anti-NAFLD Effects Research Articles

Nuciferine prevents hepatic steatosis associated with improving intestinal mucosal integrity, mucus-related microbiota and inhibiting TLR4/MyD88/NF-κB pathway in high-fat induced rats

• Nuciferine alleviated intestinal pathological damage and stimulated intestinal Tjs expression. • Nuciferine reinforced mucosal barrier through increasing goblet cells and mucin production. • Nuciferine ameliorated hepatic inflammation by inhibiting LPS-induced TLR4/MyD88/NF-κB pathway. • Nuciferine altered the abundance of mucus-related microbiota accompanied by stimulating fecal SCFAs concentrations. Nonalcoholic fatty liver disease (NAFLD) has been demonstrated to be closely associated with intestinal barrier functions. The aim of this study is to investigate the effects of nuciferine on preventing hepatic steatosis with relation to intestinal barrier functions in HFD-fed rats. The results showed nuciferine mitigated body weight gain, hyperlipemia and hepatic steatosis with regulating lipid metabolic gene expressions. Meanwhile, nuciferine decreased LPS-induced inflammation through inhibiting TLR4/MyD88/NF-κB pathway and reinforced intestinal barriers through increasing occludin and zonula occluden-1 expression, goblet cells, mucin2 (MUC2) expression. Furthermore, we found that nuciferine changed the relative abundance of mucus-related microbiota ( Akkmensia muciniphila , Ruminococcaceae ) and LPS-producing microbiota ( Desulfovibrionaceae ), increased the concentration of fecal acetic acid and propionic acid accompanied by decreased fecal pH. Together, anti-NAFLD effects of nuciferine are related to improving multiple intestinal barrier functions. These findings imply that nuciferine could be a promising agent for NAFLD with a target towards gut-liver axis.

Hepatoprotective Constituents of Macrocybe gigantea (Agaricomycetes) from India.

Non-alcoholic fatty liver disease (NAFLD) is one of the most frequent, chronic liver diseases worldwide and currently has no specific therapy. Our previous study indicated the anti-NAFLD effect of Macrocybe gigantea (Massee) Pegler & Lodge in high-fat diet-fed animals. This study aimed to isolate and identify the active hepatoprotective constituents from M. gigantea using fatty acid induced steatotic HepG2 cells as in vitro model. The effect of the test materials on the viability of HepG2 cells was analyzed using MTT assay. The HepG2 cells were treated with a mixture of palmitate-oleate to induce steatosis; after 24 h of treatment with the test materials, the intracellular lipid content was estimated using Oil Red O staining. The levels of transaminases were also estimated in the spent media. Bioassay-guided isolation of hepatoprotective constituents from M. gigantea yielded two compounds viz., ergosterol and linoleic acid; their structures were confirmed using spectroscopic data. Among these two compounds, ergosterol significantly lowered the levels of intracellular triglyceride content of fatty acid induced HepG2 cells; it also lowered the leakage of transaminases. The reductions caused by linoleic acid were not statistically significant at the tested concentrations. Detailed investigations on efficacy and safety of these compounds and M. gigantea might yield some useful leads for the management of NAFLD.

The probiotic effects of AB23A on high-fat-diet-induced non-alcoholic fatty liver disease in mice may be associated with suppressing the serum levels of lipopolysaccharides and branched-chain amino acids

Alisol B 23-acetate (AB23A) is a natural triterpenoid isolated from Rhizoma alisamatis that has been widely used as a traditional Chinese medicine (TCM). Previous studies have documented the beneficial effect of AB23A on non-alcoholic fatty liver disease (NAFLD), but the functional interactions between gut microbiota and the anti-NAFLD effect of AB23A remain unclear. In this study, we investigated the benefits of experimental treatment with AB23A on gut microbiota dysbiosis in NAFLD with an obesity model. C57BL/6J mice were administrated a high-fat diet (HFD) with or without AB23A for 12 weeks. AB23A significantly improved metabolic phenotype in the HFD-fed mice. Moreover, results of 16S rRNA gene-based amplicon sequencing in each group reveled that AB23A not only reduced the abundance of the Firmicutes/Bacteroidaeota ratio and Actinobacteriota/Bacteroidaeota ratio, but regulated the abundance of the top 10 genera, including norank_f__Muribaculaceae, Lactobacillus, Ileibacterium, Turicibacter, Faecalibaculum, the Lachnospiraceae_NK4A136_group, unclassified_f__Lachnospiraceae, and norank_f__Lachnospiraceae. AB23A significantly reduced the serum levels of lipopolysaccharide and branched-chain amino acids, which are positively correlated with the abundances of Ileibacterium and Turicibacter. Moreover, AB23A led to remarkable reductions in the activation of TLR4, NF-κB, and mTOR, and upregulated the expression of tight junction proteins, including ZO-1 and occludin. These results revealed that AB23A displayed a prebiotic capacity in HFD-fed NAFLD mice.

