Hepatic mRNA Levels Research Articles

The Anti-Obesity Compound Asperuloside Reduces Inflammation in the Liver and Hypothalamus of High-Fat-Fed Mice

Obesity produces a systemic low-grade inflammation associated with many adverse health conditions and, as we recently learned, with complications of COVID-19. Functional studies in animal models have demonstrated that asperuloside, an iridoid glycoside found in many medicinal plants, has produced promising anti-obesity results. However, the safety profile and the anti-inflammatory properties of asperuloside remain unknown. Here, we confirmed the previously reported anti-obesity properties of asperuloside, and, importantly, we performed toxicity studies assessing cell viability providing a dose reference for future animal experiments. Asperuloside significantly reduced blood levels of leptin and the mRNA levels of orexigenic peptides, such as NPY and AgRP in mice consuming HFD, with no effect on mice eating a standard chow diet. In addition, our results indicate that ASP reduced both hypothalamic and hepatic mRNA levels of pro-inflammatory cytokines such as IL-1, IL-6 and TNF-α as well as the blood levels of plasminogen activator inhibitor-1 (PAI-1), which are known to play a major role in the development of insulin resistance and cardiovascular complications. Collectively, our findings suggest that asperuloside is a safe compound for long-term use in animal models and that it reduces the elevated levels of pro-inflammatory cytokines occurring in obesity.

Replenishment of vitamin A for 7 days partially restored hepatic gene expressions altered by its deficiency in rats.

We investigated the effects of vitamin A (VA) status on metabolism of Zucker rats with different genders and genotypes, and of short-term refeeding of a VA sufficient (VAS) diet on VA deficient (VAD) animals. First, male and female Zucker lean (ZL) and fatty (ZF) rats at weaning were fed a VAD or VAS diet for 8 weeks. Second, male VAD ZL rats were fed a VAS diet for 3 (VAD-VAS3d) or 7 (VAD-VAS7d) days. The body weight (BW), blood parameters, and hepatic expressions of genes for metabolism were determined. VA deficiency reduced BW gain in ZL and ZF rats of either gender. VAD ZL rats had lower plasma glucose, insulin, and leptin levels than VAS ZL rats. VAD-VAS3d and VAD-VAS7d rats had higher plasma glucose, insulin, and leptin levels than that in the VAD rats. The hepatic mRNA levels of Gck, Cyp26a1, Srebp-1c, Igf1, Rarb, Rxra, Rxrg, Pparg, and Ppard were lowered by VA deficiency. Refeeding of the VAS diet for 3 days restored the Gck and Cyp26a1 expressions, and for 7 days restored the Gck, Cyp26a1, Igf1, and Rxrb expressions significantly. The 7-day VA replenishment partially restored the hepatic gene expressions and metabolic changes in VAD ZL rats.

Inhibition of coagulation factor XI attenuates inflammation in myocardial ischemia/reperfusion injury

Abstract Background Increasing evidence suggests that FXI is an attractive target for antithrombotic therapy because it reduces thrombosis without increasing bleeding risk. Patients with decreased levels of FXI are at reduced risk of cardiovascular diseases and thromboembolic events. We have already revealed that depletion of FXI inhibits the vascular coagulation-inflammatory circuit in angiotensin II-induced arterial hypertension. However, the effect of FXI depletion on cardiac inflammation and vascular function in ischemia/reperfusion (I/R) injury is unknown. Purpose Using FXI-depleted mice to investigate the role of FXI in inflammation response post cardiac I/R injury. Methods 8–12 weeks old C57BL/6J male mice were injected intraperitoneally with FXI antisense oligonucleotide (FXI ASO) or scrambled controls for a period of 2 weeks. Then we temporarily ligated the left anterior descending (LAD) for 45 minutes to induce myocardial ischemia, followed by the reperfusion for 72 hours (ischemia/reperfusion injury, IRI). Myocardial inflammation and vascular function were analyzed by flow cytometry, real-time PCR, vascular relaxation studies from isolated aortic segment in organ chamber and chemiluminescence photon counting of oxidative burst in whole blood. Results FXI ASO treatment reduced hepatic FXI mRNA levels and prolonged activated partial thromboplastin time. Compared to scrambled ASO injected mice, oxidative burst from whole blood and endothelial dysfunction were decreased in FXI ASO injected mice with IRI. Compared to control groups, depletion of FXI attenuated cardiac infiltration of CD45+CD11b+ cells, especially LyG-LyChigh monocytes and LyG+ neutrophils at day 3 in I/R injury. Furthermore, the expression levels of adhesion molecules and expression of pro-inflammatory cytokines, such as Vcam-1, CCL2, IL-6 and IL-1b, in ischemic myocardium were significantly decreased in the FXI depleted mice of I/R injury. Conclusion Our results suggest that Inhibition of FXI leads to reduction of vascular dysfunction and ROS production in I/R injury, as well as attenuation of the inflammatory response and the influx of inflammatory cells in ischemic myocardium. This indicates that FXI could be a potential target for further treatment in cardiac IRI. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): TICARDIO project has received funding from the European Union's Horizon 2020 research and Innovation programme under the Marie Skłodowska-Curie grant agreement No 813409.

