scholarly journals Cocktail biosynthesis of triacylglycerol by rational modulation of diacylglycerol acyltransferases in industrial oleaginous Aurantiochytrium

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Chuanzeng Lan ◽  
Sen Wang ◽  
Huidan Zhang ◽  
Zhuojun Wang ◽  
Weijian Wan ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Ex Vivo ◽  
Saturated Fatty Acids ◽  
Degree Of Unsaturation ◽  
Promising Target ◽  
Oleaginous Microorganism ◽  
Key Enzyme ◽  
Functional Distribution

Abstract Background Triacylglycerol (TAG) is an important storage lipid in organisms, depending on the degree of unsaturation of fatty acid molecules attached to glycerol; it is usually used as the feedstock for nutrition or biodiesel. However, the mechanism of assembly of saturated fatty acids (SFAs) or polyunsaturated fatty acids (PUFAs) into TAGs remains unclear for industrial oleaginous microorganism. Results Diacylglycerol acyltransferase (DGAT) is a key enzyme for TAG synthesis. Hence, ex vivo (in yeast), and in vivo functions of four DGAT2s (DGAT2A, DGAT2B, DGAT2C, and DGAT2D) in industrial oleaginous thraustochytrid Aurantiochytrium sp. SD116 were analyzed. Results revealed that DGAT2C was mainly responsible for connecting PUFA to the sn-3 position of TAG molecules. However, DGAT2A and DGAT2D target SFA and/or MUFA. Conclusions There are two specific TAG assembly routes in Aurantiochytrium. The “saturated fatty acid (SFA) TAG lane” primarily produces SFA-TAGs mainly mediated by DGAT2D whose function is complemented by DGAT2A. And, the “polyunsaturated fatty acid (PUFA) TAG lane” primarily produces PUFA-TAGs via DGAT2C. In this study, we demonstrated the functional distribution pattern of four DGAT2s in oleaginous thraustochytrid Aurantiochytrium, and provided a promising target to rationally design TAG molecular with the desired characteristics.

Profiling substrate fluxes in the isolated working mouse heart using 13C-labeled substrates: focusing on the origin and fate of pyruvate and citrate carbons

2004 ◽  
Vol 286 (4) ◽  
pp. H1461-H1470 ◽  
Author(s):  
Maya Khairallah ◽  
François Labarthe ◽  
Bertrand Bouchard ◽  
Gawiyou Danialou ◽  
Basil J. Petrof ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Ex Vivo ◽  
Heart Function ◽  
Acid Oxidation ◽  
Mouse Heart ◽  
Relative Contribution ◽  
Cardiac Functions ◽  
Lactate And Pyruvate

The availability of genetically modified mice requires the development of methods to assess heart function and metabolism in the intact beating organ. With the use of radioactive substrates and ex vivo perfusion of the mouse heart in the working mode, previous studies have documented glucose and fatty acid oxidation pathways. This study was aimed at characterizing the metabolism of other potentially important exogenous carbohydrate sources, namely, lactate and pyruvate. This was achieved by using 13C-labeling methods. The mouse heart perfusion setup and buffer composition were optimized to reproduce conditions close to the in vivo milieu in terms of workload, cardiac functions, and substrate-hormone supply to the heart (11 mM glucose, 0.8 nM insulin, 50 μM carnitine, 1.5 mM lactate, 0.2 mM pyruvate, 5 nM epinephrine, 0.7 mM oleate, and 3% albumin). The use of three differentially 13C-labeled carbohydrates and a 13C-labeled long-chain fatty acid allowed the quantitative assessment of the metabolic origin and fate of tissue pyruvate as well as the relative contribution of substrates feeding acetyl-CoA (pyruvate and fatty acids) and oxaloacetate (pyruvate) for mitochondrial citrate synthesis. Beyond concurring with the notion that the mouse heart preferentially uses fatty acids for energy production (63.5 ± 3.9%) and regulates its fuel selection according to the Randle cycle, our study reports for the first time in the mouse heart the following findings. First, exogenous lactate is the major carbohydrate contributing to pyruvate formation (42.0 ± 2.3%). Second, lactate and pyruvate are constantly being taken up and released by the heart, supporting the concept of compartmentation of lactate and glucose metabolism. Finally, mitochondrial anaplerotic pyruvate carboxylation and citrate efflux represent 4.9 ± 1.8 and 0.8 ± 0.1%, respectively, of the citric acid cycle flux and are modulated by substrate supply. The described 13C-labeling strategy combined with an experimental setup that enables continuous monitoring of physiological parameters offers a unique model to clarify the link between metabolic alterations, cardiac dysfunction, and disease development.