Anti-NAFLD Effect of Djulis Hull and Its Major Compound, Rutin, in Mice with High-Fat Diet (HFD)-Induced Obesity.

Nonalcoholic fatty liver disease (NAFLD) has become the main cause of chronic liver disease worldwide, and the increasing trend of NAFLD has burdened the healthcare system. NAFLD encompasses a wide range of liver pathologies, from simple benign hepatocyte steatosis to more severe inflammatory nonalcoholic steatohepatitis. Djulis (Chenopodium formosanum Koidz.) is traditionally used as a native cereal and a food supplement that promotes human health through its antioxidant, hepatoprotection, skin protection, hypolipidemic, hypoglycemic, and antitumor effects. Djulis hull, regarded as agricultural waste, is usually removed during food processing and contains high rutin content. The present study evaluated the anti-NAFLD effect of Djulis hull and its major compound, rutin, in mice with high-fat diet (HFD)-induced obesity. Male C57BL/6J mice were randomly divided into one of five diet groups (n = 6 per group) and fed the following for 16 weeks: (1) normal diet group (ND), (2) HFD group (HFD), (3) HFD and oral gavage of low dose (50 mg/kg) of Djulis hull crude extract group (HFD/LCE), (4) HFD and oral gavage of high dose (250 mg/kg) of Djulis hull crude extract group (HFD/HCE), or (5) HFD and oral gavage (50 mg/kg) of rutin (HFD/R) group. We found that Djulis hull crude extract markedly reduced HFD-induced elevation in body weight and fat around the kidney weights, hepatic injury indicators (AST and ALT), and steatosis and hypertrophy. Furthermore, Djulis hull crude extract administration significantly affected DG(20:4/18:1), PA(22:0/17:1), PC(10:0/17:0), and PA(18:4/20:5) in HFD-induced obese mice. In addition, treating HFD-induced obese rats with Djulis hull crude extract significantly increased fatty acid oxidation by increasing the protein expression of phosphorylated AMP-activated protein kinase, peroxisome proliferator-activated receptor-α, and hepatic carnitine palmitoyltransferase-1 in the liver. Moreover, the administration of Djulis hull crude extract significantly decreased the inflammatory response (PPARγ, IL-6, and TNF-α) to modulate oxidative damage. Therefore, Djulis hull crude extract attenuated the progression of NAFLD by reducing inflammation mediated by PPARγ and enhancing the expression levels of genes involved in fatty acid oxidation mediated by AMPK signaling.

Carnosol alleviates nonalcoholic fatty liver disease by inhibiting mitochondrial dysfunction and apoptosis through targeting of PRDX3

Mitochondrial dysfunction is a major factor in nonalcoholic fatty liver disease (NAFLD), preceding insulin resistance and hepatic steatosis. Carnosol (CAR) is a kind of diterpenoid with antioxidant, anti-inflammatory and antitumor activities. Peroxiredoxin 3 (PRDX3), a mitochondrial H2O2-eliminating enzyme, undergoes overoxidation and subsequent inactivation under oxidative stress. The purpose of this study was to investigate the protective effect of the natural phenolic compound CAR on NAFLD via PRDX3. Mice fed a high-fat diet (HFD) and AML-12 cells treated with palmitic acid (PA) were used to detect the molecular mechanism of CAR in NAFLD. We found that pharmacological treatment with CAR notably moderated HFD- and PA- induced steatosis and liver injury, as shown by biochemical assays, Oil Red O and Nile Red staining. Further mechanistic investigations revealed that CAR exerted anti-NAFLD effects by inhibiting mitochondrial oxidative stress, perturbation of mitochondrial dynamics, and apoptosis in vivo and in vitro. The decreased protein and mRNA levels of PRDX3 were accompanied by intense oxidative stress after PA intervention. Interestingly, CAR specifically bound PRDX3, as shown by molecular docking assays, and increased the expression of PRDX3. However, the hepatoprotection of CAR in NAFLD was largely abolished by specific PRDX3 siRNA, which increased mitochondrial dysfunction and exacerbated apoptosis in vitro. In conclusion, CAR suppressed lipid accumulation, mitochondrial dysfunction and hepatocyte apoptosis by activating PRDX3, mitigating the progression of NAFLD, and thus, CAR may represent a promising candidate for clinical treatment of steatosis.

