Hepatic Protein Research Articles

Liver protein and metabolite biolabels reveal hepatoprotective effects and active compounds of Eucommiae folium: Exploration of new application of herb based on multi-omics and bioinformatics

A biolabel-led research based on multi-omics and bioinformatics was applied to analyze the application value of Eucommiae folium (EF) in liver cirrhosis, as well as the mechanism of action and material basis. Multi-omics were used to analyze the biolabels and key pathways of EF intervention in liver tissue. Subsequently, based on the information, bioinformatics was used to analyze the application value of EF in liver disease, as well the mechanism of action and material basis. Finally, histopathological and target expression analyses in an animal model were used to verify biolabels analysis results. Multi-omics showed that 18 proteins and 10 metabolites involved in five key pathways were screened as biolabels. Bioinformatics suggested that the application value of EF for liver cirrhosis may be the highest among the liver diseases that it may treat. Additionally, EF and five active compounds (curcumol, eucalyptol, (+)-catechin, naringenin, and quercetin) may protect the cirrhotic liver against the excessive energy expenditure and hepatic stellate cells activation through suppressing the oxidative phosphorylation pathway in a CCl4-induced mouse model. This study provides reference and evidence for the application value of EF in liver diseases, especially liver cirrhosis.

Hepatic ChREBP orchestrates intrahepatic carbohydrate metabolism to limit hepatic glucose 6-phosphate and glycogen accumulation in a mouse model for acute Glycogen Storage Disease type Ib

ObjectiveCarbohydrate Response Element Binding Protein (ChREBP) is a glucose 6-phosphate (G6P)-sensitive transcription factor that acts as a metabolic switch to maintain intracellular glucose and phosphate homeostasis. Hepatic ChREBP is well-known for its regulatory role in glycolysis, the pentose phosphate pathway, and de novo lipogenesis. The physiological role of ChREBP in hepatic glycogen metabolism and blood glucose regulation has not been assessed in detail, and ChREBP's contribution to carbohydrate flux adaptations in hepatic Glycogen Storage Disease type 1 (GSD I) requires further investigation. MethodsThe current study aimed to investigate the role of ChREBP as a regulator of glycogen metabolism in response to hepatic G6P accumulation, using a model for acute hepatic GSD type Ib. The immediate biochemical and regulatory responses to hepatic G6P accumulation were evaluated upon G6P transporter inhibition by the chlorogenic acid S4048 in mice that were either treated with a short hairpin RNA (shRNA) directed against ChREBP (shChREBP) or a scrambled shRNA (shSCR). Complementary stable isotope experiments were performed to quantify hepatic carbohydrate fluxes in vivo. ResultsShChREBP treatment normalized the S4048-mediated induction of hepatic ChREBP target genes to levels observed in vehicle- and shSCR-treated controls. In parallel, hepatic shChREBP treatment in S4048-infused mice resulted in a more pronounced accumulation of hepatic glycogen and further reduction of blood glucose levels compared to shSCR treatment. Hepatic ChREBP knockdown modestly increased glucokinase (GCK) flux in S4048-treated mice while it enhanced UDP-glucose turnover as well as glycogen synthase and phosphorylase fluxes. Hepatic GCK mRNA and protein levels were induced by shChREBP treatment in both vehicle- and S4048-treated mice, while glycogen synthase 2 (GYS2) and glycogen phosphorylase (PYGL) mRNA and protein levels were reduced. Finally, knockdown of hepatic ChREBP expression reduced starch domain binding protein 1 (STBD1) mRNA and protein levels while it inhibited acid alpha-glucosidase (GAA) activity, suggesting reduced capacity for lysosomal glycogen breakdown. ConclusionsOur data show that ChREBP activation controls hepatic glycogen and blood glucose levels in acute hepatic GSD Ib through concomitant regulation of glucose phosphorylation, glycogenesis, and glycogenolysis. ChREBP-mediated control of GCK enzyme levels aligns with corresponding adaptations in GCK flux. In contrast, ChREBP activation in response to acute hepatic GSD Ib exerts opposite effects on GYS2/PYGL enzyme levels and their corresponding fluxes, indicating that GYS2/PYGL expression levels are not limiting to their respective fluxes under these conditions.

Mango (Mangifera indica L.) seed kernel extract suppresses hyperglycemia by modulating pancreatic β cell apoptosis and dysfunction and hepatic glucose metabolism in diabetic rats.

