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Benabdelkamel H, Sebaa R, AlMalki RH, Masood A, Alfadda AA, Abdel Rahman AM. Untargeted metabolomics reveals the impact of Liraglutide treatment on metabolome profiling and metabolic pathways in type-2 diabetes mellitus. Saudi Pharm J 2024; 32:102172. [PMID: 39381269 PMCID: PMC11458941 DOI: 10.1016/j.jsps.2024.102172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2024] [Accepted: 09/11/2024] [Indexed: 10/10/2024] Open
Abstract
Liraglutide, a type2 diabetes mellitus (T2DM)-related treatment, improves glycemic control and reduces the risks of adverse cardiovascular events in T2DM patients. However, the underlying mechanisms of the above-mentioned beneficial effects of Liraglutide are not well understood. To have better understanding of these mechanisms, we aimed to study the metabolic impacts of Liraglutide on the metabolome and corresponding pathways in T2DM patients, especially metabolism plays a very fundamental role in health and diseases and is influenced by drugs. In this study, plasma samples collected from T2DM patients (n = 20) and taken pre- and post-Liraglutide treatment were used for untargeted metabolomics analyses, including metabolome profiling and metabolic pathway/network analyses. The metabolome profiling analyses identified 93 endogenous metabolites that were significantly affected by Liraglutide treatment where 49 and 44 metabolites were up and down regulated, respectively. Liraglutide caused metabolic alterations impacting metabolic pathways such as pentose and glucuronate interconversion and alanine, aspartate and glutamate metabolism in T2DM patients. Since the last-mentioned pathways are affected by Liraglutide, it could explain partially the overall beneficial effects of Liraglutide in T2DM, especially that glucuronate interconversion pathway is known by its important roles in eliminating toxic and undesirable substances from the human body to maintain good health status. In addition, the metabolism of amino acids induced by Liraglutide could improve the function of immune cells, strengthening the immunity of T2DM patients. Also, Liraglutide induced the level of other metabolites that help in the defense mechanism against oxidative events. Overall, the findings of this study provide a deeper understanding of the underlying mechanisms involved in the beneficial effects of Liraglutide in T2DM from the metabolic aspect.
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Affiliation(s)
- Hicham Benabdelkamel
- Proteomics Resource Unit, Obesity Research Center, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Rajaa Sebaa
- Department of Medical Laboratories, College of Applied Medical Sciences, Shaqra University, Shaqra 11961, Saudi Arabia
| | - Reem H. AlMalki
- Metabolomics Section, Department of Clinical Genomics, Center for Genomics Medicine, King Faisal Specialist Hospital and Research Centre (KFSHRC), Riyadh 11211, Saudi Arabia
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Afshan Masood
- Proteomics Resource Unit, Obesity Research Center, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Assim A. Alfadda
- Proteomics Resource Unit, Obesity Research Center, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- Department of Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Anas M. Abdel Rahman
- Metabolomics Section, Department of Clinical Genomics, Center for Genomics Medicine, King Faisal Specialist Hospital and Research Centre (KFSHRC), Riyadh 11211, Saudi Arabia
- Department of Biochemistry and Molecular Medicine, College of Medicine, Al Faisal University, Riyadh 11533, Saudi Arabia
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2
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Sulekha A, Osborne MJ, Gasiorek J, Borden KLB. 1H, 13C, 15N Backbone and sidechain chemical shift assignments of the C-terminal domain of human UDP-glucuronosyltransferase 2B17 (UGT2B17-C). BIOMOLECULAR NMR ASSIGNMENTS 2023; 17:67-73. [PMID: 36757531 DOI: 10.1007/s12104-023-10122-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/01/2023] [Indexed: 06/02/2023]
Abstract
UDP-glucuronosyltransferases are the principal enzymes involved in the glucuronidation of metabolites and xenobiotics for physiological clearance in humans. Though glucuronidation is an indispensable process in the phase II metabolic pathway, UGT-mediated glucuronidation of most prescribed drugs (> 55%) and clinical evidence of UGT-associated drug resistance are major concerns for therapeutic development. While UGTs are highly conserved enzymes, they manifest unique substrate and inhibitor specificity which is poorly understood given the dearth of experimentally determined full-length structures. Such information is important not only to conceptualize their specificity but is central to the design of inhibitors specific to a given UGT in order to avoid toxicity associated with pan-UGT inhibitors. Here, we provide the 1H, 13C and 15N backbone (~ 90%) and sidechain (~ 62%) assignments for the C-terminal domain of UGT2B17, which can be used to determine the molecular binding sites of inhibitor and substrate, and to understand the atomic basis for inhibitor selectivity between UGT2B17 and other members of the UGT2B subfamily. Given the physiological relevance of UGT2B17 in the elimination of hormone-based cancer drugs, these assignments will contribute towards dissecting the structural basis for substrate specificity, selective inhibitor recognition and other aspects of enzyme activity with the goal of selectively overcoming glucuronidation-based drug resistance.
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Affiliation(s)
- Anamika Sulekha
- Department of Pathology and Cell Biology and Institute of Research in Immunology and Cancer (IRIC), Université de Montréal, Pavilion Marcelle‑Coutu, Chemin Polytechnique, Montreal, QC, Canada
| | - Michael J Osborne
- Department of Pathology and Cell Biology and Institute of Research in Immunology and Cancer (IRIC), Université de Montréal, Pavilion Marcelle‑Coutu, Chemin Polytechnique, Montreal, QC, Canada
| | - Jadwiga Gasiorek
- Department of Pathology and Cell Biology and Institute of Research in Immunology and Cancer (IRIC), Université de Montréal, Pavilion Marcelle‑Coutu, Chemin Polytechnique, Montreal, QC, Canada
| | - Katherine L B Borden
- Department of Pathology and Cell Biology and Institute of Research in Immunology and Cancer (IRIC), Université de Montréal, Pavilion Marcelle‑Coutu, Chemin Polytechnique, Montreal, QC, Canada.
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3
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Sun G, Liao J, Kurze E, Hoffmann TD, Steinchen W, McGraphery K, Habegger R, Marek L, Catici DAM, Ludwig C, Jing T, Hoffmann T, Song C, Schwab W. Apocarotenoids are allosteric effectors of a dimeric plant glycosyltransferase involved in defense and lignin formation. THE NEW PHYTOLOGIST 2023; 238:2080-2098. [PMID: 36908092 DOI: 10.1111/nph.18875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 03/02/2023] [Indexed: 05/04/2023]
Abstract
Glycosyltransferases are nature's versatile tools to tailor the functionalities of proteins, carbohydrates, lipids, and small molecules by transferring sugars. Prominent substrates are hydroxycoumarins such as scopoletin, which serve as natural plant protection agents. Similarly, C13-apocarotenoids, which are oxidative degradation products of carotenoids/xanthophylls, protect plants by repelling pests and attracting pest predators. We show that C13-apocarotenoids interact with the plant glycosyltransferase NbUGT72AY1 and induce conformational changes in the enzyme catalytic center ultimately reducing its inherent UDP-α-d-glucose glucohydrolase activity and increasing its catalytic activity for productive hydroxycoumarin substrates. By contrast, C13-apocarotenoids show no effect on the catalytic activity toward monolignol lignin precursors, which are competitive substrates. In vivo studies in tobacco plants (Nicotiana benthamiana) confirmed increased glycosylation activity upon apocarotenoid supplementation. Thus, hydroxycoumarins and apocarotenoids represent specialized damage-associated molecular patterns, as they each provide precise information about the plant compartments damaged by pathogen attack. The molecular basis for the C13-apocarotenoid-mediated interplay of two plant protective mechanisms and their function as allosteric enhancers opens up potential applications of the natural products in agriculture and pharmaceutical industry.
