High-fat Diet-induced Mouse Model Research Articles

Downregulated microRNA-130b-5p prevents lipid accumulation and insulin resistance in a murine model of nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) amplifies the risk of various liver diseases, ranging from simple steatosis to nonalcoholic steatohepatitis, fibrosis, and cirrhosis, and ultimately hepatocellular carcinoma. Accumulating evidence suggests the involvement of aberrant microRNAs (miRNAs or miRs) in the activation of cellular stress, inflammation, and fibrogenesis in hepatic cells at different stages of NAFLD and liver fibrosis. Here, we explored the potential role of miR-130b-5p in the pathogenesis of NAFLD, including lipid accumulation and insulin resistance, as well as the underlying mechanism. Initially, the expression of miR-130b-5p and insulin-like growth factor binding protein 2 (IGFBP2) was examined in the established high-fat diet-induced NAFLD mouse models. Then, the interaction between miR-130b-5p and IGFBP2 was validated using dual luciferase reporter assay. The effects of miR-130b-5p and IGFBP2 on lipid accumulation and insulin resistance, as well as the AKT pathway-related proteins, were evaluated using gain or loss-of-function approaches. miR-130b-5p was upregulated, and IGFBP2 was downregulated in liver tissues of NAFLD mice. miR-130b-5p targeted IGFBP2 and downregulated its expression. MiR-130b-5p inhibition or IGFBP2 overexpression reduced the expression of SREBP-1, LXRα, ChREBP, stearoyl CoA desaturase 1, acetyl CoA carboxylase 1, and fatty acid synthase, and levels of fasting blood glucose, fasting insulin, and homeostasis model assessment-insulin resistance, while increasing the ratio of p-AKT/AKT in NAFLD mice. Overall, downregulation of miR-130b-5p can prevent hepatic lipid accumulation and insulin resistance in NAFLD by activating IGFBP2-dependent AKT pathway, highlighting the potential use of anti-miR-130b-5p as therapeutic approaches for the prevention and treatment of NAFLD.

Odontogenic infection by Porphyromonas gingivalis exacerbates fibrosis in NASH via hepatic stellate cell activation

Odontogenic infection of Porphyromonas gingivalis (P.g.), a major periodontal pathogen, exacerbates pathological progression of non-alcoholic steatohepatitis (NASH). In this study, we aimed to clarify the detailed mechanism in which P.g. induced hepatic stellate cells (HSCs; key effector cells in liver fibrosis) activation. In the liver of high fat diet-induced NASH mouse model with P.g. odontogenic infection, immunolocalization of P.g. was detected. The number of hepatic crown-like structure, which was macrophage aggregation and related to liver fibrosis, was drastically increased and fibrosis area was also increased through upregulating immunoexpression of Phosphorylated Smad2 (key signaling molecule of TGF-β1) and Galectin-3. P.g.-secreted trypsin-like enzyme [gingipain; an activator of protease-activated receptor 2 (PAR2)] stimulated HSC proliferation and differentiation through Smad and ERK signaling induced by TGF-β1 produced from HSCs with P.g.-infection. Further, Galectin-3 produced from HSCs with P.g. infection and P.g.-derived LPS/lipoprotein stimulation stabilized TGFβ-receptor II resulting in increasing sensitivity for TGF-β1, finally leading to HSC differentiation via activating Smad and ERK signaling. In addition to them, hepatocytes (main component cells of liver) contributed to HSC activation through TGF-β1 and Galectin-3 production in paracrine manner. Collectively, P.g.-odontogenic infection exacerbates fibrosis of NASH by HSC activation through TGF-β1 and Gal-3 production from HSCs and hepatocytes.

Swimming Exercise Protects against Insulin Resistance via Regulating Oxidative Stress through Nox4 and AKT Signaling in High-Fat Diet-Fed Mice.

