The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
H. Alex Brown - One of the best experts on this subject based on the ideXlab platform.
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Extensive sphingolipid depletion does not affect lipid raft integrity or lipid raft localization and efflux function of the ABC transporter MRP1
Biochemical Journal, 2010Co-Authors: Karin Klappe, Anne-jan Dijkhuis, Ina Hummel, Annie Van Dam, Pavlina T. Ivanova, Stephen B. Milne, David S. Myers, H. Alex Brown, Hjalmar P. Permentier, Jan Willem KokAbstract:We show that highly efficient depletion of sphingolipids in two different cell lines does not abrogate the ability to isolate Lubrol-based DRMs (detergent-resistant membranes) or detergent-free lipid rafts from these cells. Compared with control, DRM/detergent-free lipid raft fractions contain equal amounts of protein, cholesterol and phospholipid, whereas the classical DRM/lipid raft markers Src, caveolin-1 and flotillin display the same gradient distribution. DRMs/detergent-free lipid rafts themselves are severely depleted of sphingolipids. The fatty acid profile of the remaining sphingolipids as well as that of the Glycerophospholipids shows several differences compared with control, most prominently an increase in highly saturated C 16 species. The Glycerophospholipid headgroup composition is unchanged in sphingolipid-depleted cells and cell-derived detergent-free lipid rafts. Sphingolipid depletion does not alter the localization of MRP1 (multidrug-resistance-related protein 1) in DRMs/detergent-free lipid rafts or MRP1-mediated efflux of carboxyfluorescein. We conclude that extensive sphingolipid depletion does not affect lipid raft integrity in two cell lines and does not affect the function of the lipid-raft-associated protein MRP1.
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Extensive sphingolipid depletion does not affect lipid raft integrity or lipid raft localization and efflux function of the ABC transporter MRP1
Biochemical Journal, 2010Co-Authors: Karin Klappe, Anne-jan Dijkhuis, Ina Hummel, Annie Van Dam, Pavlina T. Ivanova, Stephen B. Milne, David S. Myers, H. Alex Brown, Hjalmar P. Permentier, Jan Willem KokAbstract:We show that highly efficient depletion of sphingolipids in two different cell lines does not abrogate the ability to isolate lubrol-based detergent-resistant membranes (DRMs) or detergent-free lipid rafts from these cells. Compared to control, DRM/detergent-free lipid raft fractions contain equal amounts of protein, cholesterol and phospholipid, while the classical DRM/lipid raft markers Src, caveolin-1 (Cav-1) and flotillin display the same gradient distribution. DRMs/detergent-free lipid rafts themselves are severely depleted of sphingolipids. The fatty acid profile of the remaining sphingolipids as well as that of the Glycerophospholipids shows several differences compared to control, most prominently an increase of highly saturated C16 species. The Glycerophospholipid headgroup composition is unchanged in sphingolipid depleted cells and cell-derived detergent-free lipid rafts. Sphingolipid depletion does not alter the localization of multidrug resistance-related protein 1 (MRP1) in DRMs/detergent-free lipid rafts or MRP1-mediated efflux of carboxyfluorescein. We conclude that extensive sphingolipid depletion does not affect lipid raft integrity in two cell lines and does not affect the function of the lipid raft-associated protein MRP1.
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Capture and release of alkyne-derivatized Glycerophospholipids using cobalt chemistry
Nature chemical biology, 2010Co-Authors: Stephen B. Milne, Keri A. Tallman, Remigiusz A. Serwa, Carol A. Rouzer, Michelle D. Armstrong, Lawrence J. Marnett, Charles M. Lukehart, Ned A. Porter, H. Alex BrownAbstract:Alkyne-modified phospholipids can be unambiguously identified and differentiated from native species in complex mixtures by formation of dicobalthexacarbonyl complexes. This reaction is specific for alkynes and is unaffected by other Glycerophospholipid-related moieties. Enrichment of cells with alkyne-derivatized fatty acids or Glycerophospholipids followed by solid-phase sequestration and release is a promising new method for unequivocally monitoring individual Glycerophospholipids following incorporation into cells. This technique also facilitates lipidomic analysis of substrates and products.
