scholarly journals Synthesis of DHA (omega-3 fatty acid): FADS2 gene polymorphisms and regulation by PPARα

OCL ◽  
2021 ◽  
Vol 28 ◽  
pp. 43
Author(s):  
Didier Majou
Keyword(s):  
Fatty Acid ◽  
Mapk Pathway ◽  
Promoter Polymorphism ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Omega 3 ◽  
Peroxisome Proliferator Activated Receptor ◽  
Omega 3 Fatty Acid ◽  
Peroxisome Proliferator Response Element ◽  
Δ6 Desaturase

In humans, in several biological systems, in particular the nervous system, the FADS2 gene transcribes Δ6-desaturase, which is the rate-limiting enzyme for converting α-linolenic acid into docosahexaenoic acid (an n-3 fatty acid). The peroxisome proliferator-activated receptor α (PPARα) modulates the transcription of FADS2 gene by interacting with a second transcription factor: the retinoid X receptor α (RXRα). These transcription factors take the form of a PPARα-RXRα heterodimer and are modulated by the ligands that modify their respective structures and enable them to bind to the peroxisome proliferator response element (PPRE) located in the promoter region of the FADS2 gene. Free estradiol induces the activation of PPARα via two pathways (i) transcription through genomic action mediated by an estrogen receptor; (ii) a non-genomic effect that allows for phosphorylation and activates PPARα via the ERK1/2-MAPK pathway. Phosphorylation is an on/off switch for PPARα transcription activity. Since Δ6-desaturase expression is retro-inhibited by free intracellular DHA in a dose-dependent manner, this position paper proposes an original hypothesis: if DHA simultaneously binds to both phosphorylated PPARα and RXRα, the resulting DHA-PPARαP-RXRα-DHA heterodimer represses FADS2 gene via PPRE. The retinoic acids-RARα-RXRα-DHA heterodimer would not dissociate from corepressors and would prevent coactivators from binding to FADS2. We speculate that SNPs, which are mostly located on PPRE, modulate the binding affinities of DHA-PPARαP-RXRα-DHA heterodimer to PPRE. The DHA-PPARαP-RXRα-DHA heterodimer’s greater affinity for PPRE results in a decreased production of D6D and DHA. FADS2 promoter polymorphism would increase the competition between DHA and other ligands, in accordance with their concentrations and affinities.

scholarly journals Mechanisms Mediating the Regulation of Peroxisomal Fatty Acid Beta-Oxidation by PPARα

2021 ◽  
Vol 22 (16) ◽  
pp. 8969
Author(s):  
Mounia Tahri-Joutey ◽  
Pierre Andreoletti ◽  
Sailesh Surapureddi ◽  
Boubker Nasser ◽  
Mustapha Cherkaoui-Malki ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Mammalian Cells ◽  
Atp Synthesis ◽  
Peroxisome Proliferator ◽  
Beta Oxidation ◽  
Peroxisome Proliferator Activated Receptor ◽  
Oxidation Pathway ◽  
Oxidative Phosphorylation Pathway ◽  
Peroxisome Proliferator Response Element ◽  
Peroxisomal Fatty Acid

In mammalian cells, two cellular organelles, mitochondria and peroxisomes, share the ability to degrade fatty acid chains. Although each organelle harbors its own fatty acid β-oxidation pathway, a distinct mitochondrial system feeds the oxidative phosphorylation pathway for ATP synthesis. At the same time, the peroxisomal β-oxidation pathway participates in cellular thermogenesis. A scientific milestone in 1965 helped discover the hepatomegaly effect in rat liver by clofibrate, subsequently identified as a peroxisome proliferator in rodents and an activator of the peroxisomal fatty acid β-oxidation pathway. These peroxisome proliferators were later identified as activating ligands of Peroxisome Proliferator-Activated Receptor α (PPARα), cloned in 1990. The ligand-activated heterodimer PPARα/RXRα recognizes a DNA sequence, called PPRE (Peroxisome Proliferator Response Element), corresponding to two half-consensus hexanucleotide motifs, AGGTCA, separated by one nucleotide. Accordingly, the assembled complex containing PPRE/PPARα/RXRα/ligands/Coregulators controls the expression of the genes involved in liver peroxisomal fatty acid β-oxidation. This review mobilizes a considerable number of findings that discuss miscellaneous axes, covering the detailed expression pattern of PPARα in species and tissues, the lessons from several PPARα KO mouse models and the modulation of PPARα function by dietary micronutrients.

scholarly journals Genistin: A Novel Potent Anti-Adipogenic and Anti-Lipogenic Agent

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2042 ◽  
Author(s):  
Yae Rim Choi ◽  
Jaewon Shim ◽  
Min Jung Kim
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Binding Protein ◽  
Regulatory Element ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Atp Citrate Lyase ◽  
Peroxisome Proliferator Activated Receptor ◽  
Fatty Acid Binding ◽  
Specific Proteins

