of CCl4 to obese mice reduced the ratio of reduced glutathione to oxidized glutathione, superoxide dismutase activity and mitochondrial DNA copy number, leading to the development of chronic oxidative stress, increased numbers of apoptotic cells and increased levels of both tumour necrosis factor-α and transforming growth factor-β mRNA. The resulting inflammation led to increased hydroxyproline content in the liver and fibrosis. The present study demonstrates that multiple administration of CCl4 to HFD-fed obese mice induces chronic oxidative stress that triggers inflammation and apoptosis and leads to the development of fibrosis in the liver, resulting in progression from fatty liver to steatohepatitis. This murine model will be useful in the research of hepatic disorders.

Topics: Alanine Transaminase; Animals; Apoptosis; Carbon Tetrachloride; Diet, High-Fat; Disease Models, Animal; DNA Copy Number Variations; DNA, Mitochondrial; Fatty Liver; Fibrosis; Glutathione; Glutathione Disulfide; Inflammation; Liver; Liver Diseases; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Obesity; Oxidative Stress; RNA, Messenger; Superoxide Dismutase; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Sympathetic nervous system (SNS) signalling regulates murine hepatic fibrogenesis through effects on hepatic stellate cells (HSC), and obesity-related hypertension with SNS activation accelerates progression of non-alcoholic fatty liver disease (NAFLD), the commonest cause of chronic liver disease. NAFLD may lead to cirrhosis. The effects of the SNS neurotransmitters norepinephrine (NE), epinephrine (EPI) and neuropeptide Y (NPY) on human primary HSC (hHSC) function and in NAFLD pathogenesis are poorly understood.. to determine the mechanistic effects of NE/EPI/NPY on phenotypic changes in cultured hHSC, and to study SNS signalling in human NAFLD livers.. Freshly isolated hHSC were assessed for expression of cathecholamine/neuropeptide Y receptors and for the synthesis of NE/EPI. The effects of NE/EPI/NPY and adrenoceptor antagonists prazosin (PRZ)/propranolol (PRL) on hHSC fibrogenic functions and the involved kinases and interleukin pathways were examined. Human livers with proven NAFLD were then assessed for upregulation of SNS signalling components.. Activated hHSC express functional α/β-adrenoceptors and NPY receptors, which are upregulated in the livers of patients with cirrhotic NAFLD. hHSC in culture synthesize and release NE/EPI, required for their optimal basal growth and survival. Exogenous NE/EPI and NPY dose-dependently induced hHSC proliferation, mediated via p38 MAP, PI3K and MEK signalling. NE and EPI but not NPY increased expression of collagen-1α2 via TGF-β without involvement of the pro-fibrogenic cytokines leptin, IL-4 and IL-13 or the anti-fibrotic cytokine IL-10.. hHSC synthesize and require cathecholamines for optimal survival and fibrogenic functionality. Activated hHSC express directly fibrogenic α/β-adrenoceptors and NPY receptors, upregulated in human cirrhotic NAFLD. Adrenoceptor and NPY antagonists may be novel anti-fibrotic agents in human NAFLD.

Topics: Base Sequence; Catecholamines; Cells, Cultured; Chromatography, High Pressure Liquid; Collagen; DNA Primers; Fatty Liver; Hepatic Stellate Cells; Humans; Interleukins; Liver Cirrhosis; Neuropeptide Y; Non-alcoholic Fatty Liver Disease; Norepinephrine; Receptors, Adrenergic; Reverse Transcriptase Polymerase Chain Reaction; Sympathetic Nervous System; Transforming Growth Factor beta; Up-Regulation

Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent, chronic liver diseases, worldwide. It is a multifactorial disease caused by complex interactions between genetic, epigenetic and environmental factors. Recently, several microRNAs, some of which epigenetically regulated, have been found to be up- and/or down-regulated during NAFLD development. However, in NAFLD, the essential role of the Polycomb Group protein Enhancer of Zeste Homolog 2 (EZH2), which controls the epigenetic silencing of specific genes and/or microRNAs by trimethylating Lys27 on histone H3, still remains unknown. In this study, we demonstrate that the nuclear expression/activity of the EZH2 protein is down-regulated both in livers from NAFLD rats and in the free fatty acid-treated HepG2. The drop in EZH2 is inversely correlated with: (i) lipid accumulation; (ii) the expression of pro-inflammatory markers including TNF-α and TGF-β; and (iii) the expression of miR-200b and miR-155. Consistently, the pharmacological inhibition of EZH2 by 3-Deazaneplanocin A (DZNep) significantly reduces EZH2 expression/activity, while it increases lipid accumulation, inflammatory molecules and microRNAs. In conclusion, the results of this study suggest that the defective activity of EZH2 can enhance the NAFLD development by favouring steatosis and the de-repression of the inflammatory genes and that of specific microRNAs.