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Identification of atypical ether-linked Glycerophospholipid species in macrophages by mass spectrometry
Journal of lipid research, 2009Co-Authors: Pavlina T. Ivanova, Stephen B. Milne, H. Alex BrownAbstract:A large scale profiling and analysis of Glycerophospholipid species in macrophages has facilitated the identification of several rare and atypical Glycerophospholipid species. By using liquid chromatography tandem mass spectrometry and comparison of the elution and fragmentation properties of the rare lipids to synthetic standards, we were able to identify an array of ether-linked phosphatidylinositols (PIs), phosphatidic acids, phosphatidylserines (PSs), very long chain phosphatidylethanolamines (PEs), and phosphatidylcholines (PCs) as well as phosphatidylthreonines (PTs) and a wide collection of odd carbon fatty acid-containing phospholipids in macrophages. A comprehensive qualitative analysis of Glycerophospholipids from different macrophage cells was conducted. During the phospholipid profiling of the macrophage-like RAW 264.7 cells, we identified dozens of rare or previously uncharacterized phospholipids, including ether-linked PIs, PSs, and glycerophosphatidic acids, PTs, and PCs and PTs containing very long polyunsaturated fatty acids. Additionally, large numbers of phospholipids containing at least one odd carbon fatty acid were identified. Using the same methodology, we also identified many of the same species of Glycerophospholipids in resident peritoneal macrophages, foam cells, and murine bone marrow derived macrophages.
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Lipid profiling reveals Glycerophospholipid remodeling in zymosan-stimulated macrophages.
Biochemistry, 2007Co-Authors: Carol A. Rouzer, Pavlina T. Ivanova, H. Alex Brown, Mark Byrne, Lawrence J. MarnettAbstract:Comprehensive lipid profiling by mass spectrometry provides comparative data on the relative distribution of individual Glycerophospholipids within each of the major classes. Application of this method to the analysis of Glycerophospholipid remodeling in murine primary resident peritoneal macrophages (RPMs) during zymosan phagocytosis reveals significant decreases in the levels of every major arachidonic acid (20:4)-containing species of phosphatidylcholine (GPCho) and in selected 20:4-containing phosphatidylinositol (GPIns) and phosphatidylglycerol (GPGro) species. No net changes in 20:4-containing phosphatidylethanolamine (GPEtn) species were detected. Pretreatment of RPMs with LPS resulted in subtle changes in the magnitude and kinetics of the response but had no effect on the overall pattern of zymosan-induced Glycerophospholipid remodeling. Inhibition of prostaglandin (PG) synthesis with indomethacin reduced the magnitude of the changes in 20:4-containing diacyl but not alkyl acyl species. Blockade of 20:4 reacylation with thimerosal had no effect on the magnitude of the zymosan-induced changes in GPCho, GPIns, or GPGro species but revealed decreases in the level of alkyl acyl GEtn species. RAW264.7 cells contain much lower levels of phospholipid 20:4 than do RPMs and synthesize PGs poorly in response to zymosan. Pretreatment with granulocyte-macrophage colony stimulating factor, lipopolysaccharide, and interferon-gamma substantially increased the extent of 20:4 mobilization and PG synthesis in these cells. However, under conditions of maximal zymosan-dependent PG synthesis, the only Glycerophospholipid that exhibited a significant change was a 20:4-containing plasmenyl GPEtn. These results suggest that GPCho is the major ultimate source of 20:4 that is mobilized in zymosan-stimulated RPMs but that 20:4 mobilization may involve the intermediate turnover of alkyl acyl GPEtn species.
Pavlina T. Ivanova - One of the best experts on this subject based on the ideXlab platform.
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Extensive sphingolipid depletion does not affect lipid raft integrity or lipid raft localization and efflux function of the ABC transporter MRP1
Biochemical Journal, 2010Co-Authors: Karin Klappe, Anne-jan Dijkhuis, Ina Hummel, Annie Van Dam, Pavlina T. Ivanova, Stephen B. Milne, David S. Myers, H. Alex Brown, Hjalmar P. Permentier, Jan Willem KokAbstract:We show that highly efficient depletion of sphingolipids in two different cell lines does not abrogate the ability to isolate Lubrol-based DRMs (detergent-resistant membranes) or detergent-free lipid rafts from these cells. Compared with control, DRM/detergent-free lipid raft fractions contain equal amounts of protein, cholesterol and phospholipid, whereas the classical DRM/lipid raft markers Src, caveolin-1 and flotillin display the same gradient distribution. DRMs/detergent-free lipid rafts themselves are severely depleted of sphingolipids. The fatty acid profile of the remaining sphingolipids as well as that of the Glycerophospholipids shows several differences compared with control, most prominently an increase in highly saturated C 16 species. The Glycerophospholipid headgroup composition is unchanged in sphingolipid-depleted cells and cell-derived detergent-free lipid rafts. Sphingolipid depletion does not alter the localization of MRP1 (multidrug-resistance-related protein 1) in DRMs/detergent-free lipid rafts or MRP1-mediated efflux of carboxyfluorescein. We conclude that extensive sphingolipid depletion does not affect lipid raft integrity in two cell lines and does not affect the function of the lipid-raft-associated protein MRP1.
