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Passarelli MK, Ewing AG, Winograd N. Single-cell lipidomics: characterizing and imaging lipids on the surface of individual Aplysia californica neurons with cluster secondary ion mass spectrometry. Anal Chem 2013; 85:2231-8. [PMID: 23323749 PMCID: PMC3867296 DOI: 10.1021/ac303038j] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Neurons isolated from Aplysia californica , an organism with a well-defined neural network, were imaged with secondary ion mass spectrometry, C(60)-SIMS. A major lipid component of the neuronal membrane was identified as 1-hexadecyl-2-octadecenoyl-sn-glycero-3-phosphocholine [PC(16:0e/18:1)] using tandem mass spectrometry (MS/MS). The assignment was made directly off the sample surface using a C(60)-QSTAR instrument, a prototype instrument that combines an ion source with a commercial electrospray ionization/matrix-assisted laser desorption ionization (ESI/MALDI) mass spectrometer. Normal phase liquid chromatography mass spectrometry (NP-LC-MS) was used to confirm the assignment. Cholesterol and vitamin E were also identified with in situ tandem MS analyses that were compared to reference spectra obtained from purified compounds. In order to improve sensitivity on the single-cell level, the tandem MS spectrum of vitamin E reference material was used to extract and compile all the vitamin E related peaks from the cell image. The mass spectrometry images reveal heterogeneous distributions of intact lipid species, PC(16:0e/18:1), vitamin E, and cholesterol on the surface of a single neuron. The ability to detect these molecules and determine their relative distribution on the single-cell level shows that the C(60)-QSTAR is a potential platform for studying important biochemical processes, such as neuron degeneration.
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Affiliation(s)
- Melissa K. Passarelli
- Department of Chemistry, University Park, PA 16802, USA
- Department of Chemistry and Molecular Biology, The University of Gothenburg, SE-41296 Göteborg, Sweden
| | - Andrew G. Ewing
- Department of Chemistry and Molecular Biology, The University of Gothenburg, SE-41296 Göteborg, Sweden
- Department of Chemical and Biological Engineering, Chalmers University of Technology, S-41296 Göteborg, Sweden
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2
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Munteanu A, Zingg JM. Cellular, molecular and clinical aspects of vitamin E on atherosclerosis prevention. Mol Aspects Med 2007; 28:538-90. [PMID: 17825403 DOI: 10.1016/j.mam.2007.07.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Accepted: 07/23/2007] [Indexed: 02/07/2023]
Abstract
Randomised clinical trials and epidemiologic studies addressing the preventive effects of vitamin E supplementation against cardiovascular disease reported both positive and negative effects, and recent meta-analyses of the clinical studies were rather disappointing. In contrast to that, many animal studies clearly show a preventive action of vitamin E in several experimental settings, which can be explained by the molecular and cellular effects of vitamin E observed in cell cultures. This review is focusing on the molecular effects of vitamin E on the cells playing a role during atherosclerosis, in particular on the endothelial cells, vascular smooth muscle cells, monocytes/macrophages, T cells, and mast cells. Vitamin E may act by normalizing aberrant signal transduction and gene expression in antioxidant and non-antioxidant manners; in particular, over-expression of scavenger receptors and consequent foam cell formation can be prevented by vitamin E. In addition to that, the cellular effects of alpha-tocopheryl phosphate and of EPC-K1, a composite molecule between alpha-tocopheryl phosphate and l-ascorbic acid, are summarized.
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Affiliation(s)
- Adelina Munteanu
- Physiology Department, Faculty of Medicine, University of Medicine and Pharmacy Bucharest, Romania
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3
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Bradford A, Atkinson J, Fuller N, Rand RP. The effect of vitamin E on the structure of membrane lipid assemblies. J Lipid Res 2003; 44:1940-5. [PMID: 12867540 DOI: 10.1194/jlr.m300146-jlr200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The effects of vitamin E on the activity of membrane-dependent enzymes suggest that it acts indirectly by modifying some properties of the lipid host. The effects of alpha-tocopherol (alpha-T) and alpha-tocopherol hemisuccinate (alpha-THS) on phospholipid monolayer structure, curvature, and bending elasticity were examined using X-ray diffraction and the osmotic stress method. These ligands were mixed with the hexagonal phase-forming lipid, dioleoylphosphatidylethanolamine (DOPE). Increasing levels up to 50 mol% alpha-T in DOPE in excess water result in a systematic decrease in the lattice dimension. Analysis of the structural changes imposed by alpha-T shows that it contributes a spontaneous radius of curvature of -13.7 A. This unusually negative value is comparable to diacylglycerols. alpha-T does not affect the bending elasticity of these monolayers. alpha-THS in its charged form decreases membrane curvature, but in its undissociated neutral form has a qualitatively similar but reduced effect on monolayer curvature, as does alpha-T. We discuss these results in terms of the local stresses such ligands would produce in the vicinity of a membrane protein, and how one might expect proteins to respond to such stress.
