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Nitroxides protect against peroxynitrite-induced nitration and oxidation
Izabela Sadowska-Bartosz1, Agnieszka Gajewska2, Janusz Skolimowski3
1Department of Biochemistry and Cell Biology, Faculty of Biology and Agriculture, University of Rzeszów, Rzeszów, Poland.
Free Radical Biology & Medicine
|November 8, 2015
Summary
Nitroxides, including TEMPO and PROXYL derivatives, effectively prevent protein nitration and oxidation. While generally more potent against nitration, their efficacy varies with hydrophobicity and specific reactive species.
Area of Science:
- Biochemistry
- Medicinal Chemistry
- Cell Biology
Background:
- Nitroxides are recognized for their potential to inhibit detrimental protein modifications.
- Understanding the comparative efficacy of different nitroxide structures is crucial for therapeutic development.
Purpose of the Study:
- To evaluate and compare the protective effects of eleven nitroxides, derived from TEMPO and PROXYL, against protein nitration and oxidation.
- To investigate the influence of nitroxide hydrophobicity on their protective capabilities.
Main Methods:
- Assessing nitroxide efficiency in preventing fluorescein fluorescence loss and human serum albumin (HSA) nitration induced by peroxynitrite (PN).
- Evaluating nitroxide effects on dihydrorhodamine (DHR) 123 oxidation under various conditions.
- Testing nitroxide cytotoxicity and protective effects against SIN-1 in MCF-7 cells.
Main Results:
- Most nitroxides demonstrated high efficacy (nanomolar IC50) in preventing PN-induced fluorescein nitration and HSA nitration.
- Nitroxides were more effective at preventing nitration than oxidation, with a specific concentration window for DHR 123 oxidation.
- Hydrophobic nitroxides were generally less effective, except in preventing thiol oxidation where they showed superior performance, likely due to protein binding.
Conclusions:
- Nitroxides show significant promise for preventing peroxynitrite-induced oxidation and particularly nitration.
- Cellular protection against cytotoxic and nitrative effects of SIN-1 was observed with most non-hydrophobic nitroxides.
- Structure-activity relationships, particularly hydrophobicity, significantly influence nitroxide efficacy in biological systems.
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