Rhizoma curcumae Longae ameliorates high dietary carbohydrate-induced hepatic oxidative stress, inflammation in golden pompano Trachinotus ovatus

In general, starch, as a complex carbohydrate, is the most economical energy source in aquaculture for its relatively low cost. However, excessive dietary levels of carbohydrate result in pathological conditions. An 8-week feeding trial with CT (control diet, containing 21% carbohydrate), HC (a high-carbohydrate diet, containing 50% carbohydrate) and HCR (a HC diet supplemented with 0.015% Rhizoma curcumae Longae) was performed to investigate the protective effect of curcumin on high-carbohydrate-induced hepatic oxidative stress and intestine lesion in juvenile Trachinotus ovatus. In the current study, HC group significantly decreased WGR, SGR, plasma CAT activity, intestinal C4 levels, hepatic Nrf2, Keap1, Bach1, HO1, CAT, and GPX mRNA expression as well as ZO-1, Occludin, and Claudin-3, TGF-β mRNA transcription levels, while the opposite was true for plasma AST activity, hepatic MDA contents, intestinal Claudin-15, NF-κB, IL-1β, IL-6, and TNF-α mRNA expression. In contrast with the HC group, the HCR group significantly increased the activities of hepatic CAT, SOD, intestinal C3, C4, IgG and LZM levels, hepatic Nrf2, Bach1, CAT, and GPX mRNA expression as well as intestinal ZO-1, Occludin, Claudin-3, TGF-β and IL-10 mRNA expression levels, but the opposite trend was found in plasma triglyceride content, hepatic lipid deposition, hepatic Keap1 mRNA level as well as intestinal NF-κB, IL-6. In conclusion, high-carbohydrate diet can cause detrimental effect on physiological health status in Trachinotus ovatus, while adding Rhizoma curcumae Longae can improve hepatic and intestinal health status via attenuating the oxidative stress, inflammation, and reducing lipid deposition.

Constitutive androstane receptor (CAR) mediates pyrene-induced inflammatory responses in mouse liver, with increased serum amyloid A proteins and Th17 cells.

The constitutive androstane receptor (CAR), a known xenobiotic sensor, plays an important role in drug metabolism by regulating numerous genes. The polycyclic aromatic hydrocarbon pyrene, an environmental pollutant, is a CAR activator and induces mouse hepatotoxicity via CAR. Here, we investigate the molecular mechanisms of the inflammatory response in pyrene-caused mice liver injury. Effects of pyrene on the liver were investigated in wild-type and CAR knockout (KO) mice. Levels of pyrene and its urinary metabolite were analysed by high performance liquid chromatography (HPLC). Inflammatory responses were measured by qRT-PCR, western blotting, and ELISA for cytokines. Serum amyloid A proteins (SAAs) were markedly increased in the liver and serum of pyrene-exposed wild-type mice. IL-17-producing helper T cells (Th17 cells) and IL-17 levels were increased in the liver of pyrene-exposed wild-type mice. Hepatic mRNA levels of inflammatory cytokines including IL-1β, IL-6 and TNFα, and serum IL-6 levels were significantly elevated in pyrene-treated wild-type mice. However, these changes were not observed in CAR KO mice. CAR plays a crucial role in pyrene-caused mice liver inflammatory response with increased SAAs and Th17 cells. Our results suggest that serum SAAs may be a convenient biomarker for early diagnosis of liver inflammatory response caused by polycyclic aromatic hydrocarbons, including pyrene. CAR and Th17 cells may be potential targets for novel therapeutic strategies for xenobiotic-induced liver inflammation.

