acetyl-CoA Carboxylase In Adipose Tissue Research Articles

Metabolomics Approach in the Study of the Well-Defined Polyherbal Preparation Zyflamend.

Zyflamend is a highly controlled blend of 10 herbal extracts that synergistically impact multiple cell signaling pathways with anticancer and anti-inflammatory properties. More recently, its effects were shown to also modify cellular energetics, for example, activation of fatty acid oxidation and inhibition of lipogenesis. However, its general metabolic effects in vivo have yet to be explored. The objective of this study was to characterize the tissue specific metabolomes in response to supplementation of Zyflamend in mice, with a comparison of equivalent metabolomics data generated in plasma from humans supplemented with Zyflamend. Because Zyflamend has been shown to activate AMPK, the "energy sensor" of the cell, in vitro, the effects of Zyflamend on adiposity were also tested in the murine model. C57BL/6 mice were fed diets that mimicked the macro- and micronutrient composition of the U.S. diet with and without Zyflamend supplementation at human equivalent doses. Untargeted metabolomics was performed in liver, skeletal muscle, adipose, and plasma from mice consuming Zyflamend and in plasma from humans supplemented with Zyflamend at an equivalent dose. Adiposity in mice was significantly reduced in the Zyflamend-treated animals (compared with controls) without affecting body weight or weight gain. Based on KEGG pathway enrichment, purine and pyrimidine metabolism (potential regulators of AMPK) were particularly responsive to Zyflamend across all tissues, but only in mice. Consistent with the metabolomics data, Zyflamend activated AMPK and inhibited acetyl CoA-carboxylase in adipose tissue, key regulators of lipogenesis. Zyflamend reduces adipose tissue in mice through a mechanism that likely involves the activation of AMPK.

Time‐dependent comparison of conjugated linoleic acid (CLA) and conjugated nonadecadienoic acid (CNA) on lipid metabolism in mice

Conjugated linoleic acid (CLA) has shown a number of health benefits, particularly on controlling body fat. As one of CLA cognates, conjugated nonadecadienoic acid (CNA, 19‐carbon conjugated fatty acid) has been previously reported to have greater efficacy on body fat control. In this current investigation, we compared the time‐dependent effects of CNA and CLA. 12‐week‐old male CD‐1 mice were fed one of the treatment diets with 20% total fat (control, 0.5 w/w% CLA, and 0.1 w/w% CNA) for 4, 8, or 12 weeks. There was significant bodyweight decrease for both CLA and CNA groups compared to control over time, while there was no difference in food intake between treatments. The liver weights were significantly increased by CLA but not CNA treatment. Both CLA and CNA groups showed comparable adipose tissue weights which were significantly less than control, with the greatest reduction at week 12. Both CLA and CNA groups had increased white adipose tissue acetyl‐CoA carboxylase, hormone‐sensitive lipase, and uncoupling protein‐2 and decreased peroxisome proliferator‐activated receptor‐γ, fatty acid synthase, and glucose transporter 4 (GLUT4) compared to control at all time points. Muscle GLUT4 was significantly improved by both CLA and CNA treatments compared to control at all time points. In conclusion, CNA reduces body fat in mechanisms similar to those of CLA without adversely influencing liver weight. Supported by AHA SDG

Effect of dietary conjugated linoleic acid isomers on lipid metabolism in hamsters fed high-carbohydrate and high-fat diets

Dietary conjugated linoleic acids (CLA) have been reported to have a number of isomer-dependent effects on lipid metabolism including reduction in adipose tissue deposition, changes in plasma lipoprotein concentrations and hepatic lipid accumulation. The aim of this study was to compare the effect of individual CLA isomers against lipogenic and high 'Western' fat background diets. Golden Syrian hamsters were fed a high-carbohydrate rodent chow or chow supplemented with 17.25 % fat formulated to represent the type and amount of fatty acids found in a typical 'Western' diet (including 0.2 % cholesterol). Diets were further supplemented with 0.25 % (w/w) rapeseed oil, cis9, trans11 (c9,t11)-CLA or trans10, cis12 (t10,c12)-CLA. Neither isomer had a significant impact on plasma lipid or lipoprotein concentrations. The t10,c12-CLA isomer significantly reduced perirenal adipose tissue depot mass. While adipose tissue acetyl CoA carboxylase and fatty acid synthase mRNA concentrations (as measured by quantitative PCR) were unaffected by CLA, lipoprotein lipase mRNA was specifically reduced by t10,c12-CLA, on both background diets (P < 0.001). This was associated with a specific reduction of sterol regulatory element binding protein 1c expression in perirenal adipose tissue (P = 0.018). The isomers appear to have divergent effects on liver TAG content with c9,t11-CLA producing lower concentrations than t10,c12-CLA. We conclude that t10,c12-CLA modestly reduces adipose tissue deposition in the Golden Syrian hamster independently of background diet and this may possibly result from reduced uptake of lipoprotein fatty acids, as a consequence of reduced lipoprotein lipase gene expression.