Polysaccharide extract from pomelo fruitlet ameliorates diet-induced nonalcoholic fatty liver disease in hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀)

Nonalcoholic fatty liver disease (NAFLD) is common in farmed fish fed a high-fat diet (HFD), which disrupts lipid metabolism, inhibits growth performance, and poses a serious threat to sustainable aquaculture. This study explored the anti-NAFLD effect and hepatoprotective mechanism of YZW-A, a water-soluble heteroglycan extracted from the pomelo fruitlet (Citrus maxima), in hybrid grouper (Epinephelus lanceolatus♂×Epinephelus fuscoguttatus♀). Hybrid grouper were fed an HFD, with 15% lipid, supplemented with YZW-A for 56 days. In vivo, addition of YZW-A resulted in improved growth performance and feed utilization, while it reduced whole body and muscle lipid content, viscerosomatic and hepatosomatic indexes, and lipid deposition in the hepatocytes. Lipogenesis-related genes were downregulated while lipolysis-related genes were upregulated in grouper supplemented with YZW-A. Additionally, destructive morphological changes in the liver tissue cells detected in HFD-fed grouper were normalized after treatment with YZW-A. In vitro, YZW-A improved lipid emulsion-induced hepatic steatosis by modulating key factors of lipid metabolism, achieved by triggering the AMP-activated protein kinase (AMPK) pathway in the hepatocytes and activating the AMPK/Nrf2/ARE axis. These results demonstrated the therapeutic effect of YZW-A on diet-induced NAFLD in hybrid grouper and elucidated a possible mechanism underlying NAFLD prevention and suppression of further deterioration by YZW-A.

Myricetin supplementation decreases hepatic lipid synthesis and inflammation by modulating gut microbiota.

The relationship between poor invivo bioavailability and effective pharmacological activity are not yet fully clarified for many flavonoids. The analysis of flavonoids-induced alterations in the gut microbiota represents a promising approach to provide useful clues to elucidate the mechanism of action. Here, we investigate the effect of myricetin supplementation on high-fat-diet (HFD)-induced nonalcoholic fatty liver disease (NAFLD) in rats and explore the associations with the gut microbiota through high-throughput analyses. The 12-week myricetin supplementation and fecal microbiota transplantation outcomes suggest that myricetin significantly slows the development of NAFLD. Meanwhile, the anti-NAFLD effects of myricetin are associated with the modulation of the gut microbiota composition. Myricetin reduces hepatic lipid synthesis and inflammation through modulations in fecal butyric-acid-related gut microbiota and protection of the gut barrier function. This study may facilitate the elucidation of the action mechanism of flavonoids with low bioavailability.

A botanical dietary supplement from white peony and licorice attenuates nonalcoholic fatty liver disease by modulating gut microbiota and reducing inflammation

Nonalcoholic fatty liver disease (NAFLD) is an obesity-related metabolic disease that is highly associated with gut dysbiosis and inflammation. A botanical dietary supplement, mainly containing an herbal pair of white peony root and licorice as well as grape seeds and broccoli extracts (WLT), exerts auxiliary protection against chemical liver injury. However, it is unclear whether WLT protects against the development of NAFLD induced by a high energy diet. To investigate the protective role of WLT against NAFLD development induced by a high-fat and high-sucrose (HFHS) diet and its mechanism of action. We investigated the anti-NAFLD effects of WLT on a HFHS diet-induced NAFLD C57BL/6J mouse model by detecting the hepatic triglyceride (TG) level, performing histological examination of the liver tissue, and evaluating glucose tolerance and systemic inflammation. Then, we analyzed the impact of WLT on gut microbiota by 16S rRNA gene sequencing, followed by fecal microbiota transplantation. Furthermore, we performed hepatic transcriptomic analysis of mice with or without WLT treatment using the RNA sequencing approach. Our results showed that WLT supplement attenuated body weight gain, hepatic steatosis, glucose tolerance, and systemic inflammation in HFHS-fed mice. Moreover, WLT supplement altered the composition of gut microbiota, which contributed at least in part, to the anti-NAFLD effect. Meanwhile, WLT improved the intestinal integrity and comprehensively modulated the expression of hepatic genes in HFHS mice, particularly reducing the expression of genes in the toll-like receptor-mediated inflammatory pathway. WLT is protective against NAFLD formation induced by an HFHS diet, and its effect is associated with the modulation of gut microbiota and inflammation, highlighting the potential of WLT to reduce the risk of metabolic disorders as a functional dietary supplement.