Organic chromium derived from the chelation of Ganoderma lucidum polysaccharide and chromium (III) alleviates metabolic syndromes and intestinal microbiota dysbiosis induced by high-fat and high-fructose diet

Organic chromium is of great interest and has become an important chromium supplement resource in recent years because of its low toxicity and easy absorption. In our previous study, we synthesized a novel organic chromium [GLP-Cr] through the chelation of Ganoderma lucidum polysaccharide and chromium (III). The purpose of this study was to investigate the beneficial effects of GLP-Cr on the improvement of metabolic syndromes (MetS) in mice fed with a high-fat and high-fructose diet (HFHFD) and its mechanism of action. The results indicated that oral administration of GLP-Cr inhibited the excessive exaltation of body weight, glucose tolerance, fasting blood glucose and lipid levels, hepatic total cholesterol (TC), triglyceride (TG) levels caused by HFHFD. Besides, 16S rRNA amplicon sequencing showed that GLP-Cr intervention evidently ameliorated intestinal microbiota dysbiosis by changing the proportions of some intestinal microbial phylotypes. In addition, correlation network-based analysis indicated that the key intestinal microbial phylotypes were closely related to biochemical parameters associated with MetS under GLP-Cr intervention. Liver metabolomics analysis suggested that GLP-Cr intervention significantly regulated the levels of some biomarkers involved in alpha-linolenic acid metabolism, fatty acid biosynthesis, steroid hormone biosynthesis, glycerophospholipid metabolism, glycerolipid metabolism, steroid hormone biosynthesis, primary bile acid biosynthesis, and so on. Moreover, GLP-Cr intervention regulated liver mRNA levels of key genes associated with glucose and lipid metabolism. The mRNA level of glucose transporter type 4 (Glut4) was markedly increased by GLP-Cr intervention, and the mRNA levels of phosphoenolpyruvate carboxykinase (Pepck) and glucose-6-phosphatase (G6Pase) in the liver were significantly decreased. Meanwhile, GLP-Cr intervention significantly decreased hepatic mRNA levels of cluster of differentiation 36 (Cd36), acetyl-CoA carboxylase 1 (Acc1) and sterol regulatory element binding protein-1c (Srebp-1c), indicating that GLP-Cr intervention inhibited the excessive accumulation of free fatty acids in the liver. These findings suggest that the prevention of hyperglycemia and dyslipidemia by GLP-Cr may be closely related to the regulation of gut microbial composition and hepatic metabolic pathways, thus GLP-Cr can be serving as a functional component in the prevention of MetS.

Role of nuclear pregnane X receptor in Cu-induced lipid metabolism and xenobiotic responses in largemouth bass (Micropterus salmoides).

The pregnane X receptor (PXR) is a master xenobiotic-sensing receptor in response to toxic byproducts, as well as a key regulator in intermediary lipid metabolism. Therefore, the present study was conducted to investigate the potential role of PXR in mediating the lipid dysregulation and xenobiotic responses under Cu-induced stress in largemouth bass (Micropterus salmoides). Four groups of largemouth bass (52.66 ± 0.03 g) were treated with control, Cu waterborne (9.44 μmol/L), Cu+RIF (Rifampicin, 100 mg/kg, PXR activator), and Cu+KET (Ketoconazole, 20 mg/kg, PXR inhibitor) for 48 h. Results showed that Cu exposure significantly elevated the plasma stress indicators and triggered antioxidant systems to counteract Cu-induced oxidative stress. Acute Cu exposure caused liver steatosis, as indicated by the significantly higher levels of plasma triglycerides (TG), lipid droplets, and mRNA levels of lipogenesis genes in the liver. Liver injuries were detected, as shown by hepatocyte vacuolization and severe apoptotic signals after Cu exposure. Importantly, Cu exposure significantly stimulated mRNA levels of PXR, suggesting the response of this regulator in the xenobiotic response. The pharmacological intervention of PXR by the agonist and antagonist significantly altered hepatic mRNA levels of PXR, implying that RIF and KET were effective agents of PXR in largemouth bass. Administration of RIF significantly exacerbated liver steatosis, and such alterations were dependent on the regulations on pparγ and cd36 rather than srebp1 signaling, which suggested that PXR-PPARγ might be another pathway for Cu-induced lipid deposition in fish. Whereas, KET administration showed reverse effects on lipid metabolism as indicated by the lower hepatic TG levels, suppressed mRNA levels of pparγ and cd36. Activation of PXR stimulated autophagy and inhibited apoptosis, leading to lower hepatic vacuolization; while inhibition of PXR showed higher apoptotic signals, inhibition of autophagic genes and stimulation of apoptotic genes. Taken together, PXR played a cytoprotective role in Cu-induced hepatotoxicity through regulations on autophagy and apoptosis. Overall, our data has demonstrated for the first time on the dual roles of PXR as a co-regulator in mediating xenobiotic responses and lipid metabolism in fish, which implying the potential of PXR as a therapy target for xenobiotics-induced lipid dysregulation and hepatotoxicity.