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Extensive sphingolipid depletion does not affect lipid raft integrity or lipid raft localization and efflux function of the ABC transporter MRP1
Biochemical Journal, 2010Co-Authors: Karin Klappe, Anne-jan Dijkhuis, Ina Hummel, Annie Van Dam, Pavlina T. Ivanova, Stephen B. Milne, David S. Myers, H. Alex Brown, Hjalmar P. Permentier, Jan Willem KokAbstract:We show that highly efficient depletion of sphingolipids in two different cell lines does not abrogate the ability to isolate lubrol-based detergent-resistant membranes (DRMs) or detergent-free lipid rafts from these cells. Compared to control, DRM/detergent-free lipid raft fractions contain equal amounts of protein, cholesterol and phospholipid, while the classical DRM/lipid raft markers Src, caveolin-1 (Cav-1) and flotillin display the same gradient distribution. DRMs/detergent-free lipid rafts themselves are severely depleted of sphingolipids. The fatty acid profile of the remaining sphingolipids as well as that of the Glycerophospholipids shows several differences compared to control, most prominently an increase of highly saturated C16 species. The Glycerophospholipid headgroup composition is unchanged in sphingolipid depleted cells and cell-derived detergent-free lipid rafts. Sphingolipid depletion does not alter the localization of multidrug resistance-related protein 1 (MRP1) in DRMs/detergent-free lipid rafts or MRP1-mediated efflux of carboxyfluorescein. We conclude that extensive sphingolipid depletion does not affect lipid raft integrity in two cell lines and does not affect the function of the lipid raft-associated protein MRP1.
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Identification of atypical ether-linked Glycerophospholipid species in macrophages by mass spectrometry
Journal of lipid research, 2009Co-Authors: Pavlina T. Ivanova, Stephen B. Milne, H. Alex BrownAbstract:A large scale profiling and analysis of Glycerophospholipid species in macrophages has facilitated the identification of several rare and atypical Glycerophospholipid species. By using liquid chromatography tandem mass spectrometry and comparison of the elution and fragmentation properties of the rare lipids to synthetic standards, we were able to identify an array of ether-linked phosphatidylinositols (PIs), phosphatidic acids, phosphatidylserines (PSs), very long chain phosphatidylethanolamines (PEs), and phosphatidylcholines (PCs) as well as phosphatidylthreonines (PTs) and a wide collection of odd carbon fatty acid-containing phospholipids in macrophages. A comprehensive qualitative analysis of Glycerophospholipids from different macrophage cells was conducted. During the phospholipid profiling of the macrophage-like RAW 264.7 cells, we identified dozens of rare or previously uncharacterized phospholipids, including ether-linked PIs, PSs, and glycerophosphatidic acids, PTs, and PCs and PTs containing very long polyunsaturated fatty acids. Additionally, large numbers of phospholipids containing at least one odd carbon fatty acid were identified. Using the same methodology, we also identified many of the same species of Glycerophospholipids in resident peritoneal macrophages, foam cells, and murine bone marrow derived macrophages.
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Lipid profiling reveals Glycerophospholipid remodeling in zymosan-stimulated macrophages.
Biochemistry, 2007Co-Authors: Carol A. Rouzer, Pavlina T. Ivanova, H. Alex Brown, Mark Byrne, Lawrence J. MarnettAbstract:Comprehensive lipid profiling by mass spectrometry provides comparative data on the relative distribution of individual Glycerophospholipids within each of the major classes. Application of this method to the analysis of Glycerophospholipid remodeling in murine primary resident peritoneal macrophages (RPMs) during zymosan phagocytosis reveals significant decreases in the levels of every major arachidonic acid (20:4)-containing species of phosphatidylcholine (GPCho) and in selected 20:4-containing phosphatidylinositol (GPIns) and phosphatidylglycerol (GPGro) species. No net changes in 20:4-containing phosphatidylethanolamine (GPEtn) species were detected. Pretreatment of RPMs with LPS resulted in subtle changes in the magnitude and kinetics of the response but had no effect on the overall pattern of zymosan-induced Glycerophospholipid remodeling. Inhibition of prostaglandin (PG) synthesis with indomethacin reduced the magnitude of the changes in 20:4-containing diacyl but not alkyl acyl species. Blockade of 20:4 reacylation with thimerosal had no effect on the magnitude of the zymosan-induced changes in GPCho, GPIns, or GPGro species but revealed decreases in the level of alkyl acyl GEtn species. RAW264.7 cells contain much lower levels of phospholipid 20:4 than do RPMs and synthesize PGs poorly in response to zymosan. Pretreatment with granulocyte-macrophage colony stimulating factor, lipopolysaccharide, and interferon-gamma substantially increased the extent of 20:4 mobilization and PG synthesis in these cells. However, under conditions of maximal zymosan-dependent PG synthesis, the only Glycerophospholipid that exhibited a significant change was a 20:4-containing plasmenyl GPEtn. These results suggest that GPCho is the major ultimate source of 20:4 that is mobilized in zymosan-stimulated RPMs but that 20:4 mobilization may involve the intermediate turnover of alkyl acyl GPEtn species.
