scholarly journals Effect of 5-trans isomer of arachidonic acid on model liposomal membranes studied by a combined simulation and experimental approach

2018 ◽  
Author(s):  
Ioanna Tremi ◽  
Dimitrios Anagnostopoulos ◽  
Ellas Spyratou ◽  
Paraskevi Gkeka ◽  
Alexandros G. Georgakilas ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Free Radicals ◽  
Lipid Bilayers ◽  
Unsaturated Fatty Acids ◽  
Md Simulations ◽  
Γ Irradiation ◽  
Physiological Concentration ◽  
Increased Risk ◽  
Average Size

AbstractUnsaturated fatty acids are found in humans predominantly in the cis configuration. Fatty acids in the trans configuration are primarily the result of human processing (trans fats), but can also be formed endogenously by radical stress. The cis-trans isomerization of fatty acids by free radicals could be connected to several pathologies. Trans fats have been linked to an increased risk of coronary artery disease; however, the reasons for the resulting pathogenesis remain unclear. Here, we investigate the effect of a mono trans isomer of arachidonic acid (C20:4-5trans,8cis,11cis,14cis) produced by free radicals in physiological concentration on a model erythrocyte membrane using a combined experimental and theoretical approach. Molecular Dynamics (MD) simulations of two model lipid bilayers containing arachidonic acid and its 5-trans isomer in 3% mol. were carried out for this purpose. The 5-trans isomer formation in the phospholipids was catalyzed by HOCH2CH2S• radicals, generated from the corresponding thiol by γ-irradiation, in multilamellar vesicles (MLVs) of SAPC. Large unilamellar vesicles were made by the extrusion method (LUVET) as a biomimetic model for cis-trans isomerization. Atomic Force Microscopy and Dynamic Light Scattering were used to measure the average size, morphology, and the z-potential of the liposomes. Both results from MD simulations and experiments are in agreement and indicate that the two model membranes display different physicochemical properties in that the bilayers containing the trans fatty acids were more ordered and more rigid than those containing solely the cis arachidonic acid. Correspondingly, the average size of the liposomes containing trans isomers was smaller than the ones without.

β-Subunit–Dependent Modulation of hSlo BK Current by Arachidonic Acid

2007 ◽  
Vol 97 (1) ◽  
pp. 62-69 ◽  
Author(s):  
X. Sun ◽  
D. Zhou ◽  
P. Zhang ◽  
E. G. Moczydlowski ◽  
G. G. Haddad
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Conformational Changes ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Nordihydroguaiaretic Acid ◽  
Bk Channels ◽  
Bk Channel ◽  
Β Subunit ◽  
Α Subunit

In this study, we examined the effect of arachidonic acid (AA) on the BK α-subunit with or without β-subunits expressed in Xenopus oocytes. In excised patches, AA potentiated the hSlo-α current and slowed inactivation only when β2/3 subunit was co-expressed. The β2-subunit–dependent modulation by AA persisted in the presence of either superoxide dismutase or inhibitors of AA metabolism such as nordihydroguaiaretic acid and eicosatetraynoic acid, suggesting that AA acts directly rather than through its metabolites. Other cis unsaturated fatty acids (docosahexaenoic and oleic acid) also enhanced hSlo-α + β2 currents and slowed inactivation, whereas saturated fatty acids (palmitic, stearic, and caprylic acid) were without effect. Pretreatment with trypsin to remove the cytosolic inactivation domain largely occluded AA action. Intracellularly applied free synthetic β2-ball peptide induced inactivation of the hSlo-α current, and AA failed to enhance this current and slow the inactivation. These results suggest that AA removes inactivation by interacting, possibly through conformational changes, with β2 to prevent the inactivation ball from reaching its receptor. Our data reveal a novel mechanism of β-subunit–dependent modulation of BK channels by AA. In freshly dissociated mouse neocortical neurons, AA eliminated a transient component of whole cell K+ currents. BK channel inactivation may be a specific mechanism by which AA and other unsaturated fatty acids influence neuronal death/survival in neuropathological conditions.

scholarly journals Modern fat technology: what is the potential for heart health?

