TMT-based comparative proteomics reveals the role of acyl-CoA oxidase 4 in enhancing the drought stress tolerance in common buckwheat (Fagopyrum esculentum).

Drought stress has been the main abiotic factor affecting the growth, development and production of common buckwheat (Fagopyrum esculentum). To explore the response mechanisms of regulating buckwheat drought stress on the post-transcriptional and translational levels, a comparative proteomic analysis was applied to monitor the short-term proteomic variations under the drought stress in the seedling stage. From which 593 differentially abundant proteins (DAPs) were identified using the TMT-based proteomics analysis. A number of DAPs were found to be intimately correlated with the styrene degradation, phenylpropanoid biosynthesis and stimulus response, within which. The acyl-CoA oxidase 4 (ACX4), a key regulator in plant abiotic stress response, was selected for further elucidation. Overexpression of the FeACX4 not only conferred drought and salt tolerance in the Arabidopsis, but also significantly increased the root length and fresh weight in the overexpression lines plant relative to the wild type (WT) plant, accompanied by the elevated activities of catalase (CAT) and lowered malonaldehyde (MDA) and H2O2 contents, therefore allowing plants to better adapt to adverse environments. Our results provided information in the exploring of the molecular regulation mechanism responding to drought tolerance in common buckwheat.

Yiqi-Bushen-Tiaozhi Recipe Attenuated High-Fat and High-Fructose Diet Induced Nonalcoholic Steatohepatitis in Mice via Gut Microbiota.

Aim: To investigate the treating effect of Yiqi-Bushen-Tiaozhi (YBT) recipe on nonalcoholic steatohepatitis (NASH) mice, determine whether the outcome was associated with gut microbiota, and clarify the regulating mechanism. Methods: NASH mice were induced by high-fat and high-fructose diets (HFFD). In the fifth week, mice in the YBT group were orally administrated YBT (22.12g·kg-1·d-1) daily for 12 weeks. Fresh stool of mice was collected at the 16th week for fecal 16S rDNA analysis. Hepatic pathology and biochemical indicators were used to reflect the improvement of YBT on hepatic inflammation and lipid metabolism in NASH mice. Quantitative real-time PCR (qRT-PCR) was used to verify the results of PICRUSt analysis. Results: Results of the pathological and biochemical index showed that YBT could improve NASH mice. Compared with improving inflammation and hepatocyte damage, YBT may be more focused on enhancing metabolic disorders in mice, such as increasing HDL-c level. The diversity and richness of the gut microbiota of NASH mice induced by HFFD are significantly different from the normal control (NC) group. After YBT treatment, the diversity and richness of the mice microbiota will be increased to similar NC mice. Intestinimonas, Acetatifactor, Alistipes, Intestinimonas, Acetatifactor, and Alistipes have the most significant changes in the class level. PICRUSt analysis was performed to predict genomic functions based on the 16S rDNA results and reference sequencing. The efficacy of YBT in the treatment of NASH can be achieved by regulating the diversity and richness of gut microbiota. PICRUSt analysis results showed that the most relevant function of the microbiota construction variations is α- Linolenic acid (ALA) metabolism. Results of qRT-PCR showed significant differences between groups in the expression of Fatty acid desaturase 1 (FADS1), Fatty acid desaturase 2 (FADS2), Acyl-CoA Oxidase 1 (ACOX1), and Acyl-CoA Oxidase 2 (ACOX2) related to ALA metabolism. The expression of the above genes will be inhibited in the liver and small intestine of the HFFD group mice, and the expression can be restored after YBT treatment. Conclusion: YBT could treat NASH mice by improving the diversity and richness of gut microbiota and further the improvement of ALA metabolism.

Annona muricata leaf extract attenuates hepatic lipogenesis and adipogenesis.