Hepatic protective effects of Shenling Baizhu powder, a herbal compound, against inflammatory damage via TLR4/NLRP3 signalling pathway in rats with nonalcoholic fatty liver disease

High-fat diet (HFD) and inflammation are two key contributors to nonalcoholic fatty liver disease (NAFLD). Shenling Baizhu powder (SLBZP), a classical herbal compound, has been successfully used to alleviate NAFLD. However, its specific mechanisms are not fully understood. In this study, we assessed the anti-NAFLD effect of SLBZP in vivo. Rats were fed an HFD with or without SLBZP or with probiotics. At the end of week 16, an echo magnetic resonance imaging (EchoMRI) body composition analyser was used to quantitatively analyse body composition; a micro-computed tomography (micro-CT) imaging system was used to evaluate whole body and liver fat; and the Moor full-field laser perfusion imager 2 was used to assess liver microcirculation, after which, all rats were sacrificed. Then, biochemical indicators in the blood and the ultrastructure of rat livers were evaluated. Protein expression related to the liver Toll-like receptor 4 (TLR4)/Nod-like receptor family pyrin domain-containing 3 (NLRP3) signalling pathway was assessed using Western blot analysis. Further, high-throughput screening of 29 related inflammatory factors in liver tissue was performed using a cytokine array. SLBZP supplementation reduced body weight, serum free fatty acid, and insulin resistance index (P<0.05). It also ameliorated liver microcirculation and ultrastructural abnormalities. EchoMRI and micro-CT quantitative analyses showed that treatment with SLBZP reduced fat mass and visceral fat (P<0.05 and P<0.01, respectively). In addition, SLBZP decreased the expression of lipopolysaccharide (LPS)-activated TLR4/NLRP3 signalling pathway-related proteins and altered the expression levels of some inflammatory cytokines in liver tissues. SLBZP can inhibit NLRP3 inflammasome activation and interleukin-1β release by suppressing LPS-induced TLR4 expression in rats with HFD-induced NAFLD. Thus, SLBZP may be beneficial for the prevention and treatment of inflammatory damage and associated diseases.

Hepatoprotective effect of selected isoandrographolide derivatives on steatotic HepG2 cells and High Fat Diet fed rats

Non-alcoholic Fatty Liver Disease (NAFLD) is one of the growing epidemics of the globe. This study was aimed to evaluate the anti-NAFLD effect of selected IAN derivatives using in silico, in vitro and in vivo models. In silico tools viz., DataWarrior, SwissADME and Gaussian 09 were used to predict the pharmacokinetic properties and electronic distribution patterns of the derivatives; docking analysis was done with Autodock against PPARα. Toxicities of the derivatives were assessed in HepG2 cells using MTT assay. Anti-NAFLD efficacies of the derivatives were assessed in free fatty acid induced steatotic HepG2 cells. In vivo anti-NAFLD effect of active isoandrographolide (IAN) derivative, 19-propionyl isoandrographolide (IAN-19P) was assessed in High Fat Diet fed rats. In silico and in vitro studies indicated that IAN-19P showed improved drug-likeness and drug score. The toxicity of IAN-19P to HepG2 cells was comparatively less than IAN and other derivatives. In free fatty acid induced steatotic HepG2 cells, treatment with IAN-19P significantly lowered intracellular triglyceride content and leakage of LDH and transaminases. Treating High Fat Diet fed animals with IAN-19P significantly lowered plasma lipids, transaminases, LDH and GGT levels. The treatment with IAN-19P upregulated the expressions of PPARα and CPT-1. IAN-19P did not produce any noticeable adverse effect till 2g/kg concentration in acute and 250mg/kg concentration in subacute toxicity studies. This study indicated the beneficial effect of IAN-19P for the treatment of NAFLD; however robust investigations are needed to establish the potential of IAN-19P to treat NAFLD.

