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Dikalov SI, Dikalova AE, Kirilyuk IA. Coupling of phagocytic NADPH oxidase activity and mitochondrial superoxide production. Front Cardiovasc Med 2022; 9:942736. [PMID: 35966537 PMCID: PMC9366351 DOI: 10.3389/fcvm.2022.942736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/23/2022] [Indexed: 11/13/2022] Open
Abstract
Superoxide radical plays an important role in redox cell signaling and physiological processes; however, overproduction of superoxide or insufficient activity of antioxidants leads to oxidative stress and contributes to the development of pathological conditions such as endothelial dysfunction and hypertension. Meanwhile, the studies of superoxide in biological systems represent unique challenges associated with short lifetime of superoxide, insufficient reactivity of the superoxide probes, and lack of site-specific detection of superoxide. In this work we have developed 15N-and deuterium-enriched spin probe 15N-CAT1H for high sensitivity and site-specific detection of extracellular superoxide. We have tested simultaneous tracking of extracellular superoxide by 15N-CAT1H and intramitochondrial superoxide by conventional 14N-containing spin probe mitoTEMPO-H in immune cells isolated from spleen, splenocytes, under basal conditions or stimulated with inflammatory cytokines IL-17A and TNFα, NADPH oxidase activator PMA, or treated with inhibitors of mitochondrial complex I rotenone or complex III antimycin A. 15N-CAT1H provides two-fold increase in sensitivity and improves detection since EPR spectrum of 15N-CAT1 nitroxide does not overlap with biological radicals. Furthermore, concurrent use of cell impermeable 15N-CAT1H and mitochondria-targeted 14N-mitoTEMPO-H allows simultaneous detection of extracellular and mitochondrial superoxide. Analysis of IL-17A- and TNFα-induced superoxide showed parallel increase in 15N-CAT1 and 14N-mitoTEMPO signals suggesting coupling between phagocytic NADPH oxidase and mitochondria. The interplay between mitochondrial superoxide production and activity of phagocytic NADPH oxidase was further investigated in splenocytes isolated from Sham and angiotensin II infused C57Bl/6J and Nox2KO mice. Angiotensin II infusion in wild-type mice increased the extracellular basal splenocyte superoxide which was further enhanced by complex III inhibitor antimycin A, mitochondrial uncoupling agent CCCP and NADPH oxidase activator PMA. Nox2 depletion attenuated angiotensin II mediated stimulation and inhibited both extracellular and mitochondrial PMA-induced superoxide production. These data indicate that splenocytes isolated from hypertensive angiotensin II-infused mice are "primed" for enhanced superoxide production from both phagocytic NADPH oxidase and mitochondria. Our data demonstrate that novel 15N-CAT1H provides high sensitivity superoxide measurements and combination with mitoTEMPO-H allows independent and simultaneous detection of extracellular and mitochondrial superoxide. We suggest that this new approach can be used to study the site-specific superoxide production and analysis of important sources of oxidative stress in cardiovascular conditions.
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Affiliation(s)
| | - Anna E. Dikalova
- Vanderbilt University Medical Center, Nashville, TN, United States
| | - Igor A. Kirilyuk
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk, Russia
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Bognár B, Úr G, Sár C, Hankovszky OH, Hideg K, Kálai T. Synthesis and Application of Stable Nitroxide Free Radicals Fused with Carbocycles and Heterocycles. CURR ORG CHEM 2019. [DOI: 10.2174/1385272823666190318163321] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Stable nitroxide free radicals have traditionally been associated with 2,2,6,6-
tetramethylpiperidine-1-oxyl (TEMPO) or its 4-substituted derivatives as relatively inexpensive
and readily accessible compounds with limited possibilities for further chemical
modification. Over the past two decades, there has been a resurgence of interest in stable
free radicals with proper functionalization tuned for various applications. The objective of
this review is to present recent results with synthetic methodologies to achieve stable nitroxide
free radicals fused with aromatic carbocycles and heterocycles. There are two
main approaches for accessing stable nitroxide free radicals fused with arenes, e.g., isoindoline-
like nitroxides: further functionalization and oxidation of phthalimide or inventive
functionalization of pyrroline nitroxide key compounds. The latter also offers the constructions
of versatile heterocyclic scaffolds (furan, pyrrole, thiophene, 1,2-thiazole, selenophene, pyrazole,
pyrimidine, pyridine, pyridazine, 1,5-benzothiazepine) that are fused with pyrroline or tetrahydropyridine nitroxide
rings. The possible applications of these new stable nitroxide free radicals, such as covalent spin labels
and noncovalent spin probes of proteins and nucleic acids, profluorescent probes, building blocks for construction
of dual active drugs and electroactive materials, and substances for controlled free radical polymerization,
are discussed.