Annona muricata (graviola) is a medicinal plant that can be used to alleviate chronic human diseases by providing antioxidants and inducing immunomodulation. In this study, we found that treatment of AML12 hepatocytes with steam (SGE) and ethanol (EGE) extracts of graviola leaf downregulated the expression of fatty acid (FA) oxidation genes, including ACOX1, CPT1, and PPARα, with no change in the expression of FA synthesis genes. However, whereas EGE inhibited the differentiation and lipid accumulation of 3T3-L1 adipocytes and downregulated FA synthesis genes, no similar changes were observed in response to treatment with SGE. In an in vivo experiment using mice fed a high-fat diet (HFD), body weight was reduced in response to treatment with EGE, which also dose-dependently alleviated liver hepatocyte ballooning induced by the consumption of a HFD. However, genes involved in FA oxidation and the secretion of very low density lipoprotein (VLDL) were downregulated. We also found that the size of adipocytes was reduced in response to EGE treatment, and that there was a downregulated expression of genes involved in adipogenesis and FA synthesis. Furthermore, we detected increases in the levels of cholesterol in the plasma, whereas ALT activity was reduced. Collectively, these results indicates that EGE inhibits lipid influx into the liver and adipogenesis in adipose tissues. These bioactive properties of EGE indicate its potential as a natural ingredient that can be used to prevent obesity.

An Oil Rich in γ-Linolenic Acid Differently Affects Hepatic Fatty Acid Oxidation in Mice and Rats.

The effects of different dietary fats on hepatic fatty acid oxidation were compared in male ICR mice and Sprague-Dawley rats. Animals were fed diets containing 100 g/kg of either palm oil (saturated fat), safflower oil (rich in linoleic acid), an oil of evening primrose origin (γ-linolenic acid, GLA oil), perilla oil (α-linolenic acid) or fish oil (eicosapentaenoic and doxosahexaenoic acids) for 21 d. GLA, perilla and fish oils, compared with palm and safflower oils, increased the activity of fatty acid oxidation enzymes in both mice and rats, with some exceptions. In mice, GLA and fish oils greatly increased the peroxisomal palmitoyl-CoA oxidation rate, and the activity of acyl-CoA oxidase and enoyl-CoA hydratase to the same degree. The effects were much smaller with perilla oil. In rats, enhancing effects were more notable with fish oil than with GLA and perilla oils, excluding the activity of enoyl-CoA hydratase, and were comparable between GLA and perilla oils. In mice, strong enhancing effects of GLA oil, which were greater than with perilla oil and comparable to those of fish oil, were confirmed on mRNA levels of peroxisomal but not mitochondrial fatty acid oxidation enzymes. In rats, the effects of GLA and perilla oils on mRNA levels of peroxisomal and mitochondrial enzymes were indistinguishable, and lower than those observed with fish oil. Therefore, considerable diversity in the response to dietary polyunsaturated fats, especially the oil rich in γ-linolenic acid and fish oil, of hepatic fatty acid oxidation pathway exists between mice and rats.

Wound- and pathogen-activated de novo JA synthesis using different ACX isozymes in tea plant (Camellia sinensis).

Acyl-CoA oxidase (ACX; EC 1.3.3.6) plays a vital role in the biosynthesis of jasmonic acid (JA) in plant peroxisomes. We previously identified an herbivore-induced gene CsACX1 in tea plant (Camellia sinensis) and showed CsACX1 was involved in the wound-induced synthesis of jasmonic acid (JA). Here, another ACX gene CsACX3 was isolated from tea plant. CsACX3 was predicted to consist of 684 amino acid residues. CsACX3 can be induced by mechanical wounding, JA application, and infestation by the tea geometrid Ectropis obliqua Prout and the tea green leafhopper Empoasca (Matsumurasca) onukii Matsuda. These expression patterns are consistent with the previously reported expression pattern of CsACX1 under such treatments. Recombinant CsACX3 showed preference for medium-chain acyl-coA oxidase substrates (C8- to C14-CoA). CsACX3 expression could also be induced by the infection of a pathogen Colletotrichum gloeosporioides (Cgl), and the increased ACX activities in tea plants were correlated with the Cgl-induced CsACX3 expression. Cgl could not induce the expression of CsACX1, which showed preference for C12- to C16-CoA substrates. The constitutive expression of CsACX3 rescued wound-induced JA biosynthesis and enhanced the Cgl-induced JA biosynthesis in Arabidopsis mutant atacx1. However, constitutive expression of CsACX1 could not enhance the Cgl-induced JA biosynthesis in atacx1 plant. These results indicate that CsACX1 and CsACX3 functions overlap and have distinct roles in the wound- and pathogen-activated de novo JA synthesis via enzymatic routes that utilize different ACX isozymes in tea plant.

