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Więckowska M, Szelenberger R, Niemcewicz M, Harmata P, Poplawski T, Bijak M. Ochratoxin A-The Current Knowledge Concerning Hepatotoxicity, Mode of Action and Possible Prevention. Molecules 2023; 28:6617. [PMID: 37764392 PMCID: PMC10534339 DOI: 10.3390/molecules28186617] [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: 08/21/2023] [Revised: 09/10/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
Ochratoxin A (OTA) is considered as the most toxic of the other ochratoxins synthesized by various fungal species belonging to the Aspergillus and Penicillium families. OTA commonly contaminates food and beverages, resulting in animal and human health issues. The toxicity of OTA is known to cause liver damage and is still being researched. However, current findings do not provide clear insights into the toxin mechanism of action. The current studies focusing on the use of potentially protective compounds against the effects of the toxin are insufficient as they are mainly conducted on animals. Further research is required to fill the existing gaps in both fields (namely the exact OTA molecular mechanism and the prevention of its toxicity in the human liver). This review article is a summary of the so far obtained results of studies focusing on the OTA hepatotoxicity, its mode of action, and the known approaches of liver cells protection, which may be the base for expanding other research in near future.
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Affiliation(s)
- Magdalena Więckowska
- Biohazard Prevention Centre, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland; (M.W.); (R.S.); (M.N.)
| | - Rafał Szelenberger
- Biohazard Prevention Centre, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland; (M.W.); (R.S.); (M.N.)
| | - Marcin Niemcewicz
- Biohazard Prevention Centre, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland; (M.W.); (R.S.); (M.N.)
| | - Piotr Harmata
- Faculty of Advanced Technologies and Chemistry, Military University of Technology, 2 gen. S. Kaliskiego St., 00-908 Warsaw, Poland;
| | - Tomasz Poplawski
- Department of Pharmaceutical Microbiology and Biochemistry, Medical University of Lodz, 92-215 Lodz, Poland;
| | - Michał Bijak
- Biohazard Prevention Centre, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland; (M.W.); (R.S.); (M.N.)
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Maheshwari N, Khan AA, Mahmood R, Salam S. Pentachlorophenol-induced hemotoxicity diminishes antioxidant potential and oxidizes proteins, thiols, and lipids in rat blood: An in vivo study. Heliyon 2023; 9:e16240. [PMID: 37234629 PMCID: PMC10205642 DOI: 10.1016/j.heliyon.2023.e16240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 05/06/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Pentachlorophenol (PCP) is an excessively used wood preservative and pesticide, which has resulted in human exposure raising concerns about its potential toxic effects. This study is designed to evaluate the hemotoxicity of PCP in adult rats. Wistar rats were orally administered PCP (25-150 mg/kg bw) for five days while untreated (control) rats received corn oil. Animals were sacrificed, blood was taken and fractionated into plasma and red blood cells (RBC). PCP administration increased methemoglobin formation but decreased methemoglobin reductase activity. Significantly increased hydrogen peroxide level indicates initiation of oxidative stress condition in blood. PCP increased the oxidation of thiols, proteins and lipids, lowered glutathione levels, and compromised the antioxidant status of RBC in treated rats. Enzymes of the pathways of glucose breakdown, glycolysis and phosphogluconate pathway, were inhibited. Markers of liver damage were increased in the plasma of PCP-treated rats suggesting hepatotoxicity. This was confirmed by histopathological analysis of stained liver sections. Activity of xanthine oxidase, a reactive oxygen species (ROS) generating pro-oxidant enzyme, was increased. These hematological changes could be a result of the increased generation of ROS or direct chemical transformation by transient reaction species. These results show that PCP induces redox imbalance, diminishes antioxidant potential, inhibits metabolic pathways, and oxidizes cellular components in rat blood. This study suggests an elaborated possible molecular mechanism of PCP toxicity, and similar compounds so that methods can be devised to minimize its damaging effect.
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Affiliation(s)
- Nikhil Maheshwari
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, U.P., India
| | - Aijaz Ahmed Khan
- Department of Anatomy, J. N. Medical College, Aligarh Muslim University, Aligarh 202002, U.P., India
| | - Riaz Mahmood
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, U.P., India
| | - Samreen Salam
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, U.P., India
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Li Q, Li W, Zhao J, Guo X, Zou Q, Yang Z, Tian R, Peng Y, Zheng J. Glutathione Conjugation and Protein Adduction by Environmental Pollutant 2,4-Dichlorophenol In Vitro and In Vivo. Chem Res Toxicol 2020; 33:2351-2360. [PMID: 32786540 DOI: 10.1021/acs.chemrestox.0c00118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
2,4-Dichlorophenol (2,4-DCP), an environmental pollutant, was reported to cause hepatotoxicity. The biochemical mechanisms of 2,4-DCP induced liver injury remain unknown. The present study showed that 2,4-DCP is chemically reactive and spontaneously reacts with GSH and bovine serum albumin to form GSH conjugates and BSA adducts. The observed conjugation/adduction apparently involved the addition of GSH and departure of chloride via the ipso substitution pathway. Two biliary GSH conjugates and one urinary N-acetyl cysteine conjugate were observed in rats given 2,4-DCP. The N-acetyl cysteine conjugate was chemically synthesized and characterized by mass spectrometry and NMR. As expected, 2,4-DCP was found to modify hepatic protein at cysteine residues in vivo by the same chemistry. The observed protein adduction reached its peak at 15 min and revealed dose dependency. The new findings allowed us to better understand the mechanisms of the toxic action of 2,4-DCP.