2005 ◽  
Vol 64 (3) ◽  
pp. 379-386 ◽  
Author(s):  
J. E. Upritchard ◽  
M. J. Zeelenberg ◽  
H. Huizinga ◽  
P. M. Verschuren ◽  
E. A. Trautwein
Keyword(s):  
Metabolic Syndrome ◽  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Disease Risk ◽  
Saturated Fatty Acids ◽  
Saturated Fat ◽  
Blood Cholesterol ◽  
Medical Community ◽  
The Metabolic Syndrome ◽  
Increased Risk

Saturated andtrans-fatty acids raise total cholesterol and LDL-cholesterol and are known to increase the risk of CHD, while dietary unsaturated fatty acids play important roles in maintaining cardiovascular health. Replacing saturated fats with unsaturated fats in the diet often involves many complex dietary changes. Modifying the composition of foods high in saturated fat, particularly those foods that are consumed daily, can help individuals to meet the nutritional targets for reducing the risk of CHD. In the 1960s the Dutch medical community approached Unilever about the technical feasibility of producing margarine with a high-PUFA and low-saturated fatty acid composition. Margarine is an emulsion of water in liquid oil that is stabilised by a network of fat crystals. In-depth expertise of fat crystallisation processes allowed Unilever scientists to use a minimum of solid fat (saturated fatty acids) to structure a maximum level of PUFA-rich liquid oil, thus developing the first blood-cholesterol-lowering product, Becel. Over the years the composition of this spread has been modified to reflect new scientific findings and recommendations. The present paper will briefly review the developments in fat technology that have made these improvements possible. Unilever produces spreads that are low in total fat and saturated fat, virtually free oftrans-fatty acids and with levels ofn-3 andn-6 PUFA that are in line with the latest dietary recommendations for the prevention of CHD. Individuals with the metabolic syndrome have a 2–4-fold increased risk of developing CHD; therefore, these spreads could make a contribution to CHD prevention in this group. In addition, for individuals with the metabolic syndrome the spreads could be further modified to address their unique dyslipidaemia, i.e. elevated blood triacylglycerols and low HDL-cholesterol. Research conducted in the LIPGENE study and other dietary intervention studies will deliver the scientific evidence to justify further modifications in the composition of spreads that are healthy for the heart disease risk factors associated with the metabolic syndrome.

scholarly journals Unsaturated Fatty Acids Phosphorylate and Destabilize ABCA1 through a Phospholipase D2 Pathway

2005 ◽  
Vol 280 (43) ◽  
pp. 35896-35903 ◽  
Author(s):  
Yutong Wang ◽  
John F. Oram
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
Cultured Cells ◽  
Saturated Fatty Acids ◽  
Density Lipoprotein ◽  
Serine Phosphorylation ◽  
Protein Levels ◽  
Increased Risk ◽  
Abca1 Protein

Abnormal high density lipoprotein (HDL) metabolism among patients with diabetes and insulin resistance may contribute to their increased risk of atherosclerosis. ATP-binding cassette transporter ABCA1 mediates the transport of cholesterol and phospholipids from cells to HDL apolipoproteins and thus modulates HDL levels and atherogenesis. Unsaturated fatty acids, which are elevated in diabetes, impair the ABCA1 pathway in cultured cells by destabilizing ABCA1 protein. Here we examined the cellular pathway that mediates the ABCA1 destabilizing effects of fatty acids. The long-chain acyl-CoA synthetase inhibitor triacsin C completely reversed fatty acid-induced ABCA1 destabilization, indicating that fatty acids need to be activated to their CoA derivatives to enhance ABCA1 degradation. Unsaturated but not saturated fatty acids stimulated phospholipase D (PLD) activity, the PLD inhibitor 1-butanol prevented the unsaturated fatty acid-induced reduction in ABCA1 levels, and the PLD2 activator mastoparan markedly reduced ABCA1 protein levels, implicating a role for PLD2 in the ABCA1 destabilizing effects of fatty acids. Unsaturated fatty acids and mastoparan increased phosphorylation of ABCA1 serines. PLD2 small interfering RNA abolished the ability of unsaturated fatty acids to inhibit lipid transport activity, to reduce protein levels, and to increase serine phosphorylation of ABCA1. The diacylglycerol analog oleoylacetylglycerol also reduced ABCA1 protein levels and increased its serine phosphorylation, suggesting that PLD2-generated diacylglycerols promote the destabilizing phosphorylation of ABCA1. These data provide evidence that intracellular unsaturated acyl-CoA derivatives destabilize ABCA1 by activating a PLD2 signaling pathway.

