title: Biosynthesis of oxidized lipid mediators via lipoprotein-associated phospholipase A2 hydrolysis of extracellular cardiolipin induces endothelial toxicity.
abstract: We (66) have previously described an NSAID-insensitive intramitochondrial biosynthetic pathway involving oxidation of the polyunsaturated mitochondrial phospholipid, cardiolipin (CL), followed by hydrolysis [by calcium-independent mitochondrial calcium-independent phospholipase A2-γ (iPLA2γ)] of oxidized CL (CLox), leading to the formation of lysoCL and oxygenated octadecadienoic metabolites. We now describe a model system utilizing oxidative lipidomics/mass spectrometry and bioassays on cultured bovine pulmonary artery endothelial cells (BPAECs) to assess the impact of CLox that we show, in vivo, can be released to the extracellular space and may be hydrolyzed by lipoprotein-associated PLA2 (Lp-PLA2). Chemically oxidized liposomes containing bovine heart CL produced multiple oxygenated species. Addition of Lp-PLA2 hydrolyzed CLox and produced (oxygenated) monolysoCL and dilysoCL and oxidized octadecadienoic metabolites including 9- and 13-hydroxyoctadecadienoic (HODE) acids. CLox caused BPAEC necrosis that was exacerbated by Lp-PLA2 Lower doses of nonlethal CLox increased permeability of BPAEC monolayers. This effect was exacerbated by Lp-PLA2 and partially mimicked by authentic monolysoCL or 9- or 13-HODE. Control mice plasma contained virtually no detectable CLox; in contrast, 4 h after Pseudomonas aeruginosa (P. aeruginosa) infection, 34 ± 8 mol% (n = 6; P < 0.02) of circulating CL was oxidized. In addition, molar percentage of monolysoCL increased twofold after P. aeruginosa in a subgroup analyzed for these changes. Collectively, these studies suggest an important role for 1) oxidation of CL in proinflammatory environments and 2) possible hydrolysis of CLox in extracellular spaces producing lysoCL and oxidized octadecadienoic acid metabolites that may lead to impairment of pulmonary endothelial barrier function and necrosis.
authors.affiliation: Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania; University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Vascular Medicine Institute, Pittsburgh, Pennsylvania;
authors.forename: Justin R
authors.initials: JR
authors.lastname: Buland
authors.affiliation: University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania;
authors.forename: Karla J
authors.initials: KJ
authors.lastname: Wasserloos
authors.affiliation: University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania;
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Tyurin
authors.affiliation: University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania;
authors.forename: Yulia Y
authors.initials: YY
authors.lastname: Tyurina
authors.affiliation: University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania;
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Amoscato
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Acute Lung Injury Center of Excellence, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; VA Pittsburgh Health Care System, Pittsburgh, Pennsylvania; Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Rama K
authors.initials: RK
authors.lastname: Mallampalli
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Acute Lung Injury Center of Excellence, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania;
authors.forename: Bill B
authors.initials: BB
authors.lastname: Chen
authors.affiliation: Vascular Medicine Institute, Pittsburgh, Pennsylvania; Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Acute Lung Injury Center of Excellence, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania;
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.affiliation: University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Vascular Medicine Institute, Pittsburgh, Pennsylvania; Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Acute Lung Injury Center of Excellence, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania;
authors.forename: Yutong
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Vascular Medicine Institute, Pittsburgh, Pennsylvania;
authors.forename: Solomon
authors.initials: S
authors.lastname: Ofori-Acquah
authors.affiliation: University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania;
authors.forename: Valerian E
authors.initials: VE
authors.lastname: Kagan
authors.affiliation: University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania; brucep@pitt.edu.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Pitt
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000502:physiology*; D000818:Animals; D002308:Cardiolipins / Q000096:biosynthesis* / Q000097:blood; D002417:Cattle; D002478:Cells, Cultured; D017097:Electric Impedance; D042783:Endothelial Cells / Q000502:physiology*; D006868:Hydrolysis; D008810:Mice, Inbred C57BL; D010084:Oxidation-Reduction; D011552:Pseudomonas Infections / Q000097:blood; D015398:Signal Transduction
chemical_list: D002308:Cardiolipins; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase
keywords: cardiolipin; lineolic acid; lipoprotein-associated phospholipase A2; octadecadienoic acid; pulmonary endothelium