Identification of Abundant Alkyl Ether Glycerophospholipids in the Human Lens by Tandem Mass Spectrometry Techniques

Deeley, Jane M.; Thomas, Michael C.; Truscott, Roger J.W.; Mitchell, Todd W.; Blanksby, Stephen J.

doi:10.1021/ac802395d

Cited by 59 publications

(47 citation statements)

References 27 publications

(88 reference statements)

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“…While CACI-MS/MS relies on an in-source chemical modification of lipid molecules prior to any mass selection, OzID begins with the conventional electrospray ionization (ESI) of lipids that are then mass-selected before undergoing ion-molecule reactions with ozone. This technique has been used to identify isomeric lipids differing in double-bond position from complex biological extracts, including olive oil [30], human lens [31], and cow brain [32]. Here, we demonstrate, for the first time, the effectiveness of OzID analysis on conjugated lipids and report a remarkable enhancement in the rate of the ion-molecule reaction in the presence of this bonding motif.…”

Section: Introductionmentioning

confidence: 75%

Ozone-Induced Dissociation of Conjugated Lipids Reveals Significant Reaction Rate Enhancements and Characteristic Odd-Electron Product Ions

Maccarone

Campbell²,

Mitchell

et al. 2013

J. Am. Soc. Mass Spectrom.

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. Ozone-induced dissociation of conjugated lipids reveals significant reaction rate enhancements and characteristic odd-electron product ions. Journal of the American Society for Mass Spectrometry, 24 (2), 286-296.Ozone-induced dissociation of conjugated lipids reveals significant reaction rate enhancements and characteristic odd-electron product ions AbstractOzone-induced dissociation (OzID) is an alternative ion activation method that relies on the gas phase ionmolecule reaction between a mass-selected target ion and ozone in an ion trap mass spectrometer. Herein, we evaluated the performance of OzID for both the structural elucidation and selective detection of conjugated carbon-carbon double bond motifs within lipids. The relative reactivity trends for [M + X]+ ions (where X = Li, Na, K) formed via electrospray ionization (ESI) of conjugated versus nonconjugated fatty acid methyl esters (FAMEs) were examined using two different OzID-enabled linear ion-trap mass spectrometers. Compared with nonconjugated analogues, FAMEs derived from conjugated linoleic acids were found to react up to 200 times faster and to yield characteristic radical cations. The significantly enhanced reactivity of conjugated isomers means that OzID product ions can be observed without invoking a reaction delay in the experimental sequence (i.e., trapping of ions in the presence of ozone is not required). This possibility has been exploited to undertake neutral-loss scans on a triple quadrupole mass spectrometer targeting characteristic OzID transitions. Such analyses reveal the presence of conjugated double bonds in lipids extracted from selected foodstuffs. Finally, by benchmarking of the absolute ozone concentration inside the ion trap, second order rate constants for the gas phase reactions between unsaturated organic ions and ozone were obtained. These results demonstrate a significant influence of the adducting metal on reaction rate constants in the fashion Li > Na > K. second order rate constants for the gas phase reactions between unsaturated organic ions and ozone were obtained. These results demonstrate a significant influence of the adducting metal on reaction rate constants in the fashion Li > Na > K.3

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Section: Introductionmentioning

confidence: 75%

Ozone-Induced Dissociation of Conjugated Lipids Reveals Significant Reaction Rate Enhancements and Characteristic Odd-Electron Product Ions

Maccarone

Campbell²,

Mitchell

et al. 2013

J. Am. Soc. Mass Spectrom.

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“…In both classes, the major components were 1-O-alkyl ethers and the fatty acid compositions of the most abundant PE species (16:0e/18:1), (18:1e/ 18:1) and (18:0e/18:1) correlated with that of the major PS moieties (Deeley et al 2009). A pathway involving decarboxylation of PS is well known (Borkenhagen et al 1961;Kanfer and Kennedy 1964;Satre and Kennedy 1978) and PE can be converted to PSs by PS synthase 2 (Saito et al 1998).…”