This study investigated the anti-hyperglycemic action of mango seed kernel extract (MKE) and various mechanisms involved in its actions to improve pancreatic β cells and hepatic carbohydrate metabolism in diabetic rats. An intraperitoneal injection of 60mg/kg of streptozotocin (STZ) followed by 30 consecutive days of treatment with MKE (250, 500, and 1000mg/kg body weight) was used to establish a study group of diabetic rats. Using liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS) for identification, 26 chemical compounds were found in MKE and the high-performance liquid chromatography (HPLC) analysis of the MKE also revealed the existence of mangiferin, gallic acid, and quercetin. The results confirmed that in each diabetes-affected rat, MKE mitigated the heightened levels of fasting blood glucose, diabetic symptoms, glucose intolerance, total cholesterol (TC), and low-density lipoprotein-cholesterol (LDL-C). As demonstrated by a remarkable increment in serum and pancreatic insulin, the diabetic pancreatic β cell function was potentiated by treating with MKE. The effect of MKE on diabetic pancreatic apoptosis clearly reduced the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells, which was related to diminished levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and Bax and an increase in Bcl-xL protein expression. Furthermore, diabetes-induced liver damage was clearly ameliorated along with a notable reduction in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and abnormal liver histology. By enhancing anti-oxidant superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, MKE alleviated diabetes-induced pancreatic and liver oxidative damage, as demonstrated by diminished levels of malondialdehyde. In minimizing the expression levels of glucose 6-phosphatase and phosphoenolpyruvate carboxykinase-1 proteins in the diabetic liver, MKE also enhanced glycogen content and hexokinase activity. Collectively, these findings indicate that by suppressing oxidative and inflammatory processes, MKE exerts a potent anti-hyperglycemic activity in diabetic rats which serve to protect pancreatic β cell apoptosis, enhance their function, and improve hepatic glucose metabolism.

Twee patiënten met acute toxische hepatitis na recente inname van thee

Two patients with toxic hepatitis after tea ingestion Drug-induced liver injury (DILI) is common and can manifest in various degrees: from asymptomatic increased transaminases to hepatocellular jaundice with an elevated total and direct bilirubin to acute liver failure. When accompanied by jaundice, there is a mortality rate of 10%. In acute liver failure, referral to a tertiary centre is necessary. This article emphasizes the consideration of herbal and dietary supplements (HDS). The use of HDS in Europe and the US is rising. Some studies state that 1 out of 3 to 1 out of 2 Americans take dietary supplements, which raises concerns about HDS-related toxic hepatitis. HDS involve any supplement that could cause liver damage, including herbs, vitamins, minerals, amino acids and proteins. The prevalence of hepatotoxicity is underestimated. DILI is a diagnosis of exclusion. Diseases that should be excluded, are viral hepatitis, non-alcoholic steatohepatitis (NASH), alcoholic steatohepatitis (ASH), hereditary hemochromatosis, autoimmune hepatitis, Wilson’s disease and alpha-1 antitrypsin deficiency. If there is an increased total and direct bilirubin with or without cholestasis, bile duct stones and hepatobiliary malignancies should be excluded. A liver biopsy may be necessary if the diagnosis is unclear or when several diagnoses are plausible. Liver damage usually occurs within 1 to 6 months after starting the product and is usually reversible. It is important to bear in mind HDS when considering DILI as the incidence of HDS is clearly increasing.

Possible therapeutic effect of frankincense (Gum olibanum) and myrrh (Commiphora myrrha) resins extracts on DEN/CCL4 induced hepatocellular carcinoma in rats

BackgroundLiver cancer is a prominent global health concern characterized by prevalent and unregulated exposure to ubiquitous environmental hazards. Phytochemicals, naturally occurring molecules derived from plants, possess inherent qualities that exhibit anticancer effects. Numerous in vitro studies have investigated the potential impact of combining frankincense and myrrh on hepatocellular cancer. However, it is noteworthy that these investigations have yet to be extended to in vivo studies. PurposeThis research aimed to evaluate the consequences of frankincense and myrrh, individually and in combination, on the progression and development of hepatocellular carcinoma in vivo. MethodsForty-two male Sprague-Dawley rats were selected for this research, and thirty-six rats were subjected to intraperitoneal administration of DEN/CCL4. Growth-related parameters, inflammatory cytokines, lipid peroxidation, non-enzymatic and enzymatic antioxidants, hepatic function biomarkers, protein fractions, histopathological examination, and gene expression were evaluated. ResultsThe results showed that frankincense extract (group 2) (500 mg/kg) and myrrh extract (group 4) (500 mg/kg) significantly improved histopathological and biochemical assessments. The combination of both frankincense extract (250 mg/kg) and myrrh extract (250 mg/kg) (group 5) showed the best results in growth-related parameters, biochemical parameters, and histopathological examination. It also inhibited liver cancer cells' movement and invasion and blocked EMT occurrence via suppressing the signaling of the Wnt/β-catenin pathway (B-catenin: 1.44 ± 0.06; PCNA: 1.40 ± 0.08; and Cyclin D1: 1.32 ± 0.13). ConclusionThe growth-related parameters, biochemical parameters, histopathological examination, and gene expression confirmed that frankincense extract, myrrh extract, or their combination had a potential therapeutic effect with promising prospects for managing hepatocellular carcinoma (HCC).