Coffee prevents fatty liver disease induced by a high-fat diet by modulating pathways of the gut-liver axis.

Coffee consumption is inversely associated with the risk of non-alcoholic fatty liver disease (NAFLD). A gap in the literature still exists concerning the intestinal mechanisms that are involved in the protective effect of coffee consumption towards NAFLD. In this study, twenty-four C57BL/6J mice were divided into three groups each receiving a standard diet, a high-fat diet (HFD) or an HFD plus decaffeinated coffee (HFD+COFFEE) for 12 weeks. Coffee supplementation reduced HFD-induced liver macrovesicular steatosis (P < 0·01) and serum cholesterol (P < 0·001), alanine aminotransferase and glucose (P < 0·05). Accordingly, liver PPAR- α (P < 0·05) and acyl-CoA oxidase-1 (P < 0·05) as well as duodenal ATP-binding cassette (ABC) subfamily A1 (ABCA1) and subfamily G1 (ABCG1) (P < 0·05) mRNA expressions increased with coffee consumption. Compared with HFD animals, HFD+COFFEE mice had more undigested lipids in the caecal content and higher free fatty acid receptor-1 mRNA expression in the duodenum and colon. Furthermore, they showed an up-regulation of duodenal and colonic zonulin-1 (P < 0·05), duodenal claudin (P < 0·05) and duodenal peptide YY (P < 0·05) mRNA as well as a higher abundance of Alcaligenaceae in the faeces (P < 0·05). HFD+COFFEE mice had an energy intake comparable with HFD-fed mice but starting from the eighth intervention week they gained significantly less weight over time. Data altogether showed that coffee supplementation prevented HFD-induced NAFLD in mice by reducing hepatic fat deposition and metabolic derangement through modification of pathways underpinning liver fat oxidation, intestinal cholesterol efflux, energy metabolism and gut permeability. The hepatic and metabolic benefits induced by coffee were accompanied by changes in the gut microbiota.

Effect of selenium nanoparticles against abnormal fatty acid metabolism induced by hexavalent chromium in chicken's liver.

The effect of selenium on excessive fatty acid-induced apoptosis and abnormal amino acid metabolism in the liver is well known, because it is an important site in the fatty acid metabolism pathway. However, the protective role of nano-elemental selenium (nano-Se) supplementation against hexavalent chromium (K2Cr2O7)-induced abnormal fatty acid metabolism has not been evaluated yet. Therefore, we conducted chicken experiments with different nano-Se supplementation doses to investigate the role of nano-Se against Cr(VI)-induced adverse effects. For this purpose, a total of 120 1-day-old chicks were randomly divided into control group, Cr(VI)-exposed group, protection group, treatment group, prevention group, and nano-Se control group. The results of RT-qPCR showed that the nano-Se supplementation notably downregulated (P < 0.01) the messenger RNA (mRNA) expression levels of fatty acid synthase (FASN), whereas nano-Se supplementation significantly upregulated (P < 0.01) the mRNA expression level of acyl-coenzyme A oxidase 1 (ACOX1) in chicken's liver at day 35 of the experiment. Similar results were further verified by western blot analysis. Moreover, nano-Se supplementation significantly enhanced and reduced the antibody expression levels of ACOX1 and FASN in immunohistochemical analysis, respectively. Thus, finally, it was concluded that nano-Se can alleviate K2Cr2O7-induced abnormal fatty acid metabolism in chicken's liver.

Polyphenol-enriched azuki bean (Vina angularis) extract reduces the oxidative stress and prevents DNA oxidation in the hearts of streptozotocin-induced early diabetic rats.