Section: Discussionmentioning

confidence: 95%

“…The major contributors to this 6-to 8-fold decrease in total PS were PS (16:0e/18:1), PS (18:1e/18:1) and PS (18:0e/18:1), which are the most abundant PS molecules in the human lens and account for 75-90% of total PSs. These 1-O-alkyl ethers have recently been identified in the human lens (Deeley et al 2009). Diester-linked PSs were detected at much lower concentrations (~10-25% of total PSs) and showed a similar pattern of decay with age.…”

Section: Phosphatidylserinesmentioning

confidence: 98%

“…During the course of this study, we further optimized our lipid extraction procedure in order to maximize extraction efficiency for a range of animal tissues (in particular to avoid the loss of 1-O-alkenyl ethers) and improve compatibility with ESI-MS. Although the levels of 1-O-alkenyl ethers in the human lens are minimal (Deeley et al 2009), the subsequent 40 lenses were extracted as described above; however, the sulfuric acid was replaced with aqueous ammonium acetate (0.15 M) (Deeley et al 2008). No significant differences in human lens phospholipid abundance were observed between the two extraction methods; therefore, all 57 lenses were included in this study.…”

Section: Lipid Extractionmentioning

confidence: 99%

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Instability of the cellular lipidome with age

Hughes

Deeley

Blanksby

et al. 2011

AGE

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The human lens nucleus is formed in utero, and from birth onwards, there appears to be no significant turnover of intracellular proteins or membrane components. Since, in adults, this region also lacks active enzymes, it offers the opportunity to examine the intrinsic stability of macromolecules under physiological conditions. Fifty seven human lenses, ranging in age from 12 to 82 years, were dissected into nucleus and cortex, and the nuclear lipids analyzed by electrospray ionization tandem mass spectrometry. In the first four decades of life, glycerophospholipids (with the exception of lysophosphatidylethanolamines) declined rapidly, such that by age 40, their content became negligible. In contrast the level of ceramides and dihydroceramides, which were undetectable prior to age 30, increased approximately 100-fold. The concentration of sphingomyelins and dihydrosphingomyelins remained unchanged over the whole life span. As a consequence of this marked alteration in composition, the properties of fiber cell membranes in the centre of young lenses are likely to be very different from those in older lenses. Interestingly, the identification of age 40 years as a time of transition in the lipid composition of the nucleus coincides with previously reported macroscopic changes in lens properties (e.g., a massive age-related increase in lens stiffness) and related pathologies such as presbyopia. The underlying reasons for the dramatic change in the lipid profile of the human lens with age are not known, but are most likely linked to the stability of some membrane lipids in a physiological environment.

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“…The method we employ for phospholipid LC analysis allows its separation from PS and other glycerophospholipids. Using the gradient and the silica column described above, PT elutes During the comprehensive lipid profi ling of these cells, another two classes of ether-containing glycerophospholipids were identifi ed, which have not been reported previously in macrophages, but have been identifi ed in other biological tissues ( 23,24 ). The presence of ether-PA was established in the chromatographic peak fraction from RAW 264.7 and foam cells.…”

Section: Glycerophosphothreonine Detectionmentioning

confidence: 90%

Identification of atypical ether-linked glycerophospholipid species in macrophages by mass spectrometry

Ivanova

Milne

Brown

2010

Journal of Lipid Research

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Identification of Abundant Alkyl Ether Glycerophospholipids in the Human Lens by Tandem Mass Spectrometry Techniques

Abstract: Recommended CitationTruscott, Roger J.; Deeley, Jane; Mitchell, Todd W.; Thomas, Michael; and Blanksby, Stephen J.: Identification of abundant alkyl ether glycerophospholipids in the human lens by tandem mass spectrometry techniques 2009, 1920-1930.

Cited by 59 publications

References 27 publications

Ozone-Induced Dissociation of Conjugated Lipids Reveals Significant Reaction Rate Enhancements and Characteristic Odd-Electron Product Ions

Ozone-Induced Dissociation of Conjugated Lipids Reveals Significant Reaction Rate Enhancements and Characteristic Odd-Electron Product Ions

Instability of the cellular lipidome with age

Identification of atypical ether-linked glycerophospholipid species in macrophages by mass spectrometry

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