Liquorice root extract and isoliquiritigenin attenuate high-fat diet-induced hepatic steatosis and damage in rats by regulating AMPK

Objective: This study compared the ability of Liquorice roots aqueous extract (LRE) and its ingredient, isoliquiritigenin (ISL), in alleviating high-fat diet (HFD)-induced hepatic steatosis and examined if this effect involves activation of AMPK. Materials and methods: Control or HFD-fed rats were treated with the vehicle, LRE (200 mg/kg), or ISL (30 mg/kg) for 8 weeks orally. Results: ISL and LRE reduced HFD-induced hyperglycaemia, improved liver structure, lowered serum and hepatic lipids, and attenuated hepatic oxidative stress and inflammation. In the control and HFD-fed rats, ISL and LRE significantly stimulated the muscular and hepatic mRNA and protein levels of AMPK, improved oral glucose tolerance, reduced hepatic mRNA levels of SREBP1/2, and upregulated hepatic levels of PPARα and Bcl2. These effects were comparable for ISL and LRE and were prevented by co-administration of compound C, an AMPK inhibitor. Discussion and conclusion: ISL and LRE provide an effective theory to alleviate hepatic steatosis through activating AMPK.

P1560: IMR-261, A NOVEL, ORAL NRF2 ACTIVATOR, REDUCES IRON OVERLOAD IN AN EXPERIMENTAL MOUSE MODEL BY ACTIVATING BMP6-MEDIATED HEPCIDIN SYNTHESIS

Background: Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates several cellular defense mechanisms, including the oxidative stress response. Recent studies elucidated a protective role for Nrf2 under conditions of iron overload. Accumulation of toxic iron activates Nrf2, which activates Bmp6-mediated synthesis of hepcidin, thereby inhibiting ferroportin and improving iron homeostasis (Lim et al, Nat Metab 2019). IMR-261 is a novel, oral Nrf2 activator which has been tested in Phase 2 clinical trials (previously as CXA-10). Our previous work in mouse models of sickle cell disease and b-thalassemia showed that activation of Nrf2 by IMR-261 increases fetal hemoglobin (HbF) and hemoglobin (Hb), decreases markers of hemolysis and adhesion, reduces VOCs and improves ineffective erythropoiesis. Aims: The objective of this study was to evaluate the ability of IMR-261 to activate Bmp6-mediated synthesis of hepcidin (encoded by the Hamp gene), regulate iron stores and modulate transferrin saturation (TSAT) in a mouse model of iron overload. Methods: b-thalasssemic mice (Hbbth1/th1) were treated with IMR-261 at 37.5 or 50 mg/kg BID for 4 weeks. To assess activation of the Bmp6-hepcidin pathway, hepatic mRNA and plasma protein levels were measured. Iron concentrations in serum and tissue (liver, kidney and spleen) as well as markers of iron overload were also evaluated, and standard hematologic assessments were performed. Results: IMR-261 showed a significant, dose-dependent increase in hepatic mRNA levels of Bmp6 and Hamp (~3-fold increase; high dose vs vehicle) as well as Bmp6 target genes, Smad7 and Id1. A corresponding significant increase in Bmp6 and hepcidin protein levels in plasma was also observed. IMR-261 significantly decreased iron in serum by 32% (high dose vs vehicle) and in all tissues tested (34% in liver, 39% in spleen and 24% in kidney; high dose vs vehicle). Mice treated with IMR-261 also showed a significant decrease in TSAT and ferritin levels (up to 30% and 27%, respectively), as well as a reduction in GDF15 and erythropoietin (up to 72% and 48%, respectively) relative to vehicle. IMR-261 improved hematologic markers including a 30% decrease in reticulocytes and significant increases in RBCs, hemoglobin and hematocrit (consistent with our previous data). Image:Summary/Conclusion: Pharmacologic activation of Nrf2 by IMR-261 in a mouse model of iron overload activates hepcidin synthesis (likely via the Bmp6 signaling pathway) and decreases iron in serum, liver, spleen and kidney. IMR-261 also showed significant reductions in TSAT, ferritin, GDF15 and erythropoietin, which further support its role in iron homeostasis. Induction of hepcidin synthesis via Nrf2 activation is a novel therapeutic approach, and these results support further clinical development of IMR-261 as a treatment for conditions associated with iron dysregulation, including hereditary hemochromatosis.

Edible Bird's Nest Regulates Hepatic Cholesterol Metabolism through Transcriptional Regulation of Cholesterol Related Genes.