An ω-6 Fatty Acid, Dgla, Prevents Platelet Activation and Thrombosis in Vivo.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2169-2169
Author(s):  
Jennifer Yeung ◽  
Kenneth Ikei ◽  
Joanne Vesci ◽  
Theodore R Holman ◽  
Michael Holinstat
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Dietary Supplementation ◽  
Bioactive Metabolites ◽  
Induce Platelet Aggregation

Abstract Abstract 2169 Platelets play a pivotal role in thrombotic events leading to clot formation and clot stability in vivo. Uncontrolled signaling events in the platelet can result in unwanted thrombosis, which may eventually lead to the development of myocardial infarction or stroke. Previously, we have shown that ex vivo treatment of human platelets with the ω-6 fatty acid dihomo-γ-linolenic acid (DGLA) or its eicosanoid derived from 12-LOX oxidation, 12-hydroxyeicosatrienoic acid (12(S)-HETrE), inhibits PAR and collagen-induced platelet aggregation, clot retraction, and GPIIbIIIa activation. Since early studies have shown dietary supplementation of fatty acids increase fatty acid incorporation into the platelet lipid membrane (Barre, DE Lipids 1992; 27(5): 315–320; Marry, MJ Prostaglandins Leukot Essent Fatty Acids 1997; 56(3):223–223), we postulated that altering fatty acid composition in the platelet through dietary supplementation in vivo may be a viable approach to inhibiting platelet function. Therefore, a longitudinal study of wild-type mice on normal chow compared to mice supplemented with high (.5 g/kg) or low (.13 g/kg) DGLA diets was conducted. Each set of mice (7–8 mice) was given the designated diet for a period of 1, 2, or 3 months. At each time point, tail bleeding times and ex vivo platelet function in PRP were performed. Tail bleeding times from mice on the high DGLA diet were significantly prolonged by more than 15 minutes. Further, a smaller but statistically significant delay in clotting time was observed in mice on the low DGLA diet compared with control mice. Additionally, ex vivo aggregation response to collagen (1 μg/mL to 20 μg/mL) and PAR4-AP (50 μM to 500 μM) in platelets from mice on the high DGLA diet showed significant shifts to the right in their ability to induce platelet aggregation compared with control mice suggesting these mice were protected against thrombosis. JON/A and P-selectin binding to the PRP of high and low DGLA were also significantly attenuated in response to PAR4-AP. This study, which evaluated the in vivo and ex vivo effects of DGLA on regulation of platelet reactivity, supports DGLA as a potent, endogenous anti-thrombotic agent. Understanding the mechanistic details by which DGLA protects against thrombosis and maintains hemostasis through its COX-1 and 12-LOX-dependent bioactive metabolites will help to identify the potential viability of this target for anti-platelet intervention. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Fatty acid elongation by a particulate fraction from germinating pea

1980 ◽  
Vol 191 (3) ◽  
pp. 791-797 ◽  
Author(s):  
B R Jordan ◽  
J L Harwood
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
High Speed ◽  
Saturated Fatty Acids ◽  
Acyl Chain ◽  
Fatty Acid Synthetase ◽  
Acid Synthesis ◽  
Particulate Fraction