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Affiliation(s)
- Guangxin Sun
- Biotechnology of Natural Products, School of Life Sciences Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
| | - Jieren Liao
- Biotechnology of Natural Products, School of Life Sciences Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
| | - Elisabeth Kurze
- Biotechnology of Natural Products, School of Life Sciences Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
| | - Timothy D Hoffmann
- Biotechnology of Natural Products, School of Life Sciences Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
| | - Wieland Steinchen
- Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 14, 35043, Marburg, Germany
| | - Kate McGraphery
- Biotechnology of Natural Products, School of Life Sciences Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
| | - Ruth Habegger
- Biotechnology of Natural Products, School of Life Sciences Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
| | - Ludwig Marek
- Biotechnology of Natural Products, School of Life Sciences Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
| | - Dragana A M Catici
- Center for Protein Assemblies (CPA), Technical University of Munich, Ernst-Otto-Fischer-Str. 8, 85748, Garching, Germany
| | - Christina Ludwig
- Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), School of Life Sciences Weihenstephan, Technische Universität München, Gregor-Mendel-Str. 4, 85354, Freising, Germany
| | - Tingting Jing
- State Key Laboratory of Tea Plant Biology and Utilization, International Joint Laboratory on Tea Chemistry and Health Effects, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Thomas Hoffmann
- Biotechnology of Natural Products, School of Life Sciences Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
| | - Chuankui Song
- State Key Laboratory of Tea Plant Biology and Utilization, International Joint Laboratory on Tea Chemistry and Health Effects, Anhui Agricultural University, 230036, Hefei, Anhui, China
| | - Wilfried Schwab
- Biotechnology of Natural Products, School of Life Sciences Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
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4
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Liao J, Sun G, Kurze E, Steinchen W, Hoffmann TD, Song C, Zou Z, Hoffmann T, Schwab WG. Subfunctionalization of a monolignol to a phytoalexin glucosyltransferase is accompanied by substrate inhibition. PLANT COMMUNICATIONS 2023; 4:100506. [PMID: 36566353 DOI: 10.1016/j.xplc.2022.100506] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 11/16/2022] [Accepted: 12/16/2022] [Indexed: 05/11/2023]
Abstract
Uridine diphosphate-dependent glycosyltransferases (UGTs) mediate the glycosylation of plant metabolites, thereby altering their physicochemical properties and bioactivities. Plants possess numerous UGT genes, with the encoded enzymes often glycosylating multiple substrates and some exhibiting substrate inhibition kinetics, but the biological function and molecular basis of these phenomena are not fully understood. The promiscuous monolignol/phytoalexin glycosyltransferase NbUGT72AY1 exhibits substrate inhibition (Ki) at 4 μM scopoletin, whereas the highly homologous monolignol StUGT72AY2 is inhibited at 190 μM. We therefore used hydrogen/deuterium exchange mass spectrometry and structure-based mutational analyses of both proteins and introduced NbUGT72AY1 residues into StUGT72AY2 and vice versa to study promiscuity and substrate inhibition of UGTs. A single F87I and chimeric mutant of NbUGT72AY1 showed significantly reduced scopoletin substrate inhibition, whereas its monolignol glycosylation activity was almost unaffected. Reverse mutations in StUGT72AY2 resulted in increased scopoletin glycosylation, leading to enhanced promiscuity, which was accompanied by substrate inhibition. Studies of 3D structures identified open and closed UGT conformers, allowing visualization of the dynamics of conformational changes that occur during catalysis. Previously postulated substrate access tunnels likely serve as drainage channels. The results suggest a two-site model in which the second substrate molecule binds near the catalytic site and blocks product release. Mutational studies showed that minor changes in amino acid sequence can enhance the promiscuity of the enzyme and add new capabilities such as substrate inhibition without affecting existing functions. The proposed subfunctionalization mechanism of expanded promiscuity may play a role in enzyme evolution and highlights the importance of promiscuous enzymes in providing new functions.
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Affiliation(s)
- Jieren Liao
- Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354 Freising, Germany
| | - Guangxin Sun
- Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354 Freising, Germany
| | - Elisabeth Kurze
- Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354 Freising, Germany
| | - Wieland Steinchen
- Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 14, 35043 Marburg, Germany
| | - Timothy D Hoffmann
- Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354 Freising, Germany
| | - Chuankui Song
- State Key Laboratory of Tea Plant Biology and Utilization, International Joint Laboratory on Tea Chemistry and Health Effects, Anhui Agricultural University, 230036 Hefei, Anhui, P. R. China
| | - Zhiwei Zou
- Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354 Freising, Germany
| | - Thomas Hoffmann
- Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354 Freising, Germany
| | - Wilfried G Schwab
- Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354 Freising, Germany.
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5
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Jung J, Schmölzer K, Schachtschabel D, Speitling M, Nidetzky B. Selective β-Mono-Glycosylation of a C15-Hydroxylated Metabolite of the Agricultural Herbicide Cinmethylin Using Leloir Glycosyltransferases. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:5491-5499. [PMID: 33973475 PMCID: PMC8278484 DOI: 10.1021/acs.jafc.1c01321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
Cinmethylin is a well-known benzyl-ether derivative of the natural terpene 1,4-cineole that is used industrially as a pre-emergence herbicide in grass weed control for crop protection. Cinmethylin detoxification in plants has not been reported, but in animals, it prominently involves hydroxylation at the benzylic C15 methyl group. Here, we show enzymatic β-glycosylation of synthetic 15-hydroxy-cinmethylin to prepare a putative phase II detoxification metabolite of the cinmethylin in plants. We examined eight Leloir glycosyltransferases for reactivity with 15-hydroxy cinmethylin and revealed the selective formation of 15-hydroxy cinmethylin β-d-glucoside from uridine 5'-diphosphate (UDP)-glucose by the UGT71E5 from safflower (Carthamus tinctorius). The UGT71E5 showed a specific activity of 431 mU/mg, about 300-fold higher than that of apple (Malus domestica) UGT71A15 that also performed the desired 15-hydroxy cinmethylin mono-glycosylation. Bacterial glycosyltransferases (OleD from Streptomyces antibioticus, 2.9 mU/mg; GT1 from Bacillus cereus, 60 mU/mg) produced mixtures of 15-hydroxy cinmethylin mono- and disaccharide glycosides. Using UDP-glucose recycling with sucrose synthase, 15-hydroxy cinmethylin conversion with UGT71E5 efficiently provided the β-mono-glucoside (≥95% yield; ∼9 mM) suitable for biological studies.
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Affiliation(s)
- Jihye Jung
- Austrian
Centre of Industrial Biotechnology, Graz A-8010, Austria
| | | | | | | | - Bernd Nidetzky
- Austrian
Centre of Industrial Biotechnology, Graz A-8010, Austria
- Institute
of Biotechnology and Biochemical Engineering, NAWI Graz, TU Graz, Graz A-8010, Austria
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6
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Zhou J, Argikar UA, Miners JO. Enzyme Kinetics of Uridine Diphosphate Glucuronosyltransferases (UGTs). Methods Mol Biol 2021; 2342:301-338. [PMID: 34272700 DOI: 10.1007/978-1-0716-1554-6_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Glucuronidation, catalyzed by uridine diphosphate glucuronosyltransferases (UGTs), is an important process for the metabolism and clearance of many lipophilic chemicals, including drugs, environmental chemicals, and endogenous compounds. Glucuronidation is a bisubstrate reaction that requires the aglycone and the cofactor, UDP-GlcUA. Accumulating evidence suggests that the bisubstrate reaction follows a compulsory-order ternary mechanism. To simplify the kinetic modeling of glucuronidation reactions in vitro, UDP-GlcUA is usually added to incubations in large excess. Many factors have been shown to influence UGT activity and kinetics in vitro, and these must be accounted for during experimental design and data interpretation. While the assessment of drug-drug interactions resulting from UGT inhibition has been challenging in the past, the increasing availability of UGT enzyme-selective substrate and inhibitor "probes" provides the prospect for more reliable reaction phenotyping and assessment of drug-drug interaction potential. Although extrapolation of the in vitro intrinsic clearance of a glucuronidated drug often underpredicts in vivo clearance, careful selection of in vitro experimental conditions and inclusion of extrahepatic glucuronidation may improve the predictivity of in vitro-in vivo extrapolation. Physiologically based pharmacokinetic (PBPK) modeling has also shown to be of value for predicting PK of drugs eliminated by glucuronidation.