We examined the changes in the heart of rats at the early stages of streptozotocin (STZ)-induced diabetes, and whether azuki bean extract (ABE) could influence these changes. The experimental diabetic rats received 0 or 40 mg/kg of ABE orally for 4 weeks, whereas the control group rats received distilled water. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) and expression of proteins associated with peroxisomal FA ß-oxidation as well as oxidative stress markers were examined. The levels of peroxisomal ACOX1 and catalase of the diabetic groups were significantly higher than those in the control group. The levels of p62, phosphorylated-p62 (p-p62) and HO-1 in the STZ group were significantly higher than those in the control group, and the levels of p-p62, HO-1, and 8-OHdG were significantly lower by ABE administration. The STZ-induced early diabetes increases the levels of proteins related to peroxisomal FA ß-oxidation and oxidative stress markers in hearts. ABE protects diabetic hearts from oxidative damage.

Effect of Dietary Partial Hydrolysate of Phospholipids, Rich in Docosahexaenoic Acid-Bound Lysophospholipids, on Lipid and Fatty Acid Composition in Rat Serum and Liver.

Lysophospholipids have been recognized as potent biologically active lipid mediators. However, attention has not been paid to the health benefits of dietary partial hydrolysate of phospholipids (PH-PL), which is rich in docosahexaenoic acid (DHA)-bound lysophospholipids. In this study, the effects of PH-PL on serum and liver lipid profiles of rats upon administration of PH-PL are demonstrated in comparison to those of fish oil (FO), which comprises eicosapentaenoic acid (EPA) and DHA-bound triglyceride (TG). PH-PL containing EPA and DHA was prepared via enzymatic modification of squid (Todarodes pacificus) meal that is rich in phospholipids. Male Wistar rats were fed a basal diet containing soybean oil alone (7%), FO, and PH-PL. The FO and PH-PL diets had similar EPA and DHA contents. After the rats had been fed their respective diets for 28 d, their serum and liver lipid contents, fecal lipid excretion, and hepatic gene expression level were measured. The results demonstrated that compared with the soybean oil diet alone, the PH-PL diet decreased serum and liver TG contents partially because of the enhancement of liver acyl-CoA oxidase activity and suppression of liver fatty acid synthase activity. In addition, compared with the soybean oil diet, the PH-PL group exhibited lower serum cholesterol content at least in part because of the reduction of hepatic 3-hydroxy-3-methylglutaryl-CoA reductase mRNA expression level. We found that dietary administration of EPA and DHA containing PH-PL has a hypolipidemic effect that may help prevent the development lifestyle-related diseases.

The involvement of a herbivore-induced acyl-CoA oxidase gene, CsACX1, in the synthesis of jasmonic acid and its expression in flower opening in tea plant (Camellia sinensis).

The biosynthesis of jasmonic acid (JA) in plant peroxisomes requires the action of acyl-CoA oxidase (ACX; EC 1.3.3.6). Multiple isoforms of ACXs have been identified in various annual herbaceous plants, but the genes encoding these enzymes in perennial woody plants are yet to be fully investigated. In this study, an ACX gene named CsACX1 (GeneBank accession: KX650077.1) was isolated from tea plant (Camellia sinensis L.). CsACX1 was predicted to consist of 664 amino acid residues. Transcriptional analysis revealed that CsACX1 can be induced by mechanical wounding, JA application, and infestation by the tea geometrid Ectropis obliqua Prout and the tea green leafhopper Empoasca (Matsumurasca) onukii Matsuda. To further elucidate the function of CsACX1, it was heterologously expressed in a bacterial system and characterized. Recombinant CsACX1 showed preference for C12 ∼ C16-CoA substrates. The constitutive expression of CsACX1 can rescue wound-related JA biosynthesis in Arabidopsis mutant acx1. CsACX1 was expressed in different organs, predominantly in flowers. Notably, CsACX1 transcripts were detected up-regulated during flower opening, and the JA levels were correlated with CsACX1 expression. All these results enrich our knowledge of the regulatory pathway involved in the JA biosynthesis in tea, and helps further understand the defense mechanism of tea plant against insects.

