Abstract 13688: Long Chain Fatty Acid Composition Modulated by Elovl6 Plays a Critical Role in Vascular Smooth Muscle Cell Proliferation and Neointimal Formation

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Hiroki Matsui ◽  
Hiroaki Sunaga ◽  
Saki Anjo ◽  
Mas Rizky A Syamsunarno ◽  
Tatsuya Iso ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Cell Proliferation ◽  
Smooth Muscle ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Neointimal Formation ◽  
Fa Composition ◽  
And Migration ◽  
Long Chain

Introduction: Elovl6, the elongase of long chain fatty acids 6, is a rate-limiting enzyme catalyzing the elongation of saturated and monounsaturated fatty acids with 12, 14 and 16 carbons. Our recent study showed that Elovl6 is abundantly expressed in vascular smooth muscle cells (VSMC) and is dramatically induced in neointima in rat. Hypothesis: In this study, we tested the hypothesis that changes of fatty acid (FA) composition by Elovl6 affects the proliferation of VSMC and contributes to neointimal formation in vivo. Methods and Results: Abundant Elovl6 expression was observed in mice femoral artery at 2 weeks after wire-injury and in intimal thickening lesion of human coronary artery. Furthermore, Elovl6 mRNA expression in cultured human aortic SMC (HASMC) was significantly increased by platelet-derived growth factor-BB (2.4-fold, p<0.05) or hypoxic stress (6.7-fold, p<0.01) in a dose- or time-dependent manner. Furthermore, knockdown of Elovl6 expression in HASMC markedly suppressed cell proliferation (16%, relative to control, p<0.01) and migration, concomitantly induced the expression of p21 and phospholyration of AMP-activated protein kinase (p-AMPK) and suppressed mTOR expression. Consistent with in vitro data, Elovl6 deficient (Elovl6 -/-) mice at 2 weeks after injury showed markedly suppressed neointimal formation compared with wild-type (WT) mice (intima/media ratio: WT, 1.4 ± 0.6; Elovl6 -/-, 0.5 ± 0.2; Ki67-positive cells: 0.2 fold relative to WT mice; N=6-7, p<0.05). Of an importance, analysis of FA composition in SMC isolated from Elovl6 -/- mice showed that high levels of palmitic acid and low levels of oleic acid were detected as compared with that from WT mice. In accordance with these results, exogenous treatment of palmitic acid in SMC substantially suppressed cell proliferation (42%, relative to control, p<0.01) and migration, induced p21 and p-AMPK expressions. Conversely, these effects were blunted by adenovirus-mediated Elovl6-overexpression or exogenous oleic acid treatment. Conclusions: Collectively, our study demonstrates that proliferation of VSMC is tightly regulated by FA composition modulated by Elvlo6, offering a novel therapeutic target for arterial proliferative disease in which VSMC plays a key role.

scholarly journals The binding of L-tryptophan to serum albumins in the presence of non-esterified fatty acids

1975 ◽  
Vol 146 (3) ◽  
pp. 653-658 ◽  
Author(s):  
V J Cunningham ◽  
L Hay ◽  
H B Stoner
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Lauric Acid ◽  
Human Albumin ◽  
Acid Sites ◽  
Chain Fatty Acid ◽  
Serum Albumins ◽  
Long Chain

Bovine, human and rat serum albumins were defatted and palmitic acid, oleic acid and lauric acid added in various molar ratios. The binding of L-tryptophan to these albumins was measured at 20 degrees C in a 0.138 M salt solution at pH 7.4, by using an ultrafiltration technique, and analysed in terms of n, the number of available tryptophan-binding sites per albumin molecule, with apparent association constant, k. 2. n and k were 0.90 and 2.3}10(-4)M(minus-1) respectively for defatted bovine serum albumin and 0.87 and 9.7}10(-3)M(-minus-1) for human albumin. Addition of palmitic acid did not decrease n until the molar ratio, fatty acid/bovine albumin, approached and exceeded 2. The decrease in k was small and progressive. In contrast, lauric caused a marked decrease in n and k at ratios as low as 0.5. A similar distinction between the effects on n of palmitic acid and oleic acid and those of lauric acid was seen for human albumin. k for human albumin was not significantly affected by fatty acids under the conditions studied. 3. It is concluded that primary long-chain fatty acid sites interact only weakly with the tryptophan site on albumin and that inhibition of tryptophan binding occurs when secondary long-chain sites are occupied. Primary medium-chain fatty acid sites are distinct from primary long-chain sites but may be grouped with secondary long-chain sites. 4. The relationship between free and bound tryptophan in samples of rat plasma (Stoner et al., 1975) is discussed in terms of a similar but limited study of rat albumin.