Soy isoflavones are popular ingredients with anti-adipogenic and anti-lipogenic properties. The anti-adipogenic and anti-lipogenic properties of genistein are well-known, but those of genistin and glycitein remain unknown, and those of daidzein are characterized by contrasting data. Therefore, the purpose of our study was to investigate the effects of daidzein, glycitein, genistein, and genistin on adipogenesis and lipogenesis in 3T3-L1 cells. Proliferation of 3T3-L1 preadipocytes was unaffected by genistin and glycitein, but it was affected by 50 and 100 µM genistein and 100 µM daidzein for 48 h. Among the four isoflavones, only 50 and 100 µM genistin and genistein markedly suppressed lipid accumulation during adipogenesis in 3T3-L1 cells through a similar signaling pathway in a dose-dependent manner. Genistin and genistein suppress adipocyte-specific proteins and genes, such as peroxisome proliferator-activated receptor γ (PPARγ), CCAAT-enhancer-binding protein α (C/EBPα), and adipocyte binding protein 2 (aP2)/fatty acid-binding protein 4 (FABP4), and lipogenic enzymes such as ATP citrate lyase (ACL), acetyl-CoA carboxylase 1 (ACC1), and fatty acid synthase (FAS). Both isoflavones also activate AMP-activated protein kinase α (AMPKα), an essential factor in adipocyte differentiation, and inhibited sterol regulatory element-binding transcription factor 1c (SREBP-1c). These results indicate that genistin is a potent anti-adipogenic and anti-lipogenic agent.

Abstract 15015: Eicosapentaenoic Acid, but Not Docosahexaenoic Acid or a Mixed Omega-3 Fatty Acid Supplement, Inhibits Low-density Lipoprotein Oxidation in a Time-dependent Manner

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Samuel Sherratt ◽  
Peter Libby ◽  
Deepak L Bhatt ◽  
Preston Mason
Keyword(s):  
Antioxidant Activity ◽  
Fatty Acid ◽  
Eicosapentaenoic Acid ◽  
Time Dependent ◽  
Ldl Oxidation ◽  
Gas Chromatography Mass Spectrometry ◽  
Low Density ◽  
Dependent Manner ◽  
Omega 3 ◽  
Omega 3 Fatty Acid

Background: Eicosapentaenoic acid (EPA), an omega-3 fatty acid (O3FA), reduces oxidation of low-density lipoproteins (LDL) in patients with hypertriglyceridemia, an effect that may contribute to lower cardiovascular (CV) events as reported in the REDUCE-IT trial. By contrast, DHA-containing products have failed to show a reduction in CV events, which may be due, in part, to differences in antioxidant activity. We compared the effects of EPA versus DHA and a mixed O3FA (EPA/DHA) supplement on oxidation of human LDL in vitro . Methods: LDL was isolated from human plasma by isopycnic centrifugation, separated into test samples of 100 μg/mL, and incubated at 37°C for 30 min in the absence (vehicle) or presence of EPA, DHA, or mixed O3FA supplement at equimolar levels (2.5 μM). All samples were then subjected to copper-induced oxidation (20 μM) as measured by formation of malondialdehyde (MDA). The FA content of the O3FA supplement was measured using gas chromatography/mass spectrometry. Results: EPA significantly inhibited LDL oxidation in a time-dependent manner compared with vehicle; after 4 hours, EPA inhibited MDA levels by 96% compared with the vehicle oxidation level (0.51 ± 0.01 vs 11.4 ± 0.4 μM; p <0.001). While DHA exhibited antioxidant activity at 2 hours at a level below EPA (2.5 ± 0.1 vs 11.4 ± 0.4; p <0.001), even this level of activity was lost by 4 hours. The mixed O3FA supplement failed to show any antioxidant activity through 4 hours (11.4 ± 0.5 μM). Fatty acid analysis showed that the O3FA supplement, in addition to EPA and DHA, contained more than 30 other fatty acids, including saturated fats, that may have nullified any potential benefits. Conclusions: These data support potent LDL antioxidant effects of EPA that were sustained over time compared with DHA, which had a weaker, transient effect, or a mixed O3FA supplement, which had no beneficial effect at all. This potent antioxidant mechanism of EPA may contribute to reduced CV risks seen in REDUCE-IT compared with negative findings from trials using DHA-containing formulations.

scholarly journals Lactobacillus plantarumLG42 Isolated from Gajami Sik-Hae Inhibits Adipogenesis in 3T3-L1 Adipocyte

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jeong-Eun Park ◽  
Suk-Heung Oh ◽  
Youn-Soo Cha
Keyword(s):  
Transcription Factors ◽  
Fatty Acid ◽  
Lipid Accumulation ◽  
Binding Protein ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Peroxisome Proliferator Activated Receptor ◽  
Fatty Acid Binding ◽  
Intracellular Lipid Accumulation ◽  
Glycerol 3 Phosphate Dehydrogenase

