Impairment of the cytotoxic and oxidative activities of 7β-hydroxycholesterol and 7-ketocholesterol by esterification with oleate

• Published in: Biochemical and biophysical research communications 2003-04, Vol.303 (3), p.814-824
• Main Authors: Monier, Serge, Samadi, Mohammad, Prunet, Céline, Denance, Mikeäl, Laubriet, Aline, Athias, Anne, Berthier, Arnaud, Steinmetz, Eric, Jürgens, Günter, Nègre-Salvayre, Anne, Bessède, Ginette, Lemaire-Ewing, Stéphanie, Néel, Dominique, Gambert, Philippe, Lizard, Gérard
• Format: Article
• Language: English
• Subjects: 7-Ketocholesterol; 7-Ketocholesteryl-3-oleate; 7β-Hydroxycholesterol; 7β-Hydroxycholesteryl-3-oleate; 8-Oxoguanine; Apoptosis; Arteriosclerosis - etiology; Arteriosclerosis - metabolism; Arteriosclerosis - prevention & control; Cadaverine - analogs & derivatives; Cadaverine - metabolism; Cell Survival - drug effects; Cholesterol; DNA Damage; Esterification; Humans; Hydroxycholesterols - chemistry; Hydroxycholesterols - metabolism; Hydroxycholesterols - toxicity; Ketocholesterols - chemistry; Ketocholesterols - metabolism; Ketocholesterols - toxicity; Lipid peroxidation; Lipid Peroxidation - drug effects; Monodansylcadaverine; Nitric Oxide - biosynthesis; Oleic Acid - metabolism; Oxidation-Reduction; Reactive oxygen species; Superoxides - metabolism; U937 Cells
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/S0006-291X(03)00412-1

Atherosclerosis involves inflammatory processes, as well as cytotoxic and oxidative reactions. In atherosclerotic plaques, these phenomena are revealed by the presence of dead cells, oxidized lipids, and oxidative DNA damage, but the molecules triggering these events are still unknown. As 7β-hydroxycholesterol and 7-ketocholesterol, which are present at elevated concentrations in atherosclerotic lesions, are strongly cytotoxic and pro-oxidative, their effects were determined on cell death, superoxide anion and nitric oxide production, lipid peroxidation, and oxidative DNA damage. 7-Ketocholesterol- and 7β-hydroxycholesterol-induced cell death leads to a loss of mitochondrial potential, to increased permeability to propidium iodide, and to morphological nuclear changes (swelling, fragmentation, and/or condensation of nuclei). These effects are preceded by the formation of cytoplasmic monodansylcadaverine-positive structures and are associated with a rapid enhancement of cells overproducing superoxide anions, a decrease in cells producing nitric oxide, lipid peroxidation (formation of malondialdehyde and 4-hydroxynonenal adducts, low ratio of [unsaturated fatty acids]/[saturated fatty acids]) as well as oxidative DNA damage (8-oxoguanine formation). Noteworthy, none of the cytotoxic features previously observed with 7β-hydroxycholesterol and 7-ketocholesterol were noted with cholesterol, 7β-hydroxycholesteryl-3-oleate and 7-ketocholesteryl-3-oleate, with the exception of a slight increase in superoxide anion production with 7β-hydroxycholesteryl-3-oleate. This finding supports the theory that 7β-hydroxycholesterol and 7-ketocholesterol could induce cytotoxic and oxidative processes observed in atherosclerotic lesions and that esterification of these compounds may contribute to reducing atherosclerosis progression.