title: Subcellular organelle lipidomics in TLR-4-activated macrophages.
abstract: Lipids orchestrate biological processes by acting remotely as signaling molecules or locally as membrane components that modulate protein function. Detailed insight into lipid function requires knowledge of the subcellular localization of individual lipids. We report an analysis of the subcellular lipidome of the mammalian macrophage, a cell type that plays key roles in inflammation, immune responses, and phagocytosis. Nuclei, mitochondria, endoplasmic reticulum (ER), plasmalemma, and cytoplasm were isolated from RAW 264.7 macrophages in basal and activated states. Subsequent lipidomic analyses of major membrane lipid categories identified 229 individual/isobaric species, including 163 glycerophospholipids, 48 sphingolipids, 13 sterols, and 5 prenols. Major subcellular compartments exhibited substantially divergent glycerophospholipid profiles. Activation of macrophages by the Toll-like receptor 4-specific lipopolysaccharide Kdo(2)-lipid A caused significant remodeling of the subcellular lipidome. Some changes in lipid composition occurred in all compartments (e.g., increases in the levels of ceramides and the cholesterol precursors desmosterol and lanosterol). Other changes were manifest in specific organelles. For example, oxidized sterols increased and unsaturated cardiolipins decreased in mitochondria, whereas unsaturated ether-linked phosphatidylethanolamines decreased in the ER. We speculate that these changes may reflect mitochondrial oxidative stress and the release of arachidonic acid from the ER in response to cell activation.
authors.affiliation: Department of Chemistry and Biochemistry and Department of Pharmacology, University of California, San Diego, CA 92093, USA.
authors.forename: Alexander Y
authors.initials: AY
authors.lastname: Andreyev
authors.forename: Eoin
authors.initials: E
authors.lastname: Fahy
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Guan
authors.forename: Samuel
authors.initials: S
authors.lastname: Kelly
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: McDonald
authors.forename: Stephen
authors.initials: S
authors.lastname: Milne
authors.forename: David
authors.initials: D
authors.lastname: Myers
authors.forename: Hyejung
authors.initials: H
authors.lastname: Park
authors.forename: Andrea
authors.initials: A
authors.lastname: Ryan
authors.forename: Bonne M
authors.initials: BM
authors.lastname: Thompson
authors.forename: Elaine
authors.initials: E
authors.lastname: Wang
authors.forename: Yihua
authors.initials: Y
authors.lastname: Zhao
authors.forename: H Alex
authors.initials: HA
authors.lastname: Brown
authors.forename: Alfred H
authors.initials: AH
authors.lastname: Merrill
authors.forename: Christian R H
authors.initials: CR
authors.lastname: Raetz
authors.forename: David W
authors.initials: DW
authors.lastname: Russell
authors.forename: Shankar
authors.initials: S
authors.lastname: Subramaniam
authors.forename: Edward A
authors.initials: EA
authors.lastname: Dennis
mesh_terms: D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D019295:Computational Biology / Q000379:methods; D016208:Databases, Factual; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D008055:Lipids / Q000032:analysis*; D008264:Macrophages / Q000378:metabolism / Q000648:ultrastructure; D051379:Mice; D015388:Organelles / Q000737:chemistry*; D018384:Oxidative Stress; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D008055:Lipids; D051197:Toll-Like Receptor 4