Therapeutic effect of oxyberberine on obese non-alcoholic fatty liver disease rats

Berberine (BBR) has been widely used to treat non-alcoholic fatty liver disease (NAFLD). The metabolites of BBR were believed to contribute significantly to its pharmacological effects. Oxyberberine (OBB), a gut microbiota-mediated oxidative metabolite of BBR, has been firstly identified in our recent work. Here, we aimed to comparatively investigate the anti-NAFLD properties of OBB and BBR. The anti-NAFLD effect was evaluated in high-fat diet-induced obese NAFLD rats with biochemical/ELISA tests and histological staining. The related gene and protein expressions were detected by qRT-PCR and Western blotting respectively. Molecular docking and dynamic simulation were also performed to provide further insight. Results indicated OBB remarkably and dose-dependently attenuated the clinical manifestations of NAFLD, which (100 mg/kg) achieved similar therapeutic effect to metformin (300 mg/kg) and was superior to BBR of the same dose. OBB significantly inhibited aberrant phosphorylation of IRS-1 and up-regulated the downstream protein expression and phosphorylation (PI3K, p-Akt/Akt and p-GSK-3β/GSK-3β) to improve hepatic insulin signal transduction. Meanwhile, OBB treatment remarkably alleviated inflammation via down-regulating the mRNA expression of MCP-1, Cd68, Nos2, Cd11c, while enhancing Arg1 mRNA expression in white adipose tissue. Moreover, OBB exhibited closer affinity with AMPK in silicon and superior hyperphosphorylation of AMPK in vivo, leading to increased ACC mRNA expression in liver and UCP-1 protein expression in adipose tissue. Taken together, compared with BBR, OBB was more capable of maintaining lipid homeostasis between liver and WAT via attenuating hepatic insulin pathway and adipocyte inflammation, which was associated with its property of superior AMPK activator.

Si Miao Formula attenuates non-alcoholic fatty liver disease by modulating hepatic lipid metabolism and gut microbiota

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease with few therapeutic options available currently. Traditional Chinese Medicine (TCM) has been practiced for thousands of years in China and Asian countries, and regarded as an important source for identifying novel medicines for diseases. Si Miao Formula (SMF) is a classical TCM formula for the treatment of gout disease by reducing serum uric acid concentrations, while high concentration of uric acid is also an independent risk factor for NAFLD. To investigate the protective effect of SMF on NAFLD in a mouse model induced by a high fat/high sucrose (HFHS) diet. Mice received a HFHS diet over a 16-week period to induce NAFLD with or without SMF intervention. Lipid levels were measured in both the liver and serum. Histopathological staining was used to evaluate the extent of hepatic lipid accumulation. Liver transcriptomics was used to enrich differentially expressed genes and to predict regulatory pathways after gene set enrichment analysis. 16S rRNA gene sequencing was used to determine the microbial composition. Genes of liver lipid metabolism, inflammation and intestinal tight junctions were detected by qRT-PCR analysis. SMF attenuated hepatic steatosis, reduced body weight gain and lipid concentrations, improved sensitivity to insulin and also tolerance to glucose, in mice fed an HFHS diet. Hepatic transcriptomics showed that SMF downregulated the biosynthesis of fatty acids and stimulated the insulin secretion pathway. SMF significantly altered the gut microbiota composition and in particular increased the proportion of Akkermansia muciniphila. In agreement with liver transcriptomics, SMF downregulated the expression of genes implicated in the metabolism of lipids (Acly, Fas, Acc, Scd-1) and pro-inflammatory cytokines (Il-1β, Nlrp-3) in the livers. The results indicate that SMF attenuates HFHS diet-induced NAFLD and regulates hepatic lipid metabolism pathways. The anti-NAFLD effect of SMF was linked to modulation of the gut microbiota composition and in particular an increased relative abundance of Akkermansia muciniphila.

Resveratrol Improves Liver Steatosis and Insulin Resistance in Non-alcoholic Fatty Liver Disease in Association With the Gut Microbiota.

Resveratrol (RSV) is a potential alternative therapy for non-alcoholic fatty liver disease (NAFLD) that has been evaluated in many clinical trials, but the mechanisms of RSV action have not been fully elucidated. Recent studies suggested that the gut microbiota is an important RSV target; therefore, we speculated that the gut microbiota might mediate the beneficial effects of RSV in NAFLD. To verify this hypothesis, we established a high-fat diet (HFD)-induced NAFLD mouse model, which was subjected to RSV gavage to evaluate the therapeutic effects. We observed that RSV reduced liver steatosis and insulin resistance in NAFLD. RSV significantly changed the diversity and composition of the gut microbiota according to 16S rRNA sequencing. Gut microbiota gene function prediction showed that the enrichment of pathways related to lipid and glucose metabolism decreased after RSV treatment. Furthermore, correlation analysis indicated that the improvements in NAFLD metabolic indicators were closely related to the altered gut microbiota. We further fermented RSV with the gut microbiota in vitro to verify that RSV directly affected the gut microbiota. Our data suggested that the gut microbiota might be an important target through which RSV exerts its anti-NAFLD effect.

