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Dikalov SI, Dikalova AE, Morozov DA, Kirilyuk IA. Cellular accumulation and antioxidant activity of acetoxymethoxycarbonyl pyrrolidine nitroxides. Free Radic Res 2017; 52:339-350. [PMID: 29098905 DOI: 10.1080/10715762.2017.1390744] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Nitroxides are widely used in biology as antioxidants, spin labels, functional spin probes for pH, oxygen and thiol levels, and tissue redox status imaging using electron paramagnetic resonance (EPR); however, biological applications of nitroxides is hindered by fast bioreduction to EPR-silent hydroxylamines and rapid clearance. In this work, we have studied pyrrolidine nitroxides with acetoxymethoxycarbonyl groups which can undergo hydrolysis by cellular esterases to hydrophilic carboxylate derivatives resistant to bioreduction. Nitroxides containing acetoxymethoxycarbonyl groups were rapidly absorbed by cells from the media, 3,4-bis-(acetoxymethoxycarbonyl)-proxyl (DCP-AM2) and 3-(2-(bis(2-(acetoxymethoxy)-2-oxoethyl)amino)acetamido)-proxyl (DCAP-AM2) showing the strongest EPR signal of the cellular fraction. Remarkably, the EPR parameters of 3,4-dicarboxy-proxyl (DCP) and its mono- and di-acetoxymethyl esters are different, and consequent intracellular hydrolysis of acetoxymethoxycarbonyl groups in DCP-AM2 can be followed by EPR. To elucidate intracellular location of the resultant DCP, the mitochondrial fraction has been isolated. EPR measurements showed that mitochondria were the main place where DCP was finally accumulated. TEMPO derivatives showed expectedly much faster decay of EPR signal in the cellular fraction, compared to pyrrolidine nitroxides. It was found that supplementation of endothelial cells with 50 nM of DCP-AM2 completely normalised the mitochondrial superoxide level. Moreover, administration of DCP-AM2 to mice (1.4 mg/kg/day) resulted in substantial nitroxide accumulation in the tissues and significantly reduced hypertension. We found that hydroxylamine derivatives of dicarboxyproxyl nitroxide DCP-AM-H can be used for the detection of superoxide in vivo in angiotensin II model of hypertension. Infusion of DCP-AM-H in mice leads to accumulation of persistent EPR signal of nitroxide in the blood and vascular tissue in angiotensin II-infused wild-type but not in SOD2 overexpressing mice. Our data demonstrate that acetoxymethoxycarbonyl group containing nitroxides accumulate in mitochondria and demonstrate site-specific antioxidant activity.
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Affiliation(s)
- Sergey I Dikalov
- a Department of Medicine, Vanderbilt University Medical Center , Nashville , TN , USA
| | - Anna E Dikalova
- a Department of Medicine, Vanderbilt University Medical Center , Nashville , TN , USA
| | - Denis A Morozov
- b Laboratory of Nitrogen Compounds, Novosibirsk Institute of Organic Chemistry , Novosibirsk , Russia.,c Department of Organic Chemistry, Novosibirsk State University , Novosibirsk , Russia
| | - Igor A Kirilyuk
- b Laboratory of Nitrogen Compounds, Novosibirsk Institute of Organic Chemistry , Novosibirsk , Russia.,c Department of Organic Chemistry, Novosibirsk State University , Novosibirsk , Russia
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Legenzov EA, Muralidharan S, Woodcock LB, Eaton GR, Eaton SS, Rosen GM, Kao JPY. Designing Molecular Probes To Prolong Intracellular Retention: Application to Nitroxide Spin Probes. Bioconjug Chem 2016; 27:2923-2930. [PMID: 27998079 DOI: 10.1021/acs.bioconjchem.6b00595] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Targeted delivery of molecular probes into cells enables cellular imaging through optical and magnetic modalities. Probe molecules that are well retained by cells can accumulate to higher intracellular concentrations, and thus increase the signal-to-noise ratio of, and widen the temporal window for, imaging. Here we synthesize a paramagnetic spin probe bearing six ionic functional groups and show that it has long intracellular half-life (>12 h) and exceptional biostability in living cells. We demonstrate that judicious incorporation of ionic substituents on probe molecules systematically increases intracellular retention time, and should therefore be beneficial to imaging experiments.
