Effect of dietary n−3 and n−6 polyunsaturated fatty acids on lipid‐metabolizing enzymes in obese rat liver

Niot, Isabelle; Gresti, Joseph; Boichot, Jacqueline; Semporé, G.; Durand, Georges; Bézard, J.; Clouet, Pierre

doi:10.1007/bf02578245

Cited by 35 publications

(15 citation statements)

References 59 publications

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“…The ensuing increase of membrane fluidity is reported to generate a number of responses, such as the enhancement of membrane-associated phospholipase A 2 activity [43], proton leakage [44,45], and Ca 2ϩ efflux [46]. Furthermore, changes in phospholipid fatty acid composition can alter the activity of carnitine palmitoyltransferase I [47,48] and of the pyruvate carrier [49,50]. If correct, the interaction of PC-TP with mitochondria may have a profound effect on mitochondrial function, including an increased ␤-oxidation.…”

Section: Discussionmentioning

confidence: 99%

Clofibrate-Induced Relocation of Phosphatidylcholine Transfer Protein to Mitochondria in Endothelial Cells

Brouwer

Westerman

Kleinnijenhuis

et al. 2002

Experimental Cell Research

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The phosphatidylcholine transfer protein (PC-TP) is a specific transporter of phosphatidylcholine (PC) between membranes. To get more insight into its physiological function, we have studied the localization of PC-TP by microinjection of fluorescently labeled PC-TP in foetal bovine heart endothelial (FBHE) cells and by expression of an enhanced yellow fluorescent protein-PC-TP fusion protein in FBHE cells, human umbilical vein endothelial cells, and HepG2 cells. Analysis by confocal laser scanning microscopy showed that PC-TP was evenly distributed throughout the cytosol with an apparently elevated level in nuclei. By measuring the fluorescence recovery after bleaching it was established that PC-TP is highly mobile throughout the cell, with its transport into the nucleus being hindered by the nuclear envelope. Given the proposed function of PC-TP in lipid metabolism, we have tested a number of compounds (phorbol ester, bombesin, A23187, thrombin, dibutyryl cyclic AMP, oleate, clofibrate, platelet-derived growth factor, epidermal growth factor, and hydrogen peroxide) for their ability to affect intracellular PC-TP distribution. Only clofibrate (100 M) was found to have an effect, with PC-TP moving to mitochondria within 5 min of stimulation. This relocation did not occur with PC-TP(S110A), lacking the putative protein kinase C (PKC)-dependent phosphorylation site, and was restricted to the primary endothelial cells. Relocation did not occur in HepG2 cells, possibly due to the fact that clofibrate does not induce PKC activation in these cells.

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Section: Discussionmentioning

confidence: 99%

Clofibrate-Induced Relocation of Phosphatidylcholine Transfer Protein to Mitochondria in Endothelial Cells

Brouwer

Westerman

Kleinnijenhuis

et al. 2002

Experimental Cell Research

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“…Increasing membrane polyunsaturation of cells has been shown to modify the activity of various membrane enzymes (94,95). A review of major membrane proteins concluded that 5Ј nucleotidase activity increased with greater membrane unsaturation, adenylate cyclase varied between tissues, and Na ‫ם‬ -K ‫ם‬ ATPase activity decreased with increasing polyunsaturation (96).…”

Section: Influence Of Membrane Lipids On Membrane Proteinsmentioning

confidence: 98%

Mechanisms Underlying the Cost of Living in Animals

Hulbert

Else

2000

Annu. Rev. Physiol.

364

244

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The cost of living can be measured as an animal's metabolic rate. Basal metabolic rate (BMR) is factorially related to other metabolic rates. Analysis of BMR variation suggests that metabolism is a series of linked processes varying in unison. Membrane processes, such as maintenance of ion gradients, are important costs and components of BMR. Membrane bilayers in metabolically active systems are more polyunsaturated and less monounsaturated than metabolically less-active systems. Such polyunsaturated membranes have been proposed to result in an increased molecular activity of membrane proteins, and in this manner the amount of membrane and its composition can act as a pacemaker for metabolism. The potential importance of membrane acyl composition in metabolic depression, hormonal control of metabolism, the evolution of endothermy, as well as its implications for lifespan and human health, are briefly discussed.

