Abstract
We have investigated the effect of nitric oxide (NO) on apoptosis in Swiss 3T3 fibroblasts and compared it to the effect of the nitrosonium cation (NO+). Both species induced apoptosis, confirmed by electron microscopy, propidium iodide staining, DNA laddering and activation of caspases. The kinetics of triggering apoptosis were different for the two redox species: NO+ required only a 2 hour exposure, whereas NO required 24 hours. Three sources of NO were used: aqueous solutions of NO and two NO donors, S-nitrosoglutathione and S-nitroso-N-acetylpenicillamine. The time course of apoptosis induced by these two S-nitrosothiols correlated with their rate of decomposition to NO. The apoptotic effect of NO was reduced in the presence of the NO scavenger oxyhaemoglobin, or the antioxidants N-acetylcysteine and ascorbic acid, whereas in the case of NO+ these antioxidants potentiated apoptosis. Glutathione also had a potentiating effect on the cytotoxicity of NO+. This suggests that cellular antioxidants may play a role in protecting the cell from NO-induced apoptosis while NO+ may trigger apoptosis independently of oxidative stress mechanisms.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3T3 Cells / cytology*
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3T3 Cells / metabolism
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3T3 Cells / ultrastructure
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Acetylcysteine / pharmacology
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Animals
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Antidotes / pharmacology
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Antioxidants / pharmacology
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Apoptosis / drug effects
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Apoptosis / physiology*
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Ascorbic Acid / pharmacology
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Carrier Proteins / pharmacology
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Cations / metabolism*
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DNA Fragmentation
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Dose-Response Relationship, Drug
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Free Radical Scavengers / pharmacology
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Glutathione / analogs & derivatives
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Glutathione / pharmacology
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Hydrogen-Ion Concentration
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Membrane Proteins / pharmacology
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Mice
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Microscopy, Electron
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Microscopy, Fluorescence
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Mitochondria / chemistry
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Mitochondria / metabolism
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Nitric Oxide / metabolism*
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Nitric Oxide / pharmacology
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Nitroso Compounds / pharmacology
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Oxyhemoglobins / pharmacology
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Platelet Aggregation Inhibitors / pharmacology
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Poly(ADP-ribose) Polymerases / metabolism
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S-Nitrosoglutathione
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Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
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Time Factors
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Vesicular Transport Proteins*
Substances
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Antidotes
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Antioxidants
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Carrier Proteins
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Cations
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Free Radical Scavengers
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Membrane Proteins
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Nitroso Compounds
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Oxyhemoglobins
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Platelet Aggregation Inhibitors
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Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
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Vesicular Transport Proteins
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Nitric Oxide
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S-Nitrosoglutathione
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Poly(ADP-ribose) Polymerases
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Glutathione
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Ascorbic Acid
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Acetylcysteine