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Xiong J, Wang L, Feng Y, Zhen C, Hang S, Yu J, Lu H, Jiang Y. Geldanamycin confers fungicidal properties to azole by triggering the activation of succinate dehydrogenase. Life Sci 2024; 348:122699. [PMID: 38718854 DOI: 10.1016/j.lfs.2024.122699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/17/2024] [Accepted: 05/04/2024] [Indexed: 05/13/2024]
Abstract
AIMS Azoles have been widely employed for the treatment of invasive fungal diseases; however, their efficacy is diminished as pathogenic fungi tolerate them due to their fungistatic properties. Geldanamycin (GdA) can render azoles fungicidal by inhibiting the ATPase and molecular chaperone activities of heat shock protein 90 (Hsp90). Nonetheless, the clinical applicability of GdA is restricted due to its cytotoxic ansamycin scaffold structure, its induction of cytoprotective heat shock responses, and the conservative nature of Hsp90. Hence, it is imperative to elucidate the mechanism of action of GdA to confer fungicidal properties to azoles and mitigate the toxic adverse effects associated with GdA. MATERIALS AND METHODS Through various experimental methods, including the construction of gene-deleted Candida albicans mutants, in vitro drug sensitivity experiments, Western blot analysis, reactive oxygen species (ROS) assays, and succinate dehydrogenase activity assays, we identified Hsp90 client proteins associated with the tolerance of C. albicans to azoles. KEY FINDINGS It was observed that GdA effectively hindered the entry of Hsp90 into mitochondria, resulting in the alleviation of inhibitory effect of Hsp90 on succinate dehydrogenase. Consequently, the activation of succinate dehydrogenase led to an increased production of ROS. within the mitochondria, thereby facilitating the antifungal effects of azoles against C. albicans. SIGNIFICANCE This research presents a novel approach for conferring fungicidal properties to azoles, which involves specifically disrupting the interaction of between Hsp90 and succinate dehydrogenase rather than employing a non-specific inhibition of ATPase activity of Hsp90.
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Affiliation(s)
- Juan Xiong
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Li Wang
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Yanru Feng
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Cheng Zhen
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Sijin Hang
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Jinhua Yu
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Hui Lu
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China.
| | - Yuanying Jiang
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China.
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Prajapati D, Bhandari P, Zangrando E, Mukherjee PS. A water-soluble Pd 4 molecular tweezer for selective encapsulation of isomeric quinones and their recyclable extraction. Chem Sci 2024; 15:3616-3624. [PMID: 38455025 PMCID: PMC10915840 DOI: 10.1039/d3sc05093a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/24/2024] [Indexed: 03/09/2024] Open
Abstract
Quinones (QN) are one of the main components of diesel exhaust particulates that have significant detrimental effects on human health. Their extraction and purification have been challenging tasks because these atmospheric particulates exist as complex matrices consisting of inorganic and organic compounds. In this report, we introduce a new water soluble Pd4L2 molecular architecture (MT) with an unusual tweezer-shaped structure obtained by self-assembly of a newly designed phenothiazine-based tetra-imidazole donor (L) with the acceptor cis-[(tmeda)Pd(NO3)2] (M) [ tmeda = N,N,N',N'-tetramethylethane-1,2-diamine]. The molecular tweezer encapsulates some quinones existing in diesel exhaust particulates (DEPs) leading to the formation of host-guest complexes in 1 : 1 molar ratio. Moreover, MT binds phenanthrenequinone (PQ) more strongly than its isomer anthraquinone (AQ), an aspect that enables extraction of PQ with a purity of 91% from an equimolar mixture of the two isomers. Therefore, MT represents an excellent example of supramolecular receptor capable of selective aqueous extraction of PQ from PQ/AQ with many cycles of reusability.
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Affiliation(s)
- Dharmraj Prajapati
- Department of Inorganic and Physical Chemistry, Indian Institute of Science Bangalore-560012 India
| | - Pallab Bhandari
- Department of Inorganic and Physical Chemistry, Indian Institute of Science Bangalore-560012 India
| | - Ennio Zangrando
- Department of Chemical and Pharmaceuticals Sciences, University of Trieste Trieste 34127 Italy
| | - Partha Sarathi Mukherjee
- Department of Inorganic and Physical Chemistry, Indian Institute of Science Bangalore-560012 India
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Lesanavičius M, Boucher JL, Čėnas N. Reactions of Recombinant Neuronal Nitric Oxide Synthase with Redox Cycling Xenobiotics: A Mechanistic Study. Int J Mol Sci 2022; 23:ijms23020980. [PMID: 35055166 PMCID: PMC8781745 DOI: 10.3390/ijms23020980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 12/16/2022] Open
Abstract
Neuronal nitric oxide synthase (nNOS) catalyzes single-electron reduction of quinones (Q), nitroaromatic compounds (ArNO2) and aromatic N-oxides (ArN → O), and is partly responsible for their oxidative stress-type cytotoxicity. In order to expand a limited knowledge on the enzymatic mechanisms of these processes, we aimed to disclose the specific features of nNOS in the reduction of such xenobiotics. In the absence or presence of calmodulin (CAM), the reactivity of Q and ArN → O increases with their single-electron reduction midpoint potential (E17). ArNO2 form a series with lower reactivity. The calculations according to an "outer-sphere" electron transfer model show that the binding of CAM decreases the electron transfer distance from FMNH2 to quinone by 1-2 Å. The effects of ionic strength point to the interaction of oxidants with a negatively charged protein domain close to FMN, and to an increase in accessibility of the active center induced by high ionic strength. The multiple turnover experiments of nNOS show that, in parallel with reduced FAD-FMN, duroquinone reoxidizes the reduced heme, in particular its Fe2+-NO form. This finding may help to design the heme-targeted bioreductively activated agents and contribute to the understanding of the role of P-450-type heme proteins in the bioreduction of quinones and other prooxidant xenobiotics.
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Affiliation(s)
- Mindaugas Lesanavičius
- Department of Xenobiotics Biochemistry, Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania;
| | - Jean-Luc Boucher
- Laboratoire de Chimie & Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Descartes, 45 rue de Saints Pères, CEDEX 06, 75270 Paris, France;
| | - Narimantas Čėnas
- Department of Xenobiotics Biochemistry, Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania;
- Correspondence: ; Tel.: +370-223-4392
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4
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Zheng F, Gonçalves FM, Abiko Y, Li H, Kumagai Y, Aschner M. Redox toxicology of environmental chemicals causing oxidative stress. Redox Biol 2020; 34:101475. [PMID: 32336668 PMCID: PMC7327986 DOI: 10.1016/j.redox.2020.101475] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Living organisms are surrounded with heavy metals such as methylmercury, manganese, cobalt, cadmium, arsenic, as well as pesticides such as deltamethrin and paraquat, or atmospheric pollutants such as quinone. Extensive studies have demonstrated a strong link between environmental pollutants and human health. Redox toxicity is proposed as one of the main mechanisms of chemical-induced pathology in humans. Acting as both a sensor of oxidative stress and a positive regulator of antioxidants, the nuclear factor erythroid 2-related factor 2 (NRF2) has attracted recent attention. However, the role NRF2 plays in environmental pollutant-induced toxicity has not been systematically addressed. Here, we characterize NRF2 function in response to various pollutants, such as metals, pesticides and atmospheric quinones. NRF2 related signaling pathways and epigenetic regulations are also reviewed.
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Affiliation(s)
- Fuli Zheng
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, Fujian, 350122, China; Department of Molecular Pharmacology, Albert Einstein College of Medicine, Forchheimer 209, 1300 Morris Park Avenue, Bronx, NY, 10461, United States.
| | - Filipe Marques Gonçalves
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Forchheimer 209, 1300 Morris Park Avenue, Bronx, NY, 10461, United States
| | - Yumi Abiko
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, Tsukuba, 305-8575, Japan
| | - Huangyuan Li
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, Fujian, 350122, China.
| | - Yoshito Kumagai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, Tsukuba, 305-8575, Japan.
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Forchheimer 209, 1300 Morris Park Avenue, Bronx, NY, 10461, United States.
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5
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Abiko Y, Nakai Y, Luong NC, Bianco CL, Fukuto JM, Kumagai Y. Interaction of Quinone-Related Electron Acceptors with Hydropersulfide Na 2S 2: Evidence for One-Electron Reduction Reaction. Chem Res Toxicol 2019; 32:551-556. [PMID: 30719914 DOI: 10.1021/acs.chemrestox.8b00158] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We previously reported that 9,10-phenanthraquinone (9,10-PQ), an atmospheric electron acceptor, undergoes redox cycling with dithiols as electron donors, resulting in the formation of semiquinone radicals and monothiyl radicals; however, monothiols have little reactivity. Because persulfide and polysulfide species are highly reducing, we speculate that 9,10-PQ might undergo one-electron reduction with these reactive sulfides. In the present study, we explored the redox cycling capability of a variety of quinone-related electron acceptors, including 9,10-PQ, during interactions with the hydropersulfide Na2S2 and its related polysulfides. No reaction occurred when 9,10-PQ was incubated with Na2S; however, when 5 μM 9,10-PQ was incubated with either 250 μM Na2S2 or Na2S4, we detected extensive consumption of dissolved oxygen (84 μM). Under these conditions, both the semiquinone radicals of 9,10-PQ and their thiyl radical species were also detected using ESR, suggesting that a redox cycle reaction occurred utilizing one-electron reduction processes. Notably, the perthiyl radicals remained stable even under aerobic conditions. Similar phenomenon has also been observed with other electron acceptors, such as pyrroloquinoline quinone, vitamin K3, and coenzyme Q10. Our experiments with N-methoxycarbonyl penicillamine persulfide (MCPSSH), a precursor for endogenous cysteine persulfide, suggested the possibility of a redox coupling reaction with 9,10-PQ inside cells. Our study indicates that hydropersulfide and its related polysulfides are efficient electron donors that interact with quinones. Redox coupling reactions between quinoid electron acceptors and such highly reactive thiols might occur in biological systems.