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Affiliation(s)
- Qingmei Li
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Wei Li
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Jiaxing Zhao
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Xiucai Guo
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Qian Zou
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Zixin Yang
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Ruixue Tian
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Ying Peng
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Jiang Zheng
- State Key Laboratory of Functions and Applications of Medicinal Plants, Key Laboratory of Pharmaceutics of Guizhou Province, Guiyang, Guizhou 550004, P. R. China.,Key Laboratory of Environmental Pollution, Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, P. R. China.,Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
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Maheshwari N, Khan FH, Mahmood R. Pentachlorophenol-induced cytotoxicity in human erythrocytes: enhanced generation of ROS and RNS, lowered antioxidant power, inhibition of glucose metabolism, and morphological changes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:12985-13001. [PMID: 30895543 DOI: 10.1007/s11356-019-04736-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 02/27/2019] [Indexed: 06/09/2023]
Abstract
Pentachlorophenol (PCP) is a class 2B human carcinogen that is used as an insecticide, herbicide, and wood preservative. PCP is rapidly absorbed and enters the blood where it can interact with erythrocytes. We have examined the effect of PCP on human erythrocytes. Treatment of erythrocytes with PCP increased the intracellular generation of reactive oxygen and nitrogen species. It also increased lipid and protein oxidation accompanied by decrease in glutathione levels and total sulfhydryl content. The activities of all major antioxidant enzymes were altered. The antioxidant power was significantly impaired resulting in lower free radical quenching and metal reducing ability of the PCP-treated cells. PCP exposure also inhibited the activities of enzymes of glycolysis and pentose phosphate shunt, the two pathways of glucose metabolism in erythrocytes. Heme degradation was enhanced leading to the release of free iron. Incubation of erythrocytes with PCP caused significant cell lysis suggesting plasma membrane damage which was also evident from inhibition of bound enzymes. Scanning electron microscopy of erythrocytes confirmed these biochemical results and showed that PCP treatment converted the normal biconcave discoids to echinocytes and other irregularly shaped cells. Thus, PCP induces oxidative and nitrosative stress in erythrocytes, alters the enzymatic and nonenzymatic antioxidant defense systems, inhibits glucose metabolism, and causes significant modifications in cellular morphology.
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Affiliation(s)
- Nikhil Maheshwari
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, Uttar Pradesh, 202002, India
| | - Fahim Halim Khan
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, Uttar Pradesh, 202002, India
| | - Riaz Mahmood
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, Uttar Pradesh, 202002, India.
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Klopčič I, Dolenc MS. Chemicals and Drugs Forming Reactive Quinone and Quinone Imine Metabolites. Chem Res Toxicol 2018; 32:1-34. [DOI: 10.1021/acs.chemrestox.8b00213] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Ivana Klopčič
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
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6
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Liu Z, Dong W, Yang B, Peng L, Xia X, Pu L, Zhang N, Song E, Song Y. Tetrachlorobenzoquinone-Induced Nrf2 Confers Neuron-like PC12 Cells Resistance to Endoplasmic Reticulum Stress via Regulating Glutathione Synthesis and Protein Thiol Homeostasis. Chem Res Toxicol 2018; 31:1230-1239. [DOI: 10.1021/acs.chemrestox.8b00209] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Zixuan Liu
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China, 400715
| | - Wenjing Dong
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China, 400715
| | - Bingwei Yang
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China, 400715
| | - Lu Peng
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China, 400715
| | - Xiaomin Xia
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China, 400715
| | - Lanxiang Pu
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China, 400715
| | - Na Zhang
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China, 400715
| | - Erqun Song
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China, 400715
| | - Yang Song
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China, 400715
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Abstract
The European Commission requested EFSA to evaluate whether a series of dyes are covered by the ‘Guidance on methodological principles and scientific methods to be taken into account when establishing Reference Points for Action (RPAs) for non‐allowed pharmacologically active substances present in food of animal origin’ and to which group they should be attributed according to this guidance. Although these substances are not registered for use in food‐producing animals in the European Union, they may be used illegally in aquaculture for their antimicrobial properties. It was concluded that acriflavine, 3‐aminoacridine, aminoacridine, basic blue 7, brilliant green, leucobrilliant green, C.I. basic blue 26, chloranil, crystal violet, leucocrystal violet, dichlone, ethyl violet, methylene blue, new methylene blue, Nile blue, pararosaniline base, proflavine, proflavine hydrochloride, rhodamine 6G and trypan red are covered by the guidance document and belong to group I. A toxicological screening value of 0.0025 μg/kg body weight per day is applicable. Azure blue and potassium permanganate were excluded from the evaluation due to their inorganic nature.