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Affiliation(s)
- A Bradford
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada L2S 3A1
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Huang CG, Chu ZL, Wei SJ, Jiang H, Jiao BH. Effect of berberine on arachidonic acid metabolism in rabbit platelets and endothelial cells. Thromb Res 2002; 106:223-7. [PMID: 12297129 DOI: 10.1016/s0049-3848(02)00133-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The antiplatelet effect of berberine has been demonstrated in both laboratory research and clinical trials. In the present study, we show ex vivo that berberine significantly inhibited rabbit platelet aggregation induced by adenosine diphosphate, arachidonic acid, collagen or calcium ionophore A23187. The most potent inhibition was observed in collagen-induced platelet aggregation. Using radioimmunoassay, we show in vitro that berberine significantly inhibited synthesis of thromboxane A(2) in rabbit platelets induced by adenosine diphosphate, arachidonic acid or collagen in which collagen-induced thromboxane A(2) synthesis was also most potently inhibited. In our in vivo study using radioimmunoassay, the plasma prostacyclin level was reduced by 34.6% during a 30-min period after intravenous administration of 50 mg/kg of berberine. These results suggest that berberine might inhibit arachidonic acid metabolism in rabbit platelets and endothelial cells at two or more sites: cyclooxygenase in the arachidonic acid cascade and possibly the enzyme(s) for arachidonic acid liberation from membrane phospholipid(s).
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Affiliation(s)
- Cai G Huang
- Department of Biochemistry and Molecular Biology, Second Military Medical University, 800 Xiang Yin Road, Shanghai 200433, PR China.
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Wenger FA, Kilian M, Ridders J, Stahlknecht P, Schimke I, Guski H, Jacobi CA, Müller JM. Influence of antioxidative vitamins A, C and E on lipid peroxidation in BOP-induced pancreatic cancer in Syrian hamsters. Prostaglandins Leukot Essent Fatty Acids 2001; 65:165-71. [PMID: 11728167 DOI: 10.1054/plef.2001.0305] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Persistent oxidative stress is thought to play an important role in carcinogenesis. Vitamins may influence oxygen radical metabolism and thus inhibit tumor growth. In the present trial the effects of Vitamins (Vit.) A, C and E on neoplastic growth and lipid peroxidation in pancreatic tissue were evaluated on chemically-induced pancreatic adenocarcinoma in the Syrian hamster. The incidence of pancreatic cancer was decreased by Vit. A (64.3%) and Vit. C (71.4%) as compared to the control group (100%, P<0.05). All vitamins increased the activity of superoxidedismutase (SOD) in pancreatic carcinomas. Accumulation of vitamins in tumor cells seems to be responsible for high levels of SOD and consecutive intracellular increase of hydrogen peroxide levels. Since this effect is selectively toxic for tumor cells it might be one of the mechanisms decreasing the incidence of pancreatic cancer in our trial.
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Affiliation(s)
- F A Wenger
- Department of General Visceral, Vascualr and Thoracic Surgery, Charité Campus Mitte, Humboldt-University of Berlin, Germany.
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Lei H, Atkinson J. Synthesis of phytyl- and chroman-derivatized photoaffinity labels based on alpha-tocopherol. J Org Chem 2000; 65:2560-7. [PMID: 10789472 DOI: 10.1021/jo000029l] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photoaffinity analogues of alpha-tocopherol have been prepared by substituting photosensitive functional groups at either the terminus of an alkyl chain of varying length mimicking the phytyl tail or on C-3 of the chroman portion of tocopherol. The alkyl chain-modified compounds 2a-d contain a hexyl to nonyl alkyl chain extending from C-2 of the chroman, terminating in a tetrafluoroazidobenzyloxy group. These compounds were prepared starting from the commercially available Trolox acid 4, followed by esterification, protection, and reduction to the silyl-protected Trolox aldehyde 7, which was coupled using Wittig chemistry to different omega-hydroxyphosphonium bromides. Reduction of the alkene product, coupling with p-azidotetrafluorobenzyl bromide, and deprotection of the phenolic silyl group gave compounds 2a-d in excellent yields. Chroman-functionalized photoaffinity labels were synthesized starting from the protected tocopherol chromene 16b which was a key intermediate for preparation of a 3-hydroxy derivative, either by reduction of epoxides produced directly with Jacobsen's catalysts or by treatment with NBS in wet DME to give two stereoisomeric bromohydrins which were cyclized and reduced to give the phenol-protected C-3 alcohols 19a,b. These alcohols were then converted to diazoacetate esters, and the protecting group was removed to give 3-diazoacetoxy alpha-tocopherols 3a,b.