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Affiliation(s)
- Yumi Abiko
- Environmental Biology Section, Faculty of Medicine , University of Tsukuba , 1-1-1 Tennodai , Tsukuba , Ibaraki 305-8575 , Japan
| | - Yumi Nakai
- JEOL Resonance Inc. , Tokyo 196-8558 , Japan
| | - Nho C Luong
- Graduate School of Comprehensive Human Sciences , University of Tsukuba , 1-1-1 Tennodai , Tsukuba , Ibaraki 305-8575 , Japan.,Faculty of Pharmacy , Hue University of Medicine and Pharmacy , 06 Ngo Quyen , Hue , Vietnam
| | - Christopher L Bianco
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Jon M Fukuto
- Sonoma State University , Rohnert Park , California 94928 , United States
| | - Yoshito Kumagai
- Environmental Biology Section, Faculty of Medicine , University of Tsukuba , 1-1-1 Tennodai , Tsukuba , Ibaraki 305-8575 , Japan
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6
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Kumagai Y, Abiko Y, Cong NL. Chemical toxicology of reactive species in the atmosphere: two decades of progress in an electron acceptor and an electrophile. J Toxicol Sci 2017; 41:SP37-SP47. [PMID: 28003638 DOI: 10.2131/jts.41.sp37] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Air pollutants such as diesel exhaust particles (DEP) are thought to cause pulmonary diseases such as asthma as a result of oxidative stress. While DEP contain a large number of polycyclic aromatic hydrocarbons, we have focused on 9,10-phenanthrenequinone (9,10-PQ) and 1,2-naphthoquinone (1,2-NQ) because of their chemical properties based on their oxidative and chemical modification capabilities. We have found that 9,10-PQ interacts with electron donors such as NADPH (in the presence of enzymes) and dithiols, resulting in generation of excess reactive oxygen species (ROS) through redox cycling. We have also shown that 1,2-NQ is able to modify protein thiols, leading to protein adducts associated with activation of redox signal transduction pathways at lower concentrations and toxicity at higher concentrations. In this review, we briefly introduce our findings from the last two decades.
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7
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López J, de la Cruz F, Alcaraz Y, Delgado F, Vázquez MA. Quinoid systems in chemistry and pharmacology. Med Chem Res 2015. [DOI: 10.1007/s00044-015-1412-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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8
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Eiguren-Fernandez A, Di Stefano E, Schmitz DA, Guarieiro ALN, Salinas EM, Nasser E, Froines JR, Cho AK. Chemical reactivities of ambient air samples in three Southern California communities. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2015; 65:270-7. [PMID: 25947123 PMCID: PMC4425251 DOI: 10.1080/10962247.2014.988307] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
UNLABELLED The potential adverse health effects of PM2.5 (particulate matter with an aerodynamic diameter<2.5 μm) and vapor samples from three communities that neighbor railyards, Commerce (CM), Long Beach (LB), and San Bernardino (SB), were assessed by determination of chemical reactivities attributed to the induction of oxidative stress by air pollutants. The assays used were dithiothreitol (DTT)- and dihydrobenzoic acid (DHBA)-based procedures for prooxidant content and a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) assay for electrophiles. Prooxidants and electrophiles have been proposed as the reactive chemical species responsible for the induction of oxidative stress by air pollution mixtures. The PM2.5 samples from CM and LB sites showed seasonal differences in reactivities, with higher levels in the winter, whereas the SB sample differences were reversed. The reactivities in the vapor samples were all very similar, except for the summer SB samples, which contained higher levels of both prooxidants and electrophiles. The results suggest that the observed reactivities reflect general geographical differences rather than direct effects of the railyards. Distributional differences in reactivities were also observed, with PM2.5 fractions containing most of the prooxidants (74-81%) and the vapor phase most of the electrophiles (82-96%). The high levels of the vapor-phase electrophiles and their potential for adverse biological effects point out the importance of the vapor phase in assessing the potential health effects of ambient air. IMPLICATIONS PM2.5 and its corresponding vapor phase, containing semivolatile organics, were collected in three communities in the Los Angeles Basin and examined with toxicologically relevant chemical assays. The PM2.5 phase contained most of the prooxidants and the vapor phase contained most of the electrophiles, whose content was highest in summer samples from a receptor site that reflected greater photochemical processing of the air parcel during its transport. As electrophiles initiate both adverse and adaptive responses to foreign substances by biological systems, their presence in the vapor phase emphasizes the importance of this phase in the overall health effects of ambient air.
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Affiliation(s)
- Arantza Eiguren-Fernandez
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - Emma Di Stefano
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - Debra A. Schmitz
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - Aline Lefol Nani Guarieiro
- Southern California Particle Center
- Universidade Federal da Bahia, Instituto de Química, 40170290, Salvador-BA/Brasil
| | - Erika M. Salinas
- Southern California Particle Center
- División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana, Azcapotzalco, Mexico
| | - Elina Nasser
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - John R. Froines
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - Arthur K. Cho
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
- Corresponding author: Arthur K. Cho, Ph.D., CHS 21-297 Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772, UCLA, Phone: 310-825-6567,
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9
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Abiko Y, Luong NC, Kumagai Y. A Biotin-PEAC 5-maleimide labeling assay to detect electrophiles. J Toxicol Sci 2015; 40:405-11. [DOI: 10.2131/jts.40.405] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Yumi Abiko
- Faculty of Medicine, University of Tsukuba
| | - Nho Cong Luong
- Master’s Program of Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba
| | - Yoshito Kumagai
- Master’s Program of Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba
- Faculty of Medicine, University of Tsukuba
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10
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Mandal A, Kundu T, Ehret F, Bubrin M, Mobin SM, Kaim W, Lahiri GK. Varying electronic structural forms of ruthenium complexes of non-innocent 9,10-phenanthrenequinonoid ligands. Dalton Trans 2014; 43:2473-87. [DOI: 10.1039/c3dt53104j] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Bekki K, Toriba A, Tang N, Kameda T, Hayakawa K. Biological effects of polycyclic aromatic hydrocarbon derivatives. J UOEH 2013; 35:17-24. [PMID: 23475020 DOI: 10.7888/juoeh.35.17] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are included in various environmental pollutants such as airborne particles and have been reported to induce a variety of toxic effects. On the other hand, PAH derivatives are generated from PAHs both through chemical reaction in the atmosphere and metabolism in the body.PAH derivatives have become known for their specific toxicities such as estrogenic/antiestrogenic activities and oxidative stress, and correlations between the toxicities and structures of PAH derivatives have been shown in recent studies. These studies are indispensable for demonstrating the health effects of PAH derivatives, since they would contribute to the comprehensive toxicity prediction of many kinds of PAH derivatives.
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Affiliation(s)
- Kanae Bekki
- Division of Environmental Science and Engineering, Kanazawa University, Ishikawa, Japan.
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12
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Kumagai Y, Shimojo N. Possible mechanisms for induction of oxidative stress and suppression of systemic nitric oxide production caused by exposure to environmental chemicals. Environ Health Prev Med 2012; 7:141-50. [PMID: 21432269 DOI: 10.1007/bf02897942] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2002] [Accepted: 05/07/2002] [Indexed: 11/25/2022] Open
Abstract
The cytotoxic effects evoked by exposure to environmental chemicals having electrophilic properties are often attributable to covalent attachment to intracellular macromolecules through sulfhydryl groups or enzyme-mediated redox cycling, leading to the generation of reactive oxygen species (ROS). When huge amounts of ROS form they overwhelm antioxidant defenses resulting in the induction of oxidative stress. Nitric oxide (NO) which plays a crucial role in vascular tone, is formed by endothelial NO synthase (eNOS). Since a decrease in systemic NO production is implicated in the pathophysiological actions of vascular diseases, dysfunction of eNOS by environmental chemicals is associated with cardiopulmonary-related diseases and mortality. In this review, we introduce the mechanism-based toxicities (covalent attachment and redox cycling) of electrophiles. Therefore, this review will focus on the possible mechanisms for the induction of oxidative stress and impairment of NO production caused by environmental chemicals.
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Affiliation(s)
- Yoshito Kumagai
- Department of Environmental Medicine, Institute of Community Medicine, University of Tsukuba, 305-8575, Tsukuba, Ibaraki, Japan,
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13
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Li R, Kameda T, Toriba A, Hayakawa K, Lin JM. Determination of Benzo[a]pyrene-7,10-quinone in Airborne Particulates by Using a Chemiluminescence Reaction of Hydrogen Peroxide and Hydrosulfite. Anal Chem 2012; 84:3215-21. [DOI: 10.1021/ac2032063] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Ruibo Li
- State Key
Laboratory of Chemical
Resource Engineering, School of Science, Beijing University of Chemical Technology, Beijing 10029, China
- Graduate School of Natural Science
and Technology, Kanazawa University, Kakuma-machi,
Kanazawa 920-1192, Japan
- Beijing Key Laboratory of Microanalytical
Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Takayuki Kameda
- Graduate School of Natural Science
and Technology, Kanazawa University, Kakuma-machi,
Kanazawa 920-1192, Japan
| | - Akira Toriba
- Graduate School of Natural Science
and Technology, Kanazawa University, Kakuma-machi,
Kanazawa 920-1192, Japan
| | - Kazuichi Hayakawa
- Graduate School of Natural Science
and Technology, Kanazawa University, Kakuma-machi,
Kanazawa 920-1192, Japan
| | - Jin-Ming Lin
- Beijing Key Laboratory of Microanalytical
Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing 100084, China
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14
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Xiao D, Pan B, Wu M, Liu Y, Zhang D, Peng H. Sorption comparison between phenanthrene and its degradation intermediates, 9,10-phenanthrenequinone and 9-phenanthrol in soils/sediments. CHEMOSPHERE 2012; 86:183-189. [PMID: 22055310 DOI: 10.1016/j.chemosphere.2011.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 10/08/2011] [Accepted: 10/10/2011] [Indexed: 05/31/2023]
Abstract
The degradation intermediates of phenanthrene (PHE) may have increased health risks to organisms than PHE. Therefore, environmental fate and risk assessment studies should take into considerations of PHE degradation products. This study compared the sorption properties of PHE and its degradation intermediates, 9,10-phenanthrenequinone (PQN) and 9-phenanthrol (PTR) in soils, sediments and soil components. A relationship between organic carbon content (f(OC)) and single-point sorption coefficient (logK(d)) was observed for all three chemicals in 10 soils/sediments. The large intercept in the logf(OC)-logK(d) regression for PTR indicated that inorganic fractions control PTR sorption in soils/sediments. No relationship between specific surface area and K(d) was observed. This result indicated that determination of surface area based on gas sorption could not identify surface properties for PHE, PQN, and PTR sorption and thus provide limit information on sorption mechanisms. The high sorption and strong nonlinearity (low n values) of PTR in comparison to PHE suggested that the mobility of PTR could be lower than PHE. Increased mobility of PQN compared with PHE may be expected in soils/sediments because of PQN lower sorption. The varied sorption properties of the three chemicals suggested that their environmental risks should be assessed differently.
