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"Redox Imaging" to Distinguish Cells with Different Proliferative Indexes: Superoxide, Hydroperoxides, and Their Ratio as Potential Biomarkers. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:6373685. [PMID: 31089411 PMCID: PMC6476105 DOI: 10.1155/2019/6373685] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 11/12/2018] [Accepted: 01/09/2019] [Indexed: 01/11/2023]
Abstract
The present study was directed to the development of EPR methodology for distinguishing cells with different proliferative activities, using “redox imaging.” Three nitroxide radicals were used as redox sensors: (a) mito-TEMPO—cell-penetrating and localized mainly in the mitochondria; (b) methoxy-TEMPO—cell-penetrating and randomly distributed between the cytoplasm and the intracellular organelles; and (c) carboxy-PROXYL—nonpenetrating in living cells and evenly distributed in the extracellular environment. The experiments were conducted on eleven cell lines with different proliferative activities and oxidative capacities, confirmed by conventional analytical tests. The data suggest that cancer cells and noncancer cells are characterized by a completely different redox status. This can be analyzed by EPR spectroscopy using mito-TEMPO and methoxy-TEMPO, but not carboxy-PROXYL. The correlation analysis shows that the EPR signal intensity of mito-TEMPO in cell suspensions is closely related to the superoxide level. The described methodology allows the detection of overproduction of superoxide in living cells and their identification based on the intracellular redox status. The experimental data provide evidences about the role of superoxide and hydroperoxides in cell proliferation and malignancy.
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Molecular Probes for Evaluation of Oxidative Stress by In Vivo EPR Spectroscopy and Imaging: State-of-the-Art and Limitations. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5010013] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oxidative stress, defined as a misbalance between the production of reactive oxygen species and the antioxidant defenses of the cell, appears as a critical factor either in the onset or in the etiology of many pathological conditions. Several methods of detection exist. However, they usually rely on ex vivo evaluation or reports on the status of living tissues only up to a few millimeters in depth, while a whole-body, real-time, non-invasive monitoring technique is required for early diagnosis or as an aid to therapy (to monitor the action of a drug). Methods based on electron paramagnetic resonance (EPR), in association with molecular probes based on aminoxyl radicals (nitroxides) or hydroxylamines especially, have emerged as very promising to meet these standards. The principles involve monitoring the rate of decrease or increase of the EPR signal in vivo after injection of the nitroxide or the hydroxylamine probe, respectively, in a pathological versus a control situation. There have been many successful applications in various rodent models. However, current limitations lie in both the field of the technical development of the spectrometers and the molecular probes. The scope of this review will mainly focus on the latter.
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Rogawski R, Sergeyev IV, Zhang Y, Tran TH, Li Y, Tong L, McDermott AE. NMR Signal Quenching from Bound Biradical Affinity Reagents in DNP Samples. J Phys Chem B 2017; 121:10770-10781. [PMID: 29116793 PMCID: PMC5842680 DOI: 10.1021/acs.jpcb.7b08274] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We characterize the effect of specifically bound biradicals on the NMR spectra of dihydrofolate reductase from E. coli. Dynamic nuclear polarization methods enhance the signal-to-noise of solid state NMR experiments by transferring polarization from unpaired electrons of biradicals to nuclei. There has been recent interest in colocalizing the paramagnetic polarizing agents with the analyte of interest through covalent or noncovalent specific interactions. This experimental approach broadens the scope of dynamic nuclear polarization methods by offering the possibility of selective signal enhancements and the potential to work in a broad range of environments. Paramagnetic compounds can have other effects on the NMR spectroscopy of nearby nuclei, including broadening of nuclear resonances due to the proximity of the paramagnetic agent. Understanding the distance dependence of these interactions is important for the success of the technique. Here we explore paramagnetic signal quenching due to a bound biradical, specifically a biradical-derivatized trimethoprim ligand of E. coli dihydrofolate reductase. Biradical-derivatized trimethoprim has nanomolar affinity for its target, and affords strong and selective signal enhancements in dynamic nuclear polarization experiments. In this work, we show that, although the trimethoprim fragment is well ordered, the biradical (TOTAPOL) moiety is disordered when bound to the protein. The distance dependence in bleaching of NMR signal intensity allows us to detect numerous NMR signals in the protein. We present the possibility that static disorder and electron spin diffusion play roles in this observation, among other contributions. The fact that the majority of signals are observed strengthens the case for the use of high affinity or covalent radicals in dynamic nuclear polarization solid state NMR enhancement.
