title: Electrospray ionization tandem mass spectrometry of sodiated adducts of cholesteryl esters.
abstract: Cholesteryl esters (CE) are important lipid storage molecules. The present study demonstrates that sodiated adducts of CE molecular species form positive ions that can be detected in both survey scan mode as well as by exploiting class-specific fragmentation in MS/MS scan modes. A common neutral loss for CE is the loss of cholestane (NL 368.5), which can be used to specifically quantify tissue CE molecular species. Using this MS/MS technique, CE molecular species were quantified in mouse monocyte-derived macrophages (J774 cells) incubated with either linoleic (18:2) or arachidonic acid (20:4). These studies revealed that arachidonic acid was not only incorporated into the CE pool, but also was elongated resulting in the accumulation of 22:4 and 24:4 CE molecular species in macrophages. Additionally, this technique was used to quantify CE molecular species present in crude lipid extracts from plasma of female mice fed a Western diet, which led to an enrichment in CE molecular species containing monounsaturated fatty acids compared to female mice fed a normal chow diet. Last, NL 368.5 spectra revealed the oxidation of the aliphatic fatty acid residues of CE molecular species containing polyunsaturated fatty acids. Taken together, these studies demonstrate the utility of using sodiated adducts of CE in conjunction with direct infusion electrospray ionization tandem mass spectrometry to rapidly quantify CE molecular species in biological samples.
authors: Department of Biochemistry and Molecular Biology, School of Medicine, and Center for Cardiovascular Research, Saint Louis University, MO 63104, USA.
authors: John A
authors: JA
authors: Bowden
authors: Fei
authors: F
authors: Shao
authors: Carolyn J
authors: CJ
authors: Albert
authors: John W
authors: JW
authors: Lally
authors: Robert J
authors: RJ
authors: Brown
authors: Jesse D
authors: JD
authors: Procknow
authors: Alan H
authors: AH
authors: Stephenson
authors: David A
authors: DA
authors: Ford
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000032:analysis / Q000378:metabolism; D002776:Cholestanes / Q000032:analysis / Q000737:chemistry; D002788:Cholesterol Esters / Q000032:analysis*; D045424:Complex Mixtures / Q000097:blood* / Q000737:chemistry; D005260:Female; D007477:Ions / Q000737:chemistry; D019787:Linoleic Acid / Q000032:analysis / Q000378:metabolism; D050356:Lipid Metabolism; D008264:Macrophages / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D051379:Mice; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods; D014280:Triglycerides / Q000032:analysis
chemical_list: D002776:Cholestanes; D002788:Cholesterol Esters; D045424:Complex Mixtures; D007477:Ions; D014280:Triglycerides; D016718:Arachidonic Acid; D019787:Linoleic Acid