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Affiliation(s)
- Di Xiao
- Kunming University of Science & Technology, Kunming 650093, China
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15
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Kumagai Y, Shinkai Y, Miura T, Cho AK. The chemical biology of naphthoquinones and its environmental implications. Annu Rev Pharmacol Toxicol 2011; 52:221-47. [PMID: 21942631 DOI: 10.1146/annurev-pharmtox-010611-134517] [Citation(s) in RCA: 230] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Quinones are a group of highly reactive organic chemical species that interact with biological systems to promote inflammatory, anti-inflammatory, and anticancer actions and to induce toxicities. This review describes the chemistry, biochemistry, and cellular effects of 1,2- and 1,4-naphthoquinones and their derivatives. The naphthoquinones are of particular interest because of their prevalence as natural products and as environmental chemicals, present in the atmosphere as products of fuel and tobacco combustion. 1,2- and 1,4-naphthoquinones are also toxic metabolites of naphthalene, the major polynuclear aromatic hydrocarbon present in ambient air. Quinones exert their actions through two reactions: as prooxidants, reducing oxygen to reactive oxygen species; and as electrophiles, forming covalent bonds with tissue nucleophiles. The targets for these reactions include regulatory proteins such as protein tyrosine phosphatases; Kelch-like ECH-associated protein 1, the regulatory protein for NF-E2-related factor 2; and the glycolysis enzyme glyceraldehyde-3-phosphate dehydrogenase. Through their actions on regulatory proteins, quinones affect various cell signaling pathways that promote and protect against inflammatory responses and cell damage. These actions vary with the specific quinone and its concentration. Effects of exposure to naphthoquinones as environmental chemicals can vary with the physical state, i.e., whether the quinone is particle bound or is in the vapor state. The exacerbation of pulmonary diseases by air pollutants can, in part, be attributed to quinone action.
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Affiliation(s)
- Yoshito Kumagai
- Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 305-8575, Japan
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16
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Sumi D, Akimori M, Inoue KI, Takano H, Kumagai Y. 1,2-Naphthoquinone suppresses lipopolysaccharide-dependent activation of IKKβ/NF-κB/NO signaling: an alternative mechanism for the disturbance of inducible NO synthase-catalyzed NO formation. J Toxicol Sci 2011; 35:891-8. [PMID: 21139339 DOI: 10.2131/jts.35.891] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
1,2-Naphthoquinone (1,2-NQ) is an uncoupling agent for constitutive nitric oxide (NO) synthase (NOS), thereby inhibiting its catalytic activity. However, little information on whether this quinone can affect inducible NOS (iNOS) is available. To address this issue, we examined the effect of 1,2-NQ on lipopolysaccharide (LPS)-mediated induction of iNOS. Exposure of LPS-challenged RAW264.7 cells to 1,2-NQ resulted in decreased NO formation through a reduction in iNOS production. Under these conditions, LPS-induced activation of nuclear transcription factor-κB (NF-κB) coupled to phosphorylation of inhibitory κBα (IκBα) declined. Similar effects of 1,2-NQ were observed in the lungs of mice exposed to LPS. Using IκB kinase β (IKKβ)-transfected RAW264.7 cells and recombinant IKKβ protein, we found that 1,2-NQ diminished the phosphorylation of IκB by IKKβ enzymatic activity. Taken together, these results suggest that 1,2-NQ reduces iNOS-catalyzed NO production through 1) an uncoupling reaction, as reported previously, and/or 2) disruption of IKKβ/NF-κB signaling.
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Affiliation(s)
- Daigo Sumi
- Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
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17
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Kishikawa N, Nakashima H, Ohyama K, Nakashima K, Kuroda N. Determination of 9, 10-phenanthrenequinone in airborne particulates by High-Performance Liquid Chromatography with post-column fluorescence derivatization using 2-aminothiophenol. Talanta 2010; 81:1852-5. [PMID: 20441985 DOI: 10.1016/j.talanta.2010.03.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Revised: 03/25/2010] [Accepted: 03/25/2010] [Indexed: 11/26/2022]
Abstract
9, 10-Phenanthrenequinone (PQ) is regarded as a harmful environmental pollutant and its presence has been reported in atmospheric environment. The measurement of PQ in environment should be necessary to evaluate the influence of PQ on human health. We found that PQ reacted with 2-aminothiophenol under acidic condition to form fluorescent derivative which emits green fluorescence at 510nm. Based on this reaction, a simple and rapid determination method for PQ was developed by HPLC with post-column derivatization and fluorescence detection. By the proposed HPLC system, PQ was detected at 24min and the detection limit was 67fmol/injection (S/N=3). The proposed method was able to determine the atmospheric PQ concentrations by the direct injection of extract from airborne particulates.
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Affiliation(s)
- Naoya Kishikawa
- Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, Bunkyo-machi, Nagasaki, Japan
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18
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Tirapelli CR, Resstel LBM, de Oliveira AM, Corrêa FMA. Mechanisms underlying the biphasic effect of vitamin K1 (phylloquinone) on arterial blood pressure. J Pharm Pharmacol 2010; 60:889-93. [DOI: 10.1211/jpp.60.7.0010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Abstract
Phylloquinone (vitamin K1, VK1) is widely used therapeutically and intravenous administration of this quinone can induce hypotension. We aimed to investigate the mechanisms underlying the effects induced by VK1 on arterial blood pressure. With this purpose a catheter was inserted into the abdominal aorta of male Wistar rats for blood pressure and heart rate recording. Bolus intravenous injection of VK1 (0.5–20 mgkg−1) produced a transient increase in blood pressure followed by a fall. Both the pressor and depressor response induced by VK1 were dose-dependent. On the other hand, intravenous injection of VK1 did not alter heart rate. The nitric oxide synthase (NOS) inhibitor NG-nitro-l-arginine methyl ester (L-NAME, 10 and 20 mgkg−1) reduced both the increase and decrease in blood pressure induced by VK1 (5 mgkg−1). On the other hand, indometacin (10 mgkg−1), a non-selective cyclooxygenase inhibitor, did not alter the increase in mean arterial pressure (MAP) induced by VK1. However, VK1-induced fall in MAP was significantly attenuated by indometacin. We concluded that VK1 induces a dose-dependent effect on blood pressure that consists of an acute increase followed by a more sustained decrease in MAP. The hypotension induced by VK1 involves the activation of the nitric oxide (NO) pathway and the release of vasodilator prostanoid(s).
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Affiliation(s)
- Carlos R Tirapelli
- Department of Psychiatry Nursing and Human Sciences, Laboratory of Pharmacology, College of Nursing of Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Leonardo B M Resstel
- Department of Pharmacology, Faculty of Medicine of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil
| | - Ana M de Oliveira
- Department of Physics and Chemistry, Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil
| | - Fernando M A Corrêa
- Department of Pharmacology, Faculty of Medicine of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil
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19
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Venkatakrishnan P, Gairola CG, Castagnoli N, Miller RT. Naphthoquinones and bioactive compounds from tobacco as modulators of neuronal nitric oxide synthase activity. Phytother Res 2009; 23:1663-72. [PMID: 19367663 PMCID: PMC2788052 DOI: 10.1002/ptr.2789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Studies were conducted with extracts of several varieties of tobacco in search of neuronal nitric oxide synthase (nNOS) inhibitors which may be of value in the treatment of stroke. Current therapies do not directly exploit modulation of nNOS activity due to poor selectivity of the currently available nNOS inhibitors. The properties of a potentially novel nNOS inhibitor(s) derived from tobacco extracts, and the concentration-dependent, modulatory effects of the tobacco-derived naphthoquinone compound, 2,3,6-trimethyl-1,4-naphthoquinone (TMN), on nNOS activity were investigated, using 2-methyl-1,4-naphthoquinone (menadione) as a control. Up to 31 microM, both TMN and menadione stimulated nNOS-catalysed L-citrulline production. However, at higher concentrations of TMN (62.5-500 microM), the stimulation was lost in a concentration-dependent manner. With TMN, the loss of stimulation did not decrease beyond the control activity. With menadione (62.5-500 microM), the loss of stimulation surpassed that of the control (78+/-0.01% of control activity), indicating a true inhibition of nNOS activity. This study suggests that potential nNOS inhibitors are present in tobacco, most of which remain to be identified.