Anti-NAFLD effect of defatted walnut powder extract in high fat diet-induced C57BL/6 mice by modulating the gut microbiota

Walnut kernel has the actions of removing meteorism, dissipating stagnation and removing blood stasis and is used after being defatted in TCM. Defatted walnut powder extract (DWPE) has the abilities of anti-oxidation and lowering lipid levels in vivo. However, the effects and the potential mechanisms of DWPE on NAFLD have not been explored. The study were to investigate the anti-NAFLD effect of DWPE in high fat diet-induced C57BL/6 mice and demonstrate that whether DWPE developed the effect on anti-NAFLD by remodeling the compositions and abundances of gut microbiota. The inhibitory effect of DWPE on the development of NAFLD was conducted on C57BL/6 mice with a high fat diet and the regulation effect of DWPE on gut microbiota was verified on pseudo-sterile mice with treatment of broad spectrum antibiotics. The results showed that the oral administration of DWPE remarkably alleviated hepatic lipid accumulation by decreasing the levels of TG, TC, LDL, MDA and increasing HDL. Meanwhile, the expressions of NF-κB and MAPKs family proteins were reduced by DWPE compared with HFD group. Otherwise, the efficacy of anti-NAFLD of DWPE was significantly decreased after treatment of antibiotics, which indicated the key role of gut microbiota in the therapeutic process. Furthermore, sequencing of 16S rRNA gene revealed that DWPE could revert the decreased relative abundance of gut microbiota caused by the long term of a high fat diet. And the disordered microflora was remodeled by DWPE including the reduction of Erysipelotrichia, Firmicutes and Actinobacteria as well as the increment of Bacteroidetes, Clostridiales, Bacteroidales S24-7, Prevotellaceae and Bacteroides. Taken together, DWPE had a preventing effect on NAFLD, which might be associated with the regulation of gut microbiota.

Hesperetin ameliorates hepatic oxidative stress and inflammation via the PI3K/AKT-Nrf2-ARE pathway in oleic acid-induced HepG2 cells and a rat model of high-fat diet-induced NAFLD.

Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disease. Dietary supplementation has become a promising strategy for managing NAFLD. Hesperetin, a citrus flavonoid, is mainly found in citrus fruits (oranges, grapefruit, and lemons) and possesses multiple pharmacological properties, including anti-cancer, anti-Alzheimer and anti-diabetic effects. However, the anti-NAFLD effect and mechanisms of hesperetin remain unclear. In this study, we investigated the therapeutic effect of hesperetin against NAFLD and the underlying mechanism in vitro and in vivo. In oleic acid (OA)-induced HepG2 cells, hesperetin upregulated antioxidant levels (SOD/GPx/GR/GCLC/HO-1) by triggering the PI3 K/AKT-Nrf2 pathway, alleviating OA-induced reactive oxygen species (ROS) overproduction and hepatotoxicity. Furthermore, hesperetin suppressed NF-κB activation and reduced inflammatory cytokine secretion (TNF-α and IL-6). More importantly, we revealed that this anti-inflammatory effect is attributed to reduced ROS overproduction by the Nrf2 pathway, as pre-treatment with Nrf2 siRNA or an inhibitor of superoxide dismutase (SOD) or/and glutathione peroxidase (GPx) abolished hesperetin-induced NF-κB inactivation and reductions in inflammatory cytokine secretion. In a rat model of high-fat diet (HFD)-induced NAFLD, we confirmed that hesperetin relieved hepatic steatosis, oxidative stress, inflammatory cell infiltration and fibrosis. Moreover, hesperetin activated the PI3 K/AKT-Nrf2 pathway in the liver, increasing antioxidant expression and inhibiting NF-κB activation and inflammatory cytokine secretion. In summary, our results demonstrate that hesperetin ameliorates hepatic oxidative stress through the PI3 K/AKT-Nrf2 pathway and that this antioxidative effect further suppresses NF-κB-mediated inflammation during NAFLD progression. Thus, our study suggests that hesperetin may be an effective dietary supplement for improving NAFLD by suppressing hepatic oxidative stress and inflammation.

