title: Oxidized low-density lipoprotein and 15-deoxy-delta 12,14-PGJ2 increase mitochondrial complex I activity in endothelial cells.
abstract: Oxidized lipids are capable of initiating diverse cellular responses through both receptor-mediated mechanisms and direct posttranslational modification of proteins. Typically, exposure of cells to low concentrations of oxidized lipids induces cytoprotective pathways, whereas high concentrations result in apoptosis. Interestingly, mitochondria can contribute to processes that result in either cytoprotection or cell death. The role of antioxidant defenses such as glutathione in adaptation to stress has been established, but the potential interaction with mitochondrial function is unknown and is examined in this article. Human umbilical vein endothelial cells (HUVEC) were exposed to oxidized LDL (oxLDL) or the electrophilic cyclopentenone 15-deoxy-Delta 12,14-PGJ2 (15d-PGJ2). We demonstrate that complex I activity, but not citrate synthase or cytochrome-c oxidase, is significantly induced by oxLDL and 15d-PGJ2. The mechanism is not clear at present but is independent of the induction of GSH, peroxisome proliferator-activated receptor (PPAR)-gamma, and PPAR-alpha. This response is dependent on the induction of oxidative stress in the cells because it can be prevented by nitric oxide, probucol, and the SOD mimetic manganese(III) tetrakis(4-benzoic acid) porphyrin chloride. This increased complex I activity appears to contribute to protection against apoptosis induced by 4-hydroxynonenal.
authors.affiliation: Department of Pathology, University of Alabama at Birmingham, 35294, USA.
authors.forename: Erin K
authors.initials: EK
authors.lastname: Ceaser
authors.forename: Anup
authors.initials: A
authors.lastname: Ramachandran
authors.forename: Anna-Liisa
authors.initials: AL
authors.lastname: Levonen
authors.forename: Victor M
authors.initials: VM
authors.lastname: Darley-Usmar
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D002478:Cells, Cultured; D004579:Electron Transport / Q000502:physiology; D042967:Electron Transport Complex I / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology*; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000494:pharmacology*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014157:Transcription Factors / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D015854:Up-Regulation / Q000502:physiology
chemical_list: C097240:15-deoxy-delta(12,14)-prostaglandin J2; D000975:Antioxidants; D007155:Immunologic Factors; D008077:Lipoproteins, LDL; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; C099252:oxidized low density lipoprotein; D042967:Electron Transport Complex I; D005978:Glutathione; D015230:Prostaglandin D2