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Glycerophospholipid identification and quantitation by electrospray ionization mass spectrometry.
Methods in enzymology, 2007Co-Authors: Pavlina T. Ivanova, Stephen B. Milne, Mark Byrne, Yun Xiang, H. Alex BrownAbstract:Glycerophospholipids are the structural building blocks of the cellular membrane. In addition to creating a protective barrier around the cell, lipids are precursors of intracellular signaling molecules that modulate membrane trafficking and are involved in transmembrane signal transduction. Phospholipids are also increasingly recognized as important participants in the regulation and control of cellular function and disease. Analysis and characterization of lipid species by mass spectrometry (MS) have evolved and advanced with improvements in instrumentation and technology. Key advances, including the development of "soft" ionization techniques for MS such as electrospray ionization (ESI), matrix-assisted laser desorption/ionization (MALDI), and tandem mass spectrometry (MS/MS), have facilitated the analysis of complex lipid mixtures by overcoming the earlier limitations. ESI-MS has become the technique of choice for the analysis of multi-component mixtures of lipids from biological samples due to its exceptional sensitivity and capacity for high throughput. This chapter covers qualitative and quantitative MS methods used for the elucidation of Glycerophospholipid identity and quantity in cell or tissue extracts. Sections are included on the extraction, MS analysis, and data analysis of Glycerophospholipids and polyphosphoinositides.
Stephen B. Milne - One of the best experts on this subject based on the ideXlab platform.
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Extensive sphingolipid depletion does not affect lipid raft integrity or lipid raft localization and efflux function of the ABC transporter MRP1
Biochemical Journal, 2010Co-Authors: Karin Klappe, Anne-jan Dijkhuis, Ina Hummel, Annie Van Dam, Pavlina T. Ivanova, Stephen B. Milne, David S. Myers, H. Alex Brown, Hjalmar P. Permentier, Jan Willem KokAbstract:We show that highly efficient depletion of sphingolipids in two different cell lines does not abrogate the ability to isolate Lubrol-based DRMs (detergent-resistant membranes) or detergent-free lipid rafts from these cells. Compared with control, DRM/detergent-free lipid raft fractions contain equal amounts of protein, cholesterol and phospholipid, whereas the classical DRM/lipid raft markers Src, caveolin-1 and flotillin display the same gradient distribution. DRMs/detergent-free lipid rafts themselves are severely depleted of sphingolipids. The fatty acid profile of the remaining sphingolipids as well as that of the Glycerophospholipids shows several differences compared with control, most prominently an increase in highly saturated C 16 species. The Glycerophospholipid headgroup composition is unchanged in sphingolipid-depleted cells and cell-derived detergent-free lipid rafts. Sphingolipid depletion does not alter the localization of MRP1 (multidrug-resistance-related protein 1) in DRMs/detergent-free lipid rafts or MRP1-mediated efflux of carboxyfluorescein. We conclude that extensive sphingolipid depletion does not affect lipid raft integrity in two cell lines and does not affect the function of the lipid-raft-associated protein MRP1.
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Extensive sphingolipid depletion does not affect lipid raft integrity or lipid raft localization and efflux function of the ABC transporter MRP1
Biochemical Journal, 2010Co-Authors: Karin Klappe, Anne-jan Dijkhuis, Ina Hummel, Annie Van Dam, Pavlina T. Ivanova, Stephen B. Milne, David S. Myers, H. Alex Brown, Hjalmar P. Permentier, Jan Willem KokAbstract:We show that highly efficient depletion of sphingolipids in two different cell lines does not abrogate the ability to isolate lubrol-based detergent-resistant membranes (DRMs) or detergent-free lipid rafts from these cells. Compared to control, DRM/detergent-free lipid raft fractions contain equal amounts of protein, cholesterol and phospholipid, while the classical DRM/lipid raft markers Src, caveolin-1 (Cav-1) and flotillin display the same gradient distribution. DRMs/detergent-free lipid rafts themselves are severely depleted of sphingolipids. The fatty acid profile of the remaining sphingolipids as well as that of the Glycerophospholipids shows several differences compared to control, most prominently an increase of highly saturated C16 species. The Glycerophospholipid headgroup composition is unchanged in sphingolipid depleted cells and cell-derived detergent-free lipid rafts. Sphingolipid depletion does not alter the localization of multidrug resistance-related protein 1 (MRP1) in DRMs/detergent-free lipid rafts or MRP1-mediated efflux of carboxyfluorescein. We conclude that extensive sphingolipid depletion does not affect lipid raft integrity in two cell lines and does not affect the function of the lipid raft-associated protein MRP1.