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Affiliation(s)
- Priya Venkatakrishnan
- Department. of Biological Sciences, University of Texas at El Paso, El Paso, TX 79968 USA
| | - C. Gary Gairola
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536 USA
| | - Neal Castagnoli
- Dept. of Chemistry, Virginia Tech., Blacksburg, VA 24061-0212
| | - R. Timothy Miller
- Department. of Biological Sciences, University of Texas at El Paso, El Paso, TX 79968 USA
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Milko P, Roithová J. Redox Processes in the Iron(III)/9,10-Phenanthraquinone System. Inorg Chem 2009; 48:11734-42. [PMID: 19928842 DOI: 10.1021/ic901789h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Petr Milko
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Praha 6, Czech Republic
| | - Jana Roithová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Praha 6, Czech Republic
- Department of Organic Chemistry, Faculty of Sciences, Charles University in Prague, Hlavova 8, 12843 Prague 2, Czech Republic
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21
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Motoyama Y, Bekki K, Chung SW, Tang N, Kameda T, Toriba A, Taguchi K, Hayakawa K. Oxidative Stress More Strongly Induced by ortho- Than para-quinoid Polycyclic Aromatic Hydrocarbons in A549 Cells. ACTA ACUST UNITED AC 2009. [DOI: 10.1248/jhs.55.845] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yumi Motoyama
- Graduate School of Natural Science and Technology, Kanazawa University
| | - Kanae Bekki
- Graduate School of Natural Science and Technology, Kanazawa University
| | - Sang Woon Chung
- Graduate School of Natural Science and Technology, Kanazawa University
| | - Ning Tang
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Takayuki Kameda
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Akira Toriba
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Keiko Taguchi
- Department of Medical Biochemistry, Graduate School of Medicine, Tohoku University
| | - Kazuichi Hayakawa
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
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22
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Zhao H, Ma JK, Barger MW, Mercer RR, Millecchia L, Schwegler-Berry D, Castranova V, Ma JY. Reactive oxygen species- and nitric oxide-mediated lung inflammation and mitochondrial dysfunction in wild-type and iNOS-deficient mice exposed to diesel exhaust particles. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:560-570. [PMID: 19267316 DOI: 10.1080/15287390802706330] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Pulmonary responses to diesel exhaust particles (DEP) exposure are mediated through enhanced production of reactive oxygen species (ROS) and nitric oxide (NO) by alveolar macrophages (AM). The current study examined the differential roles of ROS and NO in DEP-induced lung injury using C57B/6J wild-type (WT) and inducible NO synthase knockout (iNOS KO) mice. Mice exposed by pharyngeal aspiration to DEP or carbon black particles (CB) (35 mg/kg) showed an inflammatory profile that included neutrophil infiltration, increased lactate dehydrogenase (LDH) activity, and elevated albumin content in bronchoalveolar lavage fluid (BALF) at 1, 3, and 7 d postexposure. The organic extract of DEP (DEPE) did not induce an inflammatory response. Comparing WT to iNOS KO mice, the results show that NO enhanced DEP-induced neutrophils infiltration and plasma albumin content in BALF and upregulated the production of the pro-inflammatory cytokine interleukin 12 (IL-12) by AM. DEP-exposed AM from iNOS KO mice displayed diminished production of IL-12 and, in response to ex vivo lipopolysaccharide (LPS) challenge, decreased production of IL-12 but increased production of IL-10 when compared to cells from WT mice. DEP, CB, but not DEPE, induced DNA damage and mitochondria dysfunction in AM, however, that is independent of cellular production of NO. These results demonstrate that DEP-induced immune/inflammatory responses in mice are regulated by both ROS- and NO-mediated pathways. NO did not affect ROS-mediated mitochondrial dysfunction and DNA damage but upregulated IL-12 and provided a counterbalance to the ROS-mediated adaptive stress response that downregulates IL-12 and upregulates IL-10.
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Affiliation(s)
- Hongwen Zhao
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505-2888, USA
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23
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Kumagai Y. Polycyclic Aromatic Hydrocarbon Quinones as Redox and Electrophilic Chemicals Contaminated in the Atmosphere. ACTA ACUST UNITED AC 2009. [DOI: 10.1248/jhs.55.887] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yoshito Kumagai
- Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba
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24
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Chemiluminescence assay for quinones based on generation of reactive oxygen species through the redox cycle of quinone. Anal Bioanal Chem 2008; 393:1337-43. [DOI: 10.1007/s00216-008-2541-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 11/18/2008] [Accepted: 11/24/2008] [Indexed: 10/21/2022]
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25
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Nishida CR, Ortiz de Montellano PR. Reductive heme-dependent activation of the n-oxide prodrug AQ4N by nitric oxide synthase. J Med Chem 2008; 51:5118-20. [PMID: 18681417 DOI: 10.1021/jm800496s] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Anaerobic reduction of anticancer prodrugs is a promising route to achieve targeting and selectivity in anticancer drug design. Most reductive prodrug activations involve simple electron transfer from a flavoprotein and are not amenable to specific targeting. Here, we report that the N-oxide AQ4N is reduced by a nitric oxide synthase. This reduction involves interaction with the heme iron atom in the active site and is thus subject to specific protein constraints.
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Affiliation(s)
- Clinton R Nishida
- Department of Pharmaceutical Chemistry, University of California, 600 16th Street, San Francisco, California 94158-2517, USA
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26
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Chandor A, Dijols S, Ramassamy B, Frapart Y, Mansuy D, Stuehr D, Helsby N, Boucher JL. Metabolic activation of the antitumor drug 5-(Aziridin-1-yl)-2,4-dinitrobenzamide (CB1954) by NO synthases. Chem Res Toxicol 2008; 21:836-43. [PMID: 18370414 DOI: 10.1021/tx7004234] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Nitric oxide synthases (NOSs) are flavohemeproteins that catalyze the oxidation of L-arginine to L-citrulline with formation of the signaling molecule nitric oxide (NO). In addition to their fundamental role in NO biosynthesis, NOSs are also involved in the formation of reactive oxygen and nitrogen species (RONS) and in the interactions with some drugs. 5-(Aziridin-1-yl)-2,4-dinitrobenzamide (CB1954) is a dinitroaromatic compound tested as an antitumor prodrug that requires reduction to the 2- and 4-hydroxylamines to be cytotoxic. Here, we studied the interaction of neuronal, inducible, and endothelial NOSs with CB1954. Our results showed that the three purified recombinant NOSs selectively reduced the 4-nitro group of CB1954 to the corresponding 4-hydroxylamine with minimal 2-nitroreduction. Little further two-electron reduction of the hydroxylamines to the corresponding 2- and 4-amines was observed. The reduction of CB1954 catalyzed by the neuronal NOS (nNOS) was inhibited by O 2 and a flavin/NADPH binding inhibitor, diphenyliodonium (DPI), but insensitive to the addition of the heme ligands imidazole and carbon monoxide and of l-arginine analogues. This reduction proceeded with intermediate formation of a nitro-anion free radical observed by EPR. Involvement of the reductase domain of nNOS in the reduction of CB1954 was confirmed by the ability of the isolated reductase domain of nNOS to catalyze the reaction and by the stimulating effect of Ca (2+)/calmodulin on the accumulation of 4- and 2-hydroxylamines. The recombinant inducible and endothelial NOS isoforms reduced CB1954 with lower activity but higher selectivity for the cytotoxic 4-hydroxylamine compared with nNOS. Finally, CB1954 did not modify the formation of l-citrulline and RONS catalyzed by nNOS. Our results show that all three NOS isoforms are involved in the nitroreduction of CB1954, with predominant formation of the cytotoxic 4-hydroxylamine derivative. This nitroreduction could be of interest for the selective activation of prodrugs by NOSs overexpressed in tumor cells.
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Affiliation(s)
- Alexia Chandor
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, Université R. Descartes, UMR 8601 CNRS, 45 rue des Saints-Pères, 75270 Paris cedex 06, France
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27
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Shimada H, Ohtaguro M, Miura K, Imamura Y. Inhibitory effects of diesel exhaust components and flavonoids on 20alpha-hydroxysteroid dehydrogenase activity in mouse tissues. J Enzyme Inhib Med Chem 2007; 22:445-9. [PMID: 17847711 DOI: 10.1080/14756360601162113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The inhibitory effects of diesel exhaust components and flavonoids on 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) activity were examined in cytosolic fractions from the liver, kidney and lung of male mice. 9,10-Phenanthrenequinone (9,10-PQ) and 1,2-naphthoquinone (1,2-NQ), which are contained in diesel exhaust particles (DEPs), potently inhibited 20alpha-HSD activity in liver cytosol. 9,10-PQ also inhibited the enzyme activity in lung cytosol. However, 20alpha-HSD activity in kidney cytosol was little inhibited by 9,10-PQ or 1,2-NQ. Flavonoids such as quercetin, fisetin and kaempferol exhibited high inhibitory potencies for 20alpha-HSD activity in liver cytosol, whereas these flavonoids were poor inhibitors for the enzyme activity in kidney cytosol. It is likely that several diesel exhaust components and flavonoids augment the signaling of progesterone in the liver cells, by potently inhibiting 20alpha-HSD activity in mouse liver cytosol. The possibility that there are distinct enzymes catalyzing 20alpha-HSD activity in the non-reproductive tissues of male mice is also discussed.
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Affiliation(s)
- Hideaki Shimada
- Faculty of Education, Kumamoto University, 2-40-1, Kurokami, Kumamoto, 860-8555, Japan.
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Taguchi K, Fujii S, Yamano S, Cho AK, Kamisuki S, Nakai Y, Sugawara F, Froines JR, Kumagai Y. An approach to evaluate two-electron reduction of 9,10-phenanthraquinone and redox activity of the hydroquinone associated with oxidative stress. Free Radic Biol Med 2007; 43:789-99. [PMID: 17664142 DOI: 10.1016/j.freeradbiomed.2007.05.021] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 05/11/2007] [Accepted: 05/11/2007] [Indexed: 11/30/2022]
Abstract
Quinones are widely used as medicines or redox agents. The chemical properties are based on the reactions against an electron donor. 9,10-Phenanthraquinone (PQ), which is a quinone contaminated in airborne particulate matters, forms redox cycling, not Michael addition, with electron donors. Redox cycling of PQ contributes to its toxicity, following generation of reactive oxygen species (ROS). Detoxification of quinones is generally thought to be two-electron reduction forming hydroquinones. However, a hydroquinone of PQ, 9,10-dihydroxyphenanthrene (PQH(2)), has been never detected itself, because it is quite unstable. In this paper, we succeeded in detecting PQH(2) as its stable derivative, 9,10-diacetoxyphenanthrene (DAP). However, higher concentrations of PQ (>4 microM) form disproportionately with PQH(2), producing the 9,10-phenanthraquinone radical (PQ(-)) which is a one-electron reducing product of PQ. In cellular experiments using DAP as a precursor of PQH(2), it was shown that PQH(2) plays a critical role in the oxidative protein damage and cellular toxicity of PQ, showing that two-electron reduction of PQ can also initiate redox cycling to cause oxidative stress-dependent cytotoxicity.