Topics: Adenosine; Animals; Disease Models, Animal; Down-Regulation; Enhancer of Zeste Homolog 2 Protein; Fatty Liver; Hep G2 Cells; Histones; Humans; MicroRNAs; Non-alcoholic Fatty Liver Disease; Oleic Acid; Palmitic Acid; Polycomb Repressive Complex 2; Rats; Rats, Sprague-Dawley; RNA, Messenger; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

The innate immune system, including toll-like receptor-4 (TLR4) signaling cascade and angiotensin-II (AT-II) play important roles in the progression of liver fibrosis development; the cross talk between TLR4 and AT-II has not been elucidated yet. The aim of the current study was to elucidate the effect of AT-II type 1 receptor blocker (ARB), on the liver fibrosis development, especially in conjunction with the interaction of TLR4 and AT-II in the rat model of non-alcoholic steatohepatitis.. Fischer 344 rats were fed a choline-deficient, L-amino-acid-defined diet for 8 weeks and the effects of losartan were elucidated in conjunction with activated hepatic stellate cells (Ac-HSC) activation, TLR4, nuclear factor-κB (NF-κB), and transforming growth factor-β (TGF-β) expressions. In vitro study was carried out to elucidate the effect of AT-II on several indices including TLR4, myeloid differentiation factor 88, NF-κB, and TGF-β expressions in the rat HSC.. ARB markedly inhibited liver fibrosis development along with suppression of the number of Ac-HSC and TGF-β. These inhibitory effects of ARB were almost in parallel with suppression of the hepatic TLR4 and NF-κB expressions. This in vitro study showed that AT-II significantly augmented the TLR4 expression in a dose- and time-dependent manner via AT-II type 1 receptor in the Ac-HSC. AT-II also augmented the lipopolysaccharide-induced myeloid differentiation factor 88 (MyD88), NF-κB, and TGF-β and these increments were attenuated by treatment with ARB.. These studies indicated that the cross talk between TLR4 signaling cascade and AT-II plays a pivotal role in liver fibrosis development in non-alcoholic steatohepatitis.

Topics: Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Cell Communication; Disease Models, Animal; Disease Progression; DNA Primers; Dose-Response Relationship, Drug; Fatty Liver; Gene Expression; Hepatic Stellate Cells; Liver Cirrhosis; Losartan; Male; NF-kappa B; Non-alcoholic Fatty Liver Disease; Rats; Rats, Inbred F344; Real-Time Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Time Factors; Toll-Like Receptor 4; Transforming Growth Factor beta

Chemokine-like receptor 1 (CMKLR1) ligands chemerin and resolvin E1 are suggested to have a role in non-alcoholic fatty liver disease (NAFLD). Here, expression of CMKLR1 in liver cells and NAFLD was studied. CMKLR1 was detected in primary human hepatocytes (PHH), Kupffer cells, bile-duct cells and hepatic stellate cells. In human and rodent fatty liver and in fibrotic liver of mice fed a methionine-choline deficient diet CMKLR1 was reduced. Hepatocytes are the major cells in the liver and effects of adipokines, cytokines and lipids on CMKLR1 in PHH were analyzed. Increased cellular triglyceride or cholesterol content, lipopolysaccharide, IL-6, TNF and leptin did not influence CMKLR1 levels in PHH whereas profibrotic TGFβ tended to reduce CMKLR1. Adiponectin strongly upregulated CMKLR1 mRNA and protein in PHH and hepatic CMKLR1 when injected into wild type mice. Further, CMKLR1 was suppressed in the liver of adiponectin deficient mice. These data indicate that low CMKLR1 in NAFLD may partly result from reduced adiponectin activity.

