Nitric oxide inhibits iron-induced lipid peroxidation in HL-60 cells.
Nitric oxide ((*)NO) can protect cells against the detrimental effects of reactive oxygen species. Using low-density lipoprotein as well as model systems, it has been demonstrated that (*)NO can serve as a chain-breaking antioxidant to blunt lipid peroxidation. To test the hypothesis that (*)NO can serve as a chain-breaking antioxidant in cell membranes, we examined the effect of (*)NO on iron-induced lipid peroxidation in human leukemia cells. We exposed HL-60 cells to an oxidative stress (20 microM Fe(2+)) and monitored the consumption of oxygen as a measure of lipid peroxidation. Oxygen consumption was arrested by the addition of (*)NO as a saturated aqueous solution. The duration of inhibition of oxygen consumption by (*)NO was concentration-dependent in the 0.4-1.8 microM range. The inhibition ended upon depletion of (*)NO. The addition of (*)NO prior to initiation of peroxidation delayed the onset of peroxidation; the nearer in time it was before Fe(2+) addition, the longer the inhibition. Depletion of cellular glutathione levels by d, l-buthionine-S,R-sulfoximine prior to Fe(2+) addition resulted in a more rapid initial rate of oxygen depletion and a shorter time for the (*)NO-induced inhibition of oxygen consumption. Complementary studies of this iron-induced lipid peroxidation, using thiobarbituric acid reactive substances as a marker, also demonstrated the protective effects of (*)NO. This protection of cells against lipid peroxidation also manifested itself as a reduction in trypan blue uptake, an observation demonstrating the protective effects of (*)NO on membrane integrity. We conclude that (*)NO protects HL-60 human leukemia cells from lipid peroxidation and that this protection ameliorates the toxicity of the oxidation processes initiated by Fe(2+) and dioxygen.
Kelley
E E
EE
Department of Medicine, The University of Iowa College of Medicine, Iowa City, Iowa, 52242, USA.
Wagner
B A
BA
Buettner
G R
GR
Burns
C P
CP
D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D018922:HL-60 Cells; D006801:Humans; D007501:Iron / Q000494:pharmacology*; D007700:Kinetics; D015227:Lipid Peroxidation / Q000187:drug effects / Q000502:physiology*; D008956:Models, Chemical; D009569:Nitric Oxide / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D010101:Oxygen Consumption / Q000187:drug effects; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
D017392:Thiobarbituric Acid Reactive Substances; D009569:Nitric Oxide; D007501:Iron