title: HPLC-Based Mass Spectrometry Characterizes the Phospholipid Alterations in Ether-Linked Lipid Deficiency Models Following Oxidative Stress.
abstract: Despite the fact that the discovery of ether-linked phospholipids occurred nearly a century ago, many unanswered questions remain concerning these unique lipids. Here, we characterize the ether-linked lipids of the nematode with HPLC-MS/MS and find that more than half of the phosphoethanolamine-containing lipids are ether-linked, a distribution similar to that found in mammalian membranes. To explore the biological role of ether lipids in vivo, we target fatty acyl-CoA reductase (fard-1), an essential enzyme in ether lipid synthesis, with two distinct RNAi strategies. First, when fard-1 RNAi is initiated at the start of development, the treated animals have severely reduced ether lipid abundance, resulting in a shift in the phosphatidylethanolamine lipid population to include more saturated fatty acid chains. Thus, the absence of ether lipids during development drives a significant remodeling of the membrane landscape. A later initiation of fard-1 RNAi in adulthood results in a dramatic reduction of new ether lipid synthesis as quantified with 15N-tracers; however, there is only a slight decrease in total ether lipid abundance with this adult-only fard-1 RNAi. The two RNAi strategies permit the examination of synthesis and ether lipid abundance to reveal a relationship between the amount of ether lipids and stress survival. We tested whether these species function as sacrificial antioxidants by directly examining the phospholipid population with HPLC-MS/MS after oxidative stress treatment. While there are significant changes in other phospholipids, including polyunsaturated fatty acid-containing species, we did not find any change in ether-linked lipids, suggesting that the role of ether lipids in stress resistance is not through their general consumption as free radical sinks. Our work shows that the nematode will be a useful model for future interrogation of ether lipid biosynthesis and the characterization of phospholipid changes in various stress conditions.
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
authors.forename: Robin
authors.initials: R
authors.lastname: Drechsler
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
authors.forename: Shaw-Wen
authors.initials: SW
authors.lastname: Chen
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
authors.forename: Blair C R
authors.initials: BC
authors.lastname: Dancy
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
authors.forename: Lena
authors.initials: L
authors.lastname: Mehrabkhani
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
authors.forename: Carissa Perez
authors.identifier: http://orcid.org/0000-0003-1261-9364
authors.initials: CP
authors.lastname: Olsen
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004986:Ether / Q000737:chemistry*; D050356:Lipid Metabolism; D008055:Lipids / Q000172:deficiency*; D018384:Oxidative Stress; D010743:Phospholipids / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D008055:Lipids; D010743:Phospholipids; D004986:Ether