13-hydroperoxy-9-11-octadecadienoic-acid and coelenterazine

Oxidized lipids, such as 13-hydroperoxyoctadecadienoic acid (13-HPODE), have been implicated in the pathogenesis of atherosclerosis. 13-HPODE, a constituent of oxidized low-density lipoproteins, can induce cytotoxicity of vascular smooth muscle cells (SMC), which may facilitate plaque destabilization and/or rupture. 13-HPODE-induced cytotoxicity has been linked to oxidative stress, although the mechanisms by which this occurs are unknown. In the present study, we show that 13-HPODE and 9-HPODE (10-30 microM) increased superoxide (O2*-) production and induced cytotoxicity in SMC. The 13-HPODE-induced increase in O2*- was blocked by transfecting the cells with antisense oligonucleotides against p22phox, suggesting that the O2*- was produced by NAD(P)H oxidase. Similar concentrations of the corresponding HPODE reduction products, 13-hydroxyoctadecadienoic acid (13-HODE) and 9-HODE, neither increased O2*- production nor induced cytotoxicity, while 4-hydroxy nonenal (4-HNE), an unsaturated aldehyde lipid peroxidation product, induced cytotoxicity without increasing O2*- production. Treatment with superoxide dismutase or Tiron to scavenge O2*-, or transfection with p22phox antisense oligonucleotides to inhibit O2*- production, attenuated 13-HPODE-induced cytotoxicity, but not that induced by 4-HNE. These findings suggest that activation of NAD(P)H oxidase, and production of O2*-, play an important role in lipid hydroperoxide-induced smooth muscle cytotoxicity.

Topics: Animals; Arteriosclerosis; Cell Survival; Cells, Cultured; Enzyme Activation; Free Radicals; Imidazoles; Linoleic Acids; Lipid Peroxides; Male; Membrane Transport Proteins; Microscopy, Confocal; Muscle, Smooth; NADPH Dehydrogenase; NADPH Oxidases; Oligonucleotides, Antisense; Oxidants; Oxidative Stress; Oxygen; Phosphoproteins; Pyrazines; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Superoxides; Transfection