scholarly journals Characterization of plasma unsaturated lysophosphatidylcholines in human and rat

1999 ◽  
Vol 345 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Martine CROSET ◽  
Nicole BROSSARD ◽  
Anne POLETTE ◽  
Michel LAGARDE
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Rat Plasma ◽  
Arachidonic Acid Content ◽  
Tissue Uptake ◽  
Membrane Phospholipids ◽  
Esterified Fatty Acids ◽  
The Brain ◽  
Group Shift

Unsaturated lysophosphatidylcholines (lysoPtdCho) bound to albumin circulate in blood plasma and seem to be a novel transport system for carrying polyunsaturated fatty acids (PUFA) to tissues that are rich in these fatty acids, such as the brain. The potential of these lysoPtdCho as a significant source of PUFA for cells has been assessed by comparing their plasma concentration with that of unsaturated non-esterified fatty acids (NEFA) bound to albumin. In humans, the PUFA concentration was 25.9±3.1 nmol/ml for these lysoPtdCho, compared with 33.4±9.6 nmol/ml for NEFA; in rats the equivalent values are 14.2±0.6 and 13.1±1.1 nmol/ml respectively (means±S.E.M.). The lysoPtdCho arachidonic acid content was 2-fold (human) and 5-fold (rat) higher than that of NEFA. In human and rat plasma, unsaturated lysoPtdCho were associated mainly with albumin rather than lipoproteins. The rate and extent of the acyl group shift from the sn-2 to sn-1 position of these lysoPtdCho were studied by the incubation of 1-lyso,2-[14C]C18:2n-6-glycerophosphocholine (GPC) with plasma. The rapid isomerization of this lipid occurred at pH 7 (20% isomerization within 2 min) and was not prevented by its association with albumin. The position of the acyl group in the lysoPtdCho circulating in plasma was studied by collecting blood directly in organic solvents containing 1-lyso,2-[14C]C18:2n-6-GPC as a marker of isomerization that occurred during sampling and analysis. Approx. 50% of the PUFA was located at the sn-2 position, demonstrating that substantial concentrations of 2-acyl-lysoPtdCho are present in plasma and are available for tissue uptake, where they can be reacylated at the sn-1 position to form membrane phospholipids.

scholarly journals Saturated free fatty acids and association with memory formation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tristan P. Wallis ◽  
Bharat G. Venkatesh ◽  
Vinod K. Narayana ◽  
David Kvaskoff ◽  
Alan Ho ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Free Fatty Acids ◽  
Fear Conditioning ◽  
Learning And Memory ◽  
Fear Learning ◽  
Membrane Phospholipids ◽  
The Brain ◽  
With Memory ◽  
Palmitic Acids

AbstractPolyunsaturated free fatty acids (FFAs) such as arachidonic acid, released by phospholipase activity on membrane phospholipids, have long been considered beneficial for learning and memory and are known modulators of neurotransmission and synaptic plasticity. However, the precise nature of other FFA and phospholipid changes in specific areas of the brain during learning is unknown. Here, using a targeted lipidomics approach to characterise FFAs and phospholipids across the rat brain, we demonstrated that the highest concentrations of these analytes were found in areas of the brain classically involved in fear learning and memory, such as the amygdala. Auditory fear conditioning led to an increase in saturated (particularly myristic and palmitic acids) and to a lesser extent unsaturated FFAs (predominantly arachidonic acid) in the amygdala and prefrontal cortex. Both fear conditioning and changes in FFA required activation of NMDA receptors. These results suggest a role for saturated FFAs in memory acquisition.

scholarly journals Adrenaline Stimulation of Phospholipid Metabolism in Adipocyte Ghosts

1987 ◽  
Vol 40 (4) ◽  
pp. 405
Author(s):  
David Mann ◽  
Audrey M Bersten
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Linoleic Acid ◽  
Adenylate Cyclase ◽  
Phospholipid Metabolism ◽  
Dependent Manner ◽  
Long Chain Fatty Acids ◽  
Membrane Phospholipids ◽  
Dose Dependent ◽  
Stimulation Of

The incorporation of long-chain fatty acids into phospholipids has been detected in adipocyte ghosts that were incubated with [1_14 C] stearic, [1_14 C] linoleic or [l_14C] arachidonic acid. Adrenaline and adenosine activated this incorporation within 15 s of exposure of the ghosts to the hormones and the response was dose dependent. Maximum incorporation of labelled linoleic acid occurred at 10-5 M adrenaline and 10-7 M adenosine. The a-agonist phenylephrine and the ~-agonist isoproterenol were also shown to stimulate the incorporation of fatty acid in a dose dependent manner. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol were each labelled preferentially with linoleic or arachidonic acid. p-Bromophenacylbromide, quinacrine and centrophenoxine inhibited the adrenaline-stimulated incorporation of fatty acids into ghost membrane phospholipids, and p-bromophenacylbromide also reduced the activation of adenylate cyclase by adrenaline. NaF, an activator of adenylate cyclase, like adrenaline, stimulated the incorporation of linoleic acid into ghost membrane phospholipids.