Hepatoprotective mechanism of freshwater clam extract alleviates non-alcoholic fatty liver disease: elucidated in vitro and in vivo models.

Freshwater clams (Corbicula fluminea) have long been used as a folk remedy in Chinese tradition. Their hot-water extract has been commercialized as a functional drink for liver protection. The objective of this study was to develop a product of the residual clam meat (FCR) and assess its functional compounds. The ethanol extract of FCR, designated FCRE, was identified to comprise phytosterols, polyunsaturated fatty acids (PUFAs) and carotenoids. FCRE significantly reduced lipid accumulation and cell death in HepG2 cells via decreased fatty acid synthase (FAS) activity and increased activities of carnitine palmitoyltransferase (CPT) and acyl-CoA oxidase (ACO), indicative of suppressed lipogenesis and increased ß-oxidation of fatty acids. In tilapia fed with high-fat diet (HFD), FCRE mitigated nonalcoholic steatohepatitis (NASH), which was evidenced by decreased levels of plasma aspartate transaminase (AST) and alanine transaminase (ALT), in addition to reduced total cholesterol and accumulation of triacylglycerols, particularly those of saturated and monounsaturated fatty acids. FCRE also suppressed stearoyl-CoA desaturase-1 (SCD-1) index, increased the PUFAs' n3/n6 ratio, and reduced prostaglandin E2 (PGE2) and inflammatory infiltrates in tilapia liver. Tilapia fed with HFD for 2 weeks displayed NASH symptoms, while mice took 10 weeks to display NASH symptoms. No previous study has been reported on the potential use of tilapia as an NASH model for pre-screening hepatoprotective-functional foods.

Peroxisomal Acyl-CoA Oxidase Type 1: Anti-Inflammatory and Anti-Aging Properties with a Special Emphasis on Studies with LPS and Argan Oil as a Model Transposable to Aging.

To clarify appropriateness of current claims for health and wellness virtues of argan oil, studies were conducted in inflammatory states. LPS induces inflammation with reduction of PGC1-α signaling and energy metabolism. Argan oil protected the liver against LPS toxicity and interestingly enough preservation of peroxisomal acyl-CoA oxidase type 1 (ACOX1) activity against depression by LPS. This model of LPS-driven toxicity circumvented by argan oil along with a key anti-inflammatory role attributed to ACOX1 has been here transposed to model aging. This view is consistent with known physiological role of ACOX1 in yielding precursors of specialized proresolving mediators (SPM) and with characteristics of aging and related disorders including reduced PGC1-α function and improvement by strategies rising ACOX1 (via hormonal gut FGF19 and nordihydroguaiaretic acid in metabolic syndrome and diabetes conditions) and SPM (neurodegenerative disorders, atherosclerosis, and stroke). Delay of aging to resolve inflammation results from altered production of SPM, SPM improving most aging disorders. The strategic metabolic place of ACOX1, upstream of SPM biosynthesis, along with ability of ACOX1 preservation/induction and SPM to improve aging-related disorders and known association of aging with drop in ACOX1 and SPM, all converge to conclude that ACOX1 represents a previously unsuspected and currently emerging antiaging protein.

Evaluation of Two Liver Treatment Strategies in a Mouse Model of Niemann-Pick-Disease Type C1.

Niemann-Pick-disease type C1 (NPC1) is an autosomal-recessive cholesterol-storage disorder. Besides other symptoms, NPC1 patients develop liver dysfunction and hepatosplenomegaly. The mechanisms of hepatomegaly and alterations of lipid metabolism-related genes in NPC1 disease are still poorly understood. Here, we used an NPC1 mouse model to study an additive hepatoprotective effect of a combination of 2-hydroxypropyl-ß-cyclodextrin (HPßCD), miglustat and allopregnanolone (combination therapy) with the previously established monotherapy using HPßCD. We examined transgene effects as well as treatment effects on liver morphology and hepatic lipid metabolism, focusing on hepatic cholesterol transporter genes. Livers of Npc1-/- mice showed hepatic cholesterol sequestration with consecutive liver injury, an increase of lipogenetic gene expression, e.g., HMG-CoA, a decrease of lipolytic gene expression, e.g., pparα and acox1, and a decrease of lipid transporter gene expression, e.g., acat1, abca1 and fatp2. Both, combination therapy and monotherapy, led to a reduction of hepatic lipids and an amelioration of NPC1 liver disease symptoms. Monotherapy effects were related to pparα- and acox1-associated lipolysis/ß-oxidation and to fatp2-induced fatty acid transport, whereas the combination therapy additionally increased the cholesterol transport via abca1 and apoE. However, HPßCD monotherapy additionally increased cholesterol synthesis as indicated by a marked increase of the HMG-CoA and srebp-2 mRNA expression, probably as a result of increased hepatocellular proliferation.