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8
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Analytical characterization, occurrence, transformation, and removal of the emerging disinfection byproducts halobenzoquinones in water. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.03.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Qu N, Li F, Shao B, Shao J, Zhai G, Wang F, Zhu BZ. The Unexpected and Exceptionally Facile Chemical Modification of the Phenolic Hydroxyl Group of Tyrosine by Polyhalogenated Quinones under Physiological Conditions. Chem Res Toxicol 2016; 29:1699-1705. [DOI: 10.1021/acs.chemrestox.6b00217] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Na Qu
- State
Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Centre for Eco-environmental Sciences and University of the Chinese Academy of Sciences, the Chinese Academy of Sciences, 18 Shuangqin
Road, Haidian District, Beijing 100085, P. R. China
| | - Feng Li
- State
Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Centre for Eco-environmental Sciences and University of the Chinese Academy of Sciences, the Chinese Academy of Sciences, 18 Shuangqin
Road, Haidian District, Beijing 100085, P. R. China
| | - Bo Shao
- State
Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Centre for Eco-environmental Sciences and University of the Chinese Academy of Sciences, the Chinese Academy of Sciences, 18 Shuangqin
Road, Haidian District, Beijing 100085, P. R. China
| | - Jie Shao
- State
Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Centre for Eco-environmental Sciences and University of the Chinese Academy of Sciences, the Chinese Academy of Sciences, 18 Shuangqin
Road, Haidian District, Beijing 100085, P. R. China
| | - Guijin Zhai
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- Tianjin
Research Centre of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Fuyi Wang
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Ben-Zhan Zhu
- State
Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Centre for Eco-environmental Sciences and University of the Chinese Academy of Sciences, the Chinese Academy of Sciences, 18 Shuangqin
Road, Haidian District, Beijing 100085, P. R. China
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Su C, Shi Q, Song X, Fu J, Liu Z, Wang Y, Wang Y, Xia X, Song E, Song Y. Tetrachlorobenzoquinone induces Nrf2 activation via rapid Bach1 nuclear export/ubiquitination and JNK-P62 signaling. Toxicology 2016; 363-364:48-57. [PMID: 27393035 DOI: 10.1016/j.tox.2016.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/19/2016] [Accepted: 07/04/2016] [Indexed: 12/30/2022]
Abstract
Our previous studies demonstrated that tetrachlorobenzoquinone (TCBQ), an active metabolite of pentachlorophenol, has effects on the generation of reactive oxygen species (ROS) and oxidative stress in vitro and in vivo. Nuclear factor erythroid-derived 2-like 2 (Nrf2) is a cellular sensor of electrophilic or oxidative stress that regulates the expression of antioxidant enzymes and defensive proteins. We have illustrated that TCBQ activates Nrf2 signaling by promoting the formation of the Kelch-like ECH-associated protein 1 (Keap1) cross-linking dimer and the formation of an ubiquitination switch from Nrf2 to Keap1. The activation of Nrf2 by TCBQ may serve as an adaptive response to a TCBQ-induced oxidative insult. BTB and CNC homolog 1 (Bach1) compete with Nrf2, leading to the negative regulation of the antioxidant response element (ARE). In this report, we propose that TCBQ induces the dynamic inactivation of Bach1. We observed a rapid nuclear efflux of Bach1 and an accumulation of Nrf2 in nuclei upon TCBQ treatment that precedes the binding of Nrf2 with ARE. We found that the nuclear export of Bach1 is dependent on its chromosomal region maintenance 1 (Crm1) interaction and tyrosine phosphorylation. Although TCBQ induces the ubiquitination of Bach1, TCBQ also increases the mRNA and protein levels of Bach1, returning Bach1 to normal levels. Moreover, we found that TCBQ-induced activation of Nrf2 involves c-Jun N-terminal kinase (JNK)-P62 signaling.
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Affiliation(s)
- Chuanyang Su
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China
| | - Qiong Shi
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China
| | - Xiufang Song
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China
| | - Juanli Fu
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China
| | - Zixuan Liu
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China
| | - Yawen Wang
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China
| | - Yuxin Wang
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China
| | - Xiaomin Xia
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China
| | - Erqun Song
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China.
| | - Yang Song
- Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People's Republic of China.
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Ochratoxin A: Molecular Interactions, Mechanisms of Toxicity and Prevention at the Molecular Level. Toxins (Basel) 2016; 8:111. [PMID: 27092524 PMCID: PMC4848637 DOI: 10.3390/toxins8040111] [Citation(s) in RCA: 163] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 03/31/2016] [Accepted: 04/06/2016] [Indexed: 01/28/2023] Open
Abstract
Ochratoxin A (OTA) is a widely-spread mycotoxin all over the world causing major health risks. The focus of the present review is on the molecular and cellular interactions of OTA. In order to get better insight into the mechanism of its toxicity and on the several attempts made for prevention or attenuation of its toxic action, a detailed description is given on chemistry and toxicokinetics of this mycotoxin. The mode of action of OTA is not clearly understood yet, and seems to be very complex. Inhibition of protein synthesis and energy production, induction of oxidative stress, DNA adduct formation, as well as apoptosis/necrosis and cell cycle arrest are possibly involved in its toxic action. Since OTA binds very strongly to human and animal albumin, a major emphasis is done regarding OTA-albumin interaction. Displacement of OTA from albumin by drugs and by natural flavonoids are discussed in detail, hypothesizing their potentially beneficial effect in order to prevent or attenuate the OTA-induced toxic consequences.