Nonpharmaceutical therapies such as exercise training and diet intervention are widely used for the treatment of insulin resistance (IR). Although the skeletal muscle is the major peripheral tissue of glucose metabolism under insulin stimulation, the mechanism underlying muscle IR is poorly understood. Using a high-fat diet-induced IR mouse model, we here show that NADPH oxidase 4 (Nox4) upregulation mediates the production of reactive oxygen species (ROS) that causes metabolic syndrome featuring IR. The Nox4 expression level was markedly elevated in IR mice, and Nox4 overexpression was sufficient to trigger IR. Conversely, downregulation of Nox4 expression through exercise training prevented diet-induced IR by reducing the production of ROS and enhancing the AKT signaling pathway. Thus, this study indicates that exercise might improve IR through a reduction of Nox4-induced ROS in the skeletal muscle and enhancement of AKT signal transduction.

DHA Protects Against Hepatic Steatosis by Activating Sirt1 in a High Fat Diet-Induced Nonalcoholic Fatty Liver Disease Mouse Model.

AimDocosahexaenoic acid (DHA; C22; n-3) shows beneficial effects on Non-alcoholic fatty liver disease (NAFLD). Deacetylase Sirtuin1 (Sirt1) was reported to increase energy metabolism and decrease lipogenesis. Here, we investigated whether DHA plays a role in protecting against hepatic steatosis via Sirt1.Main MethodsBoth in vivo and in vitro hepatic steatosis models were used: diet-induced obesity (DIO) model (middle-aged C57BL/6 mice fed a high-fat diet (HFD)) and palmitic acid (PA)-induced lipid accumulation cell model (HepG2 cells).Key FindingsIn DIO mice, treatment with DHA (gavage supplementation) for 8 weeks not only inhibited the lipid accumulation, but also increased fatty acids (FA) oxidation and induced triglyceride export in liver. These changes were accompanied by attenuation of inflammation. Moreover, DHA reversed the HFD-induced reduction of Sirt1 in liver. Interestingly, the beneficial effects of DHA were reversed by lentivirus-mediated Sirt1 knockdown, accompanied with increased expression of markers of lipogenesis, inflammation and reduced FA oxidation. In HepG2 cells, DHA prevented the accumulation of PA-induced lipid droplets, the decrease of FA oxidation and the reduction of Sirt1 level. Inhibition of Sirt1 by sirtinol partially reversed the beneficial effects of DHA on PA-treated cells.SignificanceDHA alleviated hepatic steatosis and reduced inflammation of liver in obese middle-aged mice by mechanisms involving Sirt1 activation.

Fish oil extracted from Coregonus peled improves obese phenotype and changes gut microbiota in a high-fat diet-induced mouse model of recurrent obesity.

Recurrent obesity is rapidly emerging as a public health problem. Previous studies have confirmed that fish oil supplementation can alleviate obesity in mice; however, the effect of fish oil on recurrent obesity remains unclear. In the present study, the modulatory effects of fish oil extracted from Coregonus peled on the phenotypes and gut microbiota of recurrent obese mice were evaluated by MRI, OGTT, and bioinformatics analysis. We found that fish oil supplementation could significantly reduce the body weight gain, net weight gain, body fat distribution, and glucose tolerance. In addition, the composition and structure of gut microbiota were significantly shifted toward those of the control group by fish oil treatment. Moreover, the relative abundance of gut microbiota, such as Bacteroidetes, Bacteroidia, Lachnospiraceae, and Bifidobacterium, was markedly responding to the rapid dietary changes between fish oil and high-fat diet. Overall, our results confirmed that the alleviation of recurrent obesity using fish oil supplementation might be modulated by altering the hysteretic behavior and memory-like function of gut microbiota. We proposed that further studies are needed to elucidate the modulation mechanism.