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Affiliation(s)
- Keiko Taguchi
- Doctoral Programs in Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
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Ohashi K, Yamazaki T, Kitamura S, Ohta S, Izumi S, Kominami S. Allosteric inhibition of rat neuronal nitric-oxide synthase caused by interference with the binding of calmodulin to the enzyme. Biochim Biophys Acta Gen Subj 2007; 1770:231-40. [PMID: 17098364 DOI: 10.1016/j.bbagen.2006.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 10/03/2006] [Accepted: 10/04/2006] [Indexed: 11/29/2022]
Abstract
A sigmoid-type dependence on the inhibitor concentration was observed in the cytochrome c reductase activity for peptide inhibitors (mastoparan and melittin), calmodulin antagonists (W-7 and tamoxifen) and monobutyltin in a reconstituted system comprised of recombinant rat neuronal nitric-oxide synthase (nNOS) and calmodulin (CaM). The increase in the concentration of CaM in the system induced a decrease in the inhibitory effect, indicating that the inhibitors might interfere with the interaction between nNOS and CaM. The changes in the fluorescence spectra of dansylated CaM caused by the addition of mastoparan, melittin and monobutyltin indicated complex formation between CaM and those compounds, which led to the decrease in the effective concentration of CaM available to nNOS. The sigmoid-type inhibition of mastoparan and melittin fit the theoretical equations quite well, assuming that two CaM molecules bind cooperatively to one nNOS homodimer. Monobutyltin, tamoxifen and W-7 were found to inhibit nNOS activity by binding to the CaM binding site of the nNOS homodimer, in addition to the binding of the inhibitors to calmodulin. These compounds inhibited the L-citrulline formation of nNOS from L-arginine, and the inhibitory effects were abrogated by raising the concentration of calmodulin. It became clear that the binding of calmodulin to nNOS can be interfered with in two ways: (1) via a decrease in the effective concentration of calmodulin caused by complex formation between the inhibitor and calmodulin, and (2) via the inhibition of the binding of calmodulin to nNOS caused by the occupation of the binding site by the inhibitor.
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Affiliation(s)
- Koji Ohashi
- Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi-cho, Hiroshima 734-8551, Japan
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Ahmed S, Fujii S, Kishikawa N, Ohba Y, Nakashima K, Kuroda N. Selective determination of quinones by high-performance liquid chromatography with on-line post column ultraviolet irradiation and peroxyoxalate chemiluminescence detection. J Chromatogr A 2006; 1133:76-82. [PMID: 16920126 DOI: 10.1016/j.chroma.2006.07.078] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 07/28/2006] [Accepted: 07/31/2006] [Indexed: 11/20/2022]
Abstract
A new HPLC method was developed for the simultaneous determination of quinones with peroxyoxalate chemiluminescence (PO-CL) detection following on-line UV irradiation. Quinones [i.e., 1,2-naphthoquinone, 1,4-naphthoquinone, 9,10-anthraquinone, 9,10-phenanthrenequinone] were UV irradiated (254 nm, 15 W) to generate hydrogen peroxide and a fluorescent product that were determined via PO-CL detection. Generation of hydrogen peroxide from quinones with on-line UV irradiation was confirmed using flow injection analysis (FIA) system whereby incorporating an enzyme column reactor immobilized with catalase. Moreover, the structure of the produced fluorophore was confirmed using LC-MS, IR, and (1)H NMR. Afterwards, the conditions for UV irradiation and PO-CL detection were optimized. The separation of four quinones by HPLC was accomplished isocratically on an ODS column within 25 min. The detection limits (signal-to-noise ratio=3) were 6.0 pmol/injection for 1,2-naphthoquinone, 4.4 pmol/injection for 1,4-naphthoquinone, 0.2 pmol/injection for 9,10-anthraquinone, and 0.45 pmol/injection for 9,10-phenanthrenequinone.
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Affiliation(s)
- Sameh Ahmed
- Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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Zhao H, Barger MW, Ma JK, Castranova V, Ma JY. Cooperation of the inducible nitric oxide synthase and cytochrome P450 1A1 in mediating lung inflammation and mutagenicity induced by diesel exhaust particles. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:1253-8. [PMID: 16882535 PMCID: PMC1552032 DOI: 10.1289/ehp.9063] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Diesel exhaust particles (DEPs) have been shown to activate oxidant generation by alveolar macrophages (AMs), alter xenobiotic metabolic pathways, and modify the balance of pro-antiinflammatory cytokines. In this study we investigated the role of nitric oxide (NO) in DEP-mediated and DEP organic extract (DEPE) -mediated inflammatory responses and evaluated the interaction of inducible NO synthase (iNOS) and cytochrome P450 1A1 (CYP1A1). Male Sprague-Dawley rats were intratracheally (IT) instilled with saline, DEPs (35 mg/kg), or DEPEs (equivalent to 35 mg DEP/kg), with or without further treatment with an iNOS inhibitor, aminoguanidine (AG; 100 mg/kg), by intraperitoneal injection 30 min before and 3, 6, and 9 hr after IT exposure. At 1 day postexposure, both DEPs and DEPEs induced iNOS expression and NO production by AMs. AG significantly lowered DEP- and DEPE-induced iNOS activity but not the protein level while attenuating DEPE- but not DEP-mediated pulmonary inflammation, airway damage, and oxidant generation by AMs. DEP or DEPE exposure resulted in elevated secretion of both interleukin (IL) -12 and IL-10 by AMs. AG significantly reduced DEP- and DEPE-activated AMs in IL-12 production. In comparison, AG inhibited IL-10 production by DEPE-exposed AMs but markedly increased its production by DEP-exposed AMs, suggesting that NO differentially regulates the pro- and antiinflammatory cytokine balance in the lung. Both DEPs and DEPEs induced CYP1A1 expression. AG strongly inhibited CYP1A1 activity and lung S9 activity-dependent 2-aminoanthracene mutagenicity. These studies show that NO plays a major role in DEPE-induced lung inflammation and CYP-dependent mutagen activation but a lesser role in particulate-induced inflammatory damage.
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Affiliation(s)
- Hongwen Zhao
- Institute of Respiratory Diseases, First Affiliated Hospital, China Medical
University, Shenyang, People’s Republic of China
| | - Mark W. Barger
- Health Effects Laboratory Division, National Institute for Occupational
Safety and Health, Morgantown, West Virginia, USA
| | - Joseph K.H. Ma
- School of Pharmacy, West Virginia University, Morgantown, West Virginia, USA
| | - Vincent Castranova
- Health Effects Laboratory Division, National Institute for Occupational
Safety and Health, Morgantown, West Virginia, USA
| | - Jane Y.C. Ma
- Health Effects Laboratory Division, National Institute for Occupational
Safety and Health, Morgantown, West Virginia, USA
- Address correspondence to J.Y.C. Ma, Pathology and Physiology Research
Branch, HELD, NIOSH, 1095 Willowdale Rd., Morgantown, WV 26505-2888 USA. Telephone: (304) 285-5844. Fax: (304) 285-5938. E-mail:
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Kishikawa N, Nakao M, Ohba Y, Nakashima K, Kuroda N. Concentration and trend of 9,10-phenanthrenequinone in airborne particulates collected in Nagasaki city, Japan. CHEMOSPHERE 2006; 64:834-8. [PMID: 16330076 DOI: 10.1016/j.chemosphere.2005.10.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 10/21/2005] [Accepted: 10/25/2005] [Indexed: 05/05/2023]
Abstract
9,10-Phenanthrenequinone (PQ), one of the components of atmospheric pollutants, has potent harmful effects on human health. PQ in airborne particulates collected in Nagasaki city was determined by HPLC with fluorescence derivatization. PQ extracted from airborne particulates using methanol was derivatized with benzaldehyde in the presence of ammonium acetate to give a fluorescent compound. The average concentration (mean+/-SD, n=52) of PQ found in airborne particulates collected from July 1997 to June 1998 was 0.287+/-0.128 ng m-3. Concentrations of PQ in winter were higher than those in summer. In a weekly variation study, PQ concentrations were higher during weekdays and lower at weekend. The levels of PQ were obviously correlated with those of phenanthrene (PH) that is considered as a parent compound of PQ. This observation suggested that PQ was emitted into the atmosphere from the same source as PH, or PQ was converted from PH in the atmosphere.
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Affiliation(s)
- Naoya Kishikawa
- Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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Tirapelli CR, De Andrade CR, Lieberman M, Laurindo FR, De Souza HP, de Oliveira AM. Vitamin K1 (phylloquinone) induces vascular endothelial dysfunction: Role of oxidative stress. Toxicol Appl Pharmacol 2006; 213:10-7. [PMID: 16256160 DOI: 10.1016/j.taap.2005.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Revised: 08/29/2005] [Accepted: 09/04/2005] [Indexed: 10/25/2022]
Abstract
We aimed to investigate the mechanisms underlying the vascular effects induced by phylloquinone (Vitamin K1; VK1). Vascular reactivity experiments, using standard muscle bath procedures, showed that VK1 (5 and 50 microM) enhances the contractile response of endothelium-intact, but not denuded, rat carotid rings to phenylephrine. Similarly, maximal contraction induced by phenylephrine was enhanced in the presence of the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME). The combination of L-NAME and VK1 did not produce any further additional effect. Pre-incubation of intact-rings with VK1 reduced both acetylcholine- and bradykinin-induced relaxation. VK1 induced an increment in tension on carotid rings submaximally pre-contracted with phenylephrine. VK1-induced increment in tension was completely abolished by endothelial removal or incubation of intact rings with L-NAME and L-NNA. Conversely, 7-nitroindazole, 1400 W, or indomethacin did not affect VK1-induced contraction. Moreover, VK1 reduced L-arginine-induced relaxation in endothelium-intact rings. Lucigenin-amplified chemiluminescence assays showed that VK1 induced an increase in the level of superoxide anions in endothelium-intact but not denuded rings. Measurement of nitrite and nitrate generation showed that VK1 did not alter nitrate formation but strongly inhibited the generation of nitrite. Finally, the superoxide anions scavenger tiron prevented the endothelial vasomotor dysfunction caused by VK1 on phenyleprine-induced contraction and acetylcholine or bradykinin-induced relaxation. In conclusion, our data show that VK1 disrupts the vasomotor function of rat carotid. Our results suggest that VK1-induced oxidative stress through production of superoxide anion is interfering with the NO pathway, which in turn is responsible for the altered vascular reactivity induced by VK1.
