Abstract
Previously, we showed that NO induces thymocyte apoptosis via a caspase-1-dependent mechanism [(1) ]. In the present study, we investigated the role of heme oxygenase, catalase, bax, and p53 in this process. The NO donor, S-nitroso-N-acetyl penicillamine (SNAP), induced DNA fragmentation in thymocytes in a time- and concentration-dependent way. SNAP (100 microM) induced 50--60% apoptosis; higher doses did not increase the rate of apoptosis significantly. SNAP decreased catalase and heme iron (Fe) levels without affecting superoxide dismutase, glutathione, or total Fe stores in thymocytes. SNAP significantly increased the expression of heme oxygenase 1 (HSP-32), p53, and bax but not bcl-2. Treatment with the heme oxygenase inhibitor, tin protoporphyrin IX inhibited SNAP-induced thymocyte apoptosis. Furthermore, thymocytes from p53 null mice were resistant to NO-induced apoptosis. Our data suggest that NO may induce its cytotoxic effects on thymocytes by modulating heme oxygenase and catalase activity as well as up-regulating pro-apoptotic proteins p53 and bax.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Apoptosis / drug effects*
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Apoptosis / physiology
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Catalase / metabolism
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Coculture Techniques
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Enzyme Induction / drug effects
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Erythrocytes / cytology
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Gene Expression / drug effects
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Glutathione / metabolism
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Heme / metabolism
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Heme Oxygenase (Decyclizing) / biosynthesis
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Heme Oxygenase-1
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Iron / metabolism
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Membrane Proteins
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Mice
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Mice, Inbred BALB C
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Mice, Knockout
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Nitric Oxide / pharmacology*
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Nitric Oxide Donors / pharmacology
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Oxidative Stress / drug effects
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Oxidative Stress / physiology
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Penicillamine / analogs & derivatives
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Penicillamine / pharmacology
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Proto-Oncogene Proteins / biosynthesis
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins c-bcl-2 / biosynthesis
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Proto-Oncogene Proteins c-bcl-2 / genetics
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S-Nitroso-N-Acetylpenicillamine
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Superoxide Dismutase / metabolism
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Thymus Gland / cytology
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Thymus Gland / drug effects*
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Thymus Gland / metabolism
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Tumor Suppressor Protein p53 / biosynthesis
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / physiology*
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bcl-2-Associated X Protein
Substances
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Bax protein, mouse
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Membrane Proteins
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Nitric Oxide Donors
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-bcl-2
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Tumor Suppressor Protein p53
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bcl-2-Associated X Protein
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Nitric Oxide
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Heme
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S-Nitroso-N-Acetylpenicillamine
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Iron
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Catalase
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Heme Oxygenase (Decyclizing)
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Heme Oxygenase-1
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Hmox1 protein, mouse
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Superoxide Dismutase
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Glutathione
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Penicillamine