scholarly journals Dietary fat and the diabetic state alter insulin binding and the fatty acyl composition of the adipocyte plasma membrane

1988 ◽  
Vol 253 (2) ◽  
pp. 417-424 ◽  
Author(s):  
C J Field ◽  
E A Ryan ◽  
A B Thomson ◽  
M T Clandinin
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Insulin Binding ◽  
Fatty Acyl ◽  
Membrane Composition ◽  
Membrane Phospholipids ◽  
Diabetic State

Control and diabetic rats were fed on semi-purified high-fat diets providing a polyunsaturated/saturated fatty acid ratio (P/S) of 1.0 or 0.25, to examine the effect of diet on the fatty acid composition of major phospholipids of the adipocyte plasma membrane. Feeding the high-P/S diet (P/S = 1.0) compared with the low-P/S diet (P/S = 0.25) increased the content of polyunsaturated fatty acids in membrane phospholipids in both control and diabetic animals. The diabetic state decreased the content of polyunsaturated fatty acids, particularly arachidonic acid, in adipocyte membrane phospholipids. The decrease in arachidonic acid in membrane phospholipids of diabetic animals tended to be normalized to within the control values when high-P/S diets were given. For control animals, altered plasma-membrane composition was associated with change in insulin binding, suggesting that change in plasma-membrane composition may have physiological consequences for insulin-stimulated functions in the adipocyte.

scholarly journals ω–3 fatty acids increase the arachidonic acid content of liver cholesterol ester and plasma triacylglycerol fractions in the rat

1989 ◽  
Vol 261 (1) ◽  
pp. 11-15 ◽  
Author(s):  
M L Garg ◽  
A A Wierzbicki ◽  
A B R Thomson ◽  
M T Clandinin
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Eicosapentaenoic Acid ◽  
Fish Oil ◽  
Cholesterol Ester ◽  
Linseed Oil ◽  
Liver Cholesterol ◽  
Arachidonic Acid Content ◽  
Cholesterol Esters ◽  
Omega 6

Recent studies have demonstrated that dietary fish oils rich in eicosapentaenoic acid (C20:5,omega 3) lower the content of arachidonic acid and its metabolites in plasma and tissue phospholipids. The present study examined the fatty acid composition of cholesterol ester and triacylglycerol fractions from plasma and livers of rats fed diets enriched with saturated fatty acids (beef tallow), alpha-linolenic acid (linseed oil) or eicosapentaenoic acid (fish oil). Feeding diets containing linseed oil or fish oil for 28 days increased arachidonic acid (C20:4,omega 6) levels in the cholesterol ester fraction of liver and in the triacylglycerol fraction of the plasma lipids. Plasma cholesterol esters were depleted of C20:4,omega 6 after feeding of the diet containing either linseed oil or fish oil. The changes in C20:4,omega 6 content cannot be explained by alterations in cholesterol ester or triacylglycerol pools of plasma and liver. These results suggest that the decrease in phospholipid C20:4,omega 6 content generally observed after fish oil consumption may be partly due to a shift of C20:4,omega 6 from phospholipid to the triacylglycerol and/or cholesterol ester pools in the same tissue. Triacylglycerols and cholesterol esters may therefore play a buffering role in the homeostatic maintenance of tissue phospholipid levels of arachidonic acid.

scholarly journals Selective internalization of arachidonic acid by endothelial cells

1987 ◽  
Vol 245 (1) ◽  
pp. 151-157 ◽  
Author(s):  
E R Hall ◽  
C E Manner ◽  
J Carinhas ◽  
R Snopko ◽  
M Rafelson
Keyword(s):  
Fatty Acids ◽  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Endothelial Cell ◽  
Polyunsaturated Fatty Acids ◽  
Cell Types ◽  
Time Dependent ◽  
Asymmetric Distribution ◽  
Membrane Phospholipids ◽  
Bovine Endothelial Cell