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“…C17:0 as the internal standard, after methylation according to the procedure of Christie (31) and separation by gas chromatography, as previously described (32). ECs and congeners were purified from lipid extracts and determined by isotope dilution liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry using deuterated standards as described in the study by Bartelt et al (33).…”

Section: Lipid and Ec Analysesmentioning

confidence: 99%

Early Low-Fat Diet Enriched With Linolenic Acid Reduces Liver Endocannabinoid Tone and Improves Late Glycemic Control After a High-Fat Diet Challenge in Mice

Demizieux

Piscitelli²,

Troy-Fioramonti

et al. 2016

Diabetes

Self Cite

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Evidence suggests that alterations of glucose and lipid homeostasis induced by obesity are associated with the elevation of endocannabinoid tone. The biosynthesis of the two main endocannabinoids, N-arachidonoylethanolamine and 2-arachidonoyl-glycerol, which derive from arachidonic acid, is influenced by dietary fatty acids (FAs). We investigated whether exposure to n-3 FA at a young age may decrease tissue endocannabinoid levels and prevent metabolic disorders induced by a later high-fat diet (HFD) challenge. Three-week-old mice received a 5% lipid diet containing lard, lard plus safflower oil, or lard plus linseed oil for 10 weeks. Then, mice were challenged with a 30% lard diet for 10 additional weeks. A low n-6/n-3 FA ratio in the early diet induces a marked decrease in liver endocannabinoid levels. A similar reduction was observed in transgenic Fat-1 mice, which exhibit high tissue levels of n-3 FA compared with wild-type mice. Hepatic expression of key enzymes involved in carbohydrate and lipid metabolism was concomitantly changed. Interestingly, some gene modifications persisted after HFD challenge and were associated with improved glycemic control. These findings indicate that early dietary interventions based on n-3 FA may represent an alternative strategy to drugs for reducing endocannabinoid tone and improving metabolic parameters in the metabolic syndrome.The endocannabinoid (EC) system (ECS) is known to play a crucial role in energy homeostasis. Regulation by this system takes place at the central level by changing food intake (1), and at the peripheral level by the modification of energy metabolism (2). An overactive ECS plays a crucial role in obesity by increasing food intake (3) and lipogenesis (4), by downregulating catabolic reactions (5,6), and by promoting fat accumulation and alteration of glucose homeostasis. As a consequence, treating obesity by decreasing ECS activity has been considered. A pharmacological approach was developed, leading to the commercialization of an inverse agonist of the cannabinoid receptor type-1 (CB1R) rimonabant. However, this drug was withdrawn from the market because of its undesired central nervous system side effects (7). Meanwhile, the downregulation of ECS tone in peripheral tissues involved in energy homeostasis, either with non-brain-penetrant CB1R blockers, or inhibitors of the biosynthesis of endogenous CB1R agonists, is still considered to be a potential approach to counter the adverse events observed in obesity (8).The ECS is defined as a set of endogenous ligands (ECs), synthesized and degraded by specific enzymes and receptors that are able to bind these molecules. It includes two membrane receptors, CB1R and CB2R, and two main endogenous agonists, N-arachidonoyl-ethanolamine (AEA [or anandamide]) and 2-arachidonoyl-glycerol (2-AG). AEA is typically synthesized by the enzyme N-acylphosphatidylethanolamine phospholipase D (NAPE-PLD), although alternative pathways

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Effect of dietary n−3 and n−6 polyunsaturated fatty acids on lipid‐metabolizing enzymes in obese rat liver

Cited by 35 publications

References 59 publications

Clofibrate-Induced Relocation of Phosphatidylcholine Transfer Protein to Mitochondria in Endothelial Cells

Clofibrate-Induced Relocation of Phosphatidylcholine Transfer Protein to Mitochondria in Endothelial Cells

Mechanisms Underlying the Cost of Living in Animals

Early Low-Fat Diet Enriched With Linolenic Acid Reduces Liver Endocannabinoid Tone and Improves Late Glycemic Control After a High-Fat Diet Challenge in Mice

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