Effect of SCP-x gene ablation on branched-chain fatty acid metabolism

2007 ◽  
Vol 292 (3) ◽  
pp. G939-G951 ◽  
Author(s):  
Barbara P. Atshaves ◽  
Avery L. McIntosh ◽  
Danilo Landrock ◽  
H. Ross Payne ◽  
John T. Mackie ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Body Weight Gain ◽  
Mitochondrial Enzymes ◽  
Tissue Mass ◽  
Peroxisomal Enzyme ◽  
Reduced Body ◽  
Gene Ablation ◽  
X Gene ◽  
Branched Chain

Despite the importance of peroxisomal oxidation in branched-chain lipid (phytol, cholesterol) detoxification, little is known regarding the factors regulating the peroxisomal uptake, targeting, and metabolism of these lipids. Although in vitro data suggest that sterol carrier protein (SCP)-x plays an important role in branched-chain lipid oxidation, the full physiological significance of this peroxisomal enzyme is not completely clear. To begin to resolve this issue, SCP-x-null mice were generated by gene ablation of SCP-x from the SCP-x/SCP-2 gene and fed a phytol-enriched diet to characterize the effects of lipid overload in a system with minimal 2/3-oxoacyl-CoA thiolytic activity. It was shown that SCP-x gene ablation 1) did not result in reduced expression of SCP-2 (previously thought to be derived in considerable part by posttranslational cleavage of SCP-x); 2) increased expression levels of key enzymes involved in α- and β-oxidation; and 3) altered lipid distributions, leading to decreased hepatic fatty acid and triglyceride levels. In response to dietary phytol, lack of SCP-x resulted in 1) accumulation of phytol metabolites despite substantial upregulation of hepatic peroxisomal and mitochondrial enzymes; 2) reduced body weight gain and fat tissue mass; and 3) hepatic enlargement, increased mottling, and necrosis. In summary, the present work with SCP-x gene-ablated mice demonstrates, for the first time, a direct physiological relationship between lack of SCP-x and decreased ability to metabolize branched-chain lipids.

Effect of branched-chain fatty acid on lipid dynamics in mice lacking liver fatty acid binding protein gene

2005 ◽  
Vol 288 (3) ◽  
pp. C543-C558 ◽  
Author(s):  
Barbara P. Atshaves ◽  
Avery L. McIntosh ◽  
H. Ross Payne ◽  
John Mackie ◽  
Ann B. Kier ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Droplets ◽  
Phytanic Acid ◽  
Chain Fatty Acid ◽  
Liver Fatty Acid ◽  
Peroxisomal Enzyme ◽  
Lipid Phenotype ◽  
Gene Ablation ◽  
Branched Chain ◽  
Fabp Gene

Although a role for liver fatty acid protein (L-FABP) in the metabolism of branched-chain fatty acids has been suggested based on data obtained with cultured cells, the physiological significance of this observation remains to be demonstrated. To address this issue, the lipid phenotype and metabolism of phytanic acid, a branched-chain fatty acid, were determined in L-FABP gene-ablated mice fed a diet with and without 1% phytol (a metabolic precursor to phytanic acid). In response to dietary phytol, L-FABP gene ablation exhibited a gender-dependent lipid phenotype. Livers of phytol-fed female L-FABP−/− mice had significantly more fatty lipid droplets than male L-FABP−/− mice, whereas in phytol-fed wild-type L-FABP+/+ mice differences between males and females were not significant. Thus L-FABP gene ablation exacerbated the accumulation of lipid droplets in phytol-fed female, but not male, mice. These results were reflected in the lipid profile, where hepatic levels of triacylglycerides in phytol-fed female L-FABP−/− mice were significantly higher than in male L-FABP−/− mice. Furthermore, livers of phytol-fed female L-FABP−/− mice exhibited more necrosis than their male counterparts, consistent with the accumulation of higher levels of phytol metabolites (phytanic acid, pristanic acid) in liver and serum, in addition to increased hepatic levels of sterol carrier protein (SCP)-x, the only known peroxisomal enzyme specifically required for branched-chain fatty acid oxidation. In summary, L-FABP gene ablation exerted a significant role, especially in female mice, in branched-chain fatty acid metabolism. These effects were only partially compensated by concomitant upregulation of SCP-x in response to L-FABP gene ablation and dietary phytol.