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Affiliation(s)
- Jin Zhou
- Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT, USA.
| | - Upendra A Argikar
- Translational Medicine, Novartis Institutes for BioMedical Research, Inc., Cambridge, MA, USA
| | - John O Miners
- Department of Clinical Pharmacology, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
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7
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Vergara AG, Watson CJW, Watson JM, Chen G, Lazarus P. Altered Metabolism of Polycyclic Aromatic Hydrocarbons by UDP-Glycosyltransferase 3A2 Missense Variants. Chem Res Toxicol 2020; 33:2854-2862. [PMID: 32993298 DOI: 10.1021/acs.chemrestox.0c00233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The UDP-glycosyltransferase (UGT) family of enzymes are important in the metabolism of a variety of exogenous substances including polycyclic aromatic hydrocarbons (PAHs), a potent class of environmental carcinogens. As compared to the majority of UGT enzymes, which utilize UDP-glucuronic acid as a cosubstrate, UGT3A2 utilizes alternative cosubstrates (UDP-glucose and UDP-xylose). UGT3A2 is expressed in aerodigestive tract tissues and was highly active against multiple PAHs with both cosubstrates. The goal of the present study was to assess the functional effects of UGT3A2 missense variants (MAF ≥ 0.005) on PAH metabolism and the utilization of cosubstrates. The glycosylation activity (Vmax/Km) of all variants against simple PAHs using both cosubstrates was significantly (P < 0.05) decreased by 42-100% when compared to wild-type UGT3A2. When utilizing UDP-glucose, the variant isoforms exhibited up to a 362-fold decrease in Vmax/Km when compared to wild-type UGT3A2, with a 3.1- to 14-fold decrease for D140N, A344T, and S435Y, a 24- and 43-fold decrease for A436T and R445C, respectively, and a 147- and 362-fold decrease for Y474C and Y74N, respectively. When utilizing UDP-xylose, the variants exhibited up to a 4.0-fold decrease in Vmax/Km when compared to wild-type UGT3A2; Y74N did not exhibit activity, and Y474C did not reach saturation (Km > 4000 μM). Additionally, both wild-type and variant UGT3A2 exhibited a significant (P < 0.05) difference in their utilization of UDP-glucose vs UDP-xylose as cosubstrates using 1-OH-pyrene as substrate. These data suggest that UGT3A2 missense variants decrease the detoxification of PAHs, potentially resulting in altered individual risk for PAH-related cancers.
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Affiliation(s)
- Ana G Vergara
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington 99210, United States
| | - Christy J W Watson
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington 99210, United States
| | - Jeffrey M Watson
- Department of Chemistry and Biochemistry, Gonzaga University, Spokane, Washington 99258, United States
| | - Gang Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington 99210, United States
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington 99210, United States
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8
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Miners JO, Rowland A, Novak JJ, Lapham K, Goosen TC. Evidence-based strategies for the characterisation of human drug and chemical glucuronidation in vitro and UDP-glucuronosyltransferase reaction phenotyping. Pharmacol Ther 2020; 218:107689. [PMID: 32980440 DOI: 10.1016/j.pharmthera.2020.107689] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/26/2022]
Abstract
Enzymes of the UDP-glucuronosyltransferase (UGT) superfamily contribute to the elimination of drugs from almost all therapeutic classes. Awareness of the importance of glucuronidation as a drug clearance mechanism along with increased knowledge of the enzymology of drug and chemical metabolism has stimulated interest in the development and application of approaches for the characterisation of human drug glucuronidation in vitro, in particular reaction phenotyping (the fractional contribution of the individual UGT enzymes responsible for the glucuronidation of a given drug), assessment of metabolic stability, and UGT enzyme inhibition by drugs and other xenobiotics. In turn, this has permitted the implementation of in vitro - in vivo extrapolation approaches for the prediction of drug metabolic clearance, intestinal availability, and drug-drug interaction liability, all of which are of considerable importance in pre-clinical drug development. Indeed, regulatory agencies (FDA and EMA) require UGT reaction phenotyping for new chemical entities if glucuronidation accounts for ≥25% of total metabolism. In vitro studies are most commonly performed with recombinant UGT enzymes and human liver microsomes (HLM) as the enzyme sources. Despite the widespread use of in vitro approaches for the characterisation of drug and chemical glucuronidation by HLM and recombinant enzymes, evidence-based guidelines relating to experimental approaches are lacking. Here we present evidence-based strategies for the characterisation of drug and chemical glucuronidation in vitro, and for UGT reaction phenotyping. We anticipate that the strategies will inform practice, encourage development of standardised experimental procedures where feasible, and guide ongoing research in the field.
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Affiliation(s)
- John O Miners
- Department of Clinical Pharmacology and Flinders Centre for Innovation in Cancer, College of Medicine and Public Health, Flinders University, Adelaide, Australia.
| | - Andrew Rowland
- Department of Clinical Pharmacology and Flinders Centre for Innovation in Cancer, College of Medicine and Public Health, Flinders University, Adelaide, Australia
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Smith A, Page BDG, Collier AC, Coughtrie MWH. Homology Modeling of Human Uridine-5'-diphosphate-glucuronosyltransferase 1A6 Reveals Insights into Factors Influencing Substrate and Cosubstrate Binding. ACS OMEGA 2020; 5:6872-6887. [PMID: 32258923 PMCID: PMC7114752 DOI: 10.1021/acsomega.0c00205] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/11/2020] [Indexed: 05/05/2023]
Abstract
The elimination of numerous endogenous compounds and xenobiotics via glucuronidation by uridine-5'-diphosphate glycosyltransferase enzymes (UGTs) is an essential process of the body's chemical defense system. UGTs have distinct but overlapping substrate preferences, but the molecular basis for their substrate specificity remains poorly understood. Three-dimensional protein structures can greatly enhance our understanding of the interactions between enzymes and their substrates, but because of the inherent difficulties in purifying and crystallizing integral endoplasmic reticulum membrane proteins, no complete mammalian UGT structure has yet been produced. To address this problem, we have created a homology model of UGT1A6 using I-TASSER to explore, in detail, the interactions of human UGT1A6 with its substrates. Ligands were docked into our model in the presence of the cosubstrate uridine-5'-diphosphate-glucuronic acid, interacting residues were examined, and poses were compared to those cocrystallized with various plant and bacterial glycosyltransferases (GTs). Our model structurally resembles other GTs, and docking experiments replicated many of the expected UGT-substrate interactions. Some bias toward the template structures' protein-substrate interactions and binding preferences was evident.