Topics: Adiponectin; Aged; Animals; Bile Ducts; Choline; Diet; Fatty Liver; Female; Hepatic Stellate Cells; Hepatocytes; Humans; Kupffer Cells; Liver; Male; Methionine; Mice; Middle Aged; Non-alcoholic Fatty Liver Disease; Primary Cell Culture; Receptors, Chemokine; RNA, Messenger; Signal Transduction; Transforming Growth Factor beta; Up-Regulation

The tumor suppressor p53 is a primary sensor of stressful stimuli, controlling a number of biologic processes. The aim of our study was to examine the roles of p53 in non-alcoholic steatohepatitis (NASH).. Male wild type and p53-deficient mice were fed a methionine- and choline-deficient diet for 8 weeks to induce nutritional steatohepatitis. mRNA expression profiles in normal liver samples and liver samples from patients with non-alcoholic liver disease (NAFLD) were also evaluated.. Hepatic p53 and p66Shc signaling was enhanced in the mouse NASH model. p53 deficiency suppressed the enhanced p66Shc signaling, decreased hepatic lipid peroxidation and the number of apoptotic hepatocytes, and ameliorated progression of nutritional steatohepatitis. In primary cultured hepatocytes, transforming growth factor (TGF)-β treatment increased p53 and p66Shc signaling, leading to exaggerated reactive oxygen species (ROS) accumulation and apoptosis. Deficient p53 signaling inhibited TGF-β-induced p66Shc signaling, ROS accumulation, and hepatocyte apoptosis. Furthermore, expression levels of p53, p21, and p66Shc were significantly elevated in human NAFLD liver samples, compared with results obtained with normal liver samples. Among NAFLD patients, those with NASH had significantly higher hepatic expression levels of p53, p21, and p66Shc compared with the group with simple steatosis. A significant correlation between expression levels of p53 and p66Shc was observed.. p53 in hepatocytes regulates steatohepatitis progression by controlling p66Shc signaling, ROS levels, and apoptosis, all of which may be regulated by TGF-β. Moreover, p53/p66Shc signaling in the liver appears to be a promising target for the treatment of NASH.

Topics: Animals; Apoptosis; Caspase 3; Choline Deficiency; Cyclin-Dependent Kinase Inhibitor p21; Disease Models, Animal; Disease Progression; Fatty Liver; Hepatocytes; Humans; Male; Methionine; Mice; Mice, Inbred C57BL; Mice, Knockout; Non-alcoholic Fatty Liver Disease; Primary Cell Culture; Proto-Oncogene Proteins p21(ras); Reactive Oxygen Species; RNA, Messenger; Shc Signaling Adaptor Proteins; Signal Transduction; Src Homology 2 Domain-Containing, Transforming Protein 1; Transforming Growth Factor beta; Tumor Suppressor Protein p53; Up-Regulation