Astragalus polysaccharide attenuates nonalcoholic fatty liver disease through THDCA in high-fat diet-fed mice

Ethnopharmacological relevanceAstragalus polysaccharide (APS) extracted from Astragalus membranaceus (Fisch.) Bunge was proven to be effective in preventing high-fat diet (HFD) induced nonalcoholic fatty liver disease (NAFLD). However, the exact mechanisms were not completely elucidated. Aim of the studyThe aim was to reveal the mechanisms of APS on preventing NAFLD from the aspects of regulating bile acids (BAs) homeostasis. Materials and methodsSerum and liver BAs in HFD fed mice with or without APS intervention were quantified with an ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) system. The effect of APS on hepatic proteins involved in BAs synthesis were analyzed with Western blot. Finally, the effect of identified taurohyodeoxycholic acid (THDCA) that was significantly increased by APS on hepatic triglyceride (TG) accumulation was explored in vivo and in vitro. ResultsAPS regulated serum and liver BA profiles in HFD fed mice, especially increased serum THDCA. The levels of hepatic cholesterol 7a-hydroxylase (CYP7A1) and sterol 12a-hydroxylase (CYP8B1) which catalyzed the classical BAs synthesis pathway were significantly decreased by APS, while oxysterol 7a-hydroxylase (CYP7B1) which catalyzed the alternative BAs synthesis pathway was significantly increased by APS. THDCA reduced HFD-induced hepatic lipid accumulation and improved glucose homeostasis in mice, and decreased TG level in palmitic acid/oleic acid treated alpha mouse liver 12 (AML-12) cells. THDCA significantly downregulated the protein level of cluster of differentiation 36 (CD36) involved in fatty acid transport into the liver. Importantly, THDCA showed similar effect with APS in upregulating hepatic CYP7B1 and downregulating CYP7A1. ConclusionThis study revealed the protective effect of APS on NAFLD was associated with the regulation on BA profiles, and proved the potential anti-NAFLD effect of THDCA, highlighting the involvement of BA metabolism in efficacy of herb-derived polysaccharides on metabolism.

Does liraglutide alleviates inflammation in brain-dead donors? A randomized clinical trial.

Brain death triggers an inflammatory cascade that damages organs before procurement, adversely affecting the quality of grafts. This randomized clinical trial aimed to compare the efficacy of liraglutide compared to placebo in attenuating brain death-induced inflammation, endoplasmic reticulum stress, and oxidative stress. We conducted a double-blinded, placebo-controlled, randomized clinical trial with brain-dead donors. Fifty brain-dead donors were randomized to receive subcutaneous liraglutide or placebo. The primary outcome was the reduction in interleukin-6 (IL-6) plasma levels. Secondary outcomes were changes in other plasma pro-inflammatory (IL-1β, IFN-γ, TNF) and anti-inflammatory cytokines (IL-10), expression of antiapoptotic (BCL2), endoplasmic reticulum stress markers (DDIT3/CHOP, HSPA5/BIP), and antioxidant (SOD2, UCP2) genes, and expression TNF, DDIT3, and SOD2 proteins in liver biopsies. The liraglutide group showed lower cytokine levels compared to the placebo group during follow-up: Δ IL-6 (-28 [-182-135] vs. 32 [-10.6-70.7] pg/mL; p=0.041) and Δ IL-10 (-0.01 [-2.2-1.5] vs. 1.9 [-0.2-6.1] pg/mL; p=0.042), respectively. The administration of liraglutide did not significantly alter the expression of inflammatory, anti-apoptotic, endoplasmic reticulum stress, or antioxidant genes in the liver tissue. Similar to gene expression, expressions of proteins in liver were not affected by the administration of liraglutide. Treatment with liraglutide did not increase organ recovery rate [OR=1.2 (95% CI 0.2-8.6), p=0.82]. Liraglutide administration reduced IL-6 and prevented the increase of IL-10 plasma levels in brain-dead donors, without affecting the expression of genes and proteins related to inflammation, apoptosis, endoplasmic reticulum stress, or oxidative stress.

Exercise training adaptations in liver glycogen and glycerolipids require hepatic AMP-activated protein kinase in mice.