We investigated whether lactic acid bacteria isolated from gajami sik-hae (GLAB) are capable of reducing the intracellular lipid accumulation by downregulating the expression of adipogenesis-related genes in differentiated 3T3-L1 cells. The GLAB,Lactobacillus plantarumLG42, significantly decreased the intracellular triglyceride storage and the glycerol-3-phosphate dehydrogenase (GPDH) activity in a dose-dependent manner. mRNA expression of transcription factors like peroxisome proliferator-activated receptor (PPAR)γand CCAAT/enhancer-binding protein (C/EBP)αinvolved in adipogenesis was markedly decreased by the GLAB treatment. Moreover, the GLAB also decreased the expression level of adipogenic markers like adipocyte fatty acid binding protein (aP2), leptin, GPDH, and fatty acid translocase (CD36) significantly. These results suggest that the GLAB inhibits lipid accumulation in the differentiated adipocyte through downregulating the expression of adipogenic transcription factors and other specific genes involved in lipid metabolism.

scholarly journals Shugan Xiaozhi Decoction Attenuates Nonalcoholic Steatohepatitis by Enhancing PPARαand L-FABP Expressions in High-Fat-Fed Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Yu-feng Xing ◽  
Zhen Zhang ◽  
Wen-Jun Fu ◽  
Da-qiao Zhou ◽  
Ailsa Chui-ying Yuen ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Nonalcoholic Steatohepatitis ◽  
Chemical Constituents ◽  
Ionization Mass ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
High Fat ◽  
Peroxisome Proliferator Activated Receptor ◽  
Fatty Acid Binding ◽  
Dose Dependent

This study aimed to investigate the effects of Shugan Xiaozhi decoction (SX) on nonalcoholic steatohepatitis (NASH) induced by high-fat diet in rats. The rats were randomly divided into 6 groups, namely, control, model, fenofibrate, and three different dosage of SX (10, 20, and 40 g/kg/day, p.o.). After establishing the NASH model, at 8 weeks of the experiment, treatments were administrated intragastrically to the fenofibrate and SX groups. All rats were killed after 4 weeks of treatment. Compared with the model group, alanine aminotransferase (ALT), aspartate aminotransferase (AST), free fatty acid (FFA), total cholesterol (TC), triacylglycerol (TG), and low-density lipoprotein cholesterol (LDL) serum in the serum were significantly reduced in all SX treatment groups in a dose-dependent manner. Evidence showed that SX could protect the liver by upregulating the gene and protein expressions of peroxisome proliferator-activated receptor alpha (PPARα) and liver fatty acid binding protein (L-FABP) in a dose-dependent manner. Chemical constituents of SX were further analyzed by ultraperformance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC-ESI-MS) and 30 chemicals in the ethanolic extract were tentatively identified. To conclude, our results clearly indicated that SX could protect liver functions and relieve hepatic steatosis and inflammation.

The peroxisome proliferator-activated receptor:retinoid X receptor heterodimer is activated by fatty acids and fibrate hypolipidaemic drugs

1993 ◽  
Vol 11 (1) ◽  
pp. 37-47 ◽  
Author(s):  
I Issemann ◽  
R A Prince ◽  
J D Tugwood ◽  
S Green
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Physiological Role ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferators ◽  
Peroxisome Proliferator Activated Receptor ◽  
Peroxisomal Enzyme ◽  
Oxidase Gene ◽  
Acyl Coa Oxidase ◽  
Peroxisome Proliferator Response Element

ABSTRACT The peroxisome proliferator-activated receptor (PPAR) is a member of the steroid hormone receptor superfamily and is activated by a variety of fibrate hypolipidaemic drugs and non-genotoxic rodent hepatocarcinogens that are collectively termed peroxisome proliferators. A key marker of peroxisome proliferator action is the peroxisomal enzyme acyl CoA oxidase, which is elevated about tenfold in the livers of treated rodents. We have previously shown that a peroxisome proliferator response element (PPRE) is located 570 bp upstream of the rat peroxisomal acyl CoA oxidase gene and that PPAR binds to it. We show here that the retinoid X receptor (RXR) is required for PPAR to bind to the PPRE, and that the RXR ligand, 9-cis retinoic acid, enhances PPAR action. Retinoids may therefore modulate the action of peroxisome proliferators and PPAR may interfere with retinoid action, perhaps providing one mechanism to explain the toxicity of peroxisome proliferators. We have also shown that a variety of hypolipidaemic drugs and fatty acids can activate PPAR. This supports the suggestion that the physiological role of PPAR is to regulate fatty acid homeostasis, and provides further evidence that PPAR is the target of the fibrate class of hypolipidaemic drugs. Finally, we have demonstrated that a metabolically stabilized fatty acid is a potent PPAR activator, suggesting that fatty acids, or their acyl CoA derivatives, may be the natural ligands of PPAR.

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