scholarly journals Engineered Fatty Acid Biosynthesis inStreptomyces by Altered Catalytic Function of β-Ketoacyl-Acyl Carrier Protein Synthase III

2001 ◽  
Vol 183 (7) ◽  
pp. 2335-2342 ◽  
Author(s):  
Natalya Smirnova ◽  
Kevin A. Reynolds
Keyword(s):  
Fatty Acid ◽  
Type Strain ◽  
Wild Type Strain ◽  
Fatty Acid Biosynthesis ◽  
Acyl Carrier Protein ◽  
Chain Fatty Acid ◽  
Wild Type ◽  
Acid Biosynthesis ◽  
Branched Chain

ABSTRACT The Streptomyces glaucescens β-ketoacyl-acyl carrier protein (ACP) synthase III (KASIII) initiates straight- and branched-chain fatty acid biosynthesis by catalyzing the decarboxylative condensation of malonyl-ACP with different acyl-coenzyme A (CoA) primers. This KASIII has one cysteine residue, which is critical for forming an acyl-enzyme intermediate in the first step of the process. Three mutants (Cys122Ala, Cys122Ser, Cys122Gln) were created by site-directed mutagenesis. Plasmid-based expression of these mutants in S. glaucescens resulted in strains which generated 75 (Cys122Ala) to 500% (Cys122Gln) more straight-chain fatty acids (SCFA) than the corresponding wild-type strain. In contrast, plasmid-based expression of wild-type KASIII had no effect on fatty acid profiles. These observations are attributed to an uncoupling of the condensation and decarboxylation activities in these mutants (malonyl-ACP is thus converted to acetyl-ACP, a SCFA precursor). Incorporation experiments with perdeuterated acetic acid demonstrated that 9% of the palmitate pool of the wild-type strain was generated from an intact D3 acetyl-CoA starter unit, compared to 3% in a strain expressing the Cys122Gln KASIII. These observations support the intermediacy of malonyl-ACP in generating the SCFA precursor in a strain expressing this mutant. To study malonyl-ACP decarboxylase activity in vitro, the KASIII mutants were expressed and purified as His-tagged proteins in Escherichia coli and assayed. In the absence of the acyl-CoA substrate the Cys122Gln mutant and wild-type KASIII were shown to have comparable decarboxylase activities in vitro. The Cys122Ala mutant exhibited higher activity. This activity was inhibited for all enzymes by the presence of high concentrations of isobutyryl-CoA (>100 μM), a branched-chain fatty acid biosynthetic precursor. Under these conditions the mutant enzymes had no activity, while the wild-type enzyme functioned as a ketoacyl synthase. These observations indicate the likely upper and lower limits of isobutyryl-CoA and related acyl-CoA concentrations within S. glaucescens.

scholarly journals D-allulose ameliorates adiposity through the AMPK-SIRT1-PGC-1α pathway in HFD-induced SD rats

2021 ◽  
Author(s):  
Geum Hwa Lee ◽  
Cheng Peng ◽  
Hwa-Young Lee ◽  
Seon-Ah Park ◽  
The-Hiep Hoang ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Body Weight Gain ◽  
Chow Diet ◽  
Metabolic Dysfunction ◽  
Sprague Dawley ◽  
Metabolic Disturbances ◽  
Beneficial Effects ◽  
Reduced Body