Regular exercise elicits adaptations in glucose and lipid metabolism that allow the body to meet energy demands of subsequent exercise bouts more effectively and mitigate metabolic diseases including fatty liver. Energy discharged during the acute exercise bouts that comprise exercise training may be a catalyst for liver adaptations. During acute exercise, liver glycogenolysis and gluconeogenesis are accelerated to supply glucose to working muscle. Lower liver energy state imposed by gluconeogenesis and related pathways activates AMP-activated protein kinase (AMPK), which conserves ATP partly by promoting lipid oxidation. This study tested the hypothesis that AMPK is necessary for liver glucose and lipid adaptations to training. Liver-specific AMPKα1α2 knockout (AMPKα1α2fl/fl+AlbCre) mice and littermate controls (AMPKα1α2fl/fl) completed sedentary and exercise training protocols. Liver nutrient fluxes were quantified at rest or during acute exercise following training. Liver metabolites and molecular regulators of metabolism were assessed. Training increased liver glycogen in AMPKα1α2fl/fl mice, but not in AMPKα1α2fl/fl+AlbCre mice. The inability to increase glycogen led to lower glycogenolysis, glucose production, and circulating glucose during acute exercise in trained AMPKα1α2fl/fl+AlbCre mice. Deletion of AMPKα1α2 attenuated training-induced declines in liver diacylglycerides. In particular, training lowered the concentration of unsaturated and elongated fatty acids comprising diacylglycerides in AMPKα1α2fl/fl mice, but not in AMPKα1α2fl/fl+AlbCre mice. Training increased liver triacylglycerides and the desaturation and elongation of fatty acids in triacylglycerides of AMPKα1α2fl/fl+AlbCre mice. These lipid responses were independent of differences in tricarboxylic acid cycle fluxes. In conclusion, AMPK is required for liver training adaptations that are critical to glucose and lipid metabolism.NEW & NOTEWORTHY This study shows that the energy sensor and transducer, AMP-activated protein kinase (AMPK), is necessary for an exercise training-induced: 1) increase in liver glycogen that is necessary for accelerated glycogenolysis during exercise, 2) decrease in liver glycerolipids independent of tricarboxylic acid (TCA) cycle flux, and 3) decline in the desaturation and elongation of fatty acids comprising liver diacylglycerides. The mechanisms defined in these studies have implications for use of regular exercise or AMPK-activators in patients with fatty liver.

ANGPTL3 Deficiency and Risk of Hepatic Steatosis.

ANGPTL3 (angiopoietin-like 3) is a therapeutic target for reducing plasma levels of triglycerides and low-density lipoprotein cholesterol. A recent trial with vupanorsen, an antisense oligonucleotide targeting hepatic production of ANGPTL3, reported a dose-dependent increase in hepatic fat. It is unclear whether this adverse effect is due to an on-target effect of inhibiting hepatic ANGPTL3. We recruited participants with ANGPTL3 deficiency related to ANGPTL3 loss-of-function (LoF) mutations, along with wild-type (WT) participants from 2 previously characterized cohorts located in Campodimele, Italy, and St. Louis, MO. Magnetic resonance spectroscopy and magnetic resonance proton density fat fraction were performed to measure hepatic fat fraction and the distribution of extrahepatic fat. To estimate the causal relationship between ANGPTL3 and hepatic fat, we generated a genetic instrument of plasma ANGPTL3 levels as a surrogate for hepatic protein synthesis and performed Mendelian randomization analyses with hepatic fat in the UK Biobank study. We recruited participants with complete (n=6) or partial (n=32) ANGPTL3 deficiency related to ANGPTL3 LoF mutations, as well as WT participants (n=92) without LoF mutations. Participants with ANGPTL3 deficiency exhibited significantly lower total cholesterol (complete deficiency, 78.5 mg/dL; partial deficiency, 172 mg/dL; WT, 188 mg/dL; P<0.05 for both deficiency groups compared with WT), along with plasma triglycerides (complete deficiency, 26 mg/dL; partial deficiency, 79 mg/dL; WT, 88 mg/dL; P<0.05 for both deficiency groups compared with WT) without any significant difference in hepatic fat (complete deficiency, 9.8%; partial deficiency, 10.1%; WT, 9.9%; P>0.05 for both deficiency groups compared with WT) or severity of hepatic steatosis as assessed by magnetic resonance imaging. In addition, ANGPTL3 deficiency did not alter the distribution of extrahepatic fat. Results from Mendelian randomization analyses in 36 703 participants from the UK Biobank demonstrated that genetically determined ANGPTL3 plasma protein levels were causally associated with low-density lipoprotein cholesterol (P=1.7×10-17) and triglycerides (P=3.2×10-18) but not with hepatic fat (P=0.22). ANGPTL3 deficiency related to LoF mutations in ANGPTL3, as well as genetically determined reduction of plasma ANGPTL3 levels, is not associated with hepatic steatosis. Therapeutic approaches to inhibit ANGPTL3 production in hepatocytes are not necessarily expected to result in the increased risk for hepatic steatosis that was observed with vupanorsen.

PSI-21 The Role of N-Carbamylglutamate Supplementation During Last Third of Gestation in Nutrient Restricted Twin-Bearing Ewes