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Hu L, Su C, Song X, Shi Q, Fu J, Xia X, Xu D, Song E, Song Y. Tetrachlorobenzoquinone triggers the cleavage of Bid and promotes the cross-talk of extrinsic and intrinsic apoptotic signalings in pheochromocytoma (PC) 12 cells. Neurotoxicology 2015; 49:149-57. [DOI: 10.1016/j.neuro.2015.06.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/14/2015] [Accepted: 06/15/2015] [Indexed: 12/01/2022]
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Pfohl-Leszkowicz A, Manderville RA. An update on direct genotoxicity as a molecular mechanism of ochratoxin a carcinogenicity. Chem Res Toxicol 2011; 25:252-62. [PMID: 22054007 DOI: 10.1021/tx200430f] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Ochratoxin A (OTA) is a naturally occurring chlorophenolic fungal toxin that contaminates a wide range of food products and poses a cancer threat to humans. The mechanism of action (MOA) for OTA renal carcinogenicity is a controversial issue. In 2005, direct genotoxicity (covalent DNA adduct formation) was proposed as a MOA for OTA-mediated carcinogenicity [ Manderville , R. A. ( 2005 ) Chem. Res. Toxicol. 18 , 1091 - 1097 ]. At that time, inconsistent results had been published on OTA genotoxicity/mutagenicity, and conclusive evidence for OTA-mediated DNA adduction had been lacking. In this update, published data from the past 6-7 years are presented that provide new hypotheses for the MOA of OTA-mediated carcinogenicity. While direct genotoxicity remains a controversial issue for OTA, new findings from the Umemura and Nohmi laboratories provide definitive results for the mutagenicity of OTA in the target tissue (outer medulla) of male rat kidney that rules out oxidative DNA damage. These findings, coupled with our own efforts that provide new structural evidence for DNA adduction by OTA, has strengthened the argument for involvement of direct genotoxicity in OTA-mediated renal carcinogenesis. This MOA should be taken into consideration for OTA human risk assessment.
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Affiliation(s)
- Annie Pfohl-Leszkowicz
- Laboratoire de Génie Chimique , UMR CNRS/INPT/UPS 5503, INP/ENSA Toulouse, 1 Avenue Agrobiopole, F-31326 Auzeville-Tolosane, France.
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14
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Funk WE, Li H, Iavarone AT, Williams ER, Riby J, Rappaport SM. Enrichment of cysteinyl adducts of human serum albumin. Anal Biochem 2010; 400:61-8. [PMID: 20074543 DOI: 10.1016/j.ab.2010.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 11/23/2009] [Accepted: 01/07/2010] [Indexed: 02/03/2023]
Abstract
We report a method to enrich cysteinyl adducts of human serum albumin (HSA), representing biomarkers of exposure to systemic electrophiles. Because the major site of HSA adduction is the single free sulfhydryl group at Cys34, we used thiol-affinity resins to remove mercaptalbumin (i.e., unadducted HSA) from the cysteinyl adducts. Electrospray ionization mass spectrometry was used to detect mercaptalbumin and HSA-Cys34 modifications before and after enrichment of HSA. Differences in adduct content were detected across samples of freshly isolated, archived, and commercial HSA. Cysteinylated and glycosylated adducts were present in all samples, with abundances decreasing in the following order: commercial HSA>archived HSA>fresh HSA. After enrichment of HSA, mercaptalbumin was no longer observed in mass spectra. The ratios of HSA adducts post-/preenrichment, quantified via the Bradford assay and gel electrophoresis, were 0.029 mg adducts/mg HSA in fresh HSA and 0.323 mg adducts/mg HSA in archived HSA. The apparent elevation of adduct levels in archived samples could be due to differences in specimen preparation and storage rather than to differences in circulating HSA adducts. We conclude that thiol-affinity resins can efficiently remove mercaptalbumin from HSA samples prior to characterization and quantitation of protein adducts of reactive systemic electrophiles.
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Affiliation(s)
- William E Funk
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA
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15
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Lin PH, Waidyanatha S, Rappaport SM. Investigation of liver binding of pentachlorophenol based upon measurement of protein adducts. Biomarkers 2008; 1:232-43. [DOI: 10.3109/13547509609079363] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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16
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Gulcan HO, Liu Y, Duffel MW. Pentachlorophenol and other chlorinated phenols are substrates for human hydroxysteroid sulfotransferase hSULT2A1. Chem Res Toxicol 2008; 21:1503-8. [PMID: 18656962 PMCID: PMC2548291 DOI: 10.1021/tx800133d] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pentachlorophenol (PCP) is a persistent chemical contaminant that has been extensively investigated in terms of its toxicology and metabolism. Similar to PCP, other chlorinated phenol derivatives are also widely present in the environment from various sources. Even though some of the chlorine-substituted phenols, and particularly PCP, are well-known inhibitors of phenol sulfotransferases (SULTs), these compounds have been shown to undergo sulfation in humans. To investigate the enzymatic basis for sulfation of PCP in humans, we have studied the potential for PCP as well as the mono-, di-, tri-, and tetra-chlorinated phenols to serve as substrates for human hydroxysteroid sulfotransferase, hSULT2A1. Our results show that all of these compounds are substrates for this isoform of sulfotransferase, and the highest rates of sulfation are obtained with PCP, trichlorophenols, and tetrachlorophenols. Much lower rates of sulfation were obtained with isomers of monochlorophenol and dichlorophenol as substrates for hSULT2A1. Thus, the sulfation of polychlorinated phenols catalyzed by hSULT2A1 may be a significant component of their metabolism in humans.
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Affiliation(s)
- Hayrettin Ozan Gulcan
- DiVision of Medicinal and Natural Products Chemistry, College of Pharmacy, The University of Iowa, Iowa City, Iowa 52242, USA.