scholarly journals High rates of [1-14C]acetate incorporation into the lipid of isolated spinach chloroplasts

1976 ◽  
Vol 158 (3) ◽  
pp. 593-601 ◽  
Author(s):  
P G Roughan ◽  
C R Slack ◽  
R Holland
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Free Fatty Acids ◽  
Acid Synthesis ◽  
Polar Lipids ◽  
Acetate Incorporation ◽  
Spinach Chloroplasts ◽  
Triton X

Spinach chloroplasts, isolated by techniques yielding preparations with high O2- evolving activity, showed rates of light-dependent acetate incorporation into lipids 3-4 fold higher than any previously reported. Incorporation rates as high as 500 nmol of acetate/h per mg of chlorophyll were measured in buffered sorbitol solutions containing only NaHCO3 and [1-14C]acetate, and as high as 800 nmol/h per mg of chlorophyll when 0.13 mM-Triton X-100 was also included in the reaction media. The fatty acids synthesized were predominantly oleic (70-80% of the total fatty acid radioactivity) and palmitic (20-25%) with only minor amounts (1-5%) of linoleic acid. Linolenic acid synthesis was not detected in the system in vitro. Free fatty acids accounted for 70-90% of the radioactivity incorporated and the remainder was shared fairly evenly between 1,2-diacylglycerols and polar lipids. Oleic acid constituted 80-90% of the free fatty acids synthesized, but the diacylglycerols and polar lipids contained slightly more palmitic acid than oleic acid. Triton X-100 stimulated the synthesis of diacylglycerols 3-6 fold, but stimulated free fatty acid synthesis only 1-1.5-fold. Added glycerol 1-phosphate stimulated both the synthesis of diacylglycerols and palmitic acid relative to oleic acid, but did not increase acetate incorporation into total chloroplast lipids. CoA and ATP, when added separately, stimulated acetate incorporation into chloroplast lipids to variable extents and had no effect on the types of lipid synthesized, but when added together resulted in 34% of the incorporated acetate appearing in long-chain acyl-CoA. Pyruvate was a much less effective precursor of chloroplast fatty acids than was acetate.

scholarly journals Improved Method for Gas Chromatographic–Mass Spectrometric Analysis of 1-13C-labeled Long-Chain Fatty Acids in Plasma Samples

2002 ◽  
Vol 48 (6) ◽  
pp. 906-912 ◽  
Author(s):  
José M Hernández-Pérez ◽  
Eduard Cabré ◽  
Lourdes Fluvià ◽  
Ágata Motos ◽  
Cruz Pastor ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Isotopic Ratio ◽  
Internal Standard ◽  
Mass Spectrometric ◽  
Spectrometric Analysis ◽  
Calibration Curves ◽  
Long Chain ◽  
Chromatographic Mass