Abstract Nutrient restriction in sheep during pregnancy normally occurs in Patagonia with negative effects on ewe body condition (BCS) and reproductive performance. N-carbamylglutamate (NCG), an analogue of N-acetylglutamate, is postulated to improve urea recycling, nitrogen utilization and antioxidant capacity in ruminants. The objective of this study was to evaluate the effect of oral NCG supplementation in naturally nutrient restricted grazing twin-bearing ewes, on maternal body weight (BW) and body condition score (BCS), serum biochemical indexes and antioxidant capacity in mid-late gestation. Ten twin-bearing ewes were orally dosed once-daily with 60 mg/kg BW NCG in a water carrier from 100 to 140 days of gestation (dg) and were compared with unsupplemented controls (CON; n = 8). Maternal BW, and BCS were recorded every 10 days, from 100 to 140 dg. Blood samples were collected at the same time points to evaluate plasma metabolites (NEFA, urea, total protein, albumin, globulin, Ca, P, Mg, Cholesterol, ASAT, CK, GGT, GLDH, total bilirubin and triglycerides), antioxidant status [malondialdehyde (MDA)], and total antioxidant capacity (TAC). Ewes were managed as a single mob in a paddock with natural pasture (3.3% CP, 1.9 Mcal/kg ME), supplemented with alfalfa hay (600 g· ewe-1· /day-1; 13% CP and ME 2.2 Mcal/kg ME) from 130 dg, with a stocking rate of 0.9 ewes per hectare and a dry matter availability of 525 kg per hectare, representative of Patagonian prairie conditions. The effect of treatment on ewe BW, BCS and plasma metabolites were analyzed using REML analysis in R using lme4 R package with time (dg) and treatment (and their interaction) as fixed effects and animal as the random effect. Ewe BW increased (P &amp;lt; 0.0001) and BCS decreased (P = 0.005) with advancing gestation, but there was no effect of treatment. There was a tendency for a treatment effect (P = 0.07) on plasma urea with ~10% less concentrations in NCG than CON ewes at 130 dg (P = 0.08) and 140 dg (P = 0.04). There was a treatment by time interaction for total bilirubin (P = 0.005), phosphorus (P = 0.02), and a similar trend for albumin (P = 0.09). Ewes supplemented with NCG had~10% lower concentrations of bilirubin at 100 (P = 0.01) and 120 dg (P = 0.04), less concentrations of phosphorus (P = 0.003) and albumin (P = 0.02) at 140 dg compared with CON ewes. No other effects of treatment on blood metabolites or antioxidant status or capacity were observed. Collectively these results suggest that supplementation of nutritionally restricted ewes with 60 mg/kg BW from 100 to 140 dg did not influence BW or LWT but may have some effects on liver function, protein metabolism, urea recycling, feed intake and/or feed efficiency which warrant further investigation.*Funded by FONDECYT Project N°1221042; AgResearch Strategic Science Investment Fund.

266 Interactive Effects of Dietary Isoleucine and Valine Ratios to Lysine in Response to Varying Leucine to Lysine Ratios on Hepatic Protein Expression in Commercial Broilers

Abstract A central composite design (CCD) study was conducted to understand the relationship among dietary branched chain amino acid (BCAA) ratios and expression of proteins related to amino acid and protein metabolism in the liver of broilers. A total of 2,592 d-old Ross 344 × 708 male broilers were randomly placed in 144 floor pens. Each pen received 1 of 15 dietary treatments in a 23 CCD with 6 center points from 20 to 35 d of age, varying in digestible ratios of isoleucine:lysine (Ile:Lys; 52 to 75), valine:lysine (Val:Lys; 64 to 87), and leucine:lysine (Leu:Lys; 110 to 185). On d 35, 1 bird per pen was selected, euthanized, and liver tissue samples were collected for protein extraction and proteomic analysis via data independent acquisition protein sequencing with a timsTOF Pro 2 LC/MS/MS and Spectronaut 15 software. Dihydrolipoamide acetyltransferase (PDHX), aspartate aminotransferase (GOT2), branched-chain-amino-acid aminotransferase (BCAT1), diphosphomevalonate decarboxylase (MVD), acylamino-acid-releasing enzyme (APEH), and aspartate aminotransferase (GOT1) were identified and quantified. Protein quantification data were analyzed as a CCD using the RSREG procedure of SAS v. 9.4 with significance declared at P ≤ 0.10. When the individual AA effect in the response surface (RS) regression analysis was P ≤ 0.2, raw protein quantification data were analyzed as a 1-way ANOVA and the PDIFF option of SAS set at P ≤ 0.1 using the GLIMMIX procedure. The RS model for MVD and APEH expression were significant (P ≤ 0.0511). However, models for PDHX, GOT2, BCAT1, and GOT1 were not significant (P ≥ 0.1356) and the R2 values ≤ 0.25 for all proteins did not allow for prediction of protein expression means. No linear, quadratic, cross product, or individual BCAA ratio effects were observed for PDHX, GOT2, and BCAT1 (P ≥ 0.1977). A linear model for MVD and APEH protein expression (P ≤ 0.8030) and quadratic model for APEH (P ≤ 0.0552) were significant. MVD increased as Val:Lys ratio increased when Leu:Lys and Ile:Lys were fixed at 148 and 63 or 170 and 70, respectively (P ≤ 0.0926). Low Val:Lys ratio expressed the least hepatic APEH expression when Leu:Lys and Ile:Lys ratios were 148 and 63 or 125 and 70, respectably (P ≤ 0.0153). Hepatic MVD expression decreased as Leu:Lys ratio increased when Val:Lys and Ile:Lys were 75 and 63, respectably (P ≤ 0.0044). GOT1 expression was higher with 170 Leu:Lys ratio compared with 125, when Val:Lys and Ile:Lys ratio were 68 and 70, respectably (P ≤ 0.0460). APEH was greater with a low Ile:Lys ratio when Val:Lys and Leu:Lys were 68 and 125, respectably (P ≤ 0.0786). Varying concentrations of dietary BCAA and their interactions seem to alter hepatic protein expression and may help explain the mechanisms underlying their influence on broiler growth.

