Pro‐oxidant effects of 7‐hydroperoxycholest‐5‐en‐3β‐ol on the copper‐initiated oxidation of low density lipoprotein

Blache, Denis; Rodriguez, C.; Davignon, Jean

doi:10.1016/0014-5793(94)01348-5

Cited by 21 publications

(12 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the procedures used in the present paper, the endogenous peroxide content of the isolated LDL is an important determinant of the oxidizability of LDL for the copper-mediated oxidation, whereas using AAPH the mechanism in less dependent on the lipid peroxides. Besides fatty acid peroxides [24,25], cholesterol peroxides potentiated the Cu2+-initiated LDL oxidation [26]. However, these latter compounds did not account for the effects observed with CS in the present study since TLC-repurifled CS was as pro-oxidant as stock CS.…”

Section: Time (Mn)contrasting

confidence: 52%

Enhanced susceptibility of cholesteryl sulfate‐enriched low density lipoproteins to copper‐mediated oxidation

1995

Self Cite

View full text Add to dashboard Cite

Cholesteryl sulfate (CS) is a minor component of cell membranes, also present in lipoproteins, and its exact function is unknown. Since oxidation of low density lipoproteins (LDL) is thought to be an important determinant of atherogenesis, we investigated the influence of CS enrichment on copper-mediated oxidation of LDL. CS was found to act as a pro-oxidant, as measured by lipid oxidation parameters. The results also suggest that these effects were dependent on the sulfate group since pure cholesterol or cholesteryl acetate did not promote Cu2÷-mediated oxidation. Our findings imply that CS may affect the oxidizability and hence the potential atherogenicity of LDL.

show abstract

Section: Time (Mn)contrasting

confidence: 52%

Enhanced susceptibility of cholesteryl sulfate‐enriched low density lipoproteins to copper‐mediated oxidation

1995

Self Cite

View full text Add to dashboard Cite

show abstract

“…[10] In the present study, we investigated the respective involvement of sulfur groups in the antioxidant activity of HSA. Influence and importance of targeted modifications of Cys and Met by N-ethylmaleimide (NEM) and chloramine T (CT) were examined on HSA antioxidant activity assessed by the coppermediated oxidation of human low density lipoproteins (LDL) [11] and by the free radical-induced blood hemolysis tests. [12] Materials and methods…”

Section: Introductionmentioning

confidence: 99%

Differential effects of cysteine and methionine residues in the antioxidant activity of human serum albumin

Bourdon

Loreau

Lagrost

et al. 2005

Free Radical Research

126

View full text Add to dashboard Cite

Antioxidant properties of human serum albumin (HSA) may explain part of its beneficial role in various diseases related to free radical attack. In the present study, the antioxidant role of Cys and Met was studied by copper-mediated oxidation of human low density lipoproteins and by free radical-induced blood hemolysis which essentially assessed metal-chelating and free radical scavenging activities, respectively. Mild conditions were set up to specifically modify Cys and Met residues by N-ethylmaleimide (NEM) and chloramine T treatments, respectively. We found that Met and Cys accounted for 40-80% of total antioxidant activity of HSA. Copper binding to HSA was decreased by about 50% with chloramine T treatment of Met whereas no change was observed after NEM treatment of Cys. Although other amino acid residues are likely to be involved in anti-/prooxidant properties of HSA, from our data, we propose that Cys chiefly works as a free radical scavenger whereas Met mainly acts as a metal chelator.

show abstract

“…At higher temperatures, copper can also react nonenzymatically with cholesterol (35,36) or arachidonate (37) in the presence of oxygen to produce hydroperoxide derivatives. To test whether the ␤-amyloid reaction product was the same as that produced by copper alone, we reacted cholesterol (0.1 g) with 10 mM CuCl 2 under 100% oxygen in tetrahydrofuran at 60°C overnight.…”

Section: Figmentioning

confidence: 99%

Oxidation of Cholesterol by Amyloid Precursor Protein and β-Amyloid Peptide

Nelson

Alkon

2005

Journal of Biological Chemistry

178

129

View full text Add to dashboard Cite

Alzheimer's disease (AD) is characterized by accumulation of the neurotoxic peptide ␤-amyloid, which is produced by proteolysis of amyloid precursor protein (APP). APP is a large membrane-bound copper-binding protein that is essential in maintaining synaptic function and may play a role in synaptogenesis. ␤-Amyloid has been shown to contribute to the oxidative stress that accompanies AD. Later stages of AD are characterized by neuronal apoptosis. However, the biochemical function of APP and the mechanism of the toxicity of ␤-amyloid are still unclear. In this study, we show that both ␤-amyloid and APP can oxidize cholesterol to form 7␤-hydroxycholesterol, a proapoptotic oxysterol that was neurotoxic at nanomolar concentrations. 7␤-Hydroxycholesterol inhibited secretion of soluble APP from cultured rat hippocampal H19 -7/IGF-IR neuronal cells and inhibited tumor necrosis factor-␣-converting enzyme ␣-secretase activity but had no effect on ␤-site APPcleaving enzyme 1 activity. 7␤-Hydroxycholesterol was also a potent inhibitor of ␣-protein kinase C, with a K i of ϳ0.2 nM. The rate of reaction between cholesterol and ␤-amyloid was comparable to the rates of cholesterolmetabolizing enzymes (k cat ‫؍‬ 0.211 min ؊1 ). The rate of production of 7␤-hydroxycholesterol by APP was ϳ200 times lower than by ␤-amyloid. Oxidation of cholesterol was accompanied by stoichiometric production of hydrogen peroxide and required divalent copper. The results suggest that a function of APP may be to produce low levels of 7-hydroxycholesterol. Higher levels produced by ␤-amyloid could contribute to the oxidative stress and cell loss observed in Alzheimer's disease.

show abstract

Pro‐oxidant effects of 7‐hydroperoxycholest‐5‐en‐3β‐ol on the copper‐initiated oxidation of low density lipoprotein

Cited by 21 publications

References 23 publications

Enhanced susceptibility of cholesteryl sulfate‐enriched low density lipoproteins to copper‐mediated oxidation

Enhanced susceptibility of cholesteryl sulfate‐enriched low density lipoproteins to copper‐mediated oxidation

Differential effects of cysteine and methionine residues in the antioxidant activity of human serum albumin

Oxidation of Cholesterol by Amyloid Precursor Protein and β-Amyloid Peptide

Contact Info

Product

Resources

About