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Affiliation(s)
- H Lei
- Department of Chemistry, Brock University, St. Catharines, Ontario, Canada
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Wong JT, Chan M, Lee D, Jiang JY, Skrzypczak M, Choy PC. Phosphatidylcholine metabolism in human endothelial cells: modulation by phosphocholine. Mol Cell Biochem 2000; 207:95-100. [PMID: 10888232 DOI: 10.1023/a:1007054601256] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Phosphatidylcholine is the principal phospholipid in mammalian tissues, and a major source for the production of arachidonic acid. In this study, the effect of exogenous phosphocholine, a precursor of phosphatidylcholine biosynthesis, on the metabolism of phosphatidylcholine in human umbilical vein endothelial cells was investigated. Incubation of endothelial cells with exogenous phosphocholine at concentrations of 1 to 5 mM was found to inhibit choline uptake and its subsequent incorporation into phosphatidylcholine. Phosphocholine appeared to inhibit choline uptake in a competitive manner. Since phosphatidylcholine is metabolized mainly by the action of phospholipase A2, with the release of arachidonic acid and other fatty acids, the effect of phosphocholine on arachidonic acid release in endothelial cells was also examined. The induction of arachidonic acid release by ATP was enhanced in cells treated with 1 mM phosphocholine. In vitro assays of phospholipase A2 activity in cells incubated with phosphocholine, however, did not produced any significant change in the activity of this enzyme. The results of this study show that phosphocholine modulates the biosynthesis and catabolism of phosphatidylcholine in an indirect manner.
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Affiliation(s)
- J T Wong
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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Lei H, Marks V, Pasquale T, Atkinson JK. Synthesis of photoaffinity label analogues of alpha-tocopherol. Bioorg Med Chem Lett 1998; 8:3453-8. [PMID: 9934451 DOI: 10.1016/s0960-894x(98)00655-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Photoaffinity analogues of alpha-tocopherol have been synthesized that incorporate the photosensitive 4-azido-2,3,5,6-tetrafluorobenzyloxy group at the terminus of unbranched analogues of the naturally occurring phytyl side chain. An intermediate from these syntheses has also been used to generate a supported ligand for bioaffinity chromatography of alpha-tocopherol binding proteins.
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Affiliation(s)
- H Lei
- Department of Chemistry, Brock University, St. Catharines, Ontario, Canada
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Tran K, Lee E, Wong J, Man RY, Jay FT, Chan AC, Choy PC. Vitamin E (alpha-tocopherol) enhances arachidonic acid release in rat heart myoblastic cells through the activation of cytosolic phospholipase A2. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1997; 407:123-9. [PMID: 9321942 DOI: 10.1007/978-1-4899-1813-0_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- K Tran
- Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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Tran K, Wong JT, Lee E, Chan AC, Choy PC. Vitamin E potentiates arachidonate release and phospholipase A2 activity in rat heart myoblastic cells. Biochem J 1996; 319 ( Pt 2):385-91. [PMID: 8912671 PMCID: PMC1217780 DOI: 10.1042/bj3190385] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cytosolic phospholipase A2 (cPLA2) selectively catalyses the release of arachidonic acid from the sn-2 position of glycero-phospholipids to produce prostaglandins and leukotrienes. In this study, vitamin E enrichment of rat heart myoblastic H9c2 cells caused an increase in the release of arachidonate during ionophore (A23187) stimulation. PLA2 activity in the cytosolic fraction was also enhanced but enzyme activity in the particulate fraction was not affected by this treatment. Immunoblotting analysis with a polyclonal anti-cPLA2 antibody showed an increased level of the enzyme in vitamin E-treated cells. Direct incorporation of vitamin E into lipid vesicles in the assay mixture resulted in modulation of enzyme activity in a biphasic manner. Pretreatment of cells with phorbol 12-myristate 13-acetate, a known activator of protein kinase C, synergistically potentiated the ionophore-induced arachidonate release in both the control and vitamin E-treated cells. However, vitamin E treatment by itself did not affect the protein kinase C activity, indicating that the vitamin E-induced activation of cPLA2 was independent of the protein kinase C cascade. Collectively, these results suggest that vitamin E potentiates arachidonate release through the direct and/or indirect modulation of cPLA2 activity.
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Affiliation(s)
- K Tran
- Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Canada
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Engström K, Luostarinen R, Saldeen T. Whole blood production of thromboxane, prostacyclin and leukotriene B4 after dietary fish oil supplementation in man: effect of vitamin E. Prostaglandins Leukot Essent Fatty Acids 1996; 54:419-25. [PMID: 8888353 DOI: 10.1016/s0952-3278(96)90025-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
12 subjects were given 30 ml/day of a fish oil already stabilized with vitamin E (1.5 IU/g) and other natural antioxidants (fish oil, FO), and the same fish oil supplemented with extra vitamin E (to total 4.5 IU/g) (FO+E), in a randomized double-blind cross-over study. The whole blood production of thromboxane B2, measured in serum, was reduced after 4 weeks of ingestion of both FO+E (by 47%, P < 0.01) and of FO (by 40%, P < 0.05) whereas 6-keto-PGF1 alpha increased slightly in both cases, by 4% and 5% respectively, both NS. Leukotriene B4 production decreased on both FO+E (by 20%, NS) and FO (by 17%, P < 0.05). This study thus showed that a stabilized fish oil had marked effects on eicosanoid production, which may be important for its cardiovascular effect. Further supplementation with vitamin E had no additional effect, indicating that the vitamin E content (1.5 IU/g) in this stabilized fish oil might have been optimal.
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Affiliation(s)
- K Engström
- Department of Forensic Medicine, University of Uppsala, Sweden
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