Background: Adiposity is a major health-risk factor, and D-allulose has beneficial effects on adiposity-related metabolic disturbances. However, the modes of action underlying anti-hyperglycemic and hypolipidemic activity are partly understood. Objective: This study investigated the in vivo and in vitro effects of D-allulose involved in adipogenesis and activation of the AMPK/SIRT1/PGC-1α pathway in high-fat diet (HFD)-fed rats. Design: In this study, 8-week-old male SD (Sprague Dawley) rats were divided into five groups (n = 8/group), (1) Control (chow diet, 3.5%); (2) 60% HFD; (3) 60% HFD supplemented with allulose powder (AP) at 0.4 g/kg; (4) 60% HFD supplemented with allulose liquid (AL) at 0.4 g/kg; (5) 60% HFD supplemented with glucose (AL) at 0.4 g/kg. All the group received the product through oral gavage for 6 weeks. Control and HFD groups were gavaged with double-distilled water. Results: Rats receiving AP and AL showed reduced body weight gain and fat accumulation in HFD-fed rats. Also, supplementation of AL/AP regulated the cytokine secretion and recovered biochemical parameters to alleviate metabolic dysfunction and hepatic injury. Additionally, AL/AP administration improved adipocyte differentiation via regulation of the PPARγ and C/EBPα signaling pathway and adipogenesis-related genes owing to the combined effect of the AMPK/SIRT1 pathway. Furthermore, AL/AP treatment mediated PGC-1α expression triggering mitochondrial genesis via activating the AMPK phosphorylation and SIRT1 deacetylation activity in adipose tissue. Conclusion: The anti-adiposity activity of D-allulose is observed on a marked alleviation in adipogenesis and AMPK/SIRT1/PGC-1α deacetylation in the adipose tissue of HFD-fed rat.

scholarly journals Liver Fatty Acid-binding Protein Gene Ablation Inhibits Branched-chain Fatty Acid Metabolism in Cultured Primary Hepatocytes

2004 ◽  
Vol 279 (30) ◽  
pp. 30954-30965 ◽  
Author(s):  
Barbara P. Atshaves ◽  
Avery M. McIntosh ◽  
Olga I. Lyuksyutova ◽  
Warren Zipfel ◽  
Watt W. Webb ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Binding Protein ◽  
Acid Metabolism ◽  
Protein Gene ◽  
Primary Hepatocytes ◽  
Fatty Acid Binding ◽  
Acid Binding Protein ◽  
Gene Ablation ◽  
Binding Protein Gene ◽  
Branched Chain

Liver fatty acid binding protein gene ablation potentiates hepatic cholesterol accumulation in cholesterol-fed female mice

2006 ◽  
Vol 290 (1) ◽  
pp. G36-G48 ◽  
Author(s):  
Gregory G. Martin ◽  
Barbara P. Atshaves ◽  
Avery L. McIntosh ◽  
John T. Mackie ◽  
Ann B. Kier ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Body Weight Gain ◽  
Dietary Cholesterol ◽  
Hepatic Cholesterol ◽  
Fat Tissue ◽  
Tissue Mass ◽  
Female Mice ◽  
Gene Ablation ◽  
Fabp Gene

Although liver fatty acid binding protein (L-FABP) is postulated to influence cholesterol homeostasis, the physiological significance of this hypothesis remains to be resolved. This issue was addressed by examining the response of young (7 wk) female mice to L-FABP gene ablation and a cholesterol-rich diet. In control-fed mice, L-FABP gene ablation alone induced hepatic cholesterol accumulation (2.6-fold), increased bile acid levels, and increased body weight gain (primarily as fat tissue mass). In cholesterol-fed mice, L-FABP gene ablation further enhanced the hepatic accumulation of cholesterol (especially cholesterol ester, 12-fold) and potentiated the effects of dietary cholesterol on increased body weight gain, again mainly as fat tissue mass. However, in contrast to the effects of L-FABP gene ablation in control-fed mice, biliary levels of bile acids (as well as cholesterol and phospholipids) were reduced. These phenotypic alterations were not associated with differences in food intake. In conclusion, it was shown for the first time that L-FABP altered cholesterol metabolism and the response of female mice to dietary cholesterol. While the biliary and lipid phenotype of female wild-type L-FABP+/+ mice was sensitive to dietary cholesterol, L-FABP gene ablation dramatically enhanced many of the effects of dietary cholesterol to greatly induce hepatic cholesterol (primarily cholesterol ester) and triacylglycerol accumulation as well as to potentiate body weight gain (primarily as fat tissue mass). Taken together, these data support the hypothesis that L-FABP is involved in the physiological regulation of cholesterol metabolism, body weight gain, and obesity.