Leucrose, a Sucrose Isomer, Suppresses Hepatic Fat Accumulation by Regulating Hepatic Lipogenesis and Fat Oxidation in High-fat Diet-induced Obese Mice

Obesity is currently one of the most serious public health problems and it can lead to numerous metabolic diseases. Leucrose, d-glucopyranosyl-α-(1-5)-d-fructopyranose, is an isoform of sucrose and it is naturally found in pollen and honey. The aim of this study was to investigate the effect of leucrose on metabolic changes induced by a high-fat diet (HFD) that lead to obesity. C57BL/6 mice were fed a 60% HFD or a HFD with 25% (L25) or 50% (L50) of its total sucrose content replaced with leucrose for 12 weeks. Leucrose supplementation improved fasting blood glucose levels and hepatic triglyceride content. In addition, leucrose supplementation reduced mRNA levels of lipogenesis-related genes, including peroxisome proliferator-activated receptor γ, sterol regulatory element binding protein 1C, and fatty acid synthase in HFD mice. Conversely, mRNA levels of β oxidation-related genes, such as carnitine palmitoyltransferase 1A and acyl CoA oxidase, returned to control levels with leucrose supplementation. Taken together, these results demonstrated the therapeutic potential of leucrose to prevent metabolic abnormalities by mediating regulation of plasma glucose level and hepatic triglyceride accumulation.

Physiological effects of γ-linolenic acid and sesamin on hepatic fatty acid synthesis and oxidation.

Interrelated effects of γ-linolenic acid (GLA) and sesamin, a sesame lignan, on hepatic fatty acid synthesis and oxidation were examined. Rats were fed experimental diets supplemented with 0 or 2 g/kg sesamin (1:1 mixture of sesamin and episesamin) and containing 100 g/kg of palm oil (saturated fat), safflower oil rich in linoleic acid, or oil of evening primrose origin containing 43% GLA (GLA oil) for 18 days. In rats fed sesamin-free diets, GLA oil, compared with other oils, increased the activity and mRNA levels of various enzymes involved in fatty acid oxidation, except for some instances. Sesamin greatly increased these parameters, and the enhancing effects of sesamin on peroxisomal fatty acid oxidation rate and acyl-CoA oxidase, enoyl-CoA hydratase and acyl-CoA thioesterase activities were more exaggerated in rats fed GLA oil than in the animals fed other oils. The combination of sesamin and GLA oil also synergistically increased the mRNA levels of some peroxisomal fatty acid oxidation enzymes and of several enzymes involved in fatty acid metabolism located in other cell organelles. In the groups fed sesamin-free diets, GLA oil, compared with other oils, markedly reduced the activity and mRNA levels of various lipogenic enzymes. Sesamin reduced all these parameters, except for malic enzyme, in rats fed palm and safflower oils, but the effects were attenuated in the animals fed GLA oil. These changes by sesamin and fat type accompanied profound alterations in serum lipid levels. This may be ascribable to the changes in apolipoprotein-B-containing lipoproteins.

The odd-carbon medium-chain fatty triglyceride triheptanoin does not reduce hepatic steatosis.