Abstract Background: Gas chromatographic–mass spectrometric (GC/MS) tracking of stable-isotope-labeled substrates is useful in metabolic studies. However, GC/MS analysis of long-chain fatty acid methyl esters yields results that mostly depend on their concentration in the system. We describe a protocol aimed to obviate this and other drawbacks in plasma [1-13C]palmitic and [1-13C]oleic acid measurements. Methods: Lipoproteins were separated by sequential ultracentrifugation. Free or esterified heptadecanoic acid was used as internal standard. Fatty acids were derivatized to trimethylsilyl (TMS) esters. GC separation was in isothermal mode at 210 °C for 27 min. For both TMS-palmitate and TMS-oleate, M and [M + 1] signals were simultaneously acquired with a dual acquisition program in single-ion monitoring mode. Calibration mixtures containing increasing amounts of labeled fatty acids were prepared gravimetrically to construct calibration curves for isotopic enrichment. Likewise, five calibration curves (for increasing concentrations) were constructed for each fatty acid; this allowed selection of the most appropriate curve for the concentration in a plasma sample. Results: Oleic acid-TMS ester was clearly separated from that of its stereoisomer, elaidic acid. Within a 10-fold concentration range, the isotopic ratio was independent on the amount of the analyte in the sample, with a maximum uncertainty of 0.34% in terms of molar percent excess. In addition, the within- and between-day imprecision (CV) of the method was &lt;1%. Conclusion: Results obtained with this method are independent of concentration and sufficiently precise for tracking 1-13C-labeled palmitic and oleic acids in biological samples

scholarly journals Peroxisome-proliferator-activated receptor δ mediates the effects of long-chain fatty acids on post-confluent cell proliferation

2000 ◽  
Vol 350 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Chantal JEHL-PIETRI ◽  
Claire BASTIE ◽  
Isabelle GILLOT ◽  
Serge LUQUET ◽  
Paul A. GRIMALDI
Keyword(s):  
Fatty Acids ◽  
Cell Proliferation ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Ectopic Expression ◽  
Peroxisome Proliferator ◽  
Long Chain Fatty Acids ◽  
Control Of Gene Expression ◽  
Long Chain ◽  
Chain Fatty Acids

Nutritional long-chain fatty acids control adipose tissue mass by regulating the number and the size of adipocytes. It is now established that peroxisome-proliferator-activated receptors (PPARs) play crucial functions in the control of gene expression and the level of cell differentiation. PPARγ, which is activated by specific prostanoids, is a key factor in activating terminal differentiation and adipogenesis. We have recently demonstrated that PPARδ, once activated by fatty acids, drives the expression of a limited set of genes, including that encoding PPARγ, thereby inducing adipose differentiation. Thus far, the mechanism of action of fatty acids in the control of preadipocyte proliferation has remained unknown. We show here that PPARδ is directly implicated in fatty acid-induced cell proliferation. Ectopic expression of PPARδ renders 3T3C2 cells capable of responding to treatment with long-chain fatty acids by a resumption of mitosis, and this effect is limited to a few days after confluence. This response is restricted to PPARδ activators and, for fatty acids, takes place within the range of concentrations found to trigger differentiation of preadipocytes both in vitro and in vivo. Furthermore, the use of a mutated inactive PPARδ demonstrated that transcriptional activity of the nuclear receptor is required to mediate fatty acid-induced proliferation. These data demonstrate that PPARδ, as a transcription factor, is directly implicated in fatty acid-induced proliferation, and this could explain the hyperplastic development of adipose tissue that occurs in high-fat-fed animals.

Chloroacetamide Mode of Action, I: Inhibition of Very Long Chain Fatty Acid Synthesis in Scenedesmus acutus

1998 ◽  
Vol 53 (11-12) ◽  
pp. 995-1003 ◽  
Keyword(s):  
Fatty Acids ◽  
Cell Wall ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Acid Synthesis ◽  
Resistant Cell Line ◽  
Long Chain Fatty Acids ◽  
Scenedesmus Acutus ◽  
Long Chain ◽  
Chain Fatty Acids