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Manderville R, Pfohl-Leszkowicz A. Bioactivation and DNA adduction as a rationale for ochratoxin A carcinogenesis. WORLD MYCOTOXIN J 2008. [DOI: 10.3920/wmj2008.x039] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ochratoxin A (OTA) is a para-chlorophenolic mycotoxin produced by strains of Aspergillus and Penicillium that is widely found as a contaminant of improperly stored food products. The toxin is a potent renal carcinogen in rats, especially male, and has an implicated role in the etiology of Balkan endemic nephropathy and its associated urinary tract tumours. Although the mechanism of OTA-mediated tumour formation is not fully understood, and represents a hotly debated topic, bioactivation and subsequent DNA adduction through covalent attachment of electrophilic OTA species remains a viable mechanism for OTA-mediated carcinogenesis. In this paper we outline the established chemistry for the bioactivation of chlorophenol carcinogens and demonstrate how this chemistry relates to the bioactivation of OTA. From this basis it is predicted that OTA will form a benzoquinone electrophile following activation by cytochrome P450 enzymes and radical species following activation by enzymes with peroxidase activities. These electrophiles react preferentially with deoxyguanosine (dG) to form benzetheno adducts and C8- dG adducts, respectively. Analysis of OTA-mediated DNA adduction using the 32P-postlabelling method correlates with OTA chemistry and adduct spots derived from the quinone electrophile are generated following activation by cytochrome P450, while a C8-OTA adduct is formed following activation of OTA by peroxidase enzymes. These same adduct spots are also produced in animal (rat and pig) and human tumoral kidney tissue. This model for OTAmediated carcinogenesis is consistent with established structure-activity relationships for covalent attachment of OTA analogues and OTA toxicity. The model also provides a rationale for the synergistic effect observed for OTA in the presence of the mycotoxin citrinin and for the sexual differences observed in rat carcinogenesis where the male is particularly susceptible to OTA-mediated tumour formation.
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Affiliation(s)
- R. Manderville
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, N1G 2W1 Ontario, Canada
| | - A. Pfohl-Leszkowicz
- ENSAT, Laboratory Chemical Engineering, UMR CNRS/INPT/UPS n° 5503, 1 avenue agrobiopole, 31326 Auzeville-Tolosane, France
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Pfohl-Leszkowicz A. Chapter 7 Formation, Persistence and Significance of DNA Adduct Formation in Relation to Some Pollutants from a Broad Perspective. ADVANCES IN MOLECULAR TOXICOLOGY 2008. [DOI: 10.1016/s1872-0854(07)02007-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Pfohl-Leszkowicz A, Manderville RA. Ochratoxin A: An overview on toxicity and carcinogenicity in animals and humans. Mol Nutr Food Res 2007; 51:61-99. [PMID: 17195275 DOI: 10.1002/mnfr.200600137] [Citation(s) in RCA: 687] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Ochratoxin A (OTA) is a ubiquitous mycotoxin produced by fungi of improperly stored food products. OTA is nephrotoxic and is suspected of being the main etiological agent responsible for human Balkan endemic nephropathy (BEN) and associated urinary tract tumours. Striking similarities between OTA-induced porcine nephropathy in pigs and BEN in humans are observed. International Agency for Research on Cancer (IARC) has classified OTA as a possible human carcinogen (group 2B). Currently, the mode of carcinogenic action by OTA is unknown. OTA is genotoxic following oxidative metabolism. This activity is thought to play a central role in OTA-mediated carcinogenesis and may be divided into direct (covalent DNA adduction) and indirect (oxidative DNA damage) mechanisms of action. Evidence for a direct mode of genotoxicity has been derived from the sensitive 32P-postlabelling assay. OTA facilitates guanine-specific DNA adducts in vitro and in rat and pig kidney orally dosed, one adduct comigrates with a synthetic carbon (C)-bonded C8-dG OTA adduct standard. In this paper, our current understanding of OTA toxicity and carcinogenicity are reviewed. The available evidence suggests that OTA is a genotoxic carcinogen by induction of oxidative DNA lesions coupled with direct DNA adducts via quinone formation. This mechanism of action should be used to establish acceptable intake levels of OTA from human food sources.