Ferulic acid maintains the self-renewal capacity of embryo stem cells and adipose-derived mesenchymal stem cells in high fat diet-induced obese mice

Self-renewal is required for embryo stem cells (ESCs) and adipose-derived mesenchymal stem cells (ADMSCs). This study examined the ability of ferulic acid in mouse ESCs and ADMSCs, in a high fat diet-induced mouse model. Initially, five natural compounds of ferulic acid, xanthohumol, curcumin, ascorbic acid, and quercetin were screened in ESCs using an alkaline phosphate +(AP+) assay, as a self-renewal biomarker. A ferulic acid treatment was the highest AP+ staining in hop-hit screening compounds. Also a ferulic acid increased Nanog mRNA levels in ESCs. The in vivo effects of ferulic acid were next examined in an obese mouse model. C57BL/6 J male mice were fed either a high fat diet (HFD) or control diet with ferulic acid (5 g/kg diet) for 8 weeks. Ferulic acid exhibited weight loss and improved glucose homeostasis, lipid profiling, and hepatic steatosis in a HFD-induced mouse model. Next, ADMSCs (Sca-1+CD45−), a hallmark of fat stem cells, were then isolated and quantified from mouse abdominal adipose tissue. A HFD decreased the Sca-1+CD45− cell population of ADMSCs, but HFD-induced obese mice given ferulic acid showed an increased the Sca-1+CD45− cell population of ADMSCs. Moreover, ferulic acid enhanced NANOG mRNA levels in human ADMSCs and its related gene mRNA expression. Overall, this study suggests that ferulic acid preserves self-renewal in ESCs, and contributes to ADMSCs self-renewal and effective weight control in obesity.

Purine Catabolism Shows a Dampened Circadian Rhythmicity in a High-fat Diet-Induced Mouse Model of Obesity.

High-calorie diet, circadian rhythms and metabolic features are intimately linked. However, the mediator(s) between nutritional status, circadian rhythms and metabolism remain largely unknown. This article aims to clarify the key metabolic pathways bridging nutritional status and circadian rhythms based on a combination of metabolomics and molecular biological techniques. A mouse model of high-fat diet-induced obesity was established and serum samples were collected in obese and normal mice at different zeitgeber times. Gas chromatography/mass spectrometry, multivariate/univariate data analyses and metabolic pathway analysis were used to reveal changes in metabolism. Metabolites involved in the metabolism of purines, carbohydrates, fatty acids and amino acids were markedly perturbed in accordance with circadian related variations, among which purine catabolism showed a typical oscillation. What’s more, the rhythmicity of purine catabolism dampened in the high-fat diet group. The expressions of clock genes and metabolic enzymes in the liver were measured. The mRNA expression of Xanthine oxidase (Xor) was highly correlated with the rhythmicity of Clock, Rev-erbα and Bmal1, as well as the metabolites involved in purine catabolism. These data showed that a high-fat diet altered the circadian rhythm of metabolic pathways, especially purine catabolism. It had an obvious circadian oscillation and a high-fat diet dampened its circadian rhythmicity. It was suggested that circadian rhythmicity of purine catabolism is related to circadian oscillations of expression of Xor, Uox and corresponding clock genes.

Patchouli Alcohol from Pogostemon Cablin Prevents Development of Obesity and Improves Glucose Tolerance in High Fat Diet-induced Obese Mice (P06-107-19)