scholarly journals Perbedaan Rasio Kolesterol Total/ HDL Kelompok Kontrol dan Kelompok Diet Tinggi Minyak Sawit pada Tikus Wistar

2014 ◽  
Vol 3 (3) ◽  
Author(s):  
Yelsa Yulanda Putri ◽  
Ellyza Nasrul ◽  
Susila Sastri
Keyword(s):  
Cardiovascular Disease ◽  
Fatty Acids ◽  
Total Cholesterol ◽  
Palm Oil ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Diet Group ◽  
Control Group ◽  
Increased Risk ◽  
Post Test

AbstrakRasio kolesterol total/ HDL merupakan variabel lipoprotein terbaik dalam memprediksi risiko penyakit kardiovaskular. Peningkatan risiko penyakit kardiovaskular dapat disebabkan oleh tingginya kadar kolesterol serum. Minyak sawit mengandung 50% asam lemak jenuh dan 50% asam lemak tidak jenuh. Tujuan penelitian ini adalah mengetahui perbedaan rasio kolesterol total/ HDL antara kelompok kontrol dengan kelompok diet tinggi minyak sawit pada tikus. Penelitian ini adalah eksperimental dengan pendekatan post test only control group design. Sampel penelitian terdiri dari 10 ekor tikus Wistar jantan yang dibagi menjadi kelompok kontrol (K) dan kelompok perlakuan (P). Diet tinggi minyak sawit (minyak sawit 42.5%, 3ml/hari) diberikan pada kelompok P selama empat minggu. Analisis data menggunakan uji t independent. Hasil penelitian menunjukkan terdapat perbedaan peningkatan yang tidak bermakna antara kelompok P dan kelompok K pada rerata kolesterol, yaitu 63.66±9.9(P) 57.39±3.28(K) (p>0.05), rerata HDL 19.44±3.99(P) 17.64±2.00(K) (p>0.05), dan rerata rasio kolesterol total/ HDL 3.26±0.24 (P) 3.31±0.32 (K) (p>0.05). Kesimpulan penelitian ini adalah kadar kolesterol total, HDL, dan rasio kolesterol total/ HDL pada kelompok kontrol dan kelompok diet tinggi minyak sawit tidak berbeda.Kata kunci: diet tinggi minyak sawit, kolesterol, HDL, rasio kolesterol/ HDLAbstractThe ratio of total cholesterol/ HDL is the lipoprotein variables best predict the risk of cardiovascular disease . The increased risk of cardiovascular disease can be caused by high levels of cholesterol exciting. Palm oil contains 50% saturated fatty acids and 50% unsaturated fatty acids. The purpose of this study was to know the differences ratio of total cholesterol/ HDL between the control group and high palm oil diet group in rats. This research was experimental with post-test only control group. The study sample consisted of 10 male Wistar rats were divided into control group (K) and treated group (P). High-palm oil diet (50% palm oil, 3ml/day) was given to the group P for four weeks. Analysis of data using independent t test. The results showed there were no significant differences in improvement between groups P and groups K in mean cholesterol, 63.66 ± 9.9 (P) 57.39 ± 3.28 (K) in (p> 0.05), mean HDL 19.44 ± 3.99 (P) 17.64 ± 2.00 (K) in (p> 0.05), and the mean ratio of total cholesterol/ HDL 3.26 ± 0.24 (P) 3.31 ± 0.32 (K) in (p>0.05). The conclusion of this study is total cholesterol, HDL, and the ratio of total cholesterol/ HDL in the control group and the high palm oil diet group did not differ.Keywords: high palm oil diet, cholesterol, HDL, ratio of cholesterol/HDL

scholarly journals Eicosanoid turnover in GtoPdb v.2021.3

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Angelo A. Izzo ◽  
Jane A. Mitchell
Keyword(s):  
Oxidative Stress ◽  
Fatty Acids ◽  
Arachidonic Acid ◽  
Cytochrome P450 ◽  
Free Radicals ◽  
Phospholipase A2 ◽  
Oxidative Metabolism ◽  
Molecular Targets ◽  
Structural Analogues ◽  
Biomarkers Of Oxidative Stress