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Capture and release of alkyne-derivatized Glycerophospholipids using cobalt chemistry
Nature chemical biology, 2010Co-Authors: Stephen B. Milne, Keri A. Tallman, Remigiusz A. Serwa, Carol A. Rouzer, Michelle D. Armstrong, Lawrence J. Marnett, Charles M. Lukehart, Ned A. Porter, H. Alex BrownAbstract:Alkyne-modified phospholipids can be unambiguously identified and differentiated from native species in complex mixtures by formation of dicobalthexacarbonyl complexes. This reaction is specific for alkynes and is unaffected by other Glycerophospholipid-related moieties. Enrichment of cells with alkyne-derivatized fatty acids or Glycerophospholipids followed by solid-phase sequestration and release is a promising new method for unequivocally monitoring individual Glycerophospholipids following incorporation into cells. This technique also facilitates lipidomic analysis of substrates and products.
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Identification of atypical ether-linked Glycerophospholipid species in macrophages by mass spectrometry
Journal of lipid research, 2009Co-Authors: Pavlina T. Ivanova, Stephen B. Milne, H. Alex BrownAbstract:A large scale profiling and analysis of Glycerophospholipid species in macrophages has facilitated the identification of several rare and atypical Glycerophospholipid species. By using liquid chromatography tandem mass spectrometry and comparison of the elution and fragmentation properties of the rare lipids to synthetic standards, we were able to identify an array of ether-linked phosphatidylinositols (PIs), phosphatidic acids, phosphatidylserines (PSs), very long chain phosphatidylethanolamines (PEs), and phosphatidylcholines (PCs) as well as phosphatidylthreonines (PTs) and a wide collection of odd carbon fatty acid-containing phospholipids in macrophages. A comprehensive qualitative analysis of Glycerophospholipids from different macrophage cells was conducted. During the phospholipid profiling of the macrophage-like RAW 264.7 cells, we identified dozens of rare or previously uncharacterized phospholipids, including ether-linked PIs, PSs, and glycerophosphatidic acids, PTs, and PCs and PTs containing very long polyunsaturated fatty acids. Additionally, large numbers of phospholipids containing at least one odd carbon fatty acid were identified. Using the same methodology, we also identified many of the same species of Glycerophospholipids in resident peritoneal macrophages, foam cells, and murine bone marrow derived macrophages.
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Glycerophospholipid identification and quantitation by electrospray ionization mass spectrometry.
Methods in enzymology, 2007Co-Authors: Pavlina T. Ivanova, Stephen B. Milne, Mark Byrne, Yun Xiang, H. Alex BrownAbstract:Glycerophospholipids are the structural building blocks of the cellular membrane. In addition to creating a protective barrier around the cell, lipids are precursors of intracellular signaling molecules that modulate membrane trafficking and are involved in transmembrane signal transduction. Phospholipids are also increasingly recognized as important participants in the regulation and control of cellular function and disease. Analysis and characterization of lipid species by mass spectrometry (MS) have evolved and advanced with improvements in instrumentation and technology. Key advances, including the development of "soft" ionization techniques for MS such as electrospray ionization (ESI), matrix-assisted laser desorption/ionization (MALDI), and tandem mass spectrometry (MS/MS), have facilitated the analysis of complex lipid mixtures by overcoming the earlier limitations. ESI-MS has become the technique of choice for the analysis of multi-component mixtures of lipids from biological samples due to its exceptional sensitivity and capacity for high throughput. This chapter covers qualitative and quantitative MS methods used for the elucidation of Glycerophospholipid identity and quantity in cell or tissue extracts. Sections are included on the extraction, MS analysis, and data analysis of Glycerophospholipids and polyphosphoinositides.
Holm Holmsen - One of the best experts on this subject based on the ideXlab platform.
