title: Paraoxonase 1 protects macrophages from atherogenicity of a specific triglyceride isolated from human carotid lesion.
abstract: Human atherosclerotic lesions contain oxidized lipids that facilitate further oxidation of macrophages, LDLs, and oxidative stress (OS)-sensitive markers and inhibit the antiatherogenic enzyme paraoxonase 1 (PON1). Our aim was to isolate and identify the oxidizing agent in a human atherosclerotic lesion lipid extract (LLE) and to explore the mechanisms of oxidation and of PON1's effect on the oxidizing agent. Of the five main fractions separated from the LLE, only fraction 2 (F2) promoted macrophage reactive oxygen species (ROS) production via a mechanism requiring mitochondrial involvement, whereas the NADPH oxidase system was not involved. Incubation of F2 with PON1 abridged the former's peroxide value and reduced its capacity to oxidize OS markers. The active agent was a triglyceride composed of palmitic, oleic, and linoleic acids, with 0.3% of its linoleic moiety in oxidized form. Incubation of either F2 or an identical synthetic triglyceride with PON1 reduced their ability to oxidize macrophages, without affecting cellular accumulation of triglycerides. We conclude that macrophage ROS production by LLE occurs in the presence of a specific triglyceride and requires mitochondrial involvement. Lipid peroxide in the triglyceride can also facilitate lipid autoxidation. Both atherogenic pathways are suppressed by PON1, which acts as an antiatherogenic element.
authors.affiliation: Oxidative Stress Research Laboratory, MIGAL-Galilee Technology Center, Kiryat Shmona 11016, Israel.
authors.forename: Hagai
authors.initials: H
authors.lastname: Tavori
authors.forename: Michael
authors.initials: M
authors.lastname: Aviram
authors.forename: Soliman
authors.initials: S
authors.lastname: Khatib
authors.forename: Ramadan
authors.initials: R
authors.lastname: Musa
authors.forename: Dalit
authors.initials: D
authors.lastname: Mannheim
authors.forename: Ron
authors.initials: R
authors.lastname: Karmeli
authors.forename: Jacob
authors.initials: J
authors.lastname: Vaya
mesh_terms: D000818:Animals; D001161:Arteriosclerosis / Q000378:metabolism*; D043303:Aryldialkylphosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002340:Carotid Artery Diseases / Q000378:metabolism*; D006801:Humans; D008054:Lipid Peroxides / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D019255:NADPH Oxidases; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D014280:Triglycerides / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D008054:Lipid Peroxides; D017382:Reactive Oxygen Species; D014280:Triglycerides; D019255:NADPH Oxidases; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human; C560867:PON1 protein, mouse