Objective Hypercholesterolemia is a strong risk factor for cardiovascular diseases. Side effects associated with the use of pharmaceutical agents can cancel out their benefits. Dietary management of hypercholesterolemia is, therefore, receiving much attention due to fewer side effects. In this study, we explored the effectiveness of edible bird's nest (EBN) in the prevention of hypercholesterolemia in rats. Methods High-cholesterol diet (HCD) (4.5% cholesterol and 0.5% cholic acid) with or without EBN (low (2.5%) or high dose (20%)) was given to rats for 12 weeks, and their weights were observed. Simvastatin (10 mg/kg/day) was administered for the same period as a control drug. Serum and tissue samples were collected at the end of the study, from which biochemical parameters (lipid profiles, oxLDL, liver enzymes, urea, creatinine, uric acid, and lipase activity) and hepatic mRNA levels were measured. Results The HCD group had higher levels of serum lipids, liver enzymes, uric acid, urea, and lipase activity compared with those of the other groups. The hepatic mRNA levels of cholesterol metabolism genes (APOB, PCSK9, HMGCR, LDLR, and CYP7A1) in the HCD group also tended toward increased cholesterol production and reduced cholesterol clearance. EBN, especially the highest dose, attenuated the HCD-induced changes, partly through improving the transcriptional regulation of hepatic cholesterol metabolism genes with fold changes of 0.7, 0.6, 0.5, 1.7, and 2.7, respectively, in comparison to the HCD group. In fact, EBN produced better results than simvastatin. Conclusion Thus, the results suggest that EBN can regulate cholesterol metabolism and, therefore, be a source of functional ingredients for the management of hypercholesterolemia.

Effects of dietary Hericium erinaceus powder on growth, hematology, disease resistance, and expression of genes related immune response against thermal challenge of Nile tilapia (Oreochromis niloticus)

Functional feed additives have been promising possibilities for improving fish immune function. The present study attempts to investigate the effect of dietary Hericium erinaceus (HE) supplementation on growth performance, hematology, disease resistance, and expression of genes related immune response against thermal challenge in Nile tilapia. Four isonitrogenous and isolipidic diets were prepared: a control diet without HE supplementation (HE0), HE supplementation at 5 g/kg (HE5), 10 g/kg (HE10), and 20 g/kg (HE20). Each diet was fed to quadruplicate groups of Nile tilapia (9.96 ± 0.01 g/fish) to apparent satiation two times daily for 10 weeks. The dietary HE supplementation promoted protein productive value with a quadratic effect (P = 0.002) although it had no significant effect on other growth and feed utilization parameters (P > 0.05). In addition, the dietary HE supplementation linearly increased red blood cell count, hematocrit, and hemoglobin content (P ≤ 0.001) and quadratically increased the contents of protein and albumin, as well as the alkaline phosphatase activity (P < 0.05). The aspartate aminotransferase activity was linearly and quadratically decreased (P = 0.037, 0.017), and the plasma cortisol level was linearly decreased by increasing HE levels (P = 0.001). The microbial resistance of Nile tilapia against Streptococcus agalactiae increased in all HE-supplemented groups compared to the control group in association with the significant increases in hepatic mRNA levels of genes related immunity, including TNF-α, IL-1β, IL-6, IL-10, and TGF-β. The dietary HE supplementation did not significantly affect the pre-thermal challenge expression of HSP70cB1 mRNAs (P > 0.05), but significantly decreased HSP70cB1 transcripts and plasma cortisol levels after thermal stress challenge (P < 0.05). Therefore, it is suggested that HE at 10 g/kg can be used as a feed additive that enhances the immunity response, reduces the risk of infectious diseases caused by S. agalactiae, and improved thermal stress resistance in Nile tilapia culture.

Insights into the mechanisms of tris(2-chloroethyl) phosphate-induced growth inhibition in juvenile yellow catfish Pelteobagrus fulvidraco.

With the gradual elimination of brominated flame retardants (BFRs), the production and application of tris (2-chloroethyl) phosphate (TCEP), as a substitute of BFRs, has increased greatly. The objective of the present study was to comprehensively explore the potential adverse effects of TCEP on fish growth and the possible underlying mechanisms. To this end, juvenile yellow catfish (Pelteobagrus fulvidraco) were exposed to environmentally relevant concentrations of TCEP (0, 1, 10 and 100 µg/L) for 30 days. The results showed that exposure to high concentrations of TCEP (10 and 100 µg/L) significantly decreased body weight, body length and specific growth rate (SGR). Plasma IGF-I levels and hepatic mRNA levels of igf1 and igf1r were all reduced, while the transcriptional levels of IGFBPs (igfbp2, igfbp3, igfbp5) were significantly up-regulated in the liver of yellow catfish under exposure to 10 and 100 µg/L TCEP. TCEP-induced growth inhibition might be related to somatostatin (SS) signaling system, as evidenced by elevated mRNA transcriptions of ss in brain and its receptors (sstr2, sstr3, sstr5) in liver. In addition, fish exposed to high concentrations of TCEP displayed multiple histological alterations in liver. Taken together, these findings suggested that TCEP (>10 µg/L) might exert its inhibitory effect on fish growth through interfering with the GH/IGF axis and SS signaling system, and by impairing hepatic structures.