ObjectivesPatchouli alcohol is a sesquiterpene alcohol found in Pogostemon cablin. Recently, we observed that patchouli alcohol reduced lipid accumulation in differentiated 3T3-L1 adipocytes and increased glucose uptake in differentiated C2C12 myocytes. This study was designed to investigate anti-obese and anti-diabetic activities of patchouli alcohol using high fat diet-induced obese mouse model. MethodsForty-eight 5-week old C57BL/6 J male mice were assigned into four groups and fed with 1) normal diet (control), 2) high fat diet, 3) high fat diet with gavaging 25 mg of patchouli alcohol/kg body weight and 4) high fat diet with gavaging 50 mg of patchouli alcohol/kg body weight. High fat diet or control diets were provided to each treatment group for four weeks and then different doses of patchouli alcohol (0, 25 or 50 mg/kg body weight) was orally administered for following 8 weeks with the diet. At age of week 17, all animals were sacrificed, fat tissues were collected, and tissue weight was measured. In addition, twenty C57BL/6 J male mice were assigned into the same treatment groups above. At the end of the 8 weeks (age of week 17), the mice were fasted for 12 h and the oral glucose tolerance test was performed after intraperitoneal injection of 2 g of anhydrous glucose/kg body weight. The blood was collected from tail at 0, 15, 30, 90 and 120 min after injection and blood glucose level was analyzed using glucose meter. ResultsTreatment of patchouli alcohol (50 mg/kg body weight) significantly reduced body weight and accumulation of body fat pads which was highly induced by feeding of high fat diet. An analysis of individual fat pad weights (expressed as mg weight of fat pad/g body weight) revealed a significant decrease of epididymal and retroperitoneal fat pad in patchouli alcohol-treated mice whereas brown adipose tissue were not significantly altered. And, slightly improved glucose tolerance was observed at 90 and 120 minutes after glucose injection in mice treated with patchouli alcohol (50 mg/kg body weight) compared to those fed with high fat diet alone. ConclusionsWe propose a potential use of patchouli alcohol as an anti-obesity compound in obese population. Funding SourcesNIFA Hatch grant. Supporting Tables, Images and/or Graphs▪

2194-P: Il-6/Stat3 Pathway Contribute to the Islet Failure in High-Fat Diet-Induced Mouse Model of Obesity

Objective: This study was aimed at revealing a new mechanism mediated by IL-6/Stat3 signaling pathway on islet failure in high fat diet-induced obesity through activation of inflammation. Methods: We produced mice with non-obesity, moderate obesity and severe obesity respectively by feeding with normal diet (control), three months’ high fat diet (HFD-3M) and six months’ high fat diet (HFD-6M). Then 200 islets were isolated from the three groups and lysed for RNA extraction, following RNA-Seq analysis with MAPS (Multiplex Analysis of PolyA-linked Sequences) approach. Normal islets were cultured in vitro for IL-6 stimulation and mice with stat3 specific deletion in islet were used to prevent HFD-resulted islet failure. Results: Mice with HFD for three months and six months show significantly higher fast glucose and severe glucose intolerance than control and the morphology of islets from HFD group was obviously abnormal. Additionally, these diabetic symptoms were aggravated in pace with HFD feeding. Further analysis of RNA-seq shows that the expressions of hormones secreted by different endocrine cells were all down-regulated, including INS1, GCG, SST and PPY. On the other hand, expression of IL-6/Stat3 pathway related genes were significantly elevated, including IL-6, CCL2, CCL5, CCL11, CCL28, Tnfrsf11 and NF-kB. Stat3 in islets from HFD-3M and HFD-6M group was also activated by phosphorylation of Y705. Cultured islets with IL-6 treatment show impaired insulin secretion and increased inflammation level. Notably, mice with stat3 specific deletion in islet were able to attenuate the HFD-induced increase of inflammation and secretory deficiency of islet. Conclusions: HFD-induced obesity resulted in islet failure and the high level of serum IL-6 participate in the obesity induced islet failure through IL-6/Stat3 pathway mediated inflammation. Disclosure Z. Jiang: None. F. Teng: None. Y. Xu: None. Funding National Natural Science Foundation of China (81600597)

Niacin fine-tunes energy homeostasis through canonical GPR109A signaling.