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10
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Vergara AG, Watson CJW, Chen G, Lazarus P. UDP-Glycosyltransferase 3A Metabolism of Polycyclic Aromatic Hydrocarbons: Potential Importance in Aerodigestive Tract Tissues. Drug Metab Dispos 2020; 48:160-168. [PMID: 31836608 PMCID: PMC7011115 DOI: 10.1124/dmd.119.089284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/27/2019] [Indexed: 01/08/2023] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are potent carcinogens and are a primary risk factor for the development of lung and other aerodigestive tract cancers in smokers. The detoxification of PAHs by glucuronidation is well-characterized for the UDP-glycosyltransferase (UGT) 1A, 2A, and 2B subfamilies; however, the role of the UGT3A subfamily in PAH metabolism remains poorly understood. UGT3A enzymes are functionally distinct from other UGT subfamilies (which use UDP-glucuronic acid as a cosubstrate) due to their utilization of alternative cosubstrates (UDP-N-acetylglucosamine for UGT3A1, and UDP-glucose and UDP-xylose for UGT3A2). The goal of the present study was to characterize UGT3A glycosylation activity against PAHs and examine their expression in human aerodigestive tract tissues. In vitro metabolism assays using UGT3A2-overexpressing cell microsomes indicated that UGT3A2 exhibits glycosylation activity against all of the simple and complex PAHs tested. The V max/K m ratios for UGT3A2 activity with UDP-xylose versus UDP-glucose as the cosubstrate ranged from 0.65 to 4.4 for all PAHs tested, demonstrating that PAH glycosylation may be occurring at rates up to 4.4-fold higher with UDP-xylose than with UDP-glucose. Limited glycosylation activity was observed against PAHs with UGT3A1-overexpressing cell microsomes. While UGT3A2 exhibited low levels of hepatic expression, it was shown by western blot analysis to be widely expressed in aerodigestive tract tissues. Conversely, UGT3A1 exhibited the highest expression in liver with lower expression in aerodigestive tract tissues. These data suggest that UGT3A2 plays an important role in the detoxification of PAHs in aerodigestive tract tissues, and that there may be cosubstrate-dependent differences in the detoxification of PAHs by UGT3A2. SIGNIFICANCE STATEMENT: UGT3A2 is highly active against PAHs with either UDP-glucose or UDP-xylose as a cosubstrate. UGT3A1 exhibited low levels of activity against PAHs. UGT3A1 is highly expressed in liver while UGT3A2 is well expressed in extrahepatic tissues. UGT3A2 may be an important detoxifier of PAHs in humans.
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Affiliation(s)
- Ana G Vergara
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Christy J W Watson
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Gang Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
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11
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Zhang L, Zhu L, Qu W, Wu F, Hu M, Xie W, Liu Z, Wang C. Insight into tartrate inhibition patterns in vitro and in vivo based on cocrystal structure with UDP-glucuronosyltransferase 2B15. Biochem Pharmacol 2020; 172:113753. [DOI: 10.1016/j.bcp.2019.113753] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/10/2019] [Indexed: 01/08/2023]
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12
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Characterization of CYPs and UGTs Involved in Human Liver Microsomal Metabolism of Osthenol. Pharmaceutics 2018; 10:pharmaceutics10030141. [PMID: 30200214 PMCID: PMC6161247 DOI: 10.3390/pharmaceutics10030141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 08/27/2018] [Accepted: 08/27/2018] [Indexed: 11/25/2022] Open
Abstract
Osthenol is a prenylated coumarin isolated from the root of Angelica koreana and Angelica dahurica, and is an O-demethylated metabolite of osthole in vivo. Its various pharmacological effects have been reported previously. The metabolic pathway of osthenol was partially confirmed in rat osthole studies, and 11 metabolic products were identified in rat urine. However, the metabolic pathway of osthenol in human liver microsomes (HLM) has not been reported. In this study, we elucidated the structure of generated metabolites using a high-resolution quadrupole-orbitrap mass spectrometer (HR-MS/MS) and characterized the major human cytochrome P450 (CYP) and uridine 5′-diphospho-glucuronosyltransferase (UGT) isozymes involved in osthenol metabolism in human liver microsomes (HLMs). We identified seven metabolites (M1-M7) in HLMs after incubation in the presence of nicotinamide adenine dinucleotide phosphate (NADPH) and uridine 5′-diphosphoglucuronic acid (UDPGA). As a result, we demonstrated that osthenol is metabolized to five mono-hydroxyl metabolites (M1-M5) by CYP2D6, 1A2, and 3A4, respectively, a 7-O-glucuronide conjugate (M6) by UGT1A9, and a hydroxyl-glucuronide (M7) from M5 by UGT1A3 in HLMs. We also found that glucuronidation is the dominant metabolic pathway of osthenol in HLMs.
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13
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Walia G, Smith AD, Riches Z, Collier AC, Coughtrie MWH. The effects of UDP-sugars, UDP and Mg 2+on uridine diphosphate glucuronosyltransferase activity in human liver microsomes. Xenobiotica 2017; 48:882-890. [PMID: 28868965 DOI: 10.1080/00498254.2017.1376260] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
1. The UDP-glucuronosyltransferase (UGT) enzymes are important in the metabolism, elimination and detoxification of many xenobiotics and endogenous compounds. As extrapolation of in vitro kinetics of drug metabolizing enzymes to predict in vivo clearance rates becomes more sophisticated, it is important to ensure proper optimization of enzyme assays. The luminal location of the enzyme active site (i.e. latency), and the complexity of UGT kinetics, results in consistent under-prediction of clearance of drugs metabolized by glucuronidation. 2. We examined inhibition of UGT activity in alamethicin-disrupted human liver microsomes (HLM) by uridine diphosphate (UDP), a UGT reaction product, and its reversal by Mg2+ ions. We also determined whether UDP-sugars other than the co-substrate UDP-glucuronic acid (UDP-GlcA) affected glucuronidation. 3. We show that other UDP-sugars do not significantly influence glucuronidation. We also demonstrate that UDP inhibits HLM UGT activity and that this is reversed by including Mg2+ in the assay. The Mg2+ effect can be offset using EDTA, and is dependent on the concentration of UDP-GlcA in the assay. 4. We propose that formation of a Mg2+-UDP complex prevents UDP from affecting the enzyme. Our results suggest that 5 mM UDP-GlcA and 10 mM Mg2+ be used for UGT assays in fully disrupted HLM.
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Affiliation(s)
- Gurinder Walia
- a Faculty of Pharmaceutical Sciences, The University of British Columbia , Vancouver , Canada
| | - Alexander D Smith
- a Faculty of Pharmaceutical Sciences, The University of British Columbia , Vancouver , Canada
| | - Zoe Riches
- a Faculty of Pharmaceutical Sciences, The University of British Columbia , Vancouver , Canada
| | - Abby C Collier
- a Faculty of Pharmaceutical Sciences, The University of British Columbia , Vancouver , Canada
| | - Michael W H Coughtrie
- a Faculty of Pharmaceutical Sciences, The University of British Columbia , Vancouver , Canada
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Yang G, Ge S, Singh R, Basu S, Shatzer K, Zen M, Liu J, Tu Y, Zhang C, Wei J, Shi J, Zhu L, Liu Z, Wang Y, Gao S, Hu M. Glucuronidation: driving factors and their impact on glucuronide disposition. Drug Metab Rev 2017; 49:105-138. [PMID: 28266877 DOI: 10.1080/03602532.2017.1293682] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Glucuronidation is a well-recognized phase II metabolic pathway for a variety of chemicals including drugs and endogenous substances. Although it is usually the secondary metabolic pathway for a compound preceded by phase I hydroxylation, glucuronidation alone could serve as the dominant metabolic pathway for many compounds, including some with high aqueous solubility. Glucuronidation involves the metabolism of parent compound by UDP-glucuronosyltransferases (UGTs) into hydrophilic and negatively charged glucuronides that cannot exit the cell without the aid of efflux transporters. Therefore, elimination of parent compound via glucuronidation in a metabolic active cell is controlled by two driving forces: the formation of glucuronides by UGT enzymes and the (polarized) excretion of these glucuronides by efflux transporters located on the cell surfaces in various drug disposition organs. Contrary to the common assumption that the glucuronides reaching the systemic circulation were destined for urinary excretion, recent evidences suggest that hepatocytes are capable of highly efficient biliary clearance of the gut-generated glucuronides. Furthermore, the biliary- and enteric-eliminated glucuronides participate into recycling schemes involving intestinal microbes, which often prolong their local and systemic exposure, albeit at low systemic concentrations. Taken together, these recent research advances indicate that although UGT determines the rate and extent of glucuronide generation, the efflux and uptake transporters determine the distribution of these glucuronides into blood and then to various organs for elimination. Recycling schemes impact the apparent plasma half-life of parent compounds and their glucuronides that reach intestinal lumen, in addition to prolonging their gut and colon exposure.