Abstract Herbicidal chloroacetamides cause a very sensitive inhibition of fatty acid incorporation into an insoluble cell wall fraction of Scenedesmus acutus. The molecular basis was investigated in more detail. After incubation of the algae with [14C]oleic acid and saponification, the remaining pellet was solubilized and fractionated consecutively with chloroform / methanol, phosphate buffer, amylase, pronase, and finally with dioxane/HCl. By acid hydrolysis in dioxane a part of the cell wall residue was solubilized showing inhibition of exogenously applied oleic acid and other labelled precursors such as stearic acid, palmitic acid, and acetate. After extraction of this dioxane-soluble subfraction with hexane, HPLC could separate labelled metabolites less polar than oleic acid. T heir formation was completely inhibited by chloroacetam ides, e.g. 1 μᴍ metazachlor. This effect was also observed with the herbicidally active 5-enantiomer of metolachlor while the inactive R-enantiomer had no influence. These strongly inhibited metabolites could be characterized by radio-HPLC /MS as very long chain fatty acids (VLCFAs) with a carbon chain between 20 and 26. Incubating am etazachlor-resistant cell line of S. acutus (Mz-1) with [14C]oleic acid, V LCFA s could not be detected in the dioxane/ HCl-subfraction. Furthermore, comparing the presence of endogenous fatty acids in wildtype and mutant Mz-1 the VLCFA content of the mutant is very low, while the content of long chain fatty acids (C16 -18) is increased, particularly oleic acid. Obviously, the phytotoxicity of chloroacetam ides in S. acutus is due to inhibition of VLCFA synthesis. The resistance of the mutant to metazachlor has a bearing on the higher amount of long chain fatty acids replacing the missing VLCFAs in essential membranes or cell wall components.

THE BIOSYNTHESIS OF LONG-CHAIN FATTY ACIDS IN THE DEVELOPING CASTOR BEAN

1965 ◽  
Vol 43 (1) ◽  
pp. 49-62 ◽  
Author(s):  
D. T. Canvin
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Ricinoleic Acid ◽  
Castor Bean ◽  
Diethyl Malonate ◽  
Water Soluble ◽  
Long Chain Fatty Acids ◽  
Long Chain ◽  
Chain Fatty Acids

Acetate-1-C14 and acetate-2-C14 were supplied to slices of developing castor bean endosperm. The molecules were extensively incorporated into long-chain fatty acids, water-soluble compounds, and protein. Oleic acid was the fatty acid initially labelled from acetate and it was the precursor of ricinoleic acid. Aerobic conditions were required for the formation of oleic acid and for the conversion of oleic acid to ricinoleic acid. Under anaerobic conditions the incorporation of acetate carbon into fatty acids was inhibited more than 90% and almost all of the C14 was found in stearic and palmitic acids. Stearic acid appeared to be formed first and palmitic acid appeared to be derived from it through a shortening of the chain. The position of linoleic acid in the fatty acid interconversions was not clear except that it was not a free intermediate in the conversion of oleic acid to ricinoleic acid.Malonate-C14 was only absorbed slightly by the tissue and although absorption could be increased by the use of diethyl malonate the metabolism of the compound was not facilitated. Because of its poor utilization by the tissue the role of malonate in long-chain fatty acid synthesis in this tissue could not be ascertained.

scholarly journals Metabolic fate of oleic acid, palmitic acid and stearic acid in cultured hamster hepatocytes

1996 ◽  
Vol 316 (3) ◽  
pp. 847-852 ◽  
Author(s):  
Jennifer S. BRUCE ◽  
Andrew M. SALTER
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Stearic Acid ◽  
Palmitic Acid ◽  
Ketone Bodies ◽  
Plasma Cholesterol ◽  
Saturated Fatty Acids ◽  
Metabolic Fate ◽  
Cellular Phospholipid

Unlike other saturated fatty acids, dietary stearic acid does not appear to raise plasma cholesterol. The reason for this remains to be established, although it appears that it must be related to inherent differences in the metabolism of the fatty acid. In the present study, we have looked at the metabolism of palmitic acid and stearic acid, in comparison with oleic acid, by cultured hamster hepatocytes. Stearic acid was taken up more slowly and was poorly incorporated into both cellular and secreted triacylglycerol. Despite this, stearic acid stimulated the synthesis and secretion of triacylglycerol to the same extent as the other fatty acids. Incorporation into cellular phospholipid was lower for oleic acid than for palmitic acid and stearic acid. Desaturation of stearic acid, to monounsaturated fatty acid, was found to be greater than that of palmitic acid. Oleic acid produced from stearic acid was incorporated into both triacylglycerol and phospholipid, representing 13% and 6% respectively of the total after a 4 h incubation. Significant proportions of all of the fatty acids were oxidized, primarily to form ketone bodies, but by 8 h more oleic acid had been oxidized compared with palmitic acid and stearic acid.