BACKGROUND & AIMS: Non-alcoholic fatty-liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. Previously, we showed that a high-protein diet minimized diet-induced development of fatty liver and even reversed pre-existing steatosis. A high-protein diet leads to amino-acid catabolism, which in turn causes anaplerosis of the tricarboxylic-acid (TCA) cycle. Therefore, we hypothesized that anaplerosis of the TCA cycle could be responsible for the high-protein diet-induced improvement of NAFLD by channeling amino acids into the TCA cycle. Next we considered that an efficient anaplerotic agent, the odd-carbon medium-chain triglyceride triheptanoin (TH), might have similar beneficial effects. METHODS: C57BL/6J mice were fed low-fat (8en%) or high-fat (42en%) oleate-containing diets with or without 15en% TH for 3 weeks. RESULTS: TH treatment enhanced the hepatic capacity for fatty-acid oxidation by a selective increase in hepatic Ppara, Acox, and Cd36 expression, and a decline in plasma acetyl-carnitines. It also induced pyruvate cycling through an increased hepatic PCK1 protein concentration and it increased thermogenesis reflected by an increased Ucp2 mRNA content. TH, however, did not reduce hepatic lipid content. CONCLUSION: The comparison of the present effects of dietary triheptanoin with a previous study by our group on protein supplementation shows that the beneficial effects of the high-protein diet are not mimicked by TH. This argues against anaplerosis as the sole explanatory mechanism for the anti-steatotic effect of a high-protein diet.

Roles of Peroxisome Proliferator-Activated Receptor α in Bitter Melon Seed Oil-Corrected Lipid Disorders and Conversion of α-Eleostearic Acid into Rumenic Acid in C57BL/6J Mice.

We previously reported that bitter melon seed oil (BMSO) was an effective anti-steatosis and antiobesity agent. Since the major fatty acid α-eleostearic acid (α-ESA) in BMSO is a peroxisome proliferator-activated receptor α (PPARα) activator, the objective was to investigate the role of PPARα in BMSO-modulated lipid disorders and α-ESA metabolism. C57BL/6J wild (WD) and PPARα knockout (KO) mice were fed a high-fat diet containing BMSO (15% soybean oil + 15% BMSO, HB) or not (30% soybean oil, HS) for 5 weeks. The HB diet significantly reduced hepatic triglyceride concentrations and increased acyl-CoA oxidase activity in WD, but not in KO mice. However, regardless of genotype, body fat percentage was lowered along with upregulated protein levels of uncoupling protein 1 (UCP1) and tyrosine hydroxylase, as well as signaling pathway of cAMP-dependent protein kinase and AMP-activated protein kinase in the white adipose tissue of HB-treated groups compared to HS cohorts. In WD-HB and KO-HB groups, white adipose tissue had autophagy, apoptosis, inflammation, and browning characteristics. Without PPARα, in vivo reduction of α-ESA into rumenic acid was slightly but significantly lowered, along with remarkable reduction of hepatic retinol saturase (RetSat) expression. We concluded that BMSO-mediated anti-steatosis depended on PPARα, whereas the anti-adiposity effect was PPARα-independent. In addition, PPARα-dependent enzymes may participate in α-ESA conversion, but only have a minor role.

Dietary Fisetin Supplementation Protects Against Alcohol-Induced Liver Injury in Mice.

BACKGROUND: Overproduction of reactive oxygen species is associated with the development of alcoholic liver disease (ALD). Plant polyphenols have been used as dietary interventions for multiple diseases including ALD. The objective of this study was to determine whether dietary supplementation with fisetin, a novel flavonoid, exerts beneficial effect on alcohol-induced liver injury. METHODS: C57BL/6J mice were pair-fed with the Lieber-DeCarli control or ethanol (EtOH) diet for 4 weeks with or without fisetin supplementation at 10 mg/kg/d. RESULTS: Alcohol feeding induced lipid accumulation in the liver and increased plasma alanine aminotransferase and aspartate aminotransferase activities, which were attenuated by fisetin supplementation. The EtOH concentrations in the plasma and liver were significantly elevated by alcohol exposure but were reduced by fisetin supplementation. Although fisetin did not affect the protein expression of alcohol metabolism enzymes, the aldehyde dehydrogenase activities were significantly increased by fisetin compared to the alcohol alone group. In addition, fisetin supplementation remarkably reduced hepatic NADPH oxidase 4 levels along with decreased plasma hydrogen peroxide and hepatic superoxide and 4-hydroxynonenal levels after alcohol exposure. Alcohol-induced apoptosis and up-regulation of Fas and cleaved caspase-3 in the liver were prevented by fisetin. Moreover, fisetin supplementation attenuated alcohol-induced hepatic steatosis through increasing plasma adiponectin levels and hepatic protein levels of p-AMPK, ACOX1, CYP4A, and MTTP. CONCLUSIONS: This study demonstrated that the protective effect of fisetin on ALD is achieved by accelerating EtOH clearance and inhibition of oxidative stress. The data suggest that fisetin has a therapeutical potential for treating ALD.