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Affiliation(s)
- Carlos R Tirapelli
- Department of Pharmacology, Faculty of Medicine of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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Sun Y, Taguchi K, Sumi D, Yamano S, Kumagai Y. Inhibition of endothelial nitric oxide synthase activity and suppression of endothelium-dependent vasorelaxation by 1,2-naphthoquinone, a component of diesel exhaust particles. Arch Toxicol 2005; 80:280-5. [PMID: 16247599 DOI: 10.1007/s00204-005-0043-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Accepted: 09/28/2005] [Indexed: 10/25/2022]
Abstract
Diesel exhaust particles contain redox-active quinones, such as 9,10-phenanthraquinone (9,10-PQ) and 1,2-naphthoquinone (1,2-NQ), which act as potent electron acceptors, thereby altering electron transfer tgljoint @/Set Line Joint Styleon proteins. We have previously found that 9,10-PQ inhibits constitutive nitric oxide synthase (NOS) activity, by shunting electrons away from NADPH on the cytochrome P450 reductase domain of NOS, and thus suppresses acetylcholine (Ach)-induced vasorelaxation in the aortic ring. However, the effect of 1,2-NQ on endothelial NOS (eNOS) activity is still poorly understood. With the membrane fraction of cultured bovine aortic endothelial cells, we found that 1,2-NQ was a potent inhibitor of eNOS with an IC50 value of 1.4 microM, whereas trans-1,2-dihydroxy-1,2-dihydronaphthalene (1,2-DDN), a redox-negative naphthalene analog of 1,2-NQ, did not show such an inhibitory action. Although 1,2-DDN (5 microM) did not affect Ach-mediated vasorelaxation, 1,2-NQ caused a significant suppression of Ach-induced endothelium-dependent vasorelaxation in the aortic ring. However, 1,2-NQ did not affect sodium nitroprusside-induced endothelium-independent vasorelaxation. These results suggest that 1,2-NQ is an environmental quinone that inhibits eNOS activity, thereby disrupting NO-dependent vascular tone.
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Affiliation(s)
- Yang Sun
- Department of Environmental Medicine, Doctoral Programs in Medical Sciences, Graduate School of Comprehensive Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
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Sun Y, Iemitsu M, Shimojo N, Miyauchi T, Amamiya M, Sumi D, Hayashi T, Sun G, Shimojo N, Kumagai Y. 2,4,6-Trinitrotoluene inhibits endothelial nitric oxide synthase activity and elevates blood pressure in rats. Arch Toxicol 2005; 79:705-10. [PMID: 16025313 DOI: 10.1007/s00204-005-0003-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2005] [Accepted: 06/01/2005] [Indexed: 10/25/2022]
Abstract
2,4,6-Trinitrotoluene (TNT), which is widely used in explosives, is an important occupational and environmental pollutant. Human exposure to TNT has been reported to be associated with cardiovascular dysfunction, but the mechanism is not well understood. In this study, we examine the endothelial nitric oxide synthase (eNOS) activity and blood pressure value following TNT exposure. With a crude enzyme preparation, we found that TNT inhibited the enzyme activity of eNOS in a concentration-dependent manner (IC50 value = 49.4 microM). With an intraperitoneal administration of TNT (10 and 30 mg/kg) to rats, systolic blood pressure was significantly elevated 1 h after TNT exposure (1.2- and 1.3-fold of that of the control, respectively). Under the conditions, however, experiments with the inducible NOS inhibitor aminoguanidine revealed that an adaptive response against hypertension caused by TNT occurs. These results suggest that TNT is an environmental chemical that acts as an uncoupler of constitutive NOS isozymes, resulting in decreased nitric oxide formation associated with hypertension in rats.
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Affiliation(s)
- Yang Sun
- Doctoral Programs in Medicine Sciences, Graduate School of Comprehensive Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
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Rodriguez CE, Fukuto JM, Taguchi K, Froines J, Cho AK. The interactions of 9,10-phenanthrenequinone with glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a potential site for toxic actions. Chem Biol Interact 2005; 155:97-110. [PMID: 15950210 DOI: 10.1016/j.cbi.2005.05.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 05/10/2005] [Accepted: 05/10/2005] [Indexed: 11/27/2022]
Abstract
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the oxidative phosphorylation of glyceraldehyde 3-phosphate to 1,3-diphosphoglycerate, one of the precursors for glycolytic ATP biosynthesis. The enzyme contains an active site cysteine thiolate, which is critical for its catalytic function. As part of a continuing study of the interactions of quinones with biological systems, we have examined the susceptibility of GAPDH to inactivation by 9,10-phenanthrenequinone (9,10-PQ). In a previous study of quinone toxicity, this quinone, whose actions have been exclusively attributed to reactive oxygen species (ROS) generation, caused a reduction in the glycolytic activity of GAPDH under aerobic and anaerobic conditions, indicating indirect and possible direct actions on this enzyme. In this study, the effects of 9,10-PQ on GAPDH were examined in detail under aerobic and anaerobic conditions so that the role of oxygen could be distinguished from the direct effects of the quinone. The results indicate that, in the presence of the reducing agent DTT, GAPDH inhibition by 9,10-PQ under aerobic conditions was mostly indirect and comparable to the direct actions of exogenously-added H2O2 on this enzyme. GAPDH was also inhibited by 9,10-PQ anaerobically, but in a somewhat more complex manner. This quinone, which is not considered an electrophile, inhibited GAPDH in a time-dependent manner, consistent with irreversible modification and comparable to the electrophilic actions of 1,4-benzoquinone (1,4-BQ). Analysis of the anaerobic inactivation kinetics for the two quinones revealed comparable inactivation rate constants (k(inac)), but a much lower inhibitor binding constant (K(i)) for 1,4-BQ. Protection and thiol titration studies suggest that these quinones bind to the NAD+ binding site and modify the catalytic thiol from this site. Thus, 9,10-PQ inhibits GAPDH by two distinct mechanisms: through ROS generation that results in the oxidization of GAPDH thiols, and by an oxygen-independent mechanism that results in the modification of GAPDH catalytic thiols.
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Affiliation(s)
- Chester E Rodriguez
- Department of Pharmacology, UCLA School of Medicine, Center for the Health Sciences, Los Angeles, CA 90095-1735, USA
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Sugimoto R, Kumagai Y, Nakai Y, Ishii T. 9,10-Phenanthraquinone in diesel exhaust particles downregulates Cu,Zn-SOD and HO-1 in human pulmonary epithelial cells: intracellular iron scavenger 1,10-phenanthroline affords protection against apoptosis. Free Radic Biol Med 2005; 38:388-95. [PMID: 15629867 DOI: 10.1016/j.freeradbiomed.2004.11.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Revised: 10/29/2004] [Accepted: 11/01/2004] [Indexed: 11/27/2022]
Abstract
9,10-Phenanthraquinone (PQ), a major quinone contained in diesel exhaust particles and atmospheric PM(2.5), undergoes one-electron reduction by flavin enzymes such as NADPH-cytochrome P450 reductase, leading to production of reactive oxygen species in vitro. We have detected an ESR signal for superoxide (O(2)(-)) and hydroxyl radicals ((.)OH) by the spin trap method when PQ was mixed with P450 reductase, NADPH, and iron(III). When we examined the effects of PQ on A549 human pulmonary epithelial cells, PQ induced apoptosis with a LC(50) of approximately 7 microM. Formation of protein carbonyls was also detected in cells after treatment with PQ, suggesting that PQ induces oxidative damage. Iron chelators such as 1,10-phenanthroline (OP), desferrioxamine mesylate, and deferiprone respectively afforded protection against the toxic effects of PQ. Furthermore, treatment of A549 cells with 10-20 microM PQ for 12 h specifically down-regulated protein levels of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) and heme oxygenase-1 (HO-1) by more than 50%. Pretreatment of cells with OP (10 microM) markedly reduced the down-regulation of Cu,Zn-SOD and HO-1 and protein carbonyl formation in response to PQ. The inhibitor of Cu,Zn-SOD, diethyldithiocarbamate, enhanced the toxic effects of 5 microM PQ. The present findings suggest that PQ causes iron-mediated oxidative damage that is exacerbated by the concomitant down-regulation of Cu,Zn-SOD.
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Affiliation(s)
- Rika Sugimoto
- Majors of Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
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Reisen F, Arey J. Atmospheric reactions influence seasonal PAH and nitro-PAH concentrations in the Los Angeles basin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005. [PMID: 15667076 DOI: 10.1021/es035454l] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Ambient measurements of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs were carried out during August 2002 and January 2003 in Los Angeles, CA, a source site and in Riverside, CA, a downwind receptor site approximately 90 km to the east of Los Angeles. Atmospheric concentrations of PAHs and nitro-PAHs are of interest because both of these compound classes include potent mutagens and carcinogens. To augment our current understanding of atmospheric formation of nitro-PAHs, four sampling periods were employed to study the diurnal variations of these compounds. The PAH concentrations were highest in Los Angeles during January, as a result of traffic input at this source site undertightwintertime atmospheric inversions. In contrast, nitro-PAH levels were highest in Riverside during August, as a result of enhanced summertime photochemistry. Hydroxyl radical-initiated reactions produced nitro-PAHs in both seasons, while in winter little evidence for nitrate radical chemistry was seen. For the August samples, nitrate radical-initiated formation of nitro-PAHs is suggested by nitro-PAH isomer profiles not only at the downwind location as anticipated, but also atthe source site. In southern California, the contribution of atmospheric formation through gas-phase radical-initiated PAH reactions to the ambient burden of nitro-PAHs is dominant, with the semi-volatile nitro-PAHs being the most abundant and 2-nitrofluoranthene being the major particle-associated nitro-PAH.