Exogenous administration of unacylated ghrelin attenuates hepatic steatosis in high-fat diet-fed rats by modulating glucose homeostasis, lipogenesis, oxidative stress, and endoplasmic reticulum stress

Low levels of unacylated ghrelin (UAG) and a higher ratio of acylated ghrelin (AG)/UAG in obesity are associated with non-alcoholic fatty liver disease (NAFLD). This study tested the potential protective effect of increased circulatory levels of UAG by exogenous UAG administration on hepatic steatosis in high-fat diet (HFD)-fed rats and investigated some possible mechanisms. Rats were divided (n = 6/group) as low fat diet (LFD), LFD + UAG (200 mg/kg), HFD, HFD + UAG (50, 100, or 200 mg/kg). Treatments were given for 8 weeks. Increasing the dose of UAG increased circulatory levels of UAG and normalized the ratio of AG/UAG at the dose of 200 mg/kg. With no change in insulin levels, and in a dose-dependent manner, treatment with UAG to HFD rats attenuated the gain in food intake, body weights, and liver weights, lowered fasting glucose levels, prevented hepatic cytoplasmic vacuolization, and reduced serum and hepatic levels of cholesterol, triglycerides, and free fatty acids. They also progressively reduced levels of reactive oxygen species, lipid peroxides, tumor necrosis factor-α, and interleukin-6, as well as mRNA levels of Bax and caspase-3 but increased levels of glutathione and superoxide dismutase and mRNA levels of Bcl2. In concomitant, UAG, in a dose-response manner, significantly reduced hepatic mRNA levels of SREBP1, SREBP2, ATF-6, IRE-1, and eIF-2α but increased those of PPARα. In conclusion, reducing the circulatory ratio of AG/UAG ratio by exogenous administration of UAG attenuates HFD-induced hepatic steatosis by suppressing lipogenesis, stimulating FAs oxidation, preventing oxidative stress, inflammation, ER stress, and apoptosis.

High-fructose corn syrup intake has stronger effects on the transcription level of hepatic lipid metabolism-related genes, via DNA methylation modification, in childhood and adolescence than in other generations

AimsThis study aimed to analyze differences in sensitivity to hepatic lipid metabolism at different ages, through DNA methylation, using an experimental rat model of high-fructose corn syrup (HFCS) intake. Main methodsThe experimental was divided into three periods: childhood and adolescence (postnatal day (PD) 21–60), young adulthood (PD61–100), and adulthood (PD101–140). Rats in the different age groups were assigned to receive either water (C: control group) or 20% HFCS solution (H: HFCS-fed group). We measured hepatic mRNA levels of peroxisome proliferator-activated receptor alpha (Ppara), carnitine palmitoyltransferase 1A (Cpt1a), fatty acid synthase (Fasn), and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (Pgc1a) using real-time PCR. Additionally, we examined the DNA methylation levels of Ppara, Cpt1a, Fasn, and Pgc1a using pyrosequencing. Key findingsGene expressions of Cpt1a and Ppara in childhood and adolescence were significantly lower in the H group than in the C group. Conversely, Fasn and Pgc1a expressions were significantly higher in the H group than in the C group. Additionally, there was hypermethylation of Cpt1a and Ppara and hypomethylation of Fasn and Pgc1a in the H groups of childhood and adolescence. However, only one gene expression and methylation change was observed in young adulthood and adulthood groups. We found that HFCS intake in rats had stronger lipid metabolic effects in childhood and adolescence than in other generations, and that its mechanism involved epigenetic regulation. SignificanceWe anticipate that these research findings will be a breakthrough for elucidating the varying effects of growth stage in the future.

Hepatic Lipidomic Analysis of Dietary Different Type of Fats and Fructose Interactions in the Pathogenesis of Nonalcoholic Fatty Liver Diseases