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the psychotropic drug olanzapine zyprexa increases the area of acid Glycerophospholipid monolayers
Biophysical Chemistry, 2008Co-Authors: Signe Steinkopf, Anja Katrin Schelderup, Hanne Linn Gjerde, Jeanette Pfeiffer, Synnøve Thoresen, Anja Underhaug Gjerde, Holm HolmsenAbstract:The typical antipsychotics chlorpromazine (CPZ) and trifluoperazine (TFP) increase the mean molecular area (mma) of acidic, but not neutral, Glycerophospholipids in monolayers at pH 7.36 measured by the Langmuir technique. The atypical antipsychotic olanzapine (OLP(1)) is structurally similar to TFP. We have therefore studied the effects of OLP on Glycerophospholipid monolayers and in comparison with CPZ. Olanzapine (10 microM, in subphase, pH 7.36) influenced the isotherms (surface pressure versus mma) in monolayers of the neutral dipalmitoyl phosphatidylcholine (DPPC) and the acidic dipalmitoyl phosphatidylserine (DPPS) or 1-palmitoyl-2-oleoylphosphatidylserine (POPS) in the increasing order of mma: DPPS
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The psychotropic drug olanzapine (Zyprexa) increases the area of acid Glycerophospholipid monolayers.
Biophysical chemistry, 2008Co-Authors: Signe Steinkopf, Anja Katrin Schelderup, Hanne Linn Gjerde, Jeanette Pfeiffer, Synnøve Thoresen, Anja Underhaug Gjerde, Holm HolmsenAbstract:The typical antipsychotics chlorpromazine (CPZ) and trifluoperazine (TFP) increase the mean molecular area (mma) of acidic, but not neutral, Glycerophospholipids in monolayers at pH 7.36 measured by the Langmuir technique. The atypical antipsychotic olanzapine (OLP(1)) is structurally similar to TFP. We have therefore studied the effects of OLP on Glycerophospholipid monolayers and in comparison with CPZ. Olanzapine (10 microM, in subphase, pH 7.36) influenced the isotherms (surface pressure versus mma) in monolayers of the neutral dipalmitoyl phosphatidylcholine (DPPC) and the acidic dipalmitoyl phosphatidylserine (DPPS) or 1-palmitoyl-2-oleoylphosphatidylserine (POPS) in the increasing order of mma: DPPS
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Glycerophospholipid molecular species in platelets and brain tissues are platelets a good model for neurons
Platelets, 2006Co-Authors: Anne M Bakken, Alexander Staeffler, Hugo A Jorgensen, Holm HolmsenAbstract:The molecular classes of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) from the basal ganglia, cerebellum, cortex, erythrocytes and blood platelets of female rats were separated by an isocratic HPLC method using a silica column and ultraviolet detection. Each Glycerophospholipid class were thereafter derivatized to dimethylphosphatidic acid (PA) molecular species, separated by reverse phase HPLC and detected by an evaporative laser scatter to quantify the different Glycerophospholipid species. The distribution of molecular species in each class of the Glycerophospholipids in the three brain areas was very similar with a predominance of the 18:0/22:6 species and very little of the 18:0/20:4 species. In contrast, the 18:0/20:4 species predominated in the blood cells which had a very low proportion of 18:0/22:6. These results are discussed on the background that platelets have been extensively used as a model for neurons and our previous physicochemical observation that ...
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Glycerophospholipid molecular species in platelets and brain tissues – are platelets a good model for neurons?
Platelets, 2006Co-Authors: Anne M Bakken, Alexander Staeffler, Hugo A Jorgensen, Holm HolmsenAbstract:The molecular classes of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) from the basal ganglia, cerebellum, cortex, erythrocytes and blood platelets of female rats were separated by an isocratic HPLC method using a silica column and ultraviolet detection. Each Glycerophospholipid class were thereafter derivatized to dimethylphosphatidic acid (PA) molecular species, separated by reverse phase HPLC and detected by an evaporative laser scatter to quantify the different Glycerophospholipid species. The distribution of molecular species in each class of the Glycerophospholipids in the three brain areas was very similar with a predominance of the 18:0/22:6 species and very little of the 18:0/20:4 species. In contrast, the 18:0/20:4 species predominated in the blood cells which had a very low proportion of 18:0/22:6. These results are discussed on the background that platelets have been extensively used as a model for neurons and our previous physicochemical observation that phenothiazines appear to interact specifically with the 18:0/22:6 species of PS.