scholarly journals Multiple Mechanisms Converging on Transcription Factor EB Activation by the Natural Phenol Pterostilbene

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Martina La Spina ◽  
Michele Azzolini ◽  
Andrea Salmaso ◽  
Sofia Parrasia ◽  
Eva Galletta ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Therapeutic Potential ◽  
Body Weight Gain ◽  
Mitochondrial Respiratory Chain ◽  
Reduced Body ◽  
Diet Induced Obesity ◽  
Activation Of Transcription ◽  
Transcription Factor Eb

Pterostilbene (Pt) is a potentially beneficial plant phenol. In contrast to many other natural compounds (including the more celebrated resveratrol), Pt concentrations producing significant effects in vitro can also be reached with relative ease in vivo. Here we focus on some of the mechanisms underlying its activity, those involved in the activation of transcription factor EB (TFEB). A set of processes leading to this outcome starts with the generation of ROS, attributed to the interaction of Pt with complex I of the mitochondrial respiratory chain, and spreads to involve Ca2+ mobilization from the ER/mitochondria pool, activation of CREB and AMPK, and inhibition of mTORC1. TFEB migration to the nucleus results in the upregulation of autophagy and lysosomal and mitochondrial biogenesis. Cells exposed to several μM levels of Pt experience a mitochondrial crisis, an indication for using low doses in therapeutic or nutraceutical applications. Pt afforded significant functional improvements in a zebrafish embryo model of ColVI-related myopathy, a pathology which also involves defective autophagy. Furthermore, long-term supplementation with Pt reduced body weight gain and increased transcription levels of Ppargc1a and Tfeb in a mouse model of diet-induced obesity. These in vivo findings strengthen the in vitro observations and highlight the therapeutic potential of this natural compound.

scholarly journals Effect ofAchyranthes bidentataBlume on 3T3-L1 Adipogenesis and Rats Fed with a High-Fat Diet

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Sang Deog Oh ◽  
Mihyun Kim ◽  
Byung-Il Min ◽  
Gi Soon Choi ◽  
Sun-Kwang Kim ◽  
...  
Keyword(s):  
Body Weight ◽  
High Fat Diet ◽  
Adipocyte Differentiation ◽  
Body Weight Gain ◽  
Water Extract ◽  
High Fat ◽  
Achyranthes Bidentata ◽  
Reduced Body ◽  
Differentiation Model

The present study investigated the antiobesity effect ofAchyranthes bidentataBlume root water extract in a 3T3-L1 adipocyte differentiation model and rats fed with a high-fat diet. To investigate the effect ofAchyranthes bidentataBlume on adipogenesisin vitro, differentiating 3T3-L1 cells in adipocyte-induction media were treated every two days withAchyranthes bidentataBlume at various concentrations (1 to 25 μg/mL) for eight days. We found thatAchyranthes bidentataBlume root inhibited 3T3-L1 adipocyte differentiation without affecting cell viability, and Western blot analysis revealed that phospho-Akt expression was markedly decreased, whereas there was no significant change in perilipin expression. Furthermore, administration ofAchyranthes bidentataBlume root (0.5 g/kg body weight for six weeks) to rats fed with a high-fat diet significantly reduced body weight gain without affecting food intake, and the level of triglyceride was significantly decreased when compared to those in rats fed with only a high-fat diet. These results suggest thatAchyranthes bidentataBlume root water extract could have a beneficial effect on inhibition of adipogenesis and controlling body weight in rats fed with a high-fat diet.