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Affiliation(s)
- Annie Pfohl-Leszkowicz
- Laboratoire de Génie Chimique, UMR CNRS/INPT/UPS 5503, INP/ENSA Toulouse, Auzeville-Tolosane, France
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Waidyanatha S, Troester MA, Lindstrom AB, Rappaport SM. Measurement of hemoglobin and albumin adducts of naphthalene-1,2-oxide, 1,2-naphthoquinone and 1,4-naphthoquinone after administration of naphthalene to F344 rats. Chem Biol Interact 2002; 141:189-210. [PMID: 12385719 DOI: 10.1016/s0009-2797(02)00048-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Naphthalene-1,2-oxide (NPO), 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ) are the major metabolites of naphthalene that are thought to be responsible for the cytotoxicity and genotoxicity of this chemical. We measured cysteinyl adducts of these metabolites in hemoglobin (Hb) and albumin (Alb) from F344 rats dosed with 100-800 mg naphthalene per kg body weight. The method employs cleavage and derivatization of these adducts by trifluoroacetic anhydride and methanesulfonic acid followed by gas chromatography-mass spectrometry in negative ion chemical ionization mode. Cysteinyl adducts of both proteins with NPO, and 1,2- and 1,4-NPQ (designated NPO-Hb and -Alb, 1,2-NPQ-Hb and -Alb, and 1,4-NPQ-Hb and -Alb, respectively) were produced in a dose-dependent manner. Of the two structural isomers resulting from NPO, levels of NPO1 adducts were greater than those of NPO2 adducts in both Hb and Alb, indicating that aromatic substitution is favored in vivo at positions 1 over 2. Of the quinone adducts, 1,2-NPQ-Hb and -Alb were produced in greater quantities than 1,4-NPQ-Hb and -Alb, indicating either that the formation of 1,2-NPQ from NPO is favored or that more than one pathway leads to the formation of 1,2-NPQ. The shapes of the dose-response curves were generally nonlinear at doses above 200 mg naphthalene per kg body weight. However, the nature of nonlinearity differed, showing evidence of supralinearity for NPO-Hb, NPQ-Hb and NPQ-Alb and of sublinearity for NPO-Alb. Low background levels of 1,2-NPQ-Hb and -Alb and 1,4-NPQ-Hb and -Alb were detected in control animals without known exposure to naphthalene. However, the corresponding NPO-Hb and -Alb adducts were not detected in control animals.
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Affiliation(s)
- Suramya Waidyanatha
- Department of Environmental Sciences and Engineering, CB 7400, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7400, USA
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Zhu BZ, Zhao HT, Kalyanaraman B, Frei B. Metal-independent production of hydroxyl radicals by halogenated quinones and hydrogen peroxide: an ESR spin trapping study. Free Radic Biol Med 2002; 32:465-73. [PMID: 11864786 DOI: 10.1016/s0891-5849(01)00824-3] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The metal-independent production of hydroxyl radicals (*OH) from H(2)O(2) and tetrachloro-1,4-benzoquinone (TCBQ), a carcinogenic metabolite of the widely used wood-preservative pentachlorophenol, was studied by electron spin resonance methods. When incubated with the spin trapping agent 5,5-dimethyl-1-pyrroline N-oxide (DMPO), TCBQ and H(2)O(2) produced the DMPO/*OH adduct. The formation of DMPO/*OH was markedly inhibited by the *OH scavenging agents dimethyl sulfoxide (DMSO), ethanol, formate, and azide, with the concomitant formation of the characteristic DMPO spin trapping adducts with *CH(3), *CH(CH(3))OH, *COO(-), and *N(3), respectively. The formation of DMPO/*OH and DMPO/*CH(3) from TCBQ and H(2)O(2) in the absence and presence, respectively, of DMSO was inhibited by the trihydroxamate compound desferrioxamine, accompanied by the formation of the desferrioxamine-nitroxide radical. In contrast, DMPO/*OH and DMPO/*CH(3) formation from TCBQ and H(2)O(2) was not affected by the nonhydroxamate iron chelators bathophenanthroline disulfonate, ferrozine, and ferene, as well as the copper-specific chelator bathocuproine disulfonate. A comparative study with ferrous iron and H(2)O(2), the classic Fenton system, strongly supports our conclusion that *OH is produced by TCBQ and H(2)O(2) through a metal-independent mechanism. Metal-independent production of *OH from H(2)O(2) was also observed with several other halogenated quinones.
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Affiliation(s)
- Ben-Zhan Zhu
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
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Harvey PJ, Campanella BF, Castro PML, Harms H, Lichtfouse E, Schäffner AR, Smrcek S, Werck-Reichhart D. Phytoremediation of polyaromatic hydrocarbons, anilines and phenols. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2002; 9:29-47. [PMID: 11885416 DOI: 10.1007/bf02987315] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Phytoremediation technologies based on the combined action of plants and the microbial communities that they support within the rhizosphere hold promise in the remediation of land and waterways contaminated with hydrocarbons but they have not yet been adopted in large-scale remediation strategies. In this review plant and microbial degradative capacities, viewed as a continuum, have been dissected in order to identify where bottle-necks and limitations exist. Phenols, anilines and polyaromatic hydrocarbons (PAHs) were selected as the target classes of molecule for consideration, in part because of their common patterns of distribution, but also because of the urgent need to develop techniques to overcome their toxicity to human health. Depending on the chemical and physical properties of the pollutant, the emerging picture suggests that plants will draw pollutants including PAHs into the plant rhizosphere to varying extents via the transpiration stream. Mycorrhizosphere-bacteria and -fungi may play a crucial role in establishing plants in degraded ecosystems. Within the rhizosphere, microbial degradative activities prevail in order to extract energy and carbon skeletons from the pollutants for microbial cell growth. There has been little systematic analysis of the changing dynamics of pollutant degradation within the rhizosphere; however, the importance of plants in supplying oxygen and nutrients to the rhizosphere via fine roots, and of the beneficial effect of microorganisms on plant root growth is stressed. In addition to their role in supporting rhizospheric degradative activities, plants may possess a limited capacity to transport some of the more mobile pollutants into roots and shoots via fine roots. In those situations where uptake does occur (i.e. only limited microbial activity in the rhizosphere) there is good evidence that the pollutant may be metabolised. However, plant uptake is frequently associated with the inhibition of plant growth and an increasing tendency to oxidant stress. Pollutant tolerance seems to correlate with the ability to deposit large quantities of pollutant metabolites in the 'bound' residue fraction of plant cell walls compared to the vacuole. In this regard, particular attention is paid to the activities of peroxidases, laccases, cytochromes P450, glucosyltransferases and ABC transporters. However, despite the seemingly large diversity of these proteins, direct proof of their participation in the metabolism of industrial aromatic pollutants is surprisingly scarce and little is known about their control in the overall metabolic scheme. Little is known about the bioavailability of bound metabolites; however, there may be a need to prevent their movement into wildlife food chains. In this regard, the application to harvested plants of composting techniques based on the degradative capacity of white-rot fungi merits attention.
