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Duffel MW, Lehmler HJ. Complex roles for sulfation in the toxicities of polychlorinated biphenyls. Crit Rev Toxicol 2024; 54:92-122. [PMID: 38363552 PMCID: PMC11067068 DOI: 10.1080/10408444.2024.2311270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 01/23/2024] [Indexed: 02/17/2024]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic toxicants derived from legacy pollution sources and their formation as inadvertent byproducts of some current manufacturing processes. Metabolism of PCBs is often a critical component in their toxicity, and relevant metabolic pathways usually include their initial oxidation to form hydroxylated polychlorinated biphenyls (OH-PCBs). Subsequent sulfation of OH-PCBs was originally thought to be primarily a means of detoxication; however, there is strong evidence that it may also contribute to toxicities associated with PCBs and OH-PCBs. These contributions include either the direct interaction of PCB sulfates with receptors or their serving as a localized precursor for OH-PCBs. The formation of PCB sulfates is catalyzed by cytosolic sulfotransferases, and, when transported into the serum, these metabolites may be retained, taken up by other tissues, and subjected to hydrolysis catalyzed by intracellular sulfatase(s) to regenerate OH-PCBs. Dynamic cycling between PCB sulfates and OH-PCBs may lead to further metabolic activation of the resulting OH-PCBs. Ultimate toxic endpoints of such processes may include endocrine disruption, neurotoxicities, and many others that are associated with exposures to PCBs and OH-PCBs. This review highlights the current understanding of the complex roles that PCB sulfates can have in the toxicities of PCBs and OH-PCBs and research on the varied mechanisms that control these roles.
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Affiliation(s)
- Michael W. Duffel
- Department of Pharmaceutical Sciences & Experimental Therapeutics, College of Pharmacy, The University of Iowa, Iowa City, Iowa, 52242, United States
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa, 52242, United States
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Abstract
The cytosolic sulfotransferase (SULT) enzymes are found in human liver, kidney, intestine, and other tissues. These enzymes catalyze the transfer of the -SO3 group from 3'-phospho-adenosyl-5'-phosphosulfate (PAPS) to a nucleophilic hydroxyl or amine group in a drug substrate. SULTs are stable as dimers, with a highly conserved dimerization domain near the C-terminus of the protein. Crystal structures have revealed flexible loop regions in the native proteins, one of which, located near the dimerization domain, is thought to form a gate that changes position once PAPS is bound to the PAPS-binding site and modulates substrate access and enzyme properties. There is also evidence that oxidation and reduction of certain cysteine residues reversibly regulate the binding of the substrate and PAPS or PAP to the enzyme thus modulating sulfonation. Because SULT enzymes have two substrates, the drug and PAPS, it is common to report apparent kinetic constants with either the drug or the PAPS varied while the other is kept at a constant concentration. The kinetics of product formation can follow classic Michaelis-Menten kinetics, typically over a narrow range of substrate concentrations. Over a wide range of substrate concentrations, it is common to observe partial or complete substrate inhibition with SULT enzymes. This chapter describes the function, tissue distribution, structural features, and properties of the human SULT enzymes and presents examples of enzyme kinetics with different substrates.
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Affiliation(s)
- Margaret O James
- Department of Medicinal Chemistry, University of Florida, Gainesville, FL, USA.
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Bandookwala M, Nemani KS, Chatterjee B, Sengupta P. Reactive Metabolites: Generation and Estimation with Electrochemistry Based Analytical Strategy as an Emerging Screening Tool. CURR ANAL CHEM 2020. [DOI: 10.2174/1573411016666200131154202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Analytical scientists have constantly been in search for more efficient and
economical methods for drug simulation studies. Owing to great progress in this field, there are various
techniques available nowadays that mimic drug metabolism in the hepatic microenvironment.
The conventional in vitro and in vivo studies pose inherent methodological drawbacks due to which
alternative analytical approaches are devised for different drug metabolism experiments.
Methods:
Electrochemistry has gained attention due to its benefits over conventional metabolism
studies. Because of the protein binding nature of reactive metabolites, it is difficult to identify them
directly after formation, although the use of trapping agents aids in their successful identification.
Furthermore, various scientific reports confirmed the successful simulation of drug metabolism studies
by electrochemical cells. Electrochemical cells coupled with chromatography and mass spectrometry
made it easy for direct detection of reactive metabolites. In this review, an insight into the application
of electrochemical techniques for metabolism simulation studies has been provided. The sole
use of electrochemical cells, as well as their setups on coupling to liquid chromatography and mass
spectrometry has been discussed. The importance of metabolism prediction in early drug discovery
and development stages along with a brief overview of other conventional methods has also been
highlighted.