scholarly journals pNaKtide inhibits Na/K-ATPase reactive oxygen species amplification and attenuates adipogenesis

2015 ◽  
Vol 1 (9) ◽  
pp. e1500781 ◽  
Author(s):  
Komal Sodhi ◽  
Kyle Maxwell ◽  
Yanling Yan ◽  
Jiang Liu ◽  
Muhammad A. Chaudhry ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Metabolic Syndrome ◽  
Body Weight Gain ◽  
Oxidant Stress ◽  
Dependent Manner ◽  
Reduced Body ◽  
Obesity Phenotype ◽  
Isolated Adipocytes ◽  
Inflammatory Milieu

Obesity has become a worldwide epidemic and is a major risk factor for metabolic syndrome. Oxidative stress is known to play a role in the generation and maintenance of an obesity phenotype in both isolated adipocytes and intact animals. Because we had identified that the Na/K-ATPase can amplify oxidant signaling, we speculated that a peptide designed to inhibit this pathway, pNaKtide, might ameliorate an obesity phenotype. To test this hypothesis, we first performed studies in isolated murine preadipocytes (3T3L1 cells) and found that pNaKtide attenuated oxidant stress and lipid accumulation in a dose-dependent manner. Complementary experiments in C57Bl6 mice fed a high-fat diet corroborated our in vitro observations. Administration of pNaKtide in these mice reduced body weight gain, restored systemic redox and inflammatory milieu, and, crucially, improved insulin sensitivity. Thus, we propose that inhibition of Na/K-ATPase amplification of oxidative stress may ultimately be a novel way to combat obesity, insulin resistance, and metabolic syndrome.

In Vitro Incorporation and Metabolism of Icosapentaenoic and Docosahexaenoic Acids in Human Platelets - Effect on Aggregation

1986 ◽  
Vol 56 (01) ◽  
pp. 057-062 ◽  
Author(s):  
Martine Croset ◽  
M Lagarde
Keyword(s):  
Arachidonic Acid ◽  
Fatty Acid ◽  
Platelet Aggregation ◽  
Fatty Acid Distribution ◽  
Thromboxane A2 ◽  
Human Platelets ◽  
Aggregation Response ◽  
Docosahexaenoic Acids ◽  
Membrane Level

SummaryWashed human platelets were pre-loaded with icosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or EPA + DHA and tested for their aggregation response in comparison with control platelets. In fatty acid-rich platelets, an inhibition of the aggregation could be observed when induced by thrombin, collagen or U-46619. The strongest inhibition was observed with DHA-rich platelets and it was reduced when DHA was incorporated in the presence of EPA.Study of fatty acid distribution in cell lipids after loading showed that around 90% of EPA or DHA taken up was acylated into phospholipids and a very small amount (less than 2%) remained in their free and hydroxylated forms. DHA was more efficiently acylated into phosphatidylethanolamine (PE) than into phosphatidylinositol (PI) in contrast to what observed with EPA, and both acids were preferentially incorporated into phosphatidylcholine (PC). EPA inhibited total incorporation of DHA and increased its relative acylation into PE at the expense of PC. In contrast, DHA did not affect the acylation of EPA. Upon stimulation with, thrombin, EPA was liberated from phospholipids and oxygenated (as judged by the formation of its monohydroxy derivative) whereas DHA was much less metabolized, although consistently transferred into PE.It is concluded that EPA and DHA might affect platelet aggregation via different mechanisms when pre-loaded in phospholipids. Whereas EPA is known to alter thromboxane A2 metabolism from endogenous arachidonic acid, by competing with it, DHA might act directly at the membrane level for inhibiting aggregation.

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