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Affiliation(s)
- Balázs Bognár
- Institute of Organic and Medicinal Chemistry, Medical School, University of Pecs, Szigeti st. 12, H-7624 Pecs, Hungary
| | - Györgyi Úr
- Institute of Organic and Medicinal Chemistry, Medical School, University of Pecs, Szigeti st. 12, H-7624 Pecs, Hungary
| | - Cecília Sár
- Institute of Organic and Medicinal Chemistry, Medical School, University of Pecs, Szigeti st. 12, H-7624 Pecs, Hungary
| | - Olga H. Hankovszky
- Institute of Organic and Medicinal Chemistry, Medical School, University of Pecs, Szigeti st. 12, H-7624 Pecs, Hungary
| | - Kálmán Hideg
- Institute of Organic and Medicinal Chemistry, Medical School, University of Pecs, Szigeti st. 12, H-7624 Pecs, Hungary
| | - Tamás Kálai
- Institute of Organic and Medicinal Chemistry, Medical School, University of Pecs, Szigeti st. 12, H-7624 Pecs, Hungary
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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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Gorodetsky AA, Kirilyuk IA, Khramtsov VV, Komarov DA. Functional electron paramagnetic resonance imaging of ischemic rat heart: Monitoring of tissue oxygenation and pH. Magn Reson Med 2015; 76:350-8. [PMID: 26301868 DOI: 10.1002/mrm.25867] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/29/2015] [Accepted: 07/13/2015] [Indexed: 12/14/2022]
Abstract
PURPOSE Electron paramagnetic resonance (EPR) imaging in the spectral-spatial domain with application of soluble paramagnetic probes provides an opportunity for spatially resolved functional measurements of living objects. The purpose of this study was to develop EPR methods for visualization of oxygenation and acidosis of ischemic myocardium. METHODS EPR oxygen measurements were performed using isotopically substituted (2) H,(15) N-dicarboxyproxyl. The radical has an EPR line width of 320 mG and oxygen-induced line broadening of 0.53 mG/mm Hg, providing oxygen sensitivity down to 5 μM. pH measurements were performed using previously developed pH-sensitive imidazoline nitroxide. The radical has an EPR spectrum with pH-dependable hyperfine splitting, pK = 6.6, providing pH sensitivity of approximately 0.05 U in the physiological range. RESULTS EPR imaging of isolated and perfused rat hearts was performed in the two-dimensional + spectral domain. The spatial resolution of the measurements was about 1.4 mm. Marked tissue hypoxia was observed in the ischemic area of the heart after occlusion of the left anterior descending coronary artery. Tissue oxygenation was partly restored upon reperfusion. EPR mapping of myocardial pH indicated acidosis of the ischemic area down to pH 6.7-6.8. CONCLUSION This study demonstrates the capability of low-field EPR and the nitroxide spin probes for mapping of myocardial oxygenation and pH. The developed approaches might be used for noninvasive investigation of microenvironment on living objects. Magn Reson Med 76:350-358, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Artem A Gorodetsky
- Vorozhtsov Institute of Organic Chemistry, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russia
| | - Igor A Kirilyuk
- Vorozhtsov Institute of Organic Chemistry, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russia
| | - Valery V Khramtsov
- Heart & Lung Research Institute, Ohio State University, Columbus, Ohio, USA.,Department of Biochemistry, School of Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Denis A Komarov
- Vorozhtsov Institute of Organic Chemistry, Novosibirsk, Russia.,Meshalkin State Research Institute of Circulation Pathology, Novosibirsk, Russia
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