Eicosanoids are 20-carbon fatty acids, where the usual focus is the polyunsaturated analogue arachidonic acid and its metabolites. Arachidonic acid is thought primarily to derive from phospholipase A2 action on membrane phosphatidylcholine, and may be re-cycled to form phospholipid through conjugation with coenzyme A and subsequently glycerol derivatives. Oxidative metabolism of arachidonic acid is conducted through three major enzymatic routes: cyclooxygenases; lipoxygenases and cytochrome P450-like epoxygenases, particularly CYP2J2. Isoprostanes are structural analogues of the prostanoids (hence the nomenclature D-, E-, F-isoprostanes and isothromboxanes), which are produced in the presence of elevated free radicals in a non-enzymatic manner, leading to suggestions for their use as biomarkers of oxidative stress. Molecular targets for their action have yet to be defined.

Cyclopropane ring formation in membrane lipids of bacteria

1997 ◽  
Vol 61 (4) ◽  
pp. 429-441 ◽  
Author(s):  
D W Grogan ◽  
J E Cronan
Keyword(s):  
Fatty Acids ◽  
Double Bond ◽  
Lipid Bilayers ◽  
Unsaturated Fatty Acids ◽  
Membrane Lipids ◽  
Cyclopropane Ring ◽  
Saturated Fatty Acids ◽  
Physiological Role ◽  
Phospholipid Bilayer ◽  
Valuable Insight

It has been known for several decades that cyclopropane fatty acids (CFAs) occur in the phospholipids of many species of bacteria. CFAs are formed by the addition of a methylene group, derived from the methyl group of S-adenosylmethionine, across the carbon-carbon double bond of unsaturated fatty acids (UFAs). The C1 transfer does not involve free fatty acids or intermediates of phospholipid biosynthesis but, rather, mature phospholipid molecules already incorporated into membrane bilayers. Furthermore, CFAs are typically produced at the onset of the stationary phase in bacterial cultures. CFA formation can thus be considered a conditional, postsynthetic modification of bacterial membrane lipid bilayers. This modification is noteworthy in several respects. It is catalyzed by a soluble enzyme, although one of the substrates, the UFA double bond, is normally sequestered deep within the hydrophobic interior of the phospholipid bilayer. The enzyme, CFA synthase, discriminates between phospholipid vesicles containing only saturated fatty acids and those containing UFAs; it exhibits no affinity for vesicles of the former composition. These and other properties imply that topologically novel protein-lipid interactions occur in the biosynthesis of CFAs. The timing and extent of the UFA-to-CFA conversion in batch cultures and the widespread distribution of CFA synthesis among bacteria would seem to suggest an important physiological role for this phenomenon, yet its rationale remains unclear despite experimental tests of a variety of hypotheses. Manipulation of the CFA synthase of Escherichia coli by genetic methods has nevertheless provided valuable insight into the physiology of CFA formation. It has identified the CFA synthase gene as one of several rpoS-regulated genes of E. coli and has provided for the construction of strains in which proposed cellular functions of CFAs can be properly evaluated. Cloning and manipulation of the CFA synthase structural gene have also enabled this novel but extremely unstable enzyme to be purified and analyzed in molecular terms and have led to the identification of mechanistically related enzymes in clinically important bacterial pathogens.

ChemInform Abstract: Biomimetic Thiyl Radical Chemistry by γ-Irradiation of Micelles and Vesicles Containing Unsaturated Fatty Acids

ChemInform ◽  
2014 ◽  
Vol 45 (23) ◽  
pp. no-no
Author(s):  
Chryssostomos Chatgilialoglu ◽  
Carla Ferreri ◽  
Ioannis N. Lykakis ◽  
Branka Mihaljevic
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Thiyl Radical ◽  
Γ Irradiation ◽  
Radical Chemistry
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