Effects of feeding or abomasal infusion of canola oil in Holstein cows. 2. Gene expression and plasma concentrations of cholecystokinin and leptin

We determined the relative importance of cholecystokinin (CCK), leptin, and fatty acid concentrations in plasma in mediating the satiety effects of supplemental fat in lactating cows. Five ruminally and duodenally cannulated Holstein cows in late lactation were used in a 3 x 5 incomplete Latin square design with three treatments: 1) CONTROL: basal diet (CON), 2) CONTROL+supplementation of canola oil at 1 kg/d in the feed (FED) and 3) CONTROL+abomasal infusion of canola oil at 1 kg/d (INF). Relative to CON, feed intake was reduced by INF but not by FED. We provide evidence that both FED and INF treatments stimulated CCK gene expression in the duodenum and elevated plasma CCK concentrations. However, our results did not support a role for CCK in mediating satiety through an endocrine mechanism of action. We speculate that CCK might be acting either through paracrine and/or neurocrine routes to influence feed intake in cattle. Both FED and INF had no effect on the mRNA abundance of leptin, lipoprotein lipase, or acetyl-CoA carboxylase in adipose tissue. Plasma concentrations of leptin, insulin and IGF-I were not altered by FED or INF, indicating that these signals may not be involved in mediating short-term hypophagic effects of dietary fat. Plasma concentrations of 18:1n-9 and 18:2n-6 were significantly greater for INF than for FED or CON. We conclude that the hypophagic effects of supplemental fat in cattle depend on the amount of unsaturated fatty acids reaching the intestine and that this satiety effect is mediated through CCK, oleic acid and (or) linoleic acid, but leptin is not involved.

Effect of environmental temperature and dietary lipid supplement on activity and protein abundance of acetyl-CoA carboxylase and fatty acid synthase in skeletal muscle, liver and adipose tissues of sheep

To determine the effects of temperature and dietary lipid on the key enzymes regulating fatty acid synthesis, 24 wether lambs were exposed to three temperature treatments (+23 °C warm, 0 °C cold, or coldpairfed) and fed either a control barley-based diet or a lipid supplemented diet for a 5-wk period. After slaughter, tissue samples were collected and frozen for analysis for enzyme activity and enzyme protein abundance. Thermal environment or lipid supplementation did not affect (P &gt; 0.05) acetyl-CoA carboxylase (ACC) activity in longissimus dorsi (LD) muscle. In liver, cold exposure increased (P &lt; 0.05) while lipid supplementation depressed (P &lt; 0.05) ACC activity. In subcutaneous (SC) and mesenteric (MS) adipose tissue ACC activity was not affected (P &gt; 0.05) by cold exposure. Dietary lipid supplementation increased (P &lt; 0.05) ACC activity in both SC and MS but the increase in perirenal (PR) fat was not significant. Western-blot analysis with peroxidase-labelled streptavidin identified two isoforms of ACC (280 and 265 kDa) in LD muscle and the 280 kDa was the more abundant isoform. In liver and adipose tissues only one isoform (265 kDa) was identified but there was a poor relationship between enzyme protein abundance and activity. Neither environment nor diet affected fatty acid synthase (FAS) activity in LD or liver. Cold exposure reduced (P &lt; 0.05) FAS activity in SC tissue of ad libitum fed animals but increased FAS activity in MS tissue of pair-fed sheep and had no effect in PR fat. Dietary lipid supplementation reduced (P &lt; 0.05) FAS activity by 30% in all three fat depots. A single isoform of FAS with MW of 260 kDa was present in all tissues examined with cold exposure increasing FAS protein expression in all tissues. The results indicate that temperature and dietary lipid affect enzyme catalytic activity with differential responses in different tissues. Key words: Environmental temperature, lipid supplement, lipogenic enzymes, enzyme activity, protein abundance, sheep