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Affiliation(s)
- Fabienne Reisen
- Air Pollution Research Center, University of California, Riverside, California 92521, USA
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Lowe ER, Everett AC, Lee AJ, Lau M, Dunbar AY, Berka V, Tsai AL, Osawa Y. Time-dependent inhibition and tetrahydrobiopterin depletion of endothelial nitric-oxide synthase caused by cigarettes. Drug Metab Dispos 2005; 33:131-8. [PMID: 15470159 DOI: 10.1124/dmd.104.001891] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Smoking causes a dysfunction in endothelial nitric-oxide synthase (eNOS), which is ameliorated, in part, by administration of tetrahydrobiopterin (BH(4)). The exact mechanism by which the nitric oxide deficit occurs is unknown. We have previously shown that aqueous extracts of chemicals in cigarettes (CE) cause the suicide inactivation of neuronal NO synthase (nNOS) by interacting at the substrate-binding site. In the current study, we have found that CE directly inactivates eNOS by a process that is not affected by the natural substrate l-arginine and is distinct from the mechanism of inactivation of nNOS. We discovered that CE causes a time-, concentration-, and NADPH-dependent inactivation of eNOS in an in vitro system containing the purified enzyme, indicating a metabolic component to the inactivation. The CE-treated eNOS but not nNOS was nearly fully reactivated upon incubation with excess BH(4), suggesting that BH(4) depletion is a potential mechanism of inactivation. Moreover, in the presence of CE, eNOS catalyzed the oxidation of BH(4) to dihydrobiopterin and biopterin by a process attenuated by high concentrations of superoxide dismutase but not catalase. We speculate that a redox active component in CE, perhaps a quinone compound, causes oxidative uncoupling of eNOS to form superoxide, which in turn oxidizes BH(4). The discovery of a direct inactivation of eNOS by a compound(s) present in tobacco provides a basis not only for further study of the mechanisms responsible for the biological effects of tobacco but also a search for a potentially novel inactivator of eNOS.
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Affiliation(s)
- Ezra R Lowe
- Department of Pharmacology, University of Michigan Medical School, 1301 Medical Science Research Building III, Ann Arbor, MI 48109-0632, USA
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Kishikawa N, Wada M, Ohba Y, Nakashima K, Kuroda N. Highly sensitive and selective determination of 9,10-phenanthrenequinone in airborne particulates using high-performance liquid chromatography with pre-column derivatization and fluorescence detection. J Chromatogr A 2004; 1057:83-8. [PMID: 15584225 DOI: 10.1016/j.chroma.2004.09.080] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
9,10-Phenanthrenequinone (PQ), is one of the components of diesel exhaust particulates, has potent harmful effects on human health. For the determination of PQ in airborne particulates, a highly sensitive and selective high-performance liquid chromatography (HPLC) method was developed with fluorescence detection following the pre-column fluorescent derivatization. PQ was derivatized with benzaldehyde as a derivatizing reagent in the presence of ammonium acetate to give fluorescent 2-phenyl-1H-phenanthro [9,10-d] imidazole. The maximum fluorescence intensity of the derivative was observed by the reaction with 0.2M benzaldehyde and 0.5 M ammonium acetate at 100 degrees C for 30 min. The HPLC separation of fluorescent derivative of PQ was performed within 20 min on an ODS column with a mixture of acetonitrile-water (55:45, v/v) as a mobile phase. Highly sensitive and selective determination of PQ was attained with the detection limit of 5 fmol (S/N = 3). By the proposed method, PQ in airborne particulates was successfully determined in the range 0.26-0.30 ng/m3 (n = 3).
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Affiliation(s)
- Naoya Kishikawa
- Department of Analytical Chemistry, Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-Machi, Nagasaki 852-8521, Japan
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Rodriguez CE, Shinyashiki M, Froines J, Yu RC, Fukuto JM, Cho AK. An examination of quinone toxicity using the yeast Saccharomyces cerevisiae model system. Toxicology 2004; 201:185-96. [PMID: 15297032 DOI: 10.1016/j.tox.2004.04.016] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2004] [Revised: 04/20/2004] [Accepted: 04/24/2004] [Indexed: 10/26/2022]
Abstract
The toxicity of quinones is generally thought to occur by two mechanisms: the formation of covalent bonds with biological molecules by Michael addition chemistry and the catalytic reduction of oxygen to superoxide and other reactive oxygen species (ROS) (redox cycling). In an effort to distinguish between these general mechanisms of toxicity, we have examined the toxicity of five quinones to yeast cells as measured by their ability to reduce growth rate. Yeast cells can grow in the presence and absence of oxygen and this feature was used to evaluate the role of redox cycling in the toxicity of each quinone. Furthermore, yeast mutants deficient in superoxide dismutase (SOD) activity were used to assess the role of this antioxidant enzyme in protecting cells against quinone-induced reactive oxygen toxicity. The effects of different quinones under different conditions of exposure were compared using IC50 values (the concentration of quinone required to inhibit growth rate by 50%). For the most part, the results are consistent with the chemical properties of each quinone with the exception of 9,10-phenanthrenequinone (9,10-PQ). This quinone, which is not an electrophile, exhibited an unexpected toxicity under anaerobic conditions. Further examination revealed a potent induction of cell viability loss which poorly correlated with decreases in the GSH/2GSSG ratio but highly correlated (r2 > 0.7) with inhibition of the enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH), suggesting disruption of glycolysis by this quinone. Together, these observations suggest an unexpected oxygen-independent mechanism in the toxicity of 9,10-phenanthrenequinone.
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Affiliation(s)
- Chester E Rodriguez
- Department of Pharmacology, UCLA School of Medicine, Center for the Health Sciences, Los Angeles, CA 90095-1735, USA
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Kumagai Y, Kikushima M, Nakai Y, Shimojo N, Kunimoto M. Neuronal nitric oxide synthase (NNOS) catalyzes one-electron reduction of 2,4,6-trinitrotoluene, resulting in decreased nitric oxide production and increased nNOS gene expression: implication for oxidative stress. Free Radic Biol Med 2004; 37:350-7. [PMID: 15223068 DOI: 10.1016/j.freeradbiomed.2004.04.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2003] [Revised: 03/22/2004] [Accepted: 04/22/2004] [Indexed: 11/23/2022]
Abstract
To determine the mechanism of 2,4,6-trinitrotoluene (TNT)-induced oxidative stress involving neuronal nitric oxide synthase (nNOS), we examined alterations in enzyme activity and gene expression of nNOS by TNT, with an enzyme preparation and rat cerebellum primary neuronal cells. TNT inhibited nitric oxide formation (IC(50) = 12.4 microM) as evaluated by citrulline formation in a 20,000 g cerebellar supernatant preparation. A kinetic study revealed that TNT was a competitive inhibitor with respect to NADPH and a noncompetitive inhibitor with respect to L-arginine. It was found that purified nNOS was capable of reducing TNT, with a specific activity of 3900 nmol of NADPH oxidized/mg/min, but this reaction required CaCl(2)/calmodulin (CaM). An electron spin resonance (ESR) study indicated that superoxide (O(2)(.-)) was generated during reduction of TNT by nNOS. Exposure of rat cerebellum primary neuronal cells to TNT (25 microM) caused an intracellular generation of H(2)O(2), accompanied by a significant increase in nNOS mRNA levels. These results indicate that CaM-dependent one-electron reduction of TNT is catalyzed by nNOS, leading to a reduction in NO formation and generation of H(2)O(2) derived from O(2)(.-). Thus, it is suggested that upregulation of nNOS may represent an acute adaptation to an increase in oxidative stress during exposure to TNT.
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Affiliation(s)
- Yoshito Kumagai
- Social and Environmental Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
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Maeda S, Miyauchi T, Iemitsu M, Tanabe T, Goto K, Yamaguchi I, Matsuda M. Endothelin receptor antagonist reverses decreased NO system in the kidney in vivo during exercise. Am J Physiol Endocrinol Metab 2004; 286:E609-14. [PMID: 14665447 DOI: 10.1152/ajpendo.00373.2003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular endothelial cells produce endothelin (ET)-1, a potent vasoconstrictor peptide, and nitric oxide (NO), a potent vasodilator substance. There are interactions between ET-1 and NO. Exercise results in a marked decrease in renal blood flow. We previously reported that exercise causes an increase of ET-1 production in the kidney, whereas production of NO in the kidney is decreased. Furthermore, we recently revealed that the magnitude of decrease in blood flow to the kidney during exercise was significantly attenuated by the administration of the endothelin-A (ET(A)) receptor antagonist, strongly suggesting that endogenously increased ET-1 participates in the decrease of blood flow in the kidney during exercise. Because it was demonstrated that ET-1 depresses NO synthase (NOS) activity of cultured cells in vitro, we hypothesized that an increase of ET-1 production in kidney during exercise contributes to a decrease of NO production in kidney in vivo. We studied whether administration of the ET(A) receptor antagonist attenuates the decreases of NOS activity and NO production in the kidney during exercise. Rats performed treadmill running for 30 min after pretreatment with an ET(A) receptor antagonist (TA-0201, 0.5 mg/kg; TA-0201-treated exercise group) or vehicle (vehicle-treated exercise group). Control rats remained at rest (vehicle-treated sedentary group). Blood flow in the kidney was decreased by this exercise, but the magnitude of the decrease after pretreatment with TA-0201 was significantly smaller than that after pretreatment with vehicle. NOS activity in kidney was significantly lower in the vehicle-treated exercise group than in the vehicle-treated sedentary group, whereas that in the TA-0201-treated exercise group was significantly higher than that in the vehicle-treated exercise group. Expressions of endothelial NOS protein and NOx, the stable end product of NO, i.e., nitrite/nitrate, concentration in the kidney were significantly lower in the vehicle-treated exercise group than in the vehicle-treated sedentary group, whereas those in the TA-0201-treated exercise group were significantly higher than those in the vehicle-treated exercise group. The data suggest that increased ET-1 production in the kidney during exercise contributes to the decreases of NOS activity and NO production. Therefore, the present study provides a possibility that the exercise-induced increase in production of ET-1 in the kidney causes a decrease in blood flow in the kidney through two pathways, i.e., vasoconstrictive action and the action of attenuating NO production.
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Affiliation(s)
- Seiji Maeda
- Center for Tsukuba Advanced Research Alliance, Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan.
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Sawa T, Akaike T, Ichimori K, Akuta T, Kaneko K, Nakayama H, Stuehr DJ, Maeda H. Superoxide generation mediated by 8-nitroguanosine, a highly redox-active nucleic acid derivative. Biochem Biophys Res Commun 2004; 311:300-6. [PMID: 14592413 DOI: 10.1016/j.bbrc.2003.10.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Formation of 8-nitroguanosine may be characterized as nucleic acid modification induced by nitric oxide (NO). We show here that 8-nitroguanosine is a highly redox-active nucleic acid derivative that strongly stimulated superoxide generation from various NADPH-dependent reductases, including cytochrome P450 reductase and all isoforms of NO synthase. This reaction involves these reductases in a redox cycling reaction via single-electron reduction of 8-nitroguanosine to form 8-nitroguanosine anion radical. One electron is then transferred from this radical to molecular oxygen. 8-Nitroguanosine formed in vivo may function as a potent redox cofactor that intensifies oxyradical generation by various NADPH/reductase-like enzymes and thus participates in diverse physiological and pathological events.