DNA hypomethylation characterizes genes encoding tissue-dominant functional proteins in liver and skeletal muscle

Each tissue has a dominant set of functional proteins required to mediate tissue-specific functions. Epigenetic modifications, transcription, and translational efficiency control tissue-dominant protein production. However, the coordination of these regulatory mechanisms to achieve such tissue-specific protein production remains unclear. Here, we analyzed the DNA methylome, transcriptome, and proteome in mouse liver and skeletal muscle. We found that DNA hypomethylation at promoter regions is globally associated with liver-dominant or skeletal muscle-dominant functional protein production within each tissue, as well as with genes encoding proteins involved in ubiquitous functions in both tissues. Thus, genes encoding liver-dominant proteins, such as those involved in glycolysis or gluconeogenesis, the urea cycle, complement and coagulation systems, enzymes of tryptophan metabolism, and cytochrome P450-related metabolism, were hypomethylated in the liver, whereas those encoding-skeletal muscle-dominant proteins, such as those involved in sarcomere organization, were hypomethylated in the skeletal muscle. Thus, DNA hypomethylation characterizes genes encoding tissue-dominant functional proteins.

Differential expression of immunoregulatory cytokines in adipose tissue and liver in response to high fat and high sugar diets in female mice.

A comprehensive understanding of how dietary components impact immunoregulatory gene expression in adipose tissue (AT) and liver, and their respective contributions to metabolic health in mice, remains limited. The current study aimed to investigate the metabolic consequences of a high-sucrose diet (HSD) and a high-fat diet (HFD) in female mice with a focus on differential lipid- and sucrose-induced changes in immunoregulatory gene expression in AT and liver. Female C57BL/6 J mice were fed a purified and macronutrient matched high fat, high sugar, or control diets for 12 weeks. Mice were extensively phenotyped, including glucose and insulin tolerance tests, adipose and liver gene and protein expression analysis by qPCR and Western blot, tissue lipid analyses, as well as histological analyses. Compared to the control diet, HSD- and HFD-fed mice had significantly higher body weights, with pronounced obesity along with glucose intolerance and insulin resistance only in HFD-fed mice. HSD-fed mice exhibited an intermediate phenotype, with mild metabolic deterioration at the end of the study. AT lipid composition was significantly altered by both diets, and inflammatory gene expression was only significantly induced in HFD-fed mice. In the liver however, histological analysis revealed that both HSD- and HFD-fed mice had pronounced ectopic lipid deposition indicating hepatic steatosis, but more pronounced in HSD-fed mice. This was in line with significant induction of pro-inflammatory gene expression specifically in livers of HSD-fed mice. Overall, our findings suggest that HFD consumption in female mice induces more profound inflammation in AT with pronounced deterioration of metabolic health, whereas HSD induced more pronounced hepatic steatosis and inflammation without yet affecting glucose metabolism.

Sericin enhances ammonia detoxification by promotes urea cycle enzyme genes and activates hepatic autophagy in relation to CARD-9/MAPK pathway

Urea cycle is an important metabolic process that initiates in liver mitochondria and converts ammonia to urea. The impairment of ammonia detoxification, both primary and secondary causes, lead to hyperammonemia, a life-threatening condition affecting to the brain. Current treatments are not enough effective. In addition, our recent proteomics study in hypercholesterolemic rat model demonstrated that sericin enhances hepatic nitrogenous waste removal through carbamoyl-phosphate synthase 1 (CPS-1), aldehyde dehydrogenase-2 (ALDH-2), and uricase proteins. However, the underlining mechanisms regard to this property is not clarified yet. Therefore, the present study aims to examine the effect of sericin on urea cycle enzyme genes (CPS-1 and ornithine transcarbamylase; OTC) and proteins (mitogen-activated protein kinase; MAPK, caspase recruitment domain-containing protein 9; CARD-9, Microtubule-associated protein light chain 3; LC-3), which relate to urea production and liver homeostasis in hepatic cell line (HepG2) and hypercholesterolemic rat treated with or without sericin. qRT-PCR, immunohistochemistry, and electron microscopy techniques were performed. In vitro study determined that high dose of sericin at 1 mg/ml increased liver detoxification enzyme (Cytochrome P450 1A2; CYP1A2 and ALDH-2) and urea cycle enzyme (CPS-1 and OTC) genes. Both in HepG2 cell and rat liver mitochondria, sericin significantly downregulated CARD-9 (apoptotic protein) expression while upregulated MAPK (hepatic homeostasis protein) and LC-3 (autophagic protein) expressions. Hence, it might be concluded that sericin promotes ammonia detoxification by both increases urea cycle enzyme genes and enhances hepatic autophagy in associated with CARD-9/MAPK pathway (as shown by their own negative relationship). This study presents another beneficial property of sericin to develop an upcoming candidate for ammonia toxicity alleviation and liver function improvement.