In this study, we were aimed to evaluate the probable effect of the crud extract of Silybum marianum, with high polyphenolic content, on experimental nonalcoholic steatohepatitis (NASH). To induce NASH, a methionine and choline deficient (MCD) diet was given to N-Mary rats for 8 weeks. After NASH development, MCD-fed rats were divided into two groups: MCD groups received MCD diet and MCD+S group was fed MCD diet plus crude extract of S. marianum orally for 3 weeks. Control group was fed a normal diet for 11 weeks. Finally, all rats were sacrificed. Plasma alanine amino transferase (ALT) and aspartate amino transferase (AST) levels were evaluated. In addition, the following hepatic factors were also evaluated: liver histology, malondialdehyde (MDA) and reduced glutathione (GSH) contents, gene expressions of TNF-α and TGF-β and immunoblot evaluations of caspase-3, ERK/p-ERK, JNK/pJNK and p38/pp38. Histopathological evaluations of the liver samples revealed that treatment with the S. marianum extract has abated the severity of NASH among the MCD-fed rats. Also, a significant reduction was observed in the sera ALT and AST activities. In addition, the extract caused dramatic reduction in the elevated hepatic TNF-α and TGF-β mRNA and MDA levels along with an increase in the GSH content. Moreover, the plant extract treatments significantly lowered activation of procaspase-3 to active caspase-3 and also lowered the phosphorylated form of JNK among the same group of rats. These results suggest that the S. marianum crude extract beneficial effects on NASH are mainly due to its antioxidant and anti-inflammatory activities.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Fatty Liver; Lipid Peroxidation; Liver; Liver Function Tests; Male; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Plant Extracts; Rats; Rats, Inbred Strains; Real-Time Polymerase Chain Reaction; Seeds; Silybum marianum; Transcription, Genetic; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Connective tissue growth factor (CTGF) is induced in liver fibrosis and enhances the activity of transforming growth factor β (TGFβ). Recently we have shown that the hepatoprotective adipokine adiponectin downregulates CTGF in primary human hepatocytes (PHH). In the current study, the mechanisms mediating suppression of CTGF by adiponectin and the well described downstream effector of adiponectin receptor 2 (AdipoR2), peroxisome proliferator activated receptor α (PPARα), were analyzed in more detail. Adiponectin downregulated CTGF mRNA and protein in primary human hepatocytes (PHH) and suppression was blocked by a PPARα antagonist indicating that AdipoR2 is involved. The PPARα agonists fenofibrate and WY14643 also reduced CTGF protein in these cells. Adiponectin further impaired TGFβ-mediated upregulation of CTGF. Phosphorylation of the TGFβ downstream effectors SMAD2 and -3 was reduced in PHH incubated with adiponectin or PPARα agonists suggesting that early steps in TGFβ signal transduction are impaired. CTGF and TGFβ mRNA levels were increased in human non-fibrotic non-alcoholic steatohepatitis (NASH), and here AdipoR2 expression was significantly reduced. Current data show that CTGF and TGFβ are already induced in non-fibrotic NASH and this may be partly explained by low adiponectin bioactivity which interferes with TGFβ signaling by reducing phosphorylation of SMAD2/3 and by downregulating CTGF.

Topics: Adiponectin; Anticholesteremic Agents; Connective Tissue Growth Factor; Down-Regulation; Fatty Liver; Female; Fenofibrate; Hepatocytes; Humans; Male; Non-alcoholic Fatty Liver Disease; Phosphorylation; PPAR alpha; Primary Cell Culture; Pyrimidines; Signal Transduction; Smad2 Protein; Smad3 Protein; Transforming Growth Factor beta

Mechanisms associated with the progression of simple steatosis to non-alcoholic fatty liver disease (NAFLD) remain undefined. Regulatory T cells (T(regs)) play a critical role in regulating inflammatory processes in non-alcoholic steatohepatitis (NASH) and because T helper type 17 (Th17) functionally oppose T(reg)-mediated responses, this study focused on characterizing the role of Th17 cells using a NAFLD mouse model. C57BL/6 mice were fed either a normal diet (ND) or high fat (HF) diet for 8 weeks. Mice in the HF group had a significantly higher frequency of liver Th17 cells compared to ND-fed mice. Neutralization of interleukin (IL)-17 in HF mice ameliorated lipopolysaccharide (LPS)-induced liver injury reflected by decreased serum alanine aminotransferase (ALT) levels and reduced inflammatory cell infiltrates in the liver. In vitro, HepG2 cells cultured in the presence of free fatty acids (FFA; oleic acid and palmitic acid) for 24 h and IL-17 developed steatosis via insulin-signalling pathway interference. IL-17 and FFAs synergized to induce IL-6 production by HepG2 cells and murine primary hepatocytes which, in combination with transforming growth factor (TGF-β), expanded Th17 cells. It is likely that a similar process occurs in NASH patients, as there were significant levels of IL-17(+) cell infiltrates in NASH patient livers. The hepatic expression of Th17 cell-related genes [retinoid-related orphan receptor gamma (ROR)γt, IL-17, IL-21 and IL-23] was also increased significantly in NASH patients compared to healthy controls. Th17 cells and IL-17 were associated with hepatic steatosis and proinflammatory response in NAFLD and facilitated the transition from simple steatosis to steatohepatitis. Strategies designed to alter the balance between Th17 cells and T(regs) should be explored as a means of preventing progression to NASH and advanced liver diseases in NAFLD patients.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Cells, Cultured; Diet, High-Fat; Electrophoretic Mobility Shift Assay; Fatty Acids; Fatty Liver; Gene Expression Regulation; Hep G2 Cells; Hepatocytes; Humans; Insulin; Interleukin-17; Interleukin-6; Lipopolysaccharides; Liver; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Signal Transduction; T-Lymphocytes, Regulatory; Th17 Cells; Transforming Growth Factor beta