Conclusion:
To the best of our knowledge, this is the first article to review the electrochemistry
based strategy for the analysis of reactive metabolites. The outcome of this ‘first of its kind’ review
will significantly help the researchers in the application of electrochemistry based bioanalysis for metabolite
detection.
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Affiliation(s)
- Maria Bandookwala
- National Institute of Pharmaceutical Education and Research (NIPER) - Ahmedabad, Gujarat, India
| | - Kavya Sri Nemani
- National Institute of Pharmaceutical Education and Research (NIPER) - Ahmedabad, Gujarat, India
| | - Bappaditya Chatterjee
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management (SPPSPTM), NMIMS University, Mumbai, India
| | - Pinaki Sengupta
- National Institute of Pharmaceutical Education and Research (NIPER) - Ahmedabad, Gujarat, India
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Gallo C, Nuzzo G, d'Ippolito G, Manzo E, Sardo A, Fontana A. Sterol Sulfates and Sulfotransferases in Marine Diatoms. Methods Enzymol 2018; 605:101-138. [PMID: 29909823 DOI: 10.1016/bs.mie.2018.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sterol sulfates are widely occurring molecules in marine organisms. Their importance has been so far underestimated although many of these compounds are crucial mediators of physiological and ecological functions in other organisms. Biosynthesis of sterol sulfates is controlled by cytosolic sulfotransferases (SULTs), a varied family of enzymes that catalyze the transfer of a sulfo residue (-SO3H) from the universal donor 3'-phosphoadenosine-5'-phosphosulfate to the hydroxyl function at C-3 of the steroid skeleton. The absence of molecular tools has been the main impediment to the development of a biosynthetic study of this class of compounds in marine organisms. In fact, there is very limited information about these enzymes in marine environments. SULT activity has, however, been reported in several marine species, and, recently, the production of sterol sulfates has been linked to the control of growth in marine diatoms. In this chapter, we describe methods for the study of sterol sulfates in this lineage of marine microalgae. The main aim is to provide the tools useful to deal with the biosynthesis and regulation of these compounds and to circumvent the bottleneck of the lack of molecular information. The protocols have been designed for marine diatoms, but most of the procedures can be used for other marine organisms.
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Affiliation(s)
- Carmela Gallo
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy
| | - Genoveffa Nuzzo
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy
| | - Giuliana d'Ippolito
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy.
| | - Emiliano Manzo
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy
| | - Angela Sardo
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy
| | - Angelo Fontana
- National Research Council of Italy, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy.
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Li M, Teesch LM, Murry DJ, Pope RM, Li Y, Robertson LW, Ludewig G. Cytochrome c adducts with PCB quinoid metabolites. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2148-59. [PMID: 26062463 PMCID: PMC4676959 DOI: 10.1007/s11356-015-4801-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Accepted: 05/27/2015] [Indexed: 04/15/2023]
Abstract
Polychlorinated biphenyls (PCBs) are a group of 209 individual congeners widely used as industrial chemicals. PCBs are found as by-products in dye and paint manufacture and are legacy, ubiquitous, and persistent as human and environmental contaminants. PCBs with fewer chlorine atoms may be metabolized to hydroxy- and dihydroxy-metabolites and further oxidized to quinoid metabolites both in vitro and in vivo. Specifically, quinoid metabolites may form adducts on nucleophilic sites within cells. We hypothesized that the PCB-quinones covalently bind to cytochrome c and, thereby, cause defects in the function of cytochrome c. In this study, synthetic PCB quinones, 2-(4'-chlorophenyl)-1,4-benzoquinone (PCB3-pQ), 4-4'-chlorophenyl)-1,2-benzoquinone (PCB3-oQ), 2-(3', 5'-dichlorophenyl)-1,4-benzoquinone, 2-(3',4', 5'-trichlorophenyl)-1,4-benzoquinone, and 2-(4'-chlorophenyl)-3,6-dichloro-1,4-benzoquinone, were incubated with cytochrome c, and adducts were detected by liquid chromatography-mass spectrometry (LC-MS) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI TOF). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was employed to separate the adducted proteins, while trypsin digestion and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were applied to identify the amino acid binding sites on cytochrome c. Conformation change of cytochrome c after binding with PCB3-pQ was investigated by SYBYL-X simulation and cytochrome c function was examined. We found that more than one molecule of PCB-quinone may bind to one molecule of cytochrome c. Lysine and glutamic acid were identified as the predominant binding sites. Software simulation showed conformation changes of adducted cytochrome c. Additionally, cross-linking of cytochrome c was observed on the SDS-PAGE gel. Cytochrome c was found to lose its function as electron acceptor after incubation with PCB quinones. These data provide evidence that the covalent binding of PCB quinone metabolites to cytochrome c may be included among the toxic effects of PCBs.