The effect on product structure and volatile compounds of chicken liver by fermentation

The effect on the product structure and volatile compounds of fermented chicken liver (FCL) by Lactobacillus plantarum LP1 (L. plantarum LP1) was investigated in this study. The results of ultraviolet, fluorescence and diffraction of x-rays spectra showed that the fermentation accelerated the degradation of the chicken liver (CL) protein, with a large number of small molecule peptides. The thermal stability of FCL was significantly higher than that of CL. The total relative contents of free and essential amino acids in FCL were significantly increased compared by that of CL. Meanwhile, FCL had higher amino acid nitrogen and acidity. Moreover, the types and relative contents of volatile compounds, such as aldehydes, acids, hydrocarbons, were increased by 40.04%, 21.34% and 2.18% in FCL over those in FC, respectively. Therefore, the fermentation of chicken liver provides scientific basis for the comprehensive utilization of by-products in chicken.

Ketogenic diet alleviates β-cell dedifferentiation but aggravates hepatic lipid accumulation in db/db mice

ObjectiveThe aim of this study was to explore the effect of the ketogenic diet (KD) on β-cell dedifferentiation and hepatic lipid accumulation in db/db mice. MethodsAfter a 3-wk habituation, male db/db mice ages 8 wk were assigned into one of three groups: normal diet (ND), KD, and 75% calorie restriction (CR) group. Free access to a standard diet, a KD, and 75% of a standard diet, respectively, were given to each group. Additionally, sex-matched 8-wk-old C57BL/6 mice were used to construct a control (C) group. After a 4-wk dietary intervention, mouse body weight, fasting blood glucose (FBG), blood lipids, fasting insulin (FINS), glucose tolerance, and β-hydroxybutyric acid level were measured. The morphologies of the islet and liver were observed by hematoxylin and eosin staining. Positive expressions of β-cell–specific transcription factors in mouse islets were determined by double immunofluorescence staining. The size and number of lipid droplets in mouse liver were examined by Oil Red O staining. Real-time quantitative reverse transcription polymerase chain reaction detected relative levels of adipogenesis-associated and lipolysis-associated genes in mouse liver. Additionally, expressions of CD36 protein in the mouse liver were determined by immunohistochemical staining and Western blot. ResultsAfter a 4-wk dietary intervention, FBG, FINS, and glucose area under the curve in the KD group became significantly lower than in the ND group (all P < 0.05). Regular morphology of mouse islets was observed in the KD group, with an increased number of islet cells. The KD significantly reversed the decrease in β-cell number, disarrangement of β-cells, decline of β/α-cell ratio, and downregulation of β-cell–specific transcription factors in db/db mice. Serum levels of triacylglycerol, total cholesterol, and low-density lipoprotein cholesterol were comparable between the ND and KD groups. In contrast, serum triacylglycerol levels were significantly lower in the CR group than in the ND group (P < 0.05). Vacuolar degeneration and lipid accumulation in the liver were more prominent in the KD group than in the ND and CR groups. The mRNA levels of Pparα and Acox1 in the KD group were lower than those in the ND group, although no significant differences were detected. Relative levels of Cd36 and inflammatory genes in the mouse liver were significantly higher in the KD group than in the ND group (all P < 0.05). ConclusionThe KD significantly reduced FBG and FINS and improved glucose tolerance in db/db mice by upregulating β-cell–specific transcription factors and reversing β-cell dedifferentiation. However, the KD also induced hepatic lipid accumulation and aggravated inflammatory response in the liver of db/db mice.

Schisandrin A in Schisandra chinensis Upregulates the LDL Receptor by Inhibiting PCSK9 Protein Stabilization in Steatotic Model.

Schisandra chinensis extract (SCE) protects against hypocholesterolemia by inhibiting proprotein convertase subtilisin/kexin 9 (PCSK9) protein stabilization. We hypothesized that the hypocholesterolemic activity of SCE can be attributable to upregulation of the PCSK9 inhibition-associated low-density lipoprotein receptor (LDLR). Male mice were fed a low-fat diet or a Western diet (WD) containing SCE at 1% for 12 weeks. WD increased final body weight and blood LDL cholesterol levels as well as alanine transaminase and aspartate aminotransferase expression. However, SCE supplementation significantly attenuated the increase in blood markers caused by WD. SCE also attenuated WD-mediated increases in hepatic LDLR protein expression in the obese mice. In addition, SCE increased LDLR protein expression and attenuated cellular PCSK9 levels in HepG2 cells supplemented with delipidated serum (DLPS). Non-toxic concentrations of schisandrin A (SA), one of the active components of SCE, significantly increased LDLR expression and tended to decrease PCSK9 protein levels in DLPS-treated HepG2 cells. High levels of SA-mediated PCSK9 attenuation was not attributable to reduced PCSK9 gene expression, but was associated with free PCSK9 protein degradation in this cell model. Our findings show that PCSK9 secretion can be significantly reduced by SA treatment, contributing to reductions in free cholesterol levels.