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Affiliation(s)
- Tomohiro Sawa
- Department of Microbiology, Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 860-8556, Japan
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Barnabé N, Marusak RA, Hasinoff BB. Prevention of doxorubicin-induced damage to rat heart myocytes by arginine analog nitric oxide synthase inhibitors and their enantiomers. Nitric Oxide 2003; 9:211-6. [PMID: 14996428 DOI: 10.1016/j.niox.2003.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2003] [Revised: 12/10/2003] [Indexed: 11/22/2022]
Abstract
The clinical use of the widely used anticancer drug doxorubicin is limited by a dose-dependent cardiotoxicity. Doxorubicin can be reduced to its semiquinone free radical form by nitric oxide synthases (NOS). The release of lactate dehydrogenase (LDH) from doxorubicin-treated neonatal cardiac rat myocytes was used as a model of doxorubicin-induced cardiotoxicity. The NOS inhibitors N(G)-nitro-L-arginine methyl ester (L-NAME) and N(G)-monomethyl-L-arginine (L-NMMA) protected myocytes from doxorubicin as did their non-inhibitory enantiomers D-NAME and D-NMMA. Thus, these agents did not protect by inhibiting NOS. L-NAME, which does not act at the reductase domain of NOS, also had no effect on the production of the doxorubicin semiquinone by myocytes. Nitric oxide (NO) EPR spin trapping experiments showed that L-NAME reacted with various biological reducing agents to produce NO. Ascorbic acid was highly effective in reacting with L-NAME to produce NO, while glutathione, NADPH, and NADH were much less effective. Thus, these guanadino-substituted analogs of L-arginine likely protected through their ability to slowly produce NO by reaction with intracellular ascorbic acid. Thus, some caution must be exercised in their use. NO may exert its protective effects either by directly acting as an antioxidant or through some other NO-dependent pathway.
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Affiliation(s)
- Norman Barnabé
- Faculty of Pharmacy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
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Choo HYP, Choi S, Ryu CK, Kim HJ, Lee IY, Paeb AN, Koh HY. QSAR study of quinolinediones with inhibitory activity of endothelium-dependent vasorelaxation by CoMSIA. Bioorg Med Chem 2003; 11:2019-23. [PMID: 12670653 DOI: 10.1016/s0968-0896(03)00045-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The 3D-QSAR study of quinolinediones which showed potent inhibitory effect on the acetylcholine induced vasorelaxation of rat aorta with the endothelium was conducted by CoMSIA. The statistical result, cross-validated q(2) (0.741) and r(2) (0.960) values, gave reliability to the prediction of inhibitory activity of this series.
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Audi SH, Zhao H, Bongard RD, Hogg N, Kettenhofen NJ, Kalyanaraman B, Dawson CA, Merker MP. Pulmonary arterial endothelial cells affect the redox status of coenzyme Q0. Free Radic Biol Med 2003; 34:892-907. [PMID: 12654478 DOI: 10.1016/s0891-5849(03)00025-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The pulmonary endothelium is capable of reducing certain redox-active compounds as they pass from the systemic venous to the arterial circulation. This may have important consequences with regard to the pulmonary and systemic disposition and biochemistry of these compounds. Because quinones comprise an important class of redox-active compounds with a range of physiological, toxicological, and pharmacological activities, the objective of the present study was to determine the fate of a model quinone, coenzyme Q0 (Q), added to the extracellular medium surrounding pulmonary arterial endothelial cells in culture, with particular attention to the effect of the cells on the redox status of Q in the medium. Spectrophotometry, electron paramagnetic resonance (EPR), and high-performance liquid chromatography (HPLC) demonstrated that, when the oxidized form Q is added to the medium surrounding the cells, it is rapidly converted to its quinol form (QH2) with a small concentration of semiquinone (Q*-) also detectable. The isolation of cell plasma membrane proteins revealed an NADH-Q oxidoreductase located on the outer plasma membrane surface, which apparently participates in the reduction process. In addition, once formed the QH2 undergoes a cyanide-sensitive oxidation by the cells. Thus, the actual rate of Q reduction by the cells is greater than the net QH2 output from the cells.
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Affiliation(s)
- Said H Audi
- Department of Biomedical Engineering, Marquette University, Milwaukee, WI, USA
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Miyauchi T, Maeda S, Iemitsu M, Kobayashi T, Kumagai Y, Yamaguchi I, Matsuda M. Exercise causes a tissue-specific change of NO production in the kidney and lung. J Appl Physiol (1985) 2003; 94:60-8. [PMID: 12391092 DOI: 10.1152/japplphysiol.00269.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitric oxide (NO) is produced in the vascular endothelium and is a potent vasodilator substance that participates in the regulation of local vascular tone. Exercise causes peculiar changes in systemic and regional blood flow, i.e., an increase of systemic blood flow and a redistribution of local tissue blood flow, by which the blood flow is greatly increased in the working muscles, whereas it is decreased in some organs such as the kidney and intestine. Thus we hypothesized that exercise causes a tissue-specific change of NO production in some internal organs. We studied whether exercise affects expression of NO synthase (NOS) mRNA and protein, NOS activity, and tissue level of nitrite/nitrate (stable end products of NO) in the kidneys (in which blood flow during exercise is decreased) and lungs (in which blood flow during exercise is increased with the increase of cardiac output) of rat. Rats ran on a treadmill for 45 min at a speed of 25 m/min. Immediately after this exercise, kidneys and lungs were quickly removed. Control rats remained at rest during this 45-min period. Expression of endothelial NOS (eNOS) mRNA in the kidneys was markedly lower in exercise rats than in control rats, whereas that in the lungs was significantly higher in exercise rats than in control rats. Western blot analysis confirmed down- and upregulation of eNOS protein in the kidney and lung, respectively, after exercise. On the other hand, neither expression of neuronal NOS (nNOS) mRNA and nNOS protein nor inducible NOS (iNOS) mRNA and iNOS protein in the kidneys and lungs differed between exercise and control rats. NOS activity in the kidney was significantly lower in exercise rats than in control rats, whereas that in the lung was significantly higher in exercise rats than in control rats. On the other hand, the iNOS activity in the kidneys and lungs did not differ between exercise rats and control rats. Tissue nitrite/nitrate level in the kidneys was markedly lower in exercise rats, whereas that in the lungs was significantly higher in exercise rats. The present results show that production of NO is markedly and tissue-specifically changed in the kidney and lung by exercise.
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Affiliation(s)
- Takashi Miyauchi
- Cardiovascular Division, Department of Internal Medicine, Institute of Clinical Medicine, University of Tsukuba, Ibaraki 305-0006, Japan.
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Wright MV, Kuhn TB. CNS neurons express two distinct plasma membrane electron transport systems implicated in neuronal viability. J Neurochem 2002; 83:655-64. [PMID: 12390527 DOI: 10.1046/j.1471-4159.2002.01176.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Trans-plasma membrane electron transport is critical for maintaining cellular redox balance and viability, yet few, if any, investigations have studied it in intact primary neurons. In this investigation, extracellular reduction of 2,6-dichloroindophenol (DCIP) and ferricyanide (FeCN) were measured as indicators of trans-plasma membrane electron transport by chick forebrain neurons. Neurons readily reduced DCIP, but not FeCN unless CoQ(1), an exogenous ubiquinone analog, was added to the assays. CoQ(1) stimulated FeCN reduction in a dose-dependent manner but had no effect on DCIP reduction. Reduction of both substrates was totally inhibited by epsilon-maleimidocaproic acid (MCA), a membrane-impermeant thiol reagent, and slightly inhibited by superoxide dismutase. Diphenylene iodonium, a flavoenzyme inhibitor, completely inhibited FeCN reduction but had no affect on DCIP reduction, suggesting that these substrates are reduced by distinct redox pathways. The relationship between plasma membrane electron transport and neuronal viability was tested using the inhibitors MCA and capsaicin. MCA caused a dose-dependent decline in neuronal viability that closely paralleled its inhibition of both reductase activities. Similarly capsaicin, a NADH oxidase inhibitor, induced a rapid decline in neuronal viability. These results suggest that trans-plasma membrane electron transport helps maintain a stable redox environment required for neuronal viability.
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Affiliation(s)
- M V Wright
- Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska, USA
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Kim SH, Moon YJ, Ryu CK, Lee MG. Determination of a new isoquinolinedione derivative, 7-anilino-5,8-isoquinolinedione, in plasma, urine and tissue homogenates by high-performance liquid chromatography. J Pharm Biomed Anal 2002; 30:519-26. [PMID: 12367676 DOI: 10.1016/s0731-7085(02)00398-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A high-performance liquid chromatographic (HPLC) method was developed for the determination of a new isoquinolinedione derivative, 7-anilino-5,8-isoquinolinedione (IQO4), in rat plasma, urine, blood and tissue homogenates using diazepam as an internal standard. A 2 volume of acetonitrile was added to deproteinize the biological sample. A 50 microl aliquot of the supernatant was injected onto a C(18) reversed-phase column. The mobile phase, 0.05 M acetate buffer (pH 3):acetonitrile:methanol (40:40:20, v/v/v), was run at a flow rate of 1.5 ml/min. The column effluent was monitored using an ultraviolet detector set at 298 nm. The retention times for IQO4 and the internal standard were approximately 5 and 7 min, respectively. The detection limits of IQO4 in rat plasma, urine and tissue homogenates (including blood) were 0.05, 0.1 and 0.1 microg/ml, respectively. The coefficients of variation of the assay were below 9.4% for rat plasma, urine and tissue homogenates. No interferences from endogenous substances were found.
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Affiliation(s)
- So Hee Kim
- College of Dentistry and Research Institute of Oral Science, Kangnung National University, 123, Jibyeon-Dong, Gangnung, Gangwon-Do 210-702, South Korea
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