Desulfovibrio vulgaris, a potent acetic acid-producing bacterium, attenuates nonalcoholic fatty liver disease in mice

ABSTRACT The emerging evidence supports the use of prebiotics like herb-derived polysaccharides for treating nonalcoholic fatty liver disease (NAFLD) by modulating gut microbiome. The present study was initiated on the microbiota-dependent anti-NAFLD effect of Astragalus polysaccharides (APS) extracted from Astragalus mongholicus Bunge in high-fat diet (HFD)-fed mice. However, the exact mechanisms underlying the beneficial effects of APS on NAFLD formation remain poorly understood. Co-housing experiment was used to assess the microbiota dependent anti-NAFLD effect of APS. Then, targeted metabolomics and metagenomics were adopted for determining short-chain fatty acids (SCFAs) and bacteria that were specifically enriched by APS. Further in vitro experiment was carried out to test the capacity of SCFAs-producing of identified bacterium. Finally, the anti-NAFLD efficacy of identified bacterium was tested in HFD-fed mice. Our results first demonstrated the anti-NAFLD effect of APS in HFD-fed mice and the contribution of gut microbiota. Moreover, our results indicated that SCFAs, predominantly acetic acid were elevated in APS-supplemented mice and ex vivo experiment. Metagenomics revealed that D. vulgaris from Desulfovibrio genus was not only enriched by APS, but also a potent generator of acetic acid, which showed significant anti-NAFLD effects in HFD-fed mice. In addition, D. vulgaris modulated the hepatic gene expression pattern of lipids metabolism, particularly suppressed hepatic fatty acid synthase (FASN) and CD36 protein expression. Our results demonstrate that APS enriched D. vulgaris is effective on attenuating hepatic steatosis possibly through producing acetic acid, and modulation on hepatic lipids metabolism in mice. Further studies are warranted to explore the long-term impacts of D. vulgaris on host metabolism and the underlying mechanism.

Silencing of functional p53 attenuates NAFLD by promoting HMGB1-related autophagy induction

Background and aimNonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease worldwide, but its pathogenesis remains imprecisely understood and requires further clarification. Recently, the tumor suppressor p53 has received growing attention for its role in metabolic diseases. In this study, we performed in vivo and in vitro experiments to identify the contribution of p53–autophagy regulation to NAFLD.MethodsLivers from wild-type and p53 knockout mice as well as p53-functional HepG2 cells and p53-dysfunctional Huh7 cells were examined for autophagy status and HMGB1 translocation. In vivo and in vitro NAFLD models were established, and steatosis was detected. In the cell models, autophagy status and steatosis were examined by p53 and/or HMGB1 silencing.ResultsFirst, the silencing of p53 could induce autophagy both in vivo and in vitro. In addition, p53 knockout attenuated high-fat diet-induced NAFLD in mice. Similarly, knockdown of p53 could alleviate palmitate-induced lipid accumulation in cell models. Furthermore, high mobility group box 1 (HMGB1) was proven to contribute to the effect of silencing p53 on alleviating NAFLD in vitro as an autophagy regulator.ConclusionThe anti-NAFLD effect of functional p53 silencing is associated with the HMGB1-mediated induction of autophagy.Graphic abstract

2,3,5,4'-tetrahydroxystilbence-2-O-β-D-glucoside attenuates hepatic steatosis via IKKβ/NF-κB and Keap1-Nrf2 pathways in larval zebrafish

With the improvement of people's living standards and the change of dietary habits, Non-alcoholic fatty liver disease (NAFLD) has gradually become one of the liver diseases that endanger human health around the world. However, there are no particularly effective drugs for NAFLD in the current market. Therefore, new drug candidates which could provide high efficacy and low toxicity are needed valuable for the prevention and treatment of NAFLD. 2,3,5,4'-tetrahydroxystilbence-2-O-β-D-glucoside (TSG) is extracted from Polygonum multiflorum Thunb., and has been widely used to treat a variety of chronic diseases in China. Recently, TSG has been reported to exert various biological activities in many studies, such as lipid-lowering, anti-inflammatory and anti-oxidant activities, which indicate that TSG may have the effect of improving NAFLD. After feeding 5% high cholesterol diet to 5 days post fertilization larval zebrafish for 10 days, hepatic steatosis larval zebrafish model was established successfully. Then the effect of TSG on the improvement of hepatic steatosis larval zebrafish was studied. Moreover, the potential mechanism of TSG on anti-NAFLD effect were studied using RT-qPCR methods from multiple pathogenesis aspects of lipogenesis, lipid-lowering, inflammation, and oxidant stress. To conclude, TSG attenuates hepatic steatosis via regulating lipid metabolism related pathway, IKKβ/NF-κB anti-inflammatory pathway and Keap1-Nrf2 anti-oxidant pathway.