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Affiliation(s)
- Miao Li
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational & Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus 214 IREH, Iowa City, IA, 52242-5000, USA
| | - Lynn M Teesch
- High Resolution Mass Spectrometry Facility, The University of Iowa, Iowa City, IA, USA
| | - Daryl J Murry
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- College of Pharmacy, The University of Iowa, Iowa City, IA, USA
| | - R Marshal Pope
- Proteomics Facility, The University of Iowa, Iowa City, IA, USA
| | - Yalan Li
- Proteomics Facility, The University of Iowa, Iowa City, IA, USA
| | - Larry W Robertson
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational & Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus 214 IREH, Iowa City, IA, 52242-5000, USA
| | - Gabriele Ludewig
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA.
- Department of Occupational & Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus 214 IREH, Iowa City, IA, 52242-5000, USA.
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Bansal S, Lau AJ. Fast and sensitive quantification of human liver cytosolic lithocholic acid sulfation using ultra-high performance liquid chromatography–tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1011:171-8. [DOI: 10.1016/j.jchromb.2015.12.063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 12/29/2015] [Accepted: 12/30/2015] [Indexed: 01/18/2023]
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Bansal S, Lau AJ. Human liver cytosolic sulfotransferase 2A1-dependent dehydroepiandrosterone sulfation assay by ultra-high performance liquid chromatography–tandem mass spectrometry. J Pharm Biomed Anal 2016; 120:261-9. [DOI: 10.1016/j.jpba.2015.12.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/03/2015] [Accepted: 12/17/2015] [Indexed: 01/23/2023]
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Qin X, Lehmler HJ, Teesch LM, Robertson LW, Duffel MW. Chlorinated biphenyl quinones and phenyl-2,5-benzoquinone differentially modify the catalytic activity of human hydroxysteroid sulfotransferase hSULT2A1. Chem Res Toxicol 2013; 26:1474-85. [PMID: 24059442 DOI: 10.1021/tx400207q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Human hydroxysteroid sulfotransferase (hSULT2A1) catalyzes the sulfation of a broad range of environmental chemicals, drugs, and other xenobiotics in addition to endogenous compounds that include hydroxysteroids and bile acids. Polychlorinated biphenyls (PCBs) are persistent environmental contaminants, and oxidized metabolites of PCBs may play significant roles in the etiology of their adverse health effects. Quinones derived from the oxidative metabolism of PCBs (PCB-quinones) react with nucleophilic sites in proteins and also undergo redox cycling to generate reactive oxygen species. This, along with the sensitivity of hSULT2A1 to oxidative modification at cysteine residues, led us to hypothesize that electrophilic PCB-quinones react with hSULT2A1 to alter its catalytic function. Thus, we examined the effects of four phenylbenzoquinones on the ability of hSULT2A1 to catalyze the sulfation of the endogenous substrate, dehydroepiandrosterone (DHEA). The quinones studied were 2'-chlorophenyl-2,5-benzoquinone (2'-Cl-BQ), 4'-chlorophenyl-2,5-benzoquinone (4'-Cl-BQ), 4'-chlorophenyl-3,6-dichloro-2,5-benzoquinone (3,6,4'-triCl-BQ), and phenyl-2,5-benzoquinone (PBQ). At all concentrations examined, pretreatment of hSULT2A1 with the PCB-quinones decreased the catalytic activity of hSULT2A1. Pretreatment with low concentrations of PBQ, however, increased the catalytic activity of the enzyme, while higher concentrations inhibited catalysis. A decrease in substrate inhibition with DHEA was seen following preincubation of hSULT2A1 with all of the quinones. Proteolytic digestion of the enzyme followed by LC/MS analysis indicated PCB-quinone- and PBQ-adducts at Cys55 and Cys199, as well as oxidation products at methionines in the protein. Equilibrium binding experiments and molecular modeling suggested that changes due to these modifications may affect the nucleotide binding site and the entrance to the sulfuryl acceptor binding site of hSULT2A1.
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Affiliation(s)
- Xiaoyan Qin
- Interdisciplinary Graduate Program in Human Toxicology, University of Iowa , Iowa City, Iowa 52242, United States
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