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Affiliation(s)
- Guangyi Yang
- a Department of Pharmacy , Institute of Wudang Herbal Medicine Research, Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China.,b Hubei Provincial Technology and Research Center for Comprehensive Development of Medicinal Herbs, Hubei University of Medicine , Shiyan , Hubei , China
| | - Shufan Ge
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Rashim Singh
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Sumit Basu
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Katherine Shatzer
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Ming Zen
- d Department of Thoracic and Cardiomacrovascular Surgery , Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China
| | - Jiong Liu
- e Department of Digestive Diseases Surgery , Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China
| | - Yifan Tu
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Chenning Zhang
- a Department of Pharmacy , Institute of Wudang Herbal Medicine Research, Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China
| | - Jinbao Wei
- a Department of Pharmacy , Institute of Wudang Herbal Medicine Research, Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China
| | - Jian Shi
- f Department of Pharmacy , Institute of Translational Chinese Medicine, Guangzhou University of Chinese Medicine , Guangzhou , Guangdong , China
| | - Lijun Zhu
- f Department of Pharmacy , Institute of Translational Chinese Medicine, Guangzhou University of Chinese Medicine , Guangzhou , Guangdong , China
| | - Zhongqiu Liu
- f Department of Pharmacy , Institute of Translational Chinese Medicine, Guangzhou University of Chinese Medicine , Guangzhou , Guangdong , China
| | - Yuan Wang
- g Department of Pharmacy , College of Pharmacy, Hubei University of Medicine , Shiyan , Hubei , China
| | - Song Gao
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA.,g Department of Pharmacy , College of Pharmacy, Hubei University of Medicine , Shiyan , Hubei , China
| | - Ming Hu
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA.,g Department of Pharmacy , College of Pharmacy, Hubei University of Medicine , Shiyan , Hubei , China
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15
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Sakakibara Y, Katoh M, Imai K, Kondo Y, Asai Y, Ikushiro SI, Nadai M. Expression of UGT1A subfamily in rat brain. Biopharm Drug Dispos 2017; 37:314-9. [PMID: 27061716 DOI: 10.1002/bdd.2012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 03/25/2016] [Accepted: 03/30/2016] [Indexed: 12/25/2022]
Abstract
UDP-glucuronosyltransferase (UGT) is an enzyme that catalyses a major phase II reaction in drug metabolism. Glucuronidation occurs mainly in the liver, but UGTs are also expressed in extrahepatic tissues, where they play an important role in local metabolism. UGT1A isoforms catalyse the glucuronidation of several drugs, neurotransmitters and neurosteroids that exert pharmacological and physiological effects on the brain. The aim of the current study was to determine UGT1A mRNA expression levels and glucuronidation activities in different regions of the rat brain (namely the cerebellum, frontal cortex, parietal cortex, piriform cortex, hippocampus, medulla oblongata, olfactory bulb, striatum and thalamus). It was found that all UGT1A isoforms were expressed in all the nine regions, but their expression levels differed between the regions. The difference between the regions of the brain where the mRNA levels were highest and those where they were lowest ranged between 2.1- to 7.8-fold. Glucuronidation activities were measured using the UGT substrates such as mycophenolic acid, p-nitrophenol and umbelliferone. Glucuronidation activity was detected in all nine regions of the brain. Activity levels differed between the regions, and were highest in the cerebellum, medulla oblongata and olfactory bulb. Differences in glucuronidation activity between regions with the highest rates and those with the lowest rates ranged from 5.3- to 10.1-fold. These results will contribute to our current understanding of the physiological and pharmacokinetic roles of drug-metabolizing enzymes in the brain. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Miki Katoh
- Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Kuniyuki Imai
- Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Yuya Kondo
- Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Yuki Asai
- Faculty of Pharmacy, Meijo University, Nagoya, Japan
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Oda S, Fukami T, Yokoi T, Nakajima M. A comprehensive review of UDP-glucuronosyltransferase and esterases for drug development. Drug Metab Pharmacokinet 2015; 30:30-51. [DOI: 10.1016/j.dmpk.2014.12.001] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/24/2014] [Accepted: 12/02/2014] [Indexed: 01/24/2023]
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17
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Pugh CP, Pouncey DL, Hartman JH, Nshimiyimana R, Desrochers LP, Goodwin TE, Boysen G, Miller GP. Multiple UDP-glucuronosyltransferases in human liver microsomes glucuronidate both R- and S-7-hydroxywarfarin into two metabolites. Arch Biochem Biophys 2014; 564:244-53. [PMID: 25447818 DOI: 10.1016/j.abb.2014.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/08/2014] [Accepted: 10/15/2014] [Indexed: 01/20/2023]
Abstract
The widely used anticoagulant Coumadin (R/S-warfarin) undergoes oxidation by cytochromes P450 into hydroxywarfarins that subsequently become conjugated for excretion in urine. Hydroxywarfarins may modulate warfarin metabolism transcriptionally or through direct inhibition of cytochromes P450 and thus, UGT action toward hydroxywarfarin elimination may impact levels of the parent drugs and patient responses. Nevertheless, relatively little is known about conjugation by UDP-glucuronosyltransferases in warfarin metabolism. Herein, we identified probable conjugation sites, kinetic mechanisms and hepatic UGT isoforms involved in microsomal glucuronidation of R- and S-7-hydroxywarfarin. Both compounds underwent glucuronidation at C4 and C7 hydroxyl groups based on elution properties and spectral characteristics. Their formation demonstrated regio- and enantioselectivity by UGTs and resulted in either Michaelis-Menten or substrate inhibition kinetics. Glucuronidation at the C7 hydroxyl group occurred more readily than at the C4 group, and the reaction was overall more efficient for R-7-hydroxywarfarin due to higher affinity and rates of turnover. The use of these mechanisms and parameters to model in vivo clearance demonstrated that contributions of substrate inhibition would lead to underestimation of metabolic clearance than that predicted by Michaelis-Menten kinetics. Lastly, these processes were driven by multiple UGTs indicating redundancy in glucuronidation pathways and ultimately metabolic clearance of R- and S-7-hydroxywarfarin.
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Affiliation(s)
- C Preston Pugh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Dakota L Pouncey
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Department of Chemistry, Hendrix College, Conway, AR, USA
| | - Jessica H Hartman
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | | | | | | | - Gunnar Boysen
- Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Grover P Miller
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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18
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Troberg J, Järvinen E, Muniz M, Sneitz N, Mosorin J, Hagström M, Finel M. Dog UDP-Glucuronosyltransferase Enzymes of Subfamily 1A: Cloning, Expression, and Activity. Drug Metab Dispos 2014; 43:107-18. [DOI: 10.1124/dmd.114.059303] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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19
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Abstract
Glucuronidation, catalyzed by uridine diphosphate glucuronosyltransferases (UGTs), is an important process for the metabolism and clearance of many lipophilic chemicals, including drugs, environmental chemicals, and endogenous compounds. Glucuronidation is a bi-substrate reaction that requires the aglycone and a cofactor, UDPGA. Accumulating evidence suggests that the bi-substrate reaction follows a compulsory-order ternary mechanism. To simplify the kinetic modelling of glucuronidation reactions in vitro, UDPGA is usually added to incubations in large excess. Many factors have been shown to influence UGT activity and kinetics in vitro, and these must be accounted for in experimental design and data interpretation. Assessing drug-drug interactions (DDIs) involving UGT inhibition remains challenging. However, the increasing availability of UGT enzyme-specific substrate and inhibitor "probes" provides the prospect for more reliable reaction phenotyping and assessment of DDI potential. Although extrapolation of the in vitro intrinsic clearance of a glucuronidated drug often under-predicts in vivo clearance, careful selection of in vitro experimental conditions and inclusion of extrahepatic glucuronidation may improve the predictivity of in vitro-in vivo extrapolation (IVIVE).