ObjectiveDietary nutrient interactions are key determinants to the development of nonalcoholic fatty liver disease (NAFLD). Fat and fructose are two major components of Western diet. This study aimed to determine the combined effects of different type of dietary fats and fructose on the development of NAFLD in a murine model.MethodsMale adult C57BL/6J mice were assigned to six groups and fed with diets (AIN‐93G based) enriched with different types of fat, such as saturated fat (SF‐beef tallow), n‐6 polyunsaturated fat (n6USF‐corn oil), or n‐3 polyunsaturated fat (n3USF‐menhaden fish oil), respectively, with or without fructose supplementation through 10% fructose (w/v) in the drinking water ad lib for 20 weeks. 42% of calories was derived from the fat. Metabolic phenotypes were characterized by liver histology, plasma ALT and AST, glucose tolerance test, hepatic mRNA expression of genes involved in lipid metabolism, and lipidomic analysis of hepatic fatty acid composition.ResultsWhile both SF and n6USF fed mice developed obesity and hepatic steatosis with or without fructose, SFA fed mice were characterized with hepatomegaly, liver injury and fibrosis, which were further exacerbated by fructose; conversely, plasma triglyceride levels were lower compared to controls. Interestingly, n6USF fed mice exhibited steatosis without hepatomegaly, and this was associated with markedly elevated plasma triglyceride and free fatty acid levels, which were blunted by fructose. Moreover, fructose and n6USF led to markedly elevated glucose intolerance tests compared to controls. Hepatic lipidomic analysis revealed that total monounsaturated fatty acids, but not total SFA, exhibited a stepwise decrease from SF to n6USF and n3USF fed mice across most of the lipid pools, which parallels the hepatic triglyceride content, irrespective the presence of fructose. In line with this, hepatic mRNA levels of lipogenesis genes, including Srebf1, Scd1, Fasn, Acacaand Acacb, displayed a similar pattern of alterations (SF&gt;n6USF&gt;n3USF), suggesting that increased lipogenesis contributes to hepatic steatosis in SF and n6USF fed mice. Of note, fructose play a mild, but significant role in the alterations of specific individual fatty acids in certain fatty acid pools, despite the predominant role played by the dietary fats.ConclusionOur data suggest that excess energy from SF intake results in fat storage in the liver, likely due to impaired triglyceride secretion; whereas excess energy from n6USF intake is stored in the periphery. Both effects were exacerbated by fructose supplementation. n3USF is beneficial even in the presence of fructose.

Receptor-interacting protein kinase-1 ablation in liver parenchymal cells promotes liver fibrosis in murine NASH without affecting other symptoms.

Non-alcoholic steatohepatitis (NASH), a chronic liver disease that emerged in industrialized countries, can further progress into liver fibrosis, cirrhosis, and hepatocellular carcinoma. In the next decade, NASH is predicted to become the leading cause of liver transplantation, the only current interventional therapeutic option. Hepatocyte death, triggered by different death ligands, plays key role in its progression. Previously, we showed that the receptor-interacting protein kinase-1 (RIPK1) in hepatocytes exhibits a protective role in ligand-induced death. Now, to decipher the role of RIPK1 in NASH, Ripk1LPC-KO mice, deficient for RIPK1 only in liver parenchymal cells, and their wild-type littermates (Ripk1fl/fl) were fed for 3, 5, or 12weeks with high-fat high-cholesterol diet (HFHCD). The main clinical signs of NASH were analyzed to compare the pathophysiological state established in mice. Most of the symptoms evolved similarly whatever the genotype, whether it was the increase in liver to body weight ratio, the steatosis grade or the worsening of liver damage revealed by serum transaminase levels. In parallel, inflammation markers followed the same kinetics with significant equivalent inductions of cytokines (hepatic mRNA levels and blood cytokine concentrations) and a main peak of hepatic infiltration of immune cells at 3weeks of HFHCD. Despite this identical inflammatory response, more hepatic fibrosis was significantly evidenced at week 12 in Ripk1LPC-KO mice. This coincided with over-induced rates of transcripts of genes implied in fibrosis development (Tgfb1, Tgfbi, Timp1, and Timp2) in Ripk1LPC-KO animals. In conclusion, our results show that RIPK1 in hepatocyte limits the progression of liver fibrosis during NASH.

Reduction in the Dietary VA Status Prevents Type 2 Diabetes and Obesity in Zucker Diabetic Fatty Rats.

We hypothesized that the vitamin A (VA) status regulates type 2 diabetes (T2D) development in Zucker diabetic fatty (ZDF) rats. Zucker Lean and ZDF rats at weaning were fed a VA deficient with basal fat (VAD-BF, no VA and 22.1% fat energy), VA marginal with BF (VAM-BF, 0.35 mg retinyl palmitate (RP)/kg), VA sufficient with BF (VAS-BF, 4.0 mg RP/kg), VAD with high fat (VAD-HF, 60% fat energy), VAM-HF or VAS-HF diet for 8 weeks, including an oral glucose tolerance test (OGTT) at week 7.5. The hepatic mRNA and proteins levels were determined using real-time PCR and Western blot, respectively. The VAD-BF/HF and VAM-BF/HF diets prevented peripheral hyperglycemia and attenuated obesity in ZDF rats, which occurred in the presence of the VAS-BF/HF diets. This lowered VA status reduced venous blood hyperglycemia, hyperinsulinemia and hyperlipidemia, and improved OGTT and homeostasis model assessment for insulin resistance results in ZDF rats. The expression levels of key hepatic genes for glucose and fat metabolism were regulated by VA status and dietary fat contents. An interaction between VA and HF condition was also observed. We conclude that the reduction in the dietary VA status in both BF and HF conditions prevents T2D and obesity in ZDF rats.