The synthesis of fatty acids from [14C]malonyl-CoA was studied with a high-speed particulate fraction from germinating pea (Pisum sativum). The variety used (Feltham First) produced mainly saturated fatty acids with palmitate (30–40%) and stearate (40–60%) predominating. Several palmitate-containing lipids stimulated overall synthesis and, in addition, increased the percentage of label in stearate. The production of stearate was severely inhibited by preincubation of the microsomal fraction with snake venom phospholipase A2 or by incubation with Rhizopus arrhizus lipase. Addition of a series of di-saturated phosphatidylcholines, with different acyl constituents, resulted in stimulation of overall fatty acid synthesis as well as an increase in the radiolabelling of the fatty acid two carbon atoms longer than the acyl chain added. This chain lengthening of fatty acids donated from phosphatidylcholine was due to the action of both fatty acid synthetase and palmitate elongase. The latter would utilize dipalmitoyl phosphatidylcholine and was sensitive to arsenite whereas fatty acid synthetase would use dilauroyl phosphatidylcholine and was sensitive to cerulenin. The results are discussed in relation to previous data obtained in vivo on plant fatty acid synthesis and current suggestions for the role of phosphatidylcholine in this process.

scholarly journals Molecular composition of the phosphatidylcholines produced by the phospholipid methylation pathway in rat brain in vivo

1987 ◽  
Vol 244 (2) ◽  
pp. 325-330 ◽  
Author(s):  
M B Lakher ◽  
R J Wurtman
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Brain ◽  
Saturated Fatty Acids ◽  
Molecular Composition ◽  
Methylation Pathway ◽  
The Brain ◽  
Lateral Cerebral Ventricle ◽  
Fatty Acid Compositions

We examined the formation in vivo of molecular subspecies of brain phosphatidylcholine (PC) via the phospholipid-methylation pathway. [3H]Methionine was infused into a lateral cerebral ventricle, and 3H-labelled PC was isolated from brains of rats 0.1-18 h after the infusions. Three major subspecies of this PC, differing in their fatty acid compositions, were separated on silver-impregnated t.l.c. plates, and the proportions of radioactivities in these three PC fractions were determined. The results indicate that newly-formed PC synthesized by methylation of phosphatidylethanolamine at 0.1 h after [3H]methionine contains a significantly higher proportion of polyunsaturated subspecies (i.e. those with six or four double bonds) than does PC obtained later times after injection of [3H]methionine. This change in the composition of 3H-labelled brain PC occurs gradually and is not due to an influx of radioactive PC from the periphery. Our data suggest that polyunsaturated PC (hexaenes and tetraenes) produced in the brain by methylation of phosphatidylethanolamine turns over faster than does that containing more-saturated fatty acids.

Hepatic regulation of fatty acid synthase by insulin and T3: evidence for T3 genomic and nongenomic actions

2008 ◽  
Vol 295 (4) ◽  
pp. E884-E894 ◽  
Author(s):  
Anne Radenne ◽  
Murielle Akpa ◽  
Caroline Martel ◽  
Sabine Sawadogo ◽  
Daniel Mauvoisin ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Kinase Inhibitor ◽  
Saturated Fatty Acids ◽  
Consensus Sequence ◽  
Transcriptional Level ◽  
Nongenomic Action ◽  
Key Enzyme ◽  
Phosphorylation Mechanism

Fatty acid synthase (FAS) is a key enzyme of hepatic lipogenesis responsible for the synthesis of long-chain saturated fatty acids. This enzyme is mainly regulated at the transcriptional level by nutrients and hormones. In particular, glucose, insulin, and T3 increase FAS activity, whereas glucagon and saturated and polyunsaturated fatty acids decrease it. In the present study we show that, in liver, T3 and insulin were able to activate FAS enzymatic activity, mRNA expression, and gene transcription. We localized the T3 response element (TRE) that mediates the T3 genomic effect, on the FAS promoter between −741 and −696 bp that mediates the T3 genomic effect. We show that both T3 and insulin regulate FAS transcription via this sequence. The TRE binds a TR/RXR heterodimer even in the absence of hormone, and this binding is increased in response to T3 and/or insulin treatment. The use of H7, a serine/threonine kinase inhibitor, reveals that a phosphorylation mechanism is implicated in the transcriptional regulation of FAS in response to both hormones. Specifically, we show that T3 is able to modulate FAS transcription via a nongenomic action targeting the TRE through the activation of a PI 3-kinase-ERK1/2-MAPK-dependent pathway. Insulin also targets the TRE sequence, probably via the activation of two parallel pathways: Ras/ERK1/2 MAPK and PI 3-kinase/Akt. Finally, our data suggest that the nongenomic actions of T3 and insulin are probably common to several TREs, as we observed similar effects on a classical DR4 consensus sequence.