The asymmetric distribution of phospholipids in bovine endothelial-cell membranes was probed with 2,4,6-trinitrobenzenesulphonate and purified phospholipase A2. The data suggest that phosphotidylethanolamine is primarily located in the inner lipid bilayer, as reported for other cell types. Stearic acid is taken up by the endothelial cells and is randomly distributed among the membrane phospholipids. In contrast, the polyunsaturated fatty acids (arachidonic, eicosatrienoic and eicosapentaenoic acids) have initial incorporation into the phosphatidylcholine fraction. These fatty acids then undergo a time-dependent transfer from phosphatidylcholine to phosphatidylethanolamine. Thus we propose that endothelial cells possess a mechanism for the selective internalization of polyunsaturated fatty acids.

scholarly journals Entry of polyunsaturated fatty acids into the brain: evidence that high-density lipoprotein-induced methylation of phosphatidylethanolamine and phospholipase A2 are involved

1996 ◽  
Vol 316 (3) ◽  
pp. 805-811 ◽  
Author(s):  
Valérie MAGRET ◽  
Latifa ELKHALIL ◽  
Françoise NAZIH-SANDERSON ◽  
Françoise MARTIN ◽  
Jean-Marie BOURRE ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Polyunsaturated Fatty Acids ◽  
High Density Lipoprotein ◽  
Phospholipase A2 ◽  
Density Lipoprotein ◽  
Bovine Brain ◽  
High Density ◽  
Close Relationship ◽  
The Brain

The conversion of phosphatidylethanolamine (PE) into phosphatidylcholine (PC) by a sequence of three transmethylation reactions is shown to be stimulated by the apolipoprotein E-free subclass of high-density lipoprotein (HDL3) in isolated bovine brain capillary (BBC) membranes. HDL3-induced stimulation of BBC membranes pulsed with [methyl-14C]methionine causes a transient increase in each methylated phospholipid, i.e. phosphatidyl-N-monomethylethanolamine (PMME), phosphatidyl-NN-dimethylethanolamine (PDME) and PC. PC substrate arising from the activation of PE N-methyltransferase (PEMT) is hydrolysed by a phospholipase A2 (PLA2), as demonstrated by the accumulation of lysophosphatidylcholine (lyso-PC). When PE containing [14C]arachidonic acid in the sn-2 position ([14C]PAPE) is incorporated into BBC membranes, HDL3 stimulation induces the formation of PMME, PDME, PC and lyso-PC and the release of [14C]arachidonic acid, which correlates with the previous production of lyso-PC, suggesting that HDL3 stimulates a PLA2 that can release polyunsaturated fatty acids (PUFA). Both PEMT and PLA2 activities depend on a HDL3 concentration in the range 0–50 μg/ml and are strictly dependent on HDL3 binding, because HDL3 modified by tetranitromethane is no longer able to bind to specific receptors and to trigger PEMT and PLA2 activation. Moreover, HDL3 prelabelled with [14C]PAPE can stimulate PDME and lyso-PC synthesis in BBC membranes in the presence of S-adenosylmethionine, suggesting that HDL3 can supply BBC membranes in polyunsaturated PE and can activate enzymes involved in PE N-methylation and PUFA release. The results support the hypothesis of a close relationship between HDL3 binding, PE methylation and PUFA release, and suggest that the PC pool arising from PE could be used as a pathway for the supply of PUFA to the brain.

Biochemical characterization of an S-adenosyl-l-methionine-dependent methyltransferase (Rv0469) of Mycobacterium tuberculosis

2013 ◽  
Vol 394 (7) ◽  
pp. 871-877 ◽  
Author(s):  
Laxman S. Meena ◽  
Puneet Chopra ◽  
Ram A. Vishwakarma ◽  
Yogendra Singh
Keyword(s):  
Fatty Acids ◽  
Mycobacterium Tuberculosis ◽  
Oleic Acid ◽  
Biochemical Characterization ◽  
Short Chain Fatty Acids ◽  
Major Constituent ◽  
Membrane Phospholipids ◽  
Tuberculostearic Acid ◽  
Olefinic Double Bond

Abstract Tuberculostearic acid (l0-methylstearic acid, TSA) is a major constituent of mycobacterial membrane phospholipids, and its biosynthesis involves the direct methylation of oleic acid esterified as a component of phospholipids. The methyltransferases of mycobacteria were long proposed to be involved in the synthesis of methyl-branched short-chain fatty acids, but direct experimental evidence is still lacking. In this study, we identified the methyltransferase encoded by umaA in Mycobacterium tuberculosis H37Rv as a novel S-adenosyl-l-methionine (SAM)-dependent methyltransferase capable of catalyzing the conversion of olefinic double bond of phospholipid-linked oleic acid to biologically essential TSA. Therefore, UmaA, catalyzing such modifications, offer a viable target for chemotherapeutic intervention.

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