Selenomethionine supplementation and expression of selenosugars, selenocysteine, and other selenometabolites in rat liver.

Selenomethionine (SeMet) as a methionine analog can be incorporated into protein. In turkeys, we recently found that selenium (Se) as selenite is not metabolized to SeMet but rather to selenosugars (seleno-N-acetyl galactosamine) bound to protein as well as to selenocysteine (Sec) in selenoproteins. To characterize the metabolism of SeMet, we fed rats graded levels of SeMet from 0 to 5µg Se/g in a Se-deficient diet for 4 wk, and investigated the fate and accumulation of liver Se using high pressure liquid chromatography (HPLC) coupled with Se-specific inductively coupled plasma mass spectrometry (ICP-MS) and molecule specific (Orbitrap MS/MS) detection. Up to 0.24µg Se/g (Se requirement for maximal glutathione peroxidase activity), Sec accounted for ∼40% of total liver Se whereas SeMet only accounted for 3-11%. Analysis of water-soluble extracts found negligible low molecular weight (LMW) Se species in rats fed 0 and 0.08µg Se/g, including no SeMet. At 0.24µg Se/g and above, SeMet accounted for only 10% of LMW Se species, whereas methyl- and glutathionyl-selenosugars accounted for 70% of LMW Se species. Above the Se requirement, SeMet was ∼30% of the proteinaceous amino acids, whereas Sec levels fell to 5% in rats fed 5µg Se/g as SeMet. Last, considerably less inorganic Se was bound to liver protein with high SeMet as compared to selenite in a parallel study. SeMet is efficiently metabolized and mixes with the common Se metabolite pool, where Se is preferentially incorporated into Sec and Sec-selenoproteins until selenoproteins plateau; with high SeMet intake, Se is increasingly accumulated as LMW selenosugars and as selenosugar-decorated proteins.

Intermittent Fasting Attenuates Metabolic-Dysfunction-Associated Steatohepatitis by Enhancing the Hepatic Autophagy-Lysosome Pathway.

An intermittent fasting (IF) regimen has been shown to protect against metabolic dysfunction-associated steatohepatitis (MASH). However, the precise mechanism remains unclear. Here, we explored how IF reduced hepatic lipid accumulation, inflammation, and fibrosis in mice with MASH. The mice were fed a high-fat diet (HFD) for 30 weeks and either continued on the HFD or were subjected to IF for the final 22 weeks. IF reduced body weight, insulin resistance, and hepatic lipid accumulation in HFD-fed mice. Lipidome analysis revealed that IF modified HFD-induced hepatic lipid composition. In particular, HFD-induced impaired autophagic flux was reversed by IF. The decreased hepatic lysosome-associated membrane protein 1 level in HFD-fed mice was upregulated in HFD+IF-fed mice. However, increased hepatic lysosomal acid lipase protein levels in HFD-fed mice were reduced by IF. IF attenuated HFD-induced hepatic inflammation and galectin-3-positive Kupffer cells. In addition to the increases in hepatic hydroxyproline and lumican levels, lipocalin-2-mediated signaling was reversed in HFD-fed mice by IF. Taken together, our findings indicate that the enhancement of the autophagy-lysosomal pathway may be a critical mechanism of MASH reduction by IF.

Downregulation of Rab23 inhibits hepatocellular carcinoma by repressing SHH signaling pathway.

Hepatocellular carcinoma (HCC) is the sixth most common malignant tumors and the third leading cause of cancer-related death worldwide. As an oncogene, Rab23 has been shown to be significantly related to the growth and migration of hepatocellular carcinoma in both in vitro and in vivo studies, but its underlying mechanism remains obscure. In the present study, we examined the effect of inhibiting Rab23 expression on the pathological progression of HCC. The correlation between liver Rab23 gene expression and survival probability in human HCC patients was analyzed using the TCGA database and CPTAC database. Rab23 knockdown hepatocellular carcinoma cell line was generated through lentiviral transduction, then we established a nude HCC xenograft model by subcutaneously implanting the transfected cells. The analysis of gene and protein expression was carried out using Western blot or RT-qPCR, respectively. Flow cytometry analysis was used to detect the level of apoptosis. The expression levels of key proteins involved in the Sonic Hedgehog (SHH) signaling pathway were assessed. The results showed that HCC patients with low levels of hepatic Rab23 mRNA and protein had a better survival tendency than those with higher levels of Rab23. Cell proliferations were reduced and apoptosis levels were increased after Knocking down Rab23 in HCC cell lines. Furthermore, in vivo studies have demonstrated that suppression of the Rab23 gene results in decreased tumor size, proliferation rate, and reduced levels of SHH-related proteins Smoothened and GLI-1. The above results suggest that Rab23 is involved in the pathological progression of HCC as an important regulator of the SHH signaling pathway, which also provides an important research basis for new therapeutic strategies for HCC.