scholarly journals MLK3 promotes metabolic dysfunction induced by saturated fatty acid-enriched diet

2013 ◽  
Vol 305 (4) ◽  
pp. E549-E556 ◽  
Author(s):  
Vidya Gadang ◽  
Rohit Kohli ◽  
Andriy Myronovych ◽  
David Y. Hui ◽  
Diego Perez-Tilve ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Saturated Fatty Acid ◽  
Saturated Fatty Acids ◽  
Low Grade ◽  
Metabolic Dysfunction ◽  
Jnk Activation

Saturated fatty acids activate the c-Jun NH2-terminal kinase (JNK) pathway, resulting in chronic low-grade inflammation and the development of insulin resistance. Mixed-lineage kinase 3 (MLK3) is a mitogen-activated protein kinase kinase kinase (MAP3K) that mediates JNK activation in response to saturated fatty acids in vitro; however, the exact mechanism for diet-induced JNK activation in vivo is not known. Here, we have used MLK3-deficient mice to examine the role of MLK3 in a saturated-fat diet model of obesity. MLK3-KO mice fed a high-fat diet enriched in medium-chain saturated fatty acids for 16 wk had decreased body fat compared with wild-type (WT) mice due to increased energy expenditure independently of food consumption and physical activity. Moreover, MLK3 deficiency attenuated palmitate-induced JNK activation and M1 polarization in bone marrow-derived macrophages in vitro, and obesity induced JNK activation, macrophage infiltration into adipose tissue, and expression of proinflammatory cytokines in vivo. In addition, loss of MLK3 improved insulin resistance and decreased hepatic steatosis. Together, these data demonstrate that MLK3 promotes saturated fatty acid-induced JNK activation in vivo and diet-induced metabolic dysfunction.

Dietary phytanic acid-induced changes in tissue fatty acid profiles in mice

2020 ◽  
pp. 1-3
Author(s):  
Tomonori Nakanishi ◽  
Kazuhiro Kagamizono ◽  
Sayaka Yokoyama ◽  
Ryoji Suzuki ◽  
Hiroyuki Sakakibara ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Phytanic Acid ◽  
Biological Activities ◽  
Saturated Fatty Acids ◽  
Fatty Acid Profiles ◽  
Tissue Fatty Acid ◽  
The Brain

Abstract The aims of this research communication were to investigate the in vivo tissue accumulation of phytanic acid (PA) and any changes in the tissue fatty acid profiles in mice. Previous in vitro studies have demonstrated that PA is a milk component with the potential to cause both beneficial effects on lipid and glucose metabolism and detrimental effects on neuronal cells. However, there is limited information about its in vivo actions. In this study, mice were fed diets containing either 0.00 or 0.05% 3RS, 7R, 11R-PA, which is the isomer found in milk and the human body. After 4 weeks, adipose tissue, liver and brain were harvested and their fatty acid profiles were determined by gas chromatographic analysis. The results showed that PA and its metabolite pristanic acid accumulated in the adipose tissue of PA-fed mice, and that dietary PA decreased the hepatic compositions of several saturated fatty acids such as palmitic acid while increasing the compositions of polyunsaturated fatty acids including linoleic acid and docosahexaenoic acid. However, dietary PA neither accumulated nor had a high impact on the fatty acid profile in the brain. These results suggested that dietary PA could exert its biological activities in adipose tissue and liver, although the brain is relatively less affected by dietary PA. These data provide a basis for understanding the in vivo physiological actions of PA.

Effect of fatty acid structure on esterification by the small intestine in vitro

1963 ◽  
Vol 204 (5) ◽  
pp. 821-824 ◽  
Author(s):  
Alvin M. Gelb ◽  
Jacques I. Kessler
Keyword(s):  
Fatty Acids ◽  
Small Intestine ◽  
Fatty Acid ◽  
Small Bowel ◽  
Chain Length ◽  
Degree Of Unsaturation ◽  
Fatty Acid Structure ◽  
Acid Structure