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Affiliation(s)
- Eric A Legenzov
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
| | - Sukumaran Muralidharan
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
| | - Lukas B Woodcock
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Gerald M Rosen
- Department of Pharmaceutical Sciences, School of Pharmacy, and Center for Biomedical Engineering & Technology, School of Medicine, University of Maryland , Baltimore, Maryland 21201, United States
| | - Joseph P Y Kao
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
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Kirilyuk IA, Polienko YF, Krumkacheva OA, Strizhakov RK, Gatilov YV, Grigor’ev IA, Bagryanskaya EG. Synthesis of 2,5-Bis(spirocyclohexane)-Substituted Nitroxides of Pyrroline and Pyrrolidine Series, Including Thiol-Specific Spin Label: An Analogue of MTSSL with Long Relaxation Time. J Org Chem 2012; 77:8016-27. [DOI: 10.1021/jo301235j] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Igor A. Kirilyuk
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry Sb RAS, Academician
Lavrentjev Ave. 9, Novosibirsk, 630090, Russia
| | - Yuliya F. Polienko
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry Sb RAS, Academician
Lavrentjev Ave. 9, Novosibirsk, 630090, Russia
| | - Olesya A. Krumkacheva
- International Tomography Center SB RAS, Institutskaya str. 3a, 630090, Novosibirsk,
Russia
| | - Rodion K. Strizhakov
- International Tomography Center SB RAS, Institutskaya str. 3a, 630090, Novosibirsk,
Russia
| | - Yurii V. Gatilov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry Sb RAS, Academician
Lavrentjev Ave. 9, Novosibirsk, 630090, Russia
| | - Igor A. Grigor’ev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry Sb RAS, Academician
Lavrentjev Ave. 9, Novosibirsk, 630090, Russia
| | - Elena G. Bagryanskaya
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry Sb RAS, Academician
Lavrentjev Ave. 9, Novosibirsk, 630090, Russia
- International Tomography Center SB RAS, Institutskaya str. 3a, 630090, Novosibirsk,
Russia
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Tsai P, Cao GL, Merkel TJ, Rosen GM. Spin labelling of Bacillus anthracis endospores: a model for in vivo tracking by EPR imaging. Free Radic Res 2008; 42:49-56. [PMID: 18324523 DOI: 10.1080/10715760701787701] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Anthrax is caused by the gram-negative bacterium, Bacillus anthracis. Infection by this microbe results from delivery of the endospore form of the bacillus through direct contact, either topical or inhalation. With regard to the latter route of administration, it is proposed that endospores of B. anthracis enter the lungs and are phagocytized by host alveolar macrophages. Thereafter, it is unclear as to how endospores travel to distal loci and what tissues are the targets. Herein, this study describes the spin labelling of endospores through two different approaches with various aminoxyls. Indeed, after exposure to RAW 264.7 cells, these aminoxyl-containing endospores were phagocytized, as demonstrated by EPR spectroscopy of the infected macrophage, thus providing a potential tool for EPR imaging in animals.
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Affiliation(s)
- Pei Tsai
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
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Miyake M, Shen J, Liu S, Shi H, Liu W, Yuan Z, Pritchard A, Kao JPY, Liu KJ, Rosen GM. Acetoxymethoxycarbonyl nitroxides as electron paramagnetic resonance proimaging agents to measure O2 levels in mouse brain: a pharmacokinetic and pharmacodynamic study. J Pharmacol Exp Ther 2006; 318:1187-93. [PMID: 16757536 DOI: 10.1124/jpet.106.106245] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Measurement of O(2) concentration and distribution in brain is essential to understanding the pathophysiology of stroke. Low-frequency electron paramagnetic resonance (EPR) spectroscopy with a paramagnetic probe is an attractive imaging modality that can potentially map O(2) concentration in the brain. In a previous study, we demonstrated that, after intraperitoneal administration of 3-acetoxymethoxycarbonyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (1) to mice, this nitroxide crossed the blood-brain barrier into brain tissue where, after hydrolysis, 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (2) was liberated and entrapped. This pilot study suggested that nitroxide 1 is a proimaging agent that can deliver nitroxide 2 to brain tissue, where O(2) levels can be estimated. In the present study, we conducted a series of pharmacokinetic and pharmacodynamic experiments designed to assess the uptake of structurally disparate nitroxides into brain tissue and retention, after hydrolysis, of the anions of the corresponding nitroxide acids. From these findings, nitroxide 1 and trans-3,4-di(acetoxymethoxycarbonyl)-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (5) meet the requirement as EPR proimaging agents for mapping O(2) distribution in the brain following stroke.
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Fleming FF, Wang Q. Unsaturated nitriles: conjugate additions of carbon nucleophiles to a recalcitrant class of acceptors. Chem Rev 2003; 103:2035-77. [PMID: 12744700 DOI: 10.1021/cr020045d] [Citation(s) in RCA: 289] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fraser F Fleming
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282-1530, USA.
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