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Affiliation(s)
- Patricia J Harvey
- University of Greenwich, School of Chemical and Life Sciences, Wellington Street, London SE18 6PF, UK.
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Tsai CH, Lin PH, Waidyanatha S, Rappaport SM. Characterization of metabolic activation of pentachlorophenol to quinones and semiquinones in rodent liver. Chem Biol Interact 2001; 134:55-71. [PMID: 11248222 DOI: 10.1016/s0009-2797(00)00318-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pentachlorophenol (PCP), a widely used biocide, induces liver tumors in mice but not in rats. Metabolic activation of PCP to chlorinated quinones and semiquinones in liver cytosol from Sprague-Dawley rats and B6C3F1 mice was investigated in vitro (1) with microsomes in the presence of either beta-nicotinamide adenine dinucleotide phosphate (NADPH) or cumene hydroperoxide (CHP), (2) with CHP in the absence of microsomes, and (3) with horseradish peroxidase (HRP) and H2O2. Mono-S- and multi-S-substituted adducts of tetrachloro-1,4-benzoquinone (Cl4-1,4-BQ) and Cl4-1,2-BQ and their corresponding semiquinones [i.e. tetrachloro-1,4-benzosemiquinone (Cl4-1,4-SQ) and tetrachloro-1,2-benzosemiquinone (Cl4-1,2-SQ)] were measured by gas chromatography-mass spectrometry (GC-MS). Qualitatively, the metabolites of PCP were the same in both rats and mice for all activation systems. Induction of PCP metabolism by either 3MC or PB-treated microsomes was observed in NADPH- but not in CHP-supported systems. In rats, the amount of induction was comparable with either 3MC or PB. 3MC was a stronger inducer than PB in mice and also induced a greater amount of metabolism than in rats. This suggests that induction of specific P450 isozymes may play a role in the toxicity of PCP to mice. Both HRP/H2O2 and CHP led to production of the full spectrum of chlorinated quinones and semiquinones, confirming the direct oxidation of PCP. CHP (with or without microsomes) converted PCP into much greater quantities of quinones and semiquinones than did microsomal P450/NADPH or HRP/H2O2 in both species. This implies that, under conditions of oxidative stress, endogenous lipid hydroperoxides may increase PCP metabolism sufficiently to enhance the toxicity and carcinogenicity of PCP.
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Affiliation(s)
- C H Tsai
- Department of Environmental Sciences and Engineering, School of Public Health, University of North Carolina, CB7400, Chapel Hill, NC 27599-7400, USA
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Lambert GR, Padgett WT, George MH, Kitchin KT, Nesnow S. Quantitative analysis of alachlor protein adducts by gas chromatography-mass spectrometry. Anal Biochem 1999; 268:289-96. [PMID: 10075819 DOI: 10.1006/abio.1998.3060] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined the potential use of hemoglobin (Hb)- and serum-protein adducts of alachlor as potential biomarkers of alachlor exposure, a genotoxic and carcinogenic herbicide. The method developed was based on the observation that cleavage of S-cysteinyl alachlor-protein adducts by methanesulfonic acid gave the rearrangement product 3-(2',6'-diethylphenyl)-1, 3-thiazolidine-4-one (TZO). The structure of TZO was confirmed by mass spectroscopy, NMR spectroscopy, and independent synthesis. In the assay, treatment of alachlor-cysteinyl protein adducts by methanesulfonic acid was followed by extraction and analysis. TZO was detected and quantitated by electron-impact GC/MS in the single ion-monitoring mode. [ring-13C6]Alachlor-N-acetylcysteine was added as an internal standard prior to treatment and was converted to [ring-13C6]TZO, allowing response factors to be used to quantitate TZO concentrations. Incubations of alachlor (0-1000 microM) with human albumin and bovine serum albumin (BSA) resulted in linear adduct formation with both proteins. Maximal adduction levels of 613-1130 pmol alachlor-albumin adducts/mg protein were observed, with BSA binding close to twice that of human albumin. A linear concentration response of alachlor-Hb adducts was observed when whole blood from female CD rats was incubated with alachlor in vitro at concentrations up to 300 microM. Maximal binding was 1860 pmol alachlor-Hb adducts/mg globin. Male CD rats treated with alachlor at 150 mg/kg body wt/day ip for 0, 1, 2, and 3 days were sacrificed 4 days after final dosing. A maximal binding of 2250 pmol alachlor-Hb adducts/mg globin was observed. This assay provides a new approach for biomonitoring alachlor levels in experimental animals and has the potential for use in humans.