The incidence of overweight and obesity has become a global public health problem, constituting a major risk factor for numerous comorbidities. Despite tremendous efforts, effective pharmacological agents for the treatment of obesity are still limited. Here, we showed that in contrast to lactate receptor GPR81, niacin receptor GPR109A-deficient mice had progressive weight gain and hepatic fat accumulation. Using high-fat diet-induced mouse model of obesity, we demonstrated that niacin treatment apparently protected against obesity without affecting food intake in wild-type mice but not in GPR109A-deficient mice. Further investigation showed that niacin treatment led to a remarkable inhibition of hepatic de novo lipogenesis. Additionally, we demonstrated that niacin treatment triggered brown adipose tissue and/or white adipose tissue thermogenic activity via activation of GPR109A. Moreover, we observed that mice exposed to niacin exhibited a dramatic decrease in intestinal absorption of sterols and fatty acids. Taken together, our findings demonstrate that acting on GPR109A, niacin shows the potential to maintain energy homeostasis through multipathways, representing a potential approach to the treatment of obesity, diabetes and cardiovascular disease.-Ye, L., Cao, Z., Lai, X., Wang, W., Guo, Z., Yan, L., Wang, Y., Shi, Y., Zhou, N. Niacin fine-tunes energy homeostasis through canonical GPR109A signaling.

Liraglutide protects non-alcoholic fatty liver disease via inhibiting NLRP3 inflammasome activation in a mouse model induced by high-fat diet

Liraglutide, a glucagon-like peptide-1 (GLP-1) analogue that has recently become the first-line treatment for type 2 diabetes mellitus (T2DM), has also been reported to decrease fatty degeneration of the liver. The purpose of this study is to explore whether liraglutide improves high-fat diet-induced non-alcoholic fatty liver disease (NAFLD) in mice through inhibiting the NLRP3 inflammasome in the liver. After daily intraperitoneal injection of liraglutide (0.6 mg/kg body weight) for four weeks, the liver, liver/body weight, serum levels of ALT, AST, total cholesterol, triglycerides and LDL were significantly decreased in a high-fat diet-induced NAFLD mouse model. The hepatic steatosis among sections of H&E and Oil Red O staining was also markedly reduced after treatment with liraglutide. The expressions of NLRP3 inflammasome components (including NLRP3, ASC, and caspase-1) in the liver of mice after treatment with liraglutide were decreased substantially. In vitro studies found that the mitochondrial dysfunction in Kupffer cells induced by palmitic acid was attenuated, and the protein levels of NLRP3, ASC and caspase-1 were also decrease markedly. These results demonstrate that liraglutide was able to alleviate high-fat diet-induced hepatic steatosis via inhibiting NLRP3 inflammasome activation, suggesting that liraglutide is a potent drug that can reverse the pathological hallmarks of NAFLD.

Molecular hydrogen protects against ischemia-reperfusion injury in a mouse fatty liver model via regulating HO-1 and Sirt1 expression

Fatty liver has lower tolerance against ischemia-reperfusion (I/R) injury in liver operations, including liver transplantation. Seeking to ameliorate liver injury following I/R in fatty liver, we examined the protective effect of hydrogen (H2) saline on I/R liver injury in a methionine and choline-deficient plus high fat (MCDHF) diet-induced fatty liver mouse model. Saline containing 7 ppm H2 was administrated during the process of I/R. Livers were obtained and analyzed. Primary hepatocytes and Kupffer cells (KCs) were obtained from fatty liver and subjected to hypoxia/reoxygenation. Apoptosis-related proteins and components of the signaling pathway were analyzed after treatment with hydrogen gas. The MCDHF I/R group showed higher levels of AST and ALT in serum, TUNEL-positive apoptotic cells, F4/80 immunopositive cells, mRNA levels of inflammatory cytokines, constituents of the signaling pathway, pro-apoptotic molecules in liver, and KCs and/or primary hepatocytes, compared to the control group. In contrast, H2 treatment significantly suppressed the signs of I/R injury in fatty liver. Moreover, the expression of Bcl-2, HO-1, and Sirt1 in liver, KCs, and hepatocytes by hydrogen gas were increased, whereas caspase activation, Bax, and acetylation of p53 were suppressed by hydrogen gas. These results demonstrated that H2 treatment ameliorated I/R liver injury in a fatty liver model by reducing hepatocyte apoptosis, inhibiting macrophage activation and inflammatory cytokines, and inducing HO-1 and Sirt1 expression. Taken togather, treatment with H2 saline may have a protective effect and safe therapeutic activity during I/R events, such as in liver transplantation with fatty liver.