Hepatoprotective and anti-inflammatory effects of total flavonoids of Qu Zhi Ke (peel of Citrus changshan-huyou) on non-alcoholic fatty liver disease in rats via modulation of NF-κB and MAPKs

Citrus flavonoids, consisting of naringin, narirutin, neohesperidine, etc., have therapeutic activities for the treatment of lipometabolic disorders. The peel of Citrus changshan-huyou (Qu Zhi Ke, QZK) is a new source of flavonoids, but attracted little attention so far. QZK should possess therapeutic effects against lipometabolic disorders due to the flavonoids it contains. In this study, we extracted and purified the flavonoids of QZK (TFCH) and established an obesity-induced non-alcoholic fatty liver disease (NAFLD) model of rats. TFCH was given orally for 8 weeks, and its anti-NAFLD effects and potential mechanism were evaluated. The flavonoid chemoprofile of TFCH was determined by using HPLC. High-fat diet was employed to induce NAFLD model in rats, and six groups were set up: negative control group, reference treatment group, model group, low-dose TFCH (25mg/kg), intermediate-dose TFCH (50mg/kg), and high-dose TFCH (100mg/kg). Serum and liver levels of inflammatory cytokines and NAFLD markers were measured biochemically. The relative mRNA expressions of liver T-bet, GATA3, and TNF-α were tested by real time PCR (qPCR) analysis. The protein expression of p38 and the phosphorylation of NF-κB, ERK1/2, and p38 in liver were tested by Western blot analysis. The histopathological observation showed that TFCH attenuated hepatic lesions with significantly decreased NAFLD activity scores. The biochemical data showed that TFCH significantly suppressed both systemic and intrahepatic inflammation by inhibiting IL-1β, IL-6, IL-12, TNF-α, and IFN-γ, and the qPCR analysis revealed a Th1/Th2 related anti-inflammatory mechanism of TFCH. Western blot results clarified that TFCH exerted hepatoprotective and anti-inflammatory effects by suppression of phosphorylated NF-κB and MAPKs, indicating a mechanism associated with NF-κB and MAPK signaling pathways. QZK is a new source of Citrus flavonoids for therapeutic use, and TFCH is a promising representative of Citrus flavonoids for anti-NAFLD therapy.

Formononetin alleviates hepatic steatosis by facilitating TFEB-mediated lysosome biogenesis and lipophagy

Formononetin has been reported to ameliorate hyperlipidemia and obesity, but its effect and mechanism of action in anti-non-alcoholic fatty liver disease (NAFLD) remain unclear. Lipophagy is a critical protective mechanism during steatosis development that results in the decomposition of lipid droplets through autophagy and the prevention of cellular lipid accumulation. This study aimed to investigate the beneficial role of formononetin in treating NAFLD and explore the mechanism of lipophagy in formononetin anti-hepatic steatosis effects. Formononetin treatment significantly ameliorated hepatic steatosis in HFD mice. Consistently, formononetin also reduced FFAs-stimulated lipid accumulation in HepG2 cells and primary mouse hepatocytes. Further analysis revealed that steatosis increased LC3B-II, a marker of autophagy, but caused blockade of autophagic flux associated with a lack of lysosomes. Treatment with formononetin promoted lysosome biogenesis and autophagosome-lysosome fusion, relieving the blockade in autophagic flux and further induced lipophagy. Mechanistically, formononetin activated adenosine monophosphate activated protein kinase (AMPK) and promoted subsequent nuclear translocation of transcription factor EB (TFEB), a key regulator of lysosome biogenesis. TFEB inhibition markedly abolished formononetin-induced lysosome biogenesis, autophagosome-lysosome fusion and lipophagy and concomitantly alleviated lipid accumulation. Formononetin improved hepatic steatosis via TFEB-mediated lysosome biogenesis, which provides new evidence regarding formononetin's anti-NAFLD effects.