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20
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Wang Y, Huang H, Wu Q. Characterization of the zebrafish Ugt repertoire reveals a new class of drug-metabolizing UDP glucuronosyltransferases. Mol Pharmacol 2014; 86:62-75. [PMID: 24728488 DOI: 10.1124/mol.113.091462] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The zebrafish genome contains a gene superfamily of 40 Ugt genes that can be divided into Ugt1, Ugt2, and Ugt5 families. Because the encoded zebrafish UDP glucuronosyltransferase (UGT) proteins do not display orthologous relationships to any of the mammalian and avian UGT enzymes based on molecular phylogeny, it is difficult to predict their substrate specificity. Here, we mapped their tissue-specific expression patterns. We showed that the zebrafish UGT enzymes can be glycosylated. We determined their substrate specificity and catalytic activity toward diverse aglycone substrates. Specifically, we measured mRNA levels of each of the 40 zebrafish Ugt genes in 11 adult tissues and found that they are expressed in a tissue-specific manner. Moreover, functional analyses with the donor of UDP glucuronic acid (UDPGA) for each of the 40 zebrafish UGT proteins revealed their substrate specificity toward 10 important aglycones. In particular, UGT1A1, UGT1A7, and UGT1B1 displayed good glucuronidation activities toward most phenolic aglycones (4-methylumbelliferone, 4-nitrophenol, 1-naphthol, bisphenol A, and mycophenolic acid) and the two carboxylic acids (bilirubin and diclofenac). Importantly, some members of the UGT5, a novel UGT family identified recently, are capable of glucuronidating multiple aglycones with the donor cofactor of UDPGA. In particular, UGT5A5, UGT5B2, and UGT5E1 glucuronidate phenols and steroids with high specificity toward steroid hormones of estradiol and testosterone and estrogenic alkylphenols 4-tert-octylphenol. These results shed new insights into the mechanisms by which fish species defend themselves against vast numbers of xenobiotics via glucuronidation conjugations and may facilitate the establishment of zebrafish as a model vertebrate in toxicological, developmental, and pathologic studies.
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Affiliation(s)
- Yuanming Wang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, and State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, and Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Haiyan Huang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, and State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, and Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Qiang Wu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, and State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, and Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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21
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Ghemtio L, Soikkeli A, Yliperttula M, Hirvonen J, Finel M, Xhaard H. SVM Classification and CoMSIA Modeling of UGT1A6 Interacting Molecules. J Chem Inf Model 2014; 54:1011-26. [DOI: 10.1021/ci400577a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Leo Ghemtio
- Centre for Drug Research, ‡Division of Pharmaceutical Technology, §Division of Biopharmaceutics
and Pharmacokinetics, and ∥Division of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Helsinki, 00100 Helsinki, Finland
| | - Anne Soikkeli
- Centre for Drug Research, ‡Division of Pharmaceutical Technology, §Division of Biopharmaceutics
and Pharmacokinetics, and ∥Division of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Helsinki, 00100 Helsinki, Finland
| | - Marjo Yliperttula
- Centre for Drug Research, ‡Division of Pharmaceutical Technology, §Division of Biopharmaceutics
and Pharmacokinetics, and ∥Division of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Helsinki, 00100 Helsinki, Finland
| | - Jouni Hirvonen
- Centre for Drug Research, ‡Division of Pharmaceutical Technology, §Division of Biopharmaceutics
and Pharmacokinetics, and ∥Division of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Helsinki, 00100 Helsinki, Finland
| | - Moshe Finel
- Centre for Drug Research, ‡Division of Pharmaceutical Technology, §Division of Biopharmaceutics
and Pharmacokinetics, and ∥Division of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Helsinki, 00100 Helsinki, Finland
| | - Henri Xhaard
- Centre for Drug Research, ‡Division of Pharmaceutical Technology, §Division of Biopharmaceutics
and Pharmacokinetics, and ∥Division of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Helsinki, 00100 Helsinki, Finland
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Chau N, Elliot DJ, Lewis BC, Burns K, Johnston MR, Mackenzie PI, Miners JO. Morphine Glucuronidation and Glucosidation Represent Complementary Metabolic Pathways That Are Both Catalyzed by UDP-Glucuronosyltransferase 2B7: Kinetic, Inhibition, and Molecular Modeling Studies. J Pharmacol Exp Ther 2014; 349:126-37. [DOI: 10.1124/jpet.113.212258] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Stingl JC, Bartels H, Viviani R, Lehmann ML, Brockmöller J. Relevance of UDP-glucuronosyltransferase polymorphisms for drug dosing: A quantitative systematic review. Pharmacol Ther 2013; 141:92-116. [PMID: 24076267 DOI: 10.1016/j.pharmthera.2013.09.002] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 09/10/2013] [Indexed: 01/01/2023]
Abstract
UDP-glucuronosyltransferases (UGT) catalyze the biotransformation of many endobiotics and xenobiotics, and are coded by polymorphic genes. However, knowledge about the effects of these polymorphisms is rarely used for the individualization of drug therapy. Here, we present a quantitative systematic review of clinical studies on the impact of UGT variants on drug metabolism to clarify the potential for genotype-adjusted therapy recommendations. Data on UGT polymorphisms and dose-related pharmacokinetic parameters in man were retrieved by a systematic search in public databases. Mean estimates of pharmacokinetic parameters were extracted for each group of carriers of UGT variants to assess their effect size. Pooled estimates and relative confidence bounds were computed with a random-effects meta-analytic approach whenever multiple studies on the same variant, ethnic group, and substrate were available. Information was retrieved on 30 polymorphic metabolic pathways involving 10 UGT enzymes. For irinotecan and mycophenolic acid a wealth of data was available for assessing the impact of genetic polymorphisms on pharmacokinetics under different dosages, between ethnicities, under comedication, and under toxicity. Evidence for effects of potential clinical relevance exists for 19 drugs, but the data are not sufficient to assess effect size with the precision required to issue dose recommendations. In conclusion, compared to other drug metabolizing enzymes much less systematic research has been conducted on the polymorphisms of UGT enzymes. However, there is evidence of the existence of large monogenetic functional polymorphisms affecting pharmacokinetics and suggesting a potential use of UGT polymorphisms for the individualization of drug therapy.
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Affiliation(s)
- J C Stingl
- Research Division, Federal Institute for Drugs and Medical Devices, Bonn, Germany; Translational Pharmacology, University of Bonn Medical Faculty, Germany.
| | - H Bartels
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, University of Ulm, Germany
| | - R Viviani
- Department of Psychiatry and Psychotherapy III, University of Ulm, Germany
| | - M L Lehmann
- Research Division, Federal Institute for Drugs and Medical Devices, Bonn, Germany
| | - J Brockmöller
- Institute of Clinical Pharmacology, University of Göttingen, Germany
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Jeong HU, Kong TY, Kwon SS, Hong SW, Yeon SH, Choi JH, Lee JY, Cho YY, Lee HS. Effect of honokiol on cytochrome P450 and UDP-glucuronosyltransferase enzyme activities in human liver microsomes. Molecules 2013; 18:10681-93. [PMID: 24005963 PMCID: PMC6269737 DOI: 10.3390/molecules180910681] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 08/28/2013] [Accepted: 08/28/2013] [Indexed: 12/31/2022] Open
Abstract
Honokiol is a bioactive component isolated from the medicinal herbs Magnolia officinalis and Magnolia grandiflora that has antioxidative, anti-inflammatory, antithrombotic, and antitumor activities. The inhibitory potentials of honokiol on eight major human cytochrome P450 (CYP) enzymes 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, and 3A4, and four UDP-glucuronosyltransferases (UGTs) 1A1, 1A4, 1A9, and 2B7 in human liver microsomes were investigated using liquid chromatography-tandem mass spectrometry. Honokiol strongly inhibited CYP1A2-mediated phenacetin O-deethylation, CYP2C8-mediated amodiaquine N-deethylation, CYP2C9-mediated diclofenac 4-hydroxylation, CYP2C19-mediated [S]-mephenytoin 4-hydroxylation, and UGT1A9-mediated propofol glucuronidation with Ki values of 1.2, 4.9, 0.54, 0.57, and 0.3 μM, respectively. Honokiol also moderately inhibited CYP2B6-mediated bupropion hydroxylation and CYP2D6-mediated bufuralol 1'-hydroxylation with Ki values of 17.5 and 12.0 μM, respectively. These in vitro results indicate that honokiol has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP1A2, CYP2C8, CYP2C9, CYP2C19, and UGT1A9.