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α-Lactalbumin binding and membrane integrity—effect of charge and degree of unsaturation of Glycerophospholipids
Biochimica et biophysica acta, 2005Co-Authors: Ingunn Rødland, Øyvind Halskau, Aurora Martinez, Holm HolmsenAbstract:Several studies have shown that the physical state of the phospholipid membrane has an important role in protein-membrane interactions, involving both electrostatic and hydrophobic forces. We have investigated the influence of the interaction of the calcium-depleted, (apo)-conformation of bovine alpha-lactalbumin (BLA) on the integrity of anionic Glycerophospholipid vesicles by leakage experiments using fluorescence spectroscopy. The stability of the membranes was also studied by measuring surface tension/molecular area relationships with phospholipid monolayers. We show that the degree of unsaturation of the acyl chains and the proportion of charged phospholipid species in the membranes made of neutral and acidic Glycerophospholipids are determinants for the association of BLA with liposomes and for the impermeability of the bilayer. Particularly, tighter packing counteracted interaction with BLA, while unsaturation-leading to looser packing-promoted interaction and leakage of contents. Equimolar mixtures of neutral and acidic Glycerophospholipids were more permeable upon protein binding than pure acidic lipids. The effect of lipid structure on BLA-membrane interaction and bilayer integrity may throw new light on the membrane disrupting mechanism of a conformer of human alpha-lactalbumin (HAMLET) that induces death of tumour cells but not of normal cells.
Berthold Koletzko - One of the best experts on this subject based on the ideXlab platform.
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Dietary Effects on Plasma Glycerophospholipids.
Journal of pediatric gastroenterology and nutrition, 2015Co-Authors: Olaf Uhl, Christian Hellmuth, Hans Demmelmair, Shao J. Zhou, Maria Makrides, Colin G. Prosser, Dianne Lowry, Robert A. Gibson, Berthold KoletzkoAbstract:Human milk provides a complex mixture of animal lipids, whereas the fat supply of most modern infant formula is based on vegetable oils. We studied the effects of breast-feeding and of feeding infant formula either without or with dairy goat lipids on the composition of infant plasma Glycerophospholipids. Healthy-term infants were randomized double blind to feeding with infant formula based on whole goats' milk (GIF, approximately 60% milk fat and 40% vegetable oils) or a control cows' milk infant formula based on vegetable oils (VIF) from 2 weeks after birth. A reference group of fully breast-fed infants was also followed. At the age 4 months, blood samples were collected and plasma Glycerophospholipids were analyzed with liquid chromatography coupled to triple quadrupole mass spectrometry. The group of breast-fed infants showed significantly higher contents of Glycerophospholipid species containing sn-2 palmitic acid [PC(16:0/16:0) and PC(18:0/16:0)] and significantly higher contents of Glycerophospholipid species containing long-chain polyunsaturated fatty acids than infants in both formula groups. The GIF group demonstrated significantly higher Glycerophospholipid species containing myristic acid [LPC(14:0), PC(14:0/18:1), PC(16:0/14:0)] and palmitoleic acid [LPC(16:1), PC(16:0/16:1), and PC(16:1/18:1)] than the VIF group. We conclude that breast-feeding induces marked differences in infant plasma Glycerophospholipid profiles compared with formula feeding, whereas the studied different sources of formula fat resulted in limited effects on plasma Glycerophospholipids.
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Changes of molecular Glycerophospholipid species in plasma and red blood cells during docosahexaenoic acid supplementation.
Lipids, 2013Co-Authors: Olaf Uhl, Hans Demmelmair, Mario Klingler, Berthold KoletzkoAbstract:Docosahexaenoic acid (DHA) status is related to health and disease risk. DHA status is mainly determined by dietary DHA intake, since endogenous synthesis of DHA is limited. We aimed to investigate the changes of different molecular Glycerophospholipid species containing DHA in plasma and red blood cells (RBC) in response to increased DHA intake. Thirteen healthy adults had their diet supplemented with 510 mg DHA/day for 29 days. Fasted blood samples were taken at 11 time points and Glycerophospholipid species were analyzed by liquid chromatography mass spectrometry. In plasma, percentages of Glycerophospholipid species containing DHA increased significantly by 64-104 % relative to baseline values during supplementation, but the relative distribution between species was not markedly altered. In RBC, phosphatidylcholine (PtdCho) species containing DHA increased to a similar extent as in plasma, while phosphatidylethanolamine and phosphatidylserine species with DHA increased by only 12-25 %, respectively, which was significantly different compared to PtdCho species (p < 0.01). Despite the high increase, the contribution of DHA PtdCho species to total DHA remained minor (14 % after supplementation). In conclusion, DHA supplementation does not alter the relative distribution of DHA among Glycerophospholipid species in plasma. A majority of PtdCho species are rapidly exchanged between plasma lipoproteins and RBC membrane lipids, while there is a minor exchange of phosphatidylethanolamine and phosphatidylserine species.