Hypolipidemic Activity of Peony Seed Oil Rich in α-Linolenic, is Mediated Through Inhibition of Lipogenesis and Upregulation of Fatty Acid ß-Oxidation.

Peony seed oil (PSO) is a new resource food rich in α-Linolenic Acid(ALA) (38.66%). The objective of this study was to assess the modulatory effect of PSO on lipid metabolism. Lard oil, safflower oil (SFO), and PSO were fed to wistar rats with 1% cholesterol in the diet for 60 d. Serum and liver lipids showed significant decrease in total cholesterol (TC), triglyceride (TG), and low density lipoprotein-cholesterol (LDL-C) levels in PSO fed rats compared to lard oil and SFO fed rats. ALA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), contents were significantly increased, whereas linoleic acid (LA), arachidonic acid (AA) levels decreased in serum and liver of PSO fed rats. Feeding PSO increased ALA level and decreased n-6 to n-3 polyunsaturated fatty acid (PUFA) ratio. The hypolipidemic result of PSO indicated that PSO participated in the regulation of plasma lipid concentration and cholesterol metabolism in liver. The decreased expression of sterol regulatory element-binding proteins 1C (SREBP-1c), acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS)-reduced lipid synthesis; Activation of peroxisome proliferator-activator receptor (PPARα) accompanied by increase of uncoupling protein2 (UP2) and acyl-CoA oxidase (AOX) stimulated lipid metabolism and exerted an antiobesity effect via increasing energy expenditure for prevention of obesity.

Forms of n-3 (ALA, C18:3n-3 or DHA, C22:6n-3) Fatty Acids Affect Carcass Yield, Blood Lipids, Muscle n-3 Fatty Acids and Liver Gene Expression in Lambs.

The effects of supplementing diets with n-3 alpha-linolenic acid (ALA) and docosahexaenoic acid (DHA) on plasma metabolites, carcass yield, muscle n-3 fatty acids and liver messenger RNA (mRNA) in lambs were investigated. Lambs (n = 120) were stratified to 12 groups based on body weight (35 ± 3.1 kg), and within groups randomly allocated to four dietary treatments: basal diet (BAS), BAS with 10.7 % flaxseed supplement (Flax), BAS with 1.8 % algae supplement (DHA), BAS with Flax and DHA (FlaxDHA). Lambs were fed for 56 days. Blood samples were collected on day 0 and day 56, and plasma analysed for insulin and lipids. Lambs were slaughtered, and carcass traits measured. At 30 min and 24 h, liver and muscle samples, respectively, were collected for determination of mRNA (FADS1, FADS2, CPT1A, ACOX1) and fatty acid composition. Lambs fed Flax had higher plasma triacylglycerol, body weight, body fat and carcass yield compared with the BAS group (P < 0.001). DHA supplementation increased carcass yield and muscle DHA while lowering plasma insulin compared with the BAS diet (P < 0.01). Flax treatment increased (P < 0.001) muscle ALA concentration, while DHA treatment increased (P < 0.001) muscle DHA concentration. Liver mRNA FADS2 was higher and CPT1A lower in the DHA group (P < 0.05). The FlaxDHA diet had additive effects, including higher FADS1 and ACOX1 mRNA than for the Flax or DHA diet. In summary, supplementation with ALA or DHA modulated plasma metabolites, muscle DHA, body fat and liver gene expression differently.