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Affiliation(s)
- Hyeon-Uk Jeong
- College of Pharmacy, the Catholic University of Korea, Bucheon 420-743, Korea; E-Mails: (H.-U.J.); (T.Y.K.); (S.S.K.); (Y.Y.C.)
| | - Tae Yeon Kong
- College of Pharmacy, the Catholic University of Korea, Bucheon 420-743, Korea; E-Mails: (H.-U.J.); (T.Y.K.); (S.S.K.); (Y.Y.C.)
| | - Soon Sang Kwon
- College of Pharmacy, the Catholic University of Korea, Bucheon 420-743, Korea; E-Mails: (H.-U.J.); (T.Y.K.); (S.S.K.); (Y.Y.C.)
| | - Sung-Woon Hong
- Huons Co., Ltd., Ansan 426-791, Korea; E-Mails: (S.-W.H.); (S.H.Y.); (J.-H.C.); (J.Y.L.)
| | - Sung Hum Yeon
- Huons Co., Ltd., Ansan 426-791, Korea; E-Mails: (S.-W.H.); (S.H.Y.); (J.-H.C.); (J.Y.L.)
| | - Jun-Ho Choi
- Huons Co., Ltd., Ansan 426-791, Korea; E-Mails: (S.-W.H.); (S.H.Y.); (J.-H.C.); (J.Y.L.)
| | - Jae Young Lee
- Huons Co., Ltd., Ansan 426-791, Korea; E-Mails: (S.-W.H.); (S.H.Y.); (J.-H.C.); (J.Y.L.)
| | - Yong Yeon Cho
- College of Pharmacy, the Catholic University of Korea, Bucheon 420-743, Korea; E-Mails: (H.-U.J.); (T.Y.K.); (S.S.K.); (Y.Y.C.)
| | - Hye Suk Lee
- College of Pharmacy, the Catholic University of Korea, Bucheon 420-743, Korea; E-Mails: (H.-U.J.); (T.Y.K.); (S.S.K.); (Y.Y.C.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +82-2-2164-4061; Fax: +82-32-342-2013
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Manevski N, Troberg J, Svaluto-Moreolo P, Dziedzic K, Yli-Kauhaluoma J, Finel M. Albumin stimulates the activity of the human UDP-glucuronosyltransferases 1A7, 1A8, 1A10, 2A1 and 2B15, but the effects are enzyme and substrate dependent. PLoS One 2013; 8:e54767. [PMID: 23372764 PMCID: PMC3553014 DOI: 10.1371/journal.pone.0054767] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 12/14/2012] [Indexed: 12/05/2022] Open
Abstract
Human UDP-glucuronosyltransferases (UGTs) are important enzymes in metabolic elimination of endo- and xenobiotics. It was recently shown that addition of fatty acid free bovine serum albumin (BSA) significantly enhances in vitro activities of UGTs, a limiting factor in in vitro–in vivo extrapolation. Nevertheless, since only few human UGT enzymes were tested for this phenomenon, we have now performed detailed enzyme kinetic analysis on the BSA effects in six previously untested UGTs, using 2–4 suitable substrates for each enzyme. We also examined some of the previously tested UGTs, but using additional substrates and a lower BSA concentration, only 0.1%. The latter concentration allows the use of important but more lipophilic substrates, such as estradiol and 17-epiestradiol. In five newly tested UGTs, 1A7, 1A8, 1A10, 2A1, and 2B15, the addition of BSA enhanced, to a different degree, the in vitro activity by either decreasing reaction’s Km, increasing its Vmax, or both. In contrast, the activities of UGT2B17, another previously untested enzyme, were almost unaffected. The results of the assays with the previously tested UGTs, 1A1, 1A6, 2B4, and 2B7, were similar to the published BSA only as far as the BSA effects on the reactions’ Km are concerned. In the cases of Vmax values, however, our results differ significantly from the previously published ones, at least with some of the substrates. Hence, the magnitude of the BSA effects appears to be substrate dependent, especially with respect to Vmax increases. Additionally, the BSA effects may be UGT subfamily dependent since Km decreases were observed in members of subfamilies 1A, 2A and 2B, whereas large Vmax increases were only found in several UGT1A members. The results shed new light on the complexity of the BSA effects on the activity and enzyme kinetics of the human UGTs.
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Affiliation(s)
- Nenad Manevski
- Centre for Drug Research, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
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Terai T, Tomiyasu R, Ota T, Ueno T, Komatsu T, Hanaoka K, Urano Y, Nagano T. TokyoGreen derivatives as specific and practical fluorescent probes for UDP-glucuronosyltransferase (UGT) 1A1. Chem Commun (Camb) 2013; 49:3101-3. [DOI: 10.1039/c3cc38810g] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Augustin JM, Drok S, Shinoda T, Sanmiya K, Nielsen JK, Khakimov B, Olsen CE, Hansen EH, Kuzina V, Ekstrøm CT, Hauser T, Bak S. UDP-glycosyltransferases from the UGT73C subfamily in Barbarea vulgaris catalyze sapogenin 3-O-glucosylation in saponin-mediated insect resistance. PLANT PHYSIOLOGY 2012; 160:1881-95. [PMID: 23027665 PMCID: PMC3510118 DOI: 10.1104/pp.112.202747] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 09/30/2012] [Indexed: 05/18/2023]
Abstract
Triterpenoid saponins are bioactive metabolites that have evolved recurrently in plants, presumably for defense. Their biosynthesis is poorly understood, as is the relationship between bioactivity and structure. Barbarea vulgaris is the only crucifer known to produce saponins. Hederagenin and oleanolic acid cellobioside make some B. vulgaris plants resistant to important insect pests, while other, susceptible plants produce different saponins. Resistance could be caused by glucosylation of the sapogenins. We identified four family 1 glycosyltransferases (UGTs) that catalyze 3-O-glucosylation of the sapogenins oleanolic acid and hederagenin. Among these, UGT73C10 and UGT73C11 show highest activity, substrate specificity and regiospecificity, and are under positive selection, while UGT73C12 and UGT73C13 show lower substrate specificity and regiospecificity and are under purifying selection. The expression of UGT73C10 and UGT73C11 in different B. vulgaris organs correlates with saponin abundance. Monoglucosylated hederagenin and oleanolic acid were produced in vitro and tested for effects on P. nemorum. 3-O-β-d-Glc hederagenin strongly deterred feeding, while 3-O-β-d-Glc oleanolic acid only had a minor effect, showing that hydroxylation of C23 is important for resistance to this herbivore. The closest homolog in Arabidopsis thaliana, UGT73C5, only showed weak activity toward sapogenins. This indicates that UGT73C10 and UGT73C11 have neofunctionalized to specifically glucosylate sapogenins at the C3 position and demonstrates that C3 monoglucosylation activates resistance. As the UGTs from both the resistant and susceptible types of B. vulgaris glucosylate sapogenins and are not located in the known quantitative trait loci for resistance, the difference between the susceptible and resistant plant types is determined at an earlier stage in saponin biosynthesis.