The effect of chain length and degree of unsaturation of fatty acids (FA) on in vitro esterification by slices of hamster small intestine was observed in a medium containing C14-labeled FA. After incubation, lipids were extracted and separated and the radioactivity in the esterified lipids was measured. Comparative experiments, in which results were expressed as per cent of substrate esterified per 100 mg tissue, indicate that for saturated FA, maximal esterification occurred with myristic acid, 14 carbons. As chain length was either increased or decreased, percentage esterification decreased. FA with 8 carbons or less were only minimally esterified. Among 18-carbon FA, two unsaturated bonds significantly decreased percentage esterification, although one unsaturated bond did not. These results suggest that, at least in vitro, the small bowel esterifies FA at varying rates depending upon chain length and degree of unsaturation. These differences are in the same direction as differences in absorption and partition of FA in vivo previously reported by others.

scholarly journals Fatty Acid Conjugation Leads to Length-Dependent Antimicrobial Activity of a Synthetic Antibacterial Peptide (Pep19-4LF)

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 844
Author(s):  
Philip Storck ◽  
Florian Umstätter ◽  
Sabrina Wohlfart ◽  
Cornelius Domhan ◽  
Christian Kleist ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Antimicrobial Activity ◽  
Fatty Acid ◽  
Antimicrobial Peptide ◽  
Saturated Fatty Acids ◽  
Resistant Bacteria ◽  
Bacterial Strains ◽  
High Antimicrobial Activity ◽  
Hydrophobic Motif

The increasing number of infections caused by multidrug-resistant bacteria requires an intensified search for new antibiotics. Pep19-4LF is a synthetic antimicrobial peptide (GKKYRRFRWKFKGKLFLFG) that was previously designed with the main focus on high antimicrobial activity. The hydrophobic motif, LFLFG, was found to be essential for antimicrobial activity. However, this motif shows several limitations such as aggregation in biological media, low solubility, and small yields in peptide synthesis. In order to obtain more appropriate peptide characteristics, the hydrophobic motif was replaced with fatty acids. For this purpose, a shortened variant of Pep19-4LF (Pep19-short; GKKYRRFRWKFKGK) was synthesized and covalently linked to saturated fatty acids of different chain lengths. The peptide conjugates were tested with respect to their antibacterial activity by microdilution experiments on different bacterial strains. The length of the fatty acid was found to be directly correlated to the antimicrobial activity up to an ideal chain length (undecanoic acid, C11:0). This conjugate showed high antimicrobial activity in absence of toxicity. Time–kill studies revealed a fast and bactericidal mode of action. Furthermore, the first in vivo experiments of the conjugate in rodents demonstrated pharmacokinetics appropriate for application as a drug. These results clearly indicate that the hydrophobic motif of the peptide can be replaced by a single fatty acid of medium length, simplifying the design of this antimicrobial peptide while retaining high antimicrobial activity in the absence of toxicity.

scholarly journals Stearoyl-CoA desaturase-1 impairs the reparative properties of macrophages and microglia in the brain

2020 ◽  
Vol 217 (5) ◽  
Author(s):  
Jeroen F.J. Bogie ◽  
Elien Grajchen ◽  
Elien Wouters ◽  
Aida Garcia Corrales ◽  
Tess Dierckx ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Ex Vivo ◽  
Saturated Fatty Acids ◽  
Monounsaturated Fatty Acids ◽  
Demyelinating Diseases ◽  
Efflux Transporter ◽  
Stearoyl Coa Desaturase ◽  
Phenotypic Shift ◽  
The Brain

Failure of remyelination underlies the progressive nature of demyelinating diseases such as multiple sclerosis. Macrophages and microglia are crucially involved in the formation and repair of demyelinated lesions. Here we show that myelin uptake temporarily skewed these phagocytes toward a disease-resolving phenotype, while sustained intracellular accumulation of myelin induced a lesion-promoting phenotype. This phenotypic shift was controlled by stearoyl-CoA desaturase-1 (SCD1), an enzyme responsible for the desaturation of saturated fatty acids. Monounsaturated fatty acids generated by SCD1 reduced the surface abundance of the cholesterol efflux transporter ABCA1, which in turn promoted lipid accumulation and induced an inflammatory phagocyte phenotype. Pharmacological inhibition or phagocyte-specific deficiency of Scd1 accelerated remyelination ex vivo and in vivo. These findings identify SCD1 as a novel therapeutic target to promote remyelination.

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