Metagenomics Analysis of Gut Microbiota in a High Fat Diet-Induced Obesity Mouse Model Fed with (-)-Epigallocatechin 3-O-(3-O-Methyl) Gallate (EGCG3″Me).

(-)-Epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me) has been shown to have a modulatory effect on human intestinal microbiota, and the relationship between intestinal flora and obesity has attracted more and more attention recently. Here, the potential link between EGCG3″Me and gut microbiota composition, as well as the underlying mechanisms of the anti-obesity activity of EGCG3″Me are investigated. EGCG3″Me was prepared from oolong tea by column chromatography, and the influence of EGCG3″Me on intestinal microbiota was analyzed using a human-flora-associated high fat diet (HFD)-induced obesity mouse model by metagenomics. EGCG3″Me showed a weight reducing effect, ameliorated the HFD-induced gut dysbiosis, and significantly decreased the ratio of Firmicutes/Bacteroidetes. Moreover, the Kyoto Encyclopedia of Genes and Genomes (KEGG) database provided significant differences in differentially expressed genes in response to EGCG3″Me treatment. The results showed enrichment of genes involved in the biosynthesis of amino acids, the two-component system, ATP-binding cassette (ABC) transporters, purine metabolism, and carbon metabolism. An EGCG3″Me supplemented diet produces promising effects on gut microecology by enhancing beneficial microbial populations and by affecting metabolic pathways including amino acids biosynthesis, the two-component system, and ABC transporters, contributing to the improvement of host health.

Metagenomics analysis of gut microbiota modulatory effect of green tea polyphenols by high fat diet-induced obesity mice model

This study focused on the modulatory effect of green tea polyphenols (GTP) on human intestinal microbiota, and its underlying anti-obesity mechanisms. GTP was prepared from Chinese green tea by column chromatography, and then the influence of GTP on intestinal microbiome was analyzed with a human flora-associated (HFA) high fat diet-induced obesity mice model by metagenomics. GTP ameliorated the obesity-induced gut dysbiosis; in addition, a significant decrease was observed in Firmicutes/Bacteroidetes after GTP treatment. Moreover, KEGG pathways of ATP-binding cassette (ABC) transporters, two-component system and biosynthesis of amino acids enriched the most differentially expressed genes after GTP intervention for 8 weeks. Our results may have important implications for the use of GTP as a functional food component with potential therapeutic utility against high fat diet induced obesity, and prebiotic-like activity by modulating intestinal microbiota and affecting certain metabolic pathways, contributing to the improvement of host health.

Traditional kefir reduces weight gain and improves plasma and liver lipid profiles more successfully than a commercial equivalent in a mouse model of obesity

Kefir, a fermented milk beverage, has shown promise in alleviating obesity and associated metabolic dysfunction. However, microbial characteristics are variable among traditional kefirs, and commercial kefirs drastically differ from traditional kefir. This study investigated the ability of four traditional and one commercial kefir to control weight gain, plasma cholesterol, and liver triglycerides in a high fat diet-induced obesity mouse model. Two traditional kefirs decreased weight gain and plasma cholesterol levels. Conversely, commercial kefir had no beneficial effect. Additionally, one of the four traditional kefirs lowered liver triglycerides, which corresponded with decreases in the expression of fatty acid synthase, a gene involved in liver lipogenesis. Together with evidence of gut microbiome modulation, this study shows that traditional kefir has the potential for improving metabolic dysfunction associated with obesity. Notably, differences in kefir microbial populations may influence the ability of traditional kefir to positively impact host metabolic health.