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Comparison of the incorporation of orally administered DHA into plasma, erythrocyte and cheek cell Glycerophospholipids
The British journal of nutrition, 2012Co-Authors: Mario Klingler, Hans Demmelmair, Sabrina Klem, Berthold KoletzkoAbstract:Adequate intake of n-3 fatty acids plays an important role in human health. The analysis of various blood lipids is used as a measure of fatty acid status in humans. Cheek cell phospholipids (PL) have also been proposed as biological markers, but are rarely used in clinical studies due to limitations in sample quality and quantity. An improved method for the analysis of cheek cell Glycerophospholipid fatty acids is applied in a 29 d supplementation trial with 510 mg DHA daily. The DHA increases in cheek cell, plasma and erythrocyte Glycerophospholipids are compared. High correlations are shown for Glycerophospholipid DHA between cheek cells and plasma (r 0·88) and erythrocytes (r 0·76) before study commencement. After the daily supplementation of DHA, the half-maximal Glycerophospholipid DHA level is reached after about 4 d in plasma, 6 d in erythrocytes and 10 d in cheek cells. The mean DHA increase (mol%) relative to baseline was most prominent in plasma (186 %), followed by cheek cells (180 %) and erythrocytes (130 %). Considering a lag phase of about 5 d, cheek cells reflect short-term changes in dietary fat uptake. Based on the data of the present study, they can be used alternatively to plasma and erythrocyte PL as non-invasive n-3 fatty acid status markers.
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Efficient and specific analysis of red blood cell Glycerophospholipid fatty acid composition.
PloS one, 2012Co-Authors: Sabrina Klem, Hans Demmelmair, Mario Klingler, Berthold KoletzkoAbstract:Red blood cell (RBC) n-3 fatty acid status is related to various health outcomes. Accepted biological markers for the fatty acid status determination are RBC phospholipids, phosphatidylcholine, and phosphatidyletholamine. The analysis of these lipid fractions is demanding and time consuming and total phospholipid n-3 fatty acid levels might be affected by changes of sphingomyelin contents in the RBC membrane during n-3 supplementation. We developed a method for the specific analysis of RBC Glycerophospholipids. The application of the new method in a DHA supplementation trial and the comparison to established markers will determine the relevance of RBC GPL as a valid fatty acid status marker in humans. Methyl esters of Glycerophospholipid fatty acids are selectively generated by a two step procedure involving methanolic protein precipitation and base-catalysed methyl ester synthesis. RBC GPL solubilisation is facilitated by ultrasound treatment. Fatty acid status in RBC Glycerophospholipids and other established markers were evaluated in thirteen subjects participating in a 30 days supplementation trial (510 mg DHA/d). The intra-assay CV for GPL fatty acids ranged from 1.0 to 10.5% and the inter-assay CV from 1.3 to 10.9%. Docosahexaenoic acid supplementation significantly increased the docosahexaenoic acid contents in all analysed lipid fractions. High correlations were observed for most of the mono- and polyunsaturated fatty acids, and for the omega-3 index (r = 0.924) between RBC phospholipids and Glycerophospholipids. The analysis of RBC Glycerophospholipid fatty acids yields faster, easier and less costly results equivalent to the conventional analysis of RBC total phospholipids.
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efficient and specific analysis of red blood cell Glycerophospholipid fatty acid composition
PLOS ONE, 2012Co-Authors: Sabrina Klem, Hans Demmelmair, Mario Klingler, Berthold KoletzkoAbstract:Background Red blood cell (RBC) n-3 fatty acid status is related to various health outcomes. Accepted biological markers for the fatty acid status determination are RBC phospholipids, phosphatidylcholine, and phosphatidyletholamine. The analysis of these lipid fractions is demanding and time consuming and total phospholipid n-3 fatty acid levels might be affected by changes of sphingomyelin contents in the RBC membrane during n-3 supplementation. Aim We developed a method for the specific analysis of RBC Glycerophospholipids. The application of the new method in a DHA supplementation trial and the comparison to established markers will determine the relevance of RBC GPL as a valid fatty acid status marker in humans. Methods Methyl esters of Glycerophospholipid fatty acids are selectively generated by a two step procedure involving methanolic protein precipitation and base-catalysed methyl ester synthesis. RBC GPL solubilisation is facilitated by ultrasound treatment. Fatty acid status in RBC Glycerophospholipids and other established markers were evaluated in thirteen subjects participating in a 30 days supplementation trial (510 mg DHA/d). Outcome The intra-assay CV for GPL fatty acids ranged from 1.0 to 10.5% and the inter-assay CV from 1.3 to 10.9%. Docosahexaenoic acid supplementation significantly increased the docosahexaenoic acid contents in all analysed lipid fractions. High correlations were observed for most of the mono- and polyunsaturated fatty acids, and for the omega-3 index (r = 0.924) between RBC phospholipids and Glycerophospholipids. The analysis of RBC Glycerophospholipid fatty acids yields faster, easier and less costly results equivalent to the conventional analysis of RBC total phospholipids.