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Affiliation(s)
- G R Lambert
- Biochemistry and Pathobiology Branch (MD-68), National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
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Waidyanatha S, Yeowell-O'Connell K, Rappaport SM. A new assay for albumin and hemoglobin adducts of 1,2- and 1,4-benzoquinones. Chem Biol Interact 1998; 115:117-39. [PMID: 9826945 DOI: 10.1016/s0009-2797(98)00067-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A new method has been developed to detect mono-S-substituted cysteinyl adducts of 1,2- and 1,4-benzoquinone (BQ) in hemoglobin (Hb) and albumin (Alb). After reacting the protein with trifluoroacetic anhydride and methanesulfonic acid, the resulting isomers of O,O',S-tris-trifluoroacetyl-hydroquinone and -catechol are extracted and detected by gas-chromatography-mass spectrometry in the negative-ion chemical ionization mode. The limit of detection of the assay is about 20 pmol adduct/g protein. This assay was employed to quantitate mono-S-substituted background adducts in human and rat Hb and Alb and benzene-specific adducts in Hb and Alb from F344 rats following a single oral dosage of 50-400 mg [13C6]benzene/kg body wt. In Alb, a dose-related increase in both [13C6]1,2- and [13C6]1,4-BQ adducts was observed with [[13C6]]1,4-BQ-Alb] >> [[13C6]1,2-BQ-Alb]. The formation of [13C6]1,2-BQ-Alb was linear with increasing dosage of benzene with a slope of 2.3 (pmol adduct/g protein)/(mg/kg body wt.) (S.E. = 0.18, R2 = 0.91). However, at dosages above about 100 mg [13C6]benzene/kg body wt., the levels of 1,4-BQ-Alb were greater than proportional to the dosage. Mono-S-substituted adducts of [13C6]1,2-BQ and [13C6]1,4-BQ were not detected in Hb. The background ([12C6]) adducts of 1,2- and 1,4-BQ in 20 F344 rats were estimated (in nmol adduct/g of protein) to be 3.9 (S.E. = 0.23) and 4.9 (S.E. = 0.30) in Hb and 2.7 (S.E. = 0.24) and 11.4 (S.E. = 0.60) in Alb. At the highest dosage of 400 mg [13C6]benzene/kg body wt., background levels of 1,2-BQ-Alb were about 4-fold higher than those of the benzene-specific adducts whereas the benzene-specific levels of 1,4-BQ-Alb were about 7-fold higher than those of the background adducts. Background levels of 1,2- and 1,4-BQ adducts in 10 portions of commercial human proteins were found to be (in nmol adduct/g of protein) 1.6 (S.E. = 0.05) and 0.85 (S.E. = 0.04) in Hb and 1.6 (S.E. = 0.06) and 8.9 (S.E. = 0.36) in Alb.
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Affiliation(s)
- S Waidyanatha
- Department of Environmental Science and Engineering, School of Public Health, University of North Carolina at Chapel Hill 27599-7400, USA
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Lin PH, Waidyanatha S, Pollack GM, Rappaport SM. Dosimetry of chlorinated quinone metabolites of pentachlorophenol in the livers of rats and mice based upon measurement of protein adducts. Toxicol Appl Pharmacol 1997; 145:399-408. [PMID: 9266814 DOI: 10.1006/taap.1997.8207] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The dosimetry of chlorinated quinones arising from metabolism of pentachlorophenol (PCP), in the livers of male Sprague-Dawley rats and B6C3F1 mice was investigated via measurements of cysteinyl protein adducts and estimates of the second-order reaction rate constants between the quinones and the proteins. We had previously shown that adducts of tetrachloro-1,4-benzoquinone (Cl4-1,4-BQ) and tetrachloro-1,2-benzosemiquinone (Cl4-1,2-SQ) were observed at the highest levels in the livers of Sprague-Dawley rats to which PCP had been administered by gavage (5-40 mg/kg body wt) (Biomarkers 1, 232-243, 1996). In the current study we observed that adducts of Cl4-1,4-BQ and tetrachloro-1,2-benzoquinone (CL4-1,2-BQ) were predominant in the livers of B6C3F1 mice receiving 20 mg PCP/kg body wt. The second-order rate constants, representing in vitro reactions between Cl4-1,2-BQ and Cl4-1,4-BQ and various cysteine residues of hepatic proteins of liver cytosol and liver nuclei, were estimated to be 0.012-1.96 L(g protein)(-1) hr(-1) in rats and 0.082-1.67 L(g protein)(-1) hr(-1) in mice. The estimated tissue doses of the quinones to liver cytosol decreased in the order rat Cl4-1,4-BQ > mouse Cl4-1,4-BQ > mouse Cl4-1,2-BQ and to liver nuclei in the order mouse Cl4-1,2-BQ > mouse Cl4-1,4-BQ > rat Cl4-1,4-BQ. The corresponding doses of Cl4-1,2-SQ could not be inferred due to our inability to estimate the second-order rate constants. After aggregating the estimated contributions of all quinone species, mice had a fourfold greater dose to liver nuclei than rats, whereas rats had a threefold greater dose to liver cytosol. The increased nuclear dose to mouse liver compared to that of the rat suggests that the mouse is at greater risk to hepatic DNA damage from PCP-derived quinones. Investigation of the time course of levels of unconjugated tetrachlorohydroquinone (Cl4HQ) in the livers indicated that about 0.4% of Cl4HQ was oxidized to Cl4-1,4-BQ in both rats and mice.
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Affiliation(s)
- P H Lin
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill 27599-7400, USA
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