The modulatory effect of nanocomplexes loaded with EGCG3ʺMe on intestinal microbiota of high fat diet-induced obesity mice model

In this study, (-)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3ʺMe) was embedded in nanoparticles assembled from chitosan (CS) and caseinophosphopeptide (CPP), and the anti-obesity effect of EGCG3ʺMe-loaded chitosan-caseinophosphopeptide (CS-CPP) nanoparticles was investigated. The encapsulation efficiency of EGCG3ʺMe ranged from 72.61 to 83.25% with EGCG3ʺMe concentration changing from 1.0 to 2.5 mg/mL, and the in vitro release of EGCG3ʺMe was controllable. The administration of EGCG3ʺMe-loaded CS-CPP alleviated the changes in the serum and liver levels of high fat diet-induced obesity human flora-associated mice model dramatically. For the population of the intestinal microbiota, both EGCG3ʺMe and EGCG3ʺMe-loaded CS-CPP promoted the growth of certain beneficial bacteria and exhibited inhibitory effects on the proliferation of Bacteroides–Prevotella and Clostridium histolyticum. Furthermore, EGCG3ʺMe-loaded CS-CPP showed the best proliferative effect on Bifidobacterium and Lactobacillus–Enterococcus spp. Together, it confirmed that the encapsulation of EGCG3ʺMe by nanoparticles can effectively improve the bioactivity of EGCG3ʺMe and prevent obesity-related metabolic disorders. Practical applications The findings suggest the potential of CS-CPP nanoparticles to promote the bioavailability of EGCG3ʺMe. The administration of EGCG3ʺMe-loaded CS-CPP nanoparticles showed significant anti-obesity effects on high fat diet-induced obesity mice model as well as the modulatory effect on the intestinal microbiota. In addition, they showed the best proliferative effect for Bifidobacterium and Lactobacillus–Enterococcus spp. Due to the improved bioavailability, EGCG3ʺMe-loaded CS-CPP nanoparticles could be developed as a potential functional food to prevent obesity-related metabolic disorders in obese individuals.

Effect of obesity on global sperm methylation and gene imprinting

This study was to investigate whether high fat diet-induced obesity altered gene imprinting of sperm or global sperm DNA methylation. C57BL/6J mice at 3 week were fed on high fat diet (D12492) or control diet for 12 weeks. the mean weight of DIO mice was between 38 and 42g, mean weight of control diet mice was between 24 and 28g. With high fat diet-induced obese mouse model, differentially methylated region for imprinted gene and global genome methylation were bisulfite-sequenced. There were no significant differences between obese mouse group and control group: MEG3-IG (93.73% vs.97.26%;p=0.252),H19(98.00% vs.97.83%;p=0.920),IGF2(97.34% vs.96.25%;p=0.166),IGF2R(1.43% vs.1.11%;p=0.695), PEG3(0.19% vs.0.38%;p=0.537),MEST(0.23% vs.0.68%;p=0.315), NNAT(0.31% vs.0.00%;p=0.134) and SNRPN(1.88% vs.3.13%;p=0.628). Moreover, methylation level of individual CG site at 8 imprinted gene was also not significantly changed(p>0.05). In addition, 8942 differentially methylated regions were detected across sperm genome. Gene enrichment analysis indicated that the most enrichment items were respectively metabolic process(n=1482), RNA synthesis(n=779) and transcription(n=767). Methylation level of imprinted gene may not be significantly altered in sperm from high fat-induced obese mouse, however, genes involved in metabolic process, RNA synthesis and transcription and so on might be significantly altered.

The modulatory effect of (-)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me) on intestinal microbiota of high fat diet-induced obesity mice model

(-)-Epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me) has exhibited multiple beneficial effects on the prevention of obesity in oolong tea. However, its absorption is relatively low, and the potential to be fully utilized is not completely elucidated. Therefore, with human flora-associated (HFA) mice model, the effect of EGCG3″Me on high fat diet-induced obesity was investigated by high-throughput sequencing. The shifts in relative abundance of the dominant taxa at the phylum, family and genus levels showed the dramatically effects of EGCG3″Me. Despite significant inter-individual variation, a large increase in Bacteroidetes with concomitant decrease of Firmicutes was observed after the administration of EGCG3″Me for 8weeks, with a corresponding decrease in the Firmicutes/Bacteroidetes ratio, which reflect the modulatory effect of EGCG3″Me on intestinal microbiota. The results showed that EGCG3″Me may have prebiotic-like activity and can be used as a functional food component with potential therapeutic utility in manipulating intestinal microbiota, contributing to the prevention of gut dysbiosis.