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Affiliation(s)
- Rivkah Rogawski
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Ivan V Sergeyev
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Yinglu Zhang
- Department of Biological Sciences, Columbia University , New York, New York 10027, United States
| | - Timothy H Tran
- Department of Biological Sciences, Columbia University , New York, New York 10027, United States
| | - Yongjun Li
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Liang Tong
- Department of Biological Sciences, Columbia University , New York, New York 10027, United States
| | - Ann E McDermott
- Department of Chemistry, Columbia University , New York, New York 10027, United States
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Bačić G, Pavićević A, Peyrot F. In vivo evaluation of different alterations of redox status by studying pharmacokinetics of nitroxides using magnetic resonance techniques. Redox Biol 2015; 8:226-42. [PMID: 26827126 PMCID: PMC4753396 DOI: 10.1016/j.redox.2015.10.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/25/2015] [Indexed: 12/22/2022] Open
Abstract
Free radicals, particularly reactive oxygen species (ROS), are involved in various pathologies, injuries related to radiation, ischemia-reperfusion or ageing. Unfortunately, it is virtually impossible to directly detect free radicals in vivo, but the redox status of the whole organism or particular organ can be studied in vivo by using magnetic resonance techniques (EPR and MRI) and paramagnetic stable free radicals - nitroxides. Here we review results obtained in vivo following the pharmacokinetics of nitroxides on experimental animals (and a few in humans) under various conditions. The focus was on conditions where the redox status has been altered by induced diseases or harmful agents, clearly demonstrating that various EPR/MRI/nitroxide combinations can reliably detect metabolically induced changes in the redox status of organs. These findings can improve our understanding of oxidative stress and provide a basis for studying the effectiveness of interventions aimed to modulate oxidative stress. Also, we anticipate that the in vivo EPR/MRI approach in studying the redox status can play a vital role in the clinical management of various pathologies in the years to come providing the development of adequate equipment and probes.
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Affiliation(s)
- Goran Bačić
- EPR Laboratory, Faculty of Physical Chemistry, University of Belgrade, 11000 Belgrade, Serbia
| | - Aleksandra Pavićević
- EPR Laboratory, Faculty of Physical Chemistry, University of Belgrade, 11000 Belgrade, Serbia
| | - Fabienne Peyrot
- LCBPT, UMR 8601 CNRS - Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France; ESPE of Paris, Paris Sorbonne Université, 75016 Paris, France
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Kirilyuk IA, Bobko AA, Semenov SV, Komarov DA, Irtegova IG, Grigor'ev IA, Bagryanskaya E. Effect of Sterical Shielding on the Redox Properties of Imidazoline and Imidazolidine Nitroxides. J Org Chem 2015; 80:9118-25. [PMID: 26302173 DOI: 10.1021/acs.joc.5b01494] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The oxidant properties of the series of 2,2,5,5-tetraalkyl imidazoline and imidazolidine nitroxides were investigated. An increase in the number of bulky alkyl substituents leads to a decrease in the rate of reduction with ascorbate, which makes the electrochemical reduction potential more negative and shifts the equilibrium in the mixture of nitroxide and reference hydroxylamine (3-carboxy-1-hydroxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl-1-(15)N) toward the starting compounds. The effect of structural factors on these reactions was analyzed by means of multiple regression using the Fujita steric constant Es and the inductive Hammett constant σI. Satisfactory statistical outputs were obtained in all of the biparameter correlations, denoting that the oxidant properties of the nitroxides are determined by steric and electronic effects of the substituents. The data imply that bulky substituents can stabilize nitroxide and/or destabilize hydroxylamine.
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Affiliation(s)
- Igor A Kirilyuk
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS , Academician Lavrentjev Avenue 9, Novosibirsk, 630090, Russia.,Novosibirsk State University , Pirogova str. 2, Novosibirsk 630090, Russia
| | - Andrey A Bobko
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University , Columbus, Ohio 43210, United States
| | - Sergey V Semenov
- Novosibirsk State University , Pirogova str. 2, Novosibirsk 630090, Russia
| | - Denis A Komarov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS , Academician Lavrentjev Avenue 9, Novosibirsk, 630090, Russia.,Novosibirsk State University , Pirogova str. 2, Novosibirsk 630090, Russia
| | - Irina G Irtegova
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS , Academician Lavrentjev Avenue 9, Novosibirsk, 630090, Russia.,Novosibirsk State University , Pirogova str. 2, Novosibirsk 630090, Russia
| | - Igor A Grigor'ev
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS , Academician Lavrentjev Avenue 9, Novosibirsk, 630090, Russia
| | - Elena Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS , Academician Lavrentjev Avenue 9, Novosibirsk, 630090, Russia.,Novosibirsk State University , Pirogova str. 2, Novosibirsk 630090, Russia
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Tikhonov IV, Sen' VD, Borodin LI, Pliss EM, Golubev VA, Rusakov AI. Effect of the structure of nitroxyl radicals on the kinetics of their acid-catalyzed disproportionation. J PHYS ORG CHEM 2013. [DOI: 10.1002/poc.3247] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Vasily D. Sen'
- Institute of Problems of Chemical Physics; Russian Academy of Sciences; Chernogolovka Moscow Region Russia
| | | | | | - Valery A. Golubev
- Institute of Problems of Chemical Physics; Russian Academy of Sciences; Chernogolovka Moscow Region Russia
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