Purification and Characterization of Rat Skeletal Muscle Acetyl-CoA Carboxylase

An acetyl-CoA carboxylase has been purified from rat hindlimb muscle using ammonium sulfate fractionation and avidin-Sepharose affinity chromatography. SDS/PAGE of the isolated enzyme showed a major protein band at approximately 272 kDa and a minor band at 265 kDa. The liver acetyl-CoA carboxylase gave a major protein band at 265 kDa and a minor band at 280 kDa. Adipose tissue acetyl-CoA carboxylase migrated to the 265-kDa position on the gel. Western blots performed using streptavidin-alkaline-phosphatase suggest that the bands from the three tissues contain biotin. The present study has characterized the muscle and adipose tissue enzymes under steady-state kinetics and determined Michaelis constants for the substrates. The activation constant for citrate, an essential activator for both preparations, was 2.13 +/- 0.05 mM for the muscle enzyme and 3.02 +/- 0.12 mM for adipose tissue (P < 0.01). The Km values for the muscle acetyl-CoA carboxylase compared to the adipose tissue acetyl-CoA carboxylase were: ATP, 57.6 +/- 0.9 microM compared to 106.5 +/- 2.6 microM, P < 0.01; acetyl-CoA, 31.7 +/- 1.5 microM compared to 21.5 +/- 1.0 microM, P < 0.01; bicarbonate, 2.25 +/- 0.10 mM compared to 2.73 +/- 0.29 mM, P > 0.05. The muscle acetyl-CoA carboxylase was inhibited by malonyl-CoA (Ki = 10.6 +/- 1.0 microM) and palmitoyl-CoA (Ki = 2.2 +/- 0.3 microM). These properties are consistent with the hypothesis that regulation of acetyl-CoA carboxylase plays an important role in governing the rate of fatty acid oxidation in the skeletal muscle.

Purification and characterization of rat skeletal muscle acetyl-CoA carboxylase.

An acetyl-CoA carboxylase has been purified from rat hindlimb muscle using ammonium sulfate fractionation and avidin-Sepharose affinity chromatography. SDS/PAGE of the isolated enzyme showed a major protein band at approximately 272 kDa and a minor band at 265 kDa. The liver acetyl-CoA carboxylase gave a major protein band at 265 kDa and a minor band at 280 kDa. Adipose tissue acetyl-CoA carboxylase migrated to the 265-kDa position on the gel. Western blots performed using streptavidin-alkaline-phosphatase suggest that the bands from the three tissues contain biotin. The present study has characterized the muscle and adipose tissue enzymes under steady-state kinetics and determined Michaelis constants for the substrates. The activation constant for citrate, an essential activator for both preparations, was 2.13 +/- 0.05 mM for the muscle enzyme and 3.02 +/- 0.12 mM for adipose tissue (P < 0.01). The Km values for the muscle acetyl-CoA carboxylase compared to the adipose tissue acetyl-CoA carboxylase were: ATP, 57.6 +/- 0.9 microM compared to 106.5 +/- 2.6 microM, P < 0.01; acetyl-CoA, 31.7 +/- 1.5 microM compared to 21.5 +/- 1.0 microM, P < 0.01; bicarbonate, 2.25 +/- 0.10 mM compared to 2.73 +/- 0.29 mM, P > 0.05. The muscle acetyl-CoA carboxylase was inhibited by malonyl-CoA (Ki = 10.6 +/- 1.0 microM) and palmitoyl-CoA (Ki = 2.2 +/- 0.3 microM). These properties are consistent with the hypothesis that regulation of acetyl-CoA carboxylase plays an important role in governing the rate of fatty acid oxidation in the skeletal muscle.

Porcine somatotropin decreases acetyl-CoA carboxylase gene expression in porcine adipose tissue

Crossbred barrows were treated daily with porcine somatotropin (pST; 4 mg/d) from 79 to 127 kg BW to determine whether pST regulates the activity and gene expression of adipose tissue acetyl-CoA carboxylase (ACC), the rate limiting enzyme in de novo fatty acid synthesis. Administration of pST reduced ACC enzyme activity, protein content, and mRNA abundance in adipose tissue by 40 to 50%. When comparisons were made among all pigs, ACC enzyme activity and mRNA abundance were closely associated (r 2 = .94). In summary, our results indicate that pST decreases ACC enzyme activity and that this is associated with a significant reduction in ACC mRNA abundance. We speculate that decreased ACC enzyme activity results from a reduction in ACC protein and that this occurs because pST reduces the abundance of mRNA available for translation.

Growth-hormone-prolactin interactions in the regulation of mammary and adipose-tissue acetyl-CoA carboxylase activity and gene expression in lactating rats.

The factors and mechanisms responsible for the reciprocal changes in lipogenesis in rat mammary gland and adipose tissue during the lactation cycle have been investigated. Lactation decreased the activation status and mRNA concentration of acetyl-CoA carboxylase in adipose tissue. Litter removal decreased the mRNA concentration of acetyl-CoA carboxylase in the mammary gland and increased the enzyme's mRNA concentration and activation status in adipose tissue. Lowering serum prolactin concentration in lactating rats decreased the amount of mammary acetyl-CoA carboxylase mRNA and increased that of adipose tissue, and increased the activation status of the enzyme in adipose tissue. Decreasing serum growth hormone (GH) alone had little effect on acetyl-CoA carboxylase in lactating rats, although it did lower pup growth rate and serum concentration of insulin-like growth factor-I. Lowering serum GH concentration exacerbated the effects of decreasing serum prolactin on mammary-gland (but not adipose-tissue) acetyl-CoA carboxylase mRNA and further increased the rise in activation status of the adipose-tissue enzyme induced by decreasing serum prolactin. Changes in acetyl-CoA carboxylase mRNA in both mammary and adipose tissue were paralleled by changes in total enzyme activity except after litter removal, when there was a disproportionately large decrease in total enzyme activity of the mammary gland. Thus prolactin has a major and GH a minor role in the regulation of acetyl-CoA carboxylase activity during lactation. Changes in mammary activity in response to prolactin and GH are primarily due to alterations in gene transcription, whereas adaptation in adipose tissue involves both changes in gene transcription and activation status.