Wheat-bran autolytic peptides containing a branched-chain amino acid attenuate non-alcoholic steatohepatitis via the suppression of oxidative stress and the upregulation of AMPK/ACC in high-fat diet-fed mice.

Whole-wheat intake is known to reduce the risk of metabolic syndrome. However, the active component remains unclear. Recently, we identified bioactive peptides [leucine-arginine-proline (LRP) and leucine-glutamine‑proline(LQP)] from wheat bran autolytic hydrolysate. The present study aimed to investigate the effects of LRP and LQP on non-alcoholic steatohepatitis (NASH) in a mouse model. We also evaluated the effects of these peptides on oxidative stress and on the AMP-activated protein kinase (AMPK) signaling pathway, two major pathogenic factors of NASH. Seven‑week-old male C57BL/6 mice were fed a high-fat diet for 10weeks and administered water supplemented with 0.05%LRP, 0.20%LRP, 0.05%LQP, or 0.20%LQP (each n=5) or distilled water (control; n=5) adlibitum. Oxidative stress was evaluated by measuring the serum levels of diacron reactive oxygen metabolite (d-ROM) and biological antioxidant potential (BAP). Hepatic expression of phosphorylated AMPK and phosphorylated acetyl-CoA carboxylase (ACC) were evaluated by immunoblotting. The result showed that non‑alcoholic fatty liver disease activity score was significantly decreased in all types of treatment. Serum d-ROM levels were significantly decreased in the 0.20% LRP group, but not in the 0.05% LRP, 0.05% LQP, and 0.20% LQP groups. Serum BAP levels were significantly increased in the 0.05% LRP and 0.20% LRP groups, but not in the 0.05% LQP and 0.20% LQP groups. Immunoblotting analysis revealed that the expression of phospho-AMPK was increased whereas that of phospho-ACC was decreased in the 0.20% LQP group. In conclusion, we demonstrated that both LRP and LQP alleviated the severity of NASH in a high-fat diet-induced NASH mouse model. In addition, we showed that LRP and LQP modulated oxidative stress and upregulated AMPK/ACC, respectively. Thus, LRP and LQP may constitute clinically applicable therapeutic agents for NASH.

Chemical chaperones reduce ER stress and adipose tissue inflammation in high fat diet-induced mouse model of obesity.

Obesity, which is characteristic by chronic inflammation, is defined as abnormal or excessive fat accumulation in adipose tissues. Endoplasmic reticulum (ER) stress is increased in adipose tissue of obese state and is known to be strongly associated with chronic inflammation. The aim of this study was to investigate the effect of ER stress on adipokine secretion in obese mice and explore the potential mechanisms. In this study, we found high-fat diet induced-obesity contributed to strengthened ER stress and triggered chronic inflammation in adipose tissue. Chemical chaperones, 4-PBA and TUDCA, modified metabolic disorders and decreased the levels of inflammatory cytokines in obese mice fed a high-fat diet. The alleviation of ER stress is in accordance with the decrease of free cholesterol in adipose tissue. Furthermore chemical chaperones suppress NF-κB activity in adipose tissue of obese mice in vivo. In vitro studies showed IKK/NF-κB may be involved in the signal transduction of adipokine secretion dysfunction induced by ER stress. The present study revealed the possibility that inhibition of ER stress may be a novel drug target for metabolic abnormalities associated with obesity. Further studies are now needed to characterize the initial incentive of sustained ER stress in obese.