scholarly journals Quantitative Trait Loci and Candidate Genes Associated with Fatty Acid Content of Watermelon Seed

2014 ◽  
Vol 139 (4) ◽  
pp. 433-441 ◽  
Author(s):  
Geoffrey Meru ◽  
Cecilia McGregor
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Palmitic Acid ◽  
Acid Composition ◽  
Seed Oil ◽  
Unsaturated Fatty Acids ◽  
Watermelon Seed

Seed oil percentage (SOP) and fatty acid composition of watermelon (Citrullus lanatus) seeds are important traits in Africa, the Middle East, and Asia where the seeds provide a significant source of nutrition and income. Oil yield from watermelon seed exceeds 50% (w/w) and is high in unsaturated fatty acids, a profile comparable to that of sunflower (Helianthus annuus) and soybean (Glycine max) oil. As a result of novel non-food uses of plant-derived oils, there is an increasing need for more sources of vegetable oil. To improve the nutritive value of watermelon seed and position watermelon as a potential oil crop, it is critical to understand the genetic factors associated with SOP and fatty acid composition. Although the fatty acid composition of watermelon seed is well documented, the underlying genetic basis has not yet been studied. Therefore, the current study aimed to elucidate the quality of watermelon seed oil and identify genomic regions and candidate genes associated with fatty acid composition. Seed from an F2 population developed from a cross between an egusi type (PI 560023), known for its high SOP, and Strain II (PI 279261) was phenotyped for palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), and linoleic acid (18:2). Significant (P < 0.05) correlations were found between palmitic and oleic acid (0.24), palmitic and linoleic acid (–0.37), stearic and linoleic acid (–0.21), and oleic and linoleic acid (–0.92). A total of eight quantitative trait loci (QTL) were associated with fatty acid composition with a QTL for oleic and linoleic acid colocalizing on chromosome (Chr) 6. Eighty genes involved in fatty biosynthesis including those modulating the ratio of saturated and unsaturated fatty acids were identified from the functionally annotated genes on the watermelon draft genome. Several fatty acid biosynthesis genes were found within and in close proximity to the QTL identified in this study. A gene (Cla013264) homolog to fatty acid elongase (FAE) was found within the 1.5-likelihood-odds (LOD) interval of the QTL for palmitic acid (R2 = 7.6%) on Chr 2, whereas Cla008157, a homolog to omega-3-fatty acid desaturase and Cla008263, a homolog to FAE, were identified within the 1.5-LOD interval of the QTL for palmitic acid (R2 = 24.7%) on Chr 3. In addition, the QTL for palmitic acid on Chr 3 was located ≈0.60 Mbp from Cla002633, a gene homolog to fatty acyl- [acyl carrier protein (ACP)] thioesterase B. A gene (Cla009335) homolog to ACP was found within the flanking markers of the QTL for oleic acid (R2 = 17.9%) and linoleic acid (R2 = 21.5%) on Chr 6, whereas Cla010780, a gene homolog to acyl-ACP desaturase was located within the QTL for stearic acid (R2 = 10.2%) on Chr 7. On Chr 8, another gene (Cla013862) homolog to acyl-ACP desaturase was found within the 1.5-LOD interval of the QTL for oleic acid (R2 = 13.5%). The genes identified in this study are possible candidates for the development of functional markers for application in marker-assisted selection for fatty acid composition in watermelon seed. To the best of our knowledge, this is the first study that aimed to elucidate genetic control of the fatty acid composition of watermelon seed.

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