Protein-serine kinase from rat epididymal adipose tissue which phosphorylates and activates acetyl-CoA carboxylase. Possible role in insulin action

1. Most of the cyclic-nucleotide-independent acetyl-CoA carboxylase kinase activity in an extract of rat epididymal adipose tissue was evaluated from a Mono Q column by 0.175 M-NaCl at pH 7.4. The activity of the kinase in this fraction (fraction 1) was increased after exposure of intact tissue to insulin. 2. Incubation of purified adipose-tissue acetyl-CoA carboxylase with [gamma-32P]ATP and samples of fraction 1 led to the incorporation of up to 0.4 mol of 32P/mol of enzyme subunit. Most of the phosphorylation was on serine residues within a single tryptic peptide. This peptide, on the basis of two-dimensional t.l.c. analysis, h.p.l.c. and Superose 12 chromatography, appeared to be the same as the acetyl-CoA carboxylase peptide ('I'-peptide) which exhibits increased phosphorylation in insulin-treated tissue. 3. Phosphorylation of purified acetyl-CoA carboxylase by the kinase in fraction 1 was found to be associated with a parallel 4-fold increase in activity. However, increases in both phosphorylation and activity were much diminished if fraction 1 was treated by Centricon centrifugation to remove low-Mr components. Among these components was a potent inhibitor of acetyl-CoA carboxylase activity which appeared to be necessary for the kinase in fraction 1 to be fully active. 4. The inhibitor remains to be identified, but inhibition requires MgATP, although the inhibitor itself does not cause any phosphorylation of the carboxylase. No effects of insulin were observed on the activity of the inhibitor. 5. It is concluded that the kinase probably plays an important role in the mechanism whereby insulin brings about the well-established increases in phosphorylation and activation of acetyl-CoA carboxylase in adipose tissue.

Control of acetyl CoA carboxylase by biotin in rat liver and epididymal adipose tissue

Summary Acetyl CoA carboxylase activity in biotin-deficient rat liver was restored to normal level 30–72 hours, but not within 1 hour after intraperitoneal administration of biotin. This effect was effectively blocked by administration of cycloheximide or actinomycin D. On the other hand, epididymal adipose tissue acetyl CoA carboxylase activity from a biotin-deficient rat was doubled within 1 hour after biotin administration. Actinomycin D had no inhibitory effect on this response even after 48 hours. Two types of control mechanisms exerted by biotin are suggested, one, specific for liver, termed coenzyme induction and the other specific for adipose tissue, called coenzyme repression.

Activities of some biotin enzymes and certain aspects of gluconeogenesis during biotin deficiency

1. 1. The activities of hepatic pyruvate carboxylase, propionyl CoA carboxylase and rat adipose tissue acetyl CoA carboxylase are decreased to a minimum level within 3 weeks of biotin deprivation in chicks and rats. Liver acetyl CoA carboxylase is not so markedly affected. 2. 2. In the deficient animals, the activities of biotin enzymes appear to be restored at the same rate following biotin administration to such animals. 3. 3. The reduction in gluconeogenesis during biotin deficiency is initiated by a decrease in pyruvate carboxylase activity and subsequently enhanced by the shortage of reducing equivalents in the cytosol.

Rat epididymal adipose tissue acetyl-CoA carboxylase.

The properties of a partially purified acetyl-CoA carboxylase (acetyl-CoA:CO2 ligase (ADP), EC 6.4.1.2) from rat epididymal fat pads have been studied. The properties of the rat adipose tissue enzyme are similar to those of the liver in regard to the pH optimum and affinity for substrates and inhibitors. The rat adipose tissue carboxylase shows a pH-dependent, reversible cold inactivation.

Acetyl-CoA carboxylase from rat adipose tissue

Rat epididymal adipose tissue acetyl-CoA carboxylase activity has been shown to respond to various dietary treatments. Feeding a high dextrose diet increases the enzyme activity. In biotin-deficient rats the enzyme activity is reduced to less than a sixth of the levels found in control animals fed the deficient diet supplemented with biotin. Adipose tissue acetyl-CoA carboxylase is inhibited by both malonyl-CoA and coenzyme A. Unlike the liver enzyme, the adipose tissue carboxylase in not inactivated by cold treatment.