Phytoconstituents of Sansevieria suffruticosa N.E.Br. Leaves and Its Hepatoprotective Effect via Activation of the NRF2/ARE Signaling Pathway in an Experimentally Induced Liver Fibrosis Rat Model.

Sansevieria species possess antioxidant and hepatoprotective activities. However, the therapeutic potential of Sansevieria suffruticosa N.E.Br. in liver fibrosis was not evaluated yet. Twenty-seven phytoconstituents were tentatively identified in the phytoconstituents profile of Sansevieria suffruticosa N.E.Br. leaves extract (SSLE) using high-performance liquid chromatography coupled with mass spectrometry (HPLC-ESI/MS-MS). Using column chromatography, hesperetin, 4-hydroxybenzoic acid, ginsenoside Rg2, and quinic acid were isolated from SSLE. The hepatoprotective effect of SSLE via the activation of the NRF2 signaling pathway was evaluated using a rat model of thioacetamide-induced liver fibrosis. Five groups of 6 male adult Wistar rats were used. All animals except the normal control were injected with 200 mg/kg of TAA intraperitoneally twice weekly for 6 weeks. SSLE-treated groups were orally administered 200 and 100 mg/kg/day of the extract, two weeks before the liver fibrosis induction and were continued concomitantly with TAA injection. A reference group received 100 mg/kg b.wt of silymarin orally. SSLE treated groups exhibited a marked reduction in serum alanine transaminase (ALT), aspartate transaminase (AST) and malondialdehyde (MDA) levels compared with the TAA group. The levels of reduced glutathione (GSH) content and hepatic mRNA levels of Nrf2 and HO-1 were significantly increased. Histological findings further confirmed the protective role of SSLE against TAA. In conclusion, the aforementioned results indicated that the hepatoprotective mechanism of SSLE was exerted via activating the Nrf2 pathway to counteract oxidative stress.

Quercetin prevents insulin dysfunction in hypertensive animals.

Angiotensin II induced increase in hypertension enhances oxidative stress and compromises insulin action and pancreatic function. Quercetin-rich foods are beneficial for hypertensive and diabetic animals owing to their antioxidant function. The aim of this study was to evaluate the antioxidant effects of quercetin in hypertensive rats on insulin action, signaling, and secretion. Wistar rats were randomly divided into three groups: sham, hypertensive rats (H), and hypertensive rats supplemented with quercetin (HQ). After three months of initial hypertension, quercetin was administered at 50mg/kg/day for 30days. Our results indicate that hypertension and serum lipid peroxidation levels were reduced by quercetin supplementation. We observed increased insulin sensitivity in adipose tissue, corroborating the insulin tolerance test, HOMA index, and improvements in lipid profile. Despite normal insulin secretion at 2.8 and 20mM of glucose, animals treated with quercetin exhibited increased number of islets per section; increased protein expression of muscarinic receptor type 3, VEGF, and catalase in islets; and hepatic mRNA levels of Ide were normalized. In conclusion, supplementation with quercetin improved insulin action and prevented pancreatic and metabolic dysfunction.

Subacute and low-dose tributyltin exposure disturbs the mammalian hypothalamus-pituitary-thyroid axis in a sex-dependent manner

Tributyltin (TBT) is an endocrine disruptor chemical (EDC) capable of altering the proper function of the hypothalamus-pituitary thyroid (HPT) axis. This study aimed to evaluate the subacute effects of TBT on the HPT axis of male and female rats. A dose of 100 ng/kg/day TBT was used in both sexes over a 15-day period, and the morphophysiology and gene expression of the HPT axis were assessed. TBT exposure increased the body weight in both sexes, while food efficiency increased - only in male rats. It was also possible to note alterations in the thyroid, with the presence of a stratified epithelium, cystic degeneration, and increased interstitial collagen deposition. A reduction in T3 and T4 levels was only observed in TBT male rats. A reduction in TSH levels was observed in TBT female rats. Evaluating mRNA expression, we observed a decrease in hepatic D1 and TRH mRNA levels in TBT female rats. An increase in D2 mRNA expression in the hypothalamus was observed in TBT male rats. Additionally, no significant changes in TRH or hepatic D1 mRNA expression in TBT male rats or in hypothalamic D1 and D2 mRNA expression in TBT female rats were observed. Thus, we can conclude that TBT has different toxicological effects on male and female rats by altering thyroid gland morphophysiology, leading to abnormal HPT axis function, and even at subacute and low doses, it may be involved in complex endocrine and metabolic disorders.