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Human UDP-glucuronosyltransferase UGT2A2: cDNA construction, expression, and functional characterization in comparison with UGT2A1 and UGT2A3. Pharmacogenet Genomics 2012; 19:923-34. [PMID: 19858781 DOI: 10.1097/fpc.0b013e3283330767] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Characterize the expression and glucuronidation activities of the human uridine 5'-diphospho (UDP)-glucuronosyltransferase (UGT) 2A2. METHOD UGT2A1 was cloned from nasal mucosa mRNA. Synthetic cDNA for UGT2A2 was constructed assuming exon sharing between UGT2A1 and UGT2A2 (Mackenzie et al., Pharmacogenetics and Genomics 2005, 15:677-685). Exon 1 of UGT2A2 was amplified from genomic DNA and combined with exons 2-6 of UGT2A1. UGT2A3 was cloned from liver mRNA. Quantitative reverse-transcribed-PCR (RT-PCR) was used to evaluate the expression of all the three UGTs of subfamily 2A in different tissues. Recombinant UGT2A1, UGT2A2 and UGT2A3 were expressed in baculovirus-infected insect cells and analyzed for glucuronidation activity towards different substrates. RESULTS DNA sequencing of RT-PCR products from human nasal mucosa mRNA, confirmed exon sharing between UGT2A1 and UGT2A2. In addition, it indicated that the N-terminal signal peptide sequence of UGT2A2 is the longest among the human UGTs. Quantitative RT-PCR revealed that both UGT2A1 and UGT2A2 are mainly expressed in the nasal mucosa, and that their expression level in fetal samples was much higher than in adults. Activity assays with recombinant UGTs 2A1-2A3 showed broad substrate selectivity for UGT2A1 and UGT2A2. Although glucuronidation rates and substrate affinities were mostly higher in UGT2A1, the Km values for UDP-glucuronic acid were similar in both UGTs. In addition, there were regioselectivity differences between the two UGTs and, with a few substrates, particularly ethinylestradiol, the activity of UGT2A2 was higher. CONCLUSION UGT2A2 is mainly expressed in the nasal mucosa and it has glucuronidation activity towards several different endobiotic and xenobiotic substrates.
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Dong D, Wu B. In Silico Modeling of UDP-Glucuronosyltransferase 1A10 Substrates Using the Volsurf Approach. J Pharm Sci 2012; 101:3531-9. [DOI: 10.1002/jps.23100] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 01/28/2012] [Accepted: 02/10/2012] [Indexed: 12/12/2022]
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Manevski N, Yli-Kauhaluoma J, Finel M. UDP-glucuronic acid binds first and the aglycone substrate binds second to form a ternary complex in UGT1A9-catalyzed reactions, in both the presence and absence of bovine serum albumin. Drug Metab Dispos 2012; 40:2192-203. [PMID: 22912433 DOI: 10.1124/dmd.112.047746] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The presence of bovine serum albumin (BSA) largely modulates the enzyme kinetics parameters of the human UDP-glucuronosyltransferase (UGT) 1A9, increasing both the apparent aglycone substrate affinity of the enzyme and its limiting reaction velocity (Drug Metab Dispos 39:2117-2129, 2011). For a better understanding of the BSA effects and an examination of whether its presence changes the catalytic mechanism, we have studied the enzyme kinetics of 4-methylumbelliferone glucuronidation by UGT1A9 in the presence and absence of 0.1% BSA, using bisubstrate enzyme kinetic experiments, in both the forward and reverse directions, as well as product and dead-end inhibition. The combined results strongly suggest that the reaction mechanism of UGT1A9, and presumably other human UGTs as well, involves the formation of a compulsory-order ternary-complex, with UDP-α-d-glucuronic acid (UDPGA) as the first binding substrate. Based on the enzyme kinetic parameters measured for the forward and reverse reactions, the equilibrium constant of the overall reaction was calculated (Keq = 574) and the relative magnitudes of the reaction rate constants were elucidated. The inclusion of BSA in the bisubstrate kinetic experiments quantitatively changed the apparent enzyme kinetic parameters, presumably by removing internal inhibitors that bind to the binary enzyme-UDPGA (E-UDPGA) complex, as well as to the ternary E-UDPGA-aglycone complex. Nevertheless, the underlying compulsory-order ternary-complex mechanism with UDPGA binding first is the same in both the absence and presence of BSA. The results offer a novel understanding of UGT enzyme kinetic mechanism and BSA effects.
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Affiliation(s)
- Nenad Manevski
- Division of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
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Wu B, Wang X, Zhang S, Hu M. Accurate prediction of glucuronidation of structurally diverse phenolics by human UGT1A9 using combined experimental and in silico approaches. Pharm Res 2012; 29:1544-61. [PMID: 22302521 DOI: 10.1007/s11095-012-0666-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 01/03/2012] [Indexed: 11/26/2022]
Abstract
PURPOSE Catalytic selectivity of human UGT1A9, an important membrane-bound enzyme catalyzing glucuronidation of xenobiotics, was determined experimentally using 145 phenolics and analyzed by 3D-QSAR methods. METHODS Catalytic efficiency of UGT1A9 was determined by kinetic profiling. Quantitative structure activity relationships were analyzed using CoMFA and CoMSIA techniques. Molecular alignment of substrate structures was made by superimposing the glucuronidation site and its adjacent aromatic ring to achieve maximal steric overlap. For a substrate with multiple active glucuronidation sites, each site was considered a separate substrate. RESULTS 3D-QSAR analyses produced statistically reliable models with good predictive power (CoMFA: q2 = 0.548, r2 = 0.949, r pred 2 = 0.775; CoMSIA: q2 = 0.579, r2 = 0.876, r pred 2 = 0.700). Contour coefficient maps were applied to elucidate structural features among substrates that are responsible for selectivity differences. Contour coefficient maps were overlaid in the catalytic pocket of a homology model of UGT1A9, enabling identification of the UGT1A9 catalytic pocket with a high degree of confidence. CONCLUSION CoMFA/CoMSIA models can predict substrate selectivity and in vitro clearance of UGT1A9. Our findings also provide a possible molecular basis for understanding UGT1A9 functions and substrate selectivity.
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Affiliation(s)
- Baojian Wu
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, 1441 Moursund St., Houston, Texas 77030, USA
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Montenegro-Miranda PS, Sneitz N, de Waart DR, ten Bloemendaal L, Duijst S, de Knegt RJ, Beuers U, Finel M, Bosma PJ. Ezetimibe: A biomarker for efficacy of liver directed UGT1A1 gene therapy for inherited hyperbilirubinemia. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1223-9. [DOI: 10.1016/j.bbadis.2012.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/27/2012] [Accepted: 04/17/2012] [Indexed: 11/24/2022]
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Meech R, Miners JO, Lewis BC, Mackenzie PI. The glycosidation of xenobiotics and endogenous compounds: Versatility and redundancy in the UDP glycosyltransferase superfamily. Pharmacol Ther 2012; 134:200-18. [DOI: 10.1016/j.pharmthera.2012.01.009] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 11/24/2022]
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Tang Y, LeMaster DM, Nauwelaërs G, Gu D, Langouët S, Turesky RJ. UDP-glucuronosyltransferase-mediated metabolic activation of the tobacco carcinogen 2-amino-9H-pyrido[2,3-b]indole. J Biol Chem 2012; 287:14960-72. [PMID: 22393056 PMCID: PMC3340249 DOI: 10.1074/jbc.m111.320093] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 02/19/2012] [Indexed: 11/06/2022] Open
Abstract
2-Amino-9H-pyrido[2,3-b]indole (AαC) is a carcinogenic heterocyclic aromatic amine (HAA) that arises in tobacco smoke. UDP-glucuronosyltransferases (UGTs) are important enzymes that detoxicate many procarcinogens, including HAAs. UGTs compete with P450 enzymes, which bioactivate HAAs by N-hydroxylation of the exocyclic amine group; the resultant N-hydroxy-HAA metabolites form covalent adducts with DNA. We have characterized the UGT-catalyzed metabolic products of AαC and the genotoxic metabolite 2-hydroxyamino-9H-pyrido[2,3-b]indole (HONH-AαC) formed with human liver microsomes, recombinant human UGT isoforms, and human hepatocytes. The structures of the metabolites were elucidated by (1)H NMR and mass spectrometry. AαC and HONH-AαC underwent glucuronidation by UGTs to form, respectively, N(2)-(β-D-glucosidurony1)-2-amino-9H-pyrido[2,3-b]indole (AαC-N(2)-Gl) and N(2)-(β-D-glucosidurony1)-2-hydroxyamino-9H-pyrido[2,3-b]indole (AαC-HON(2)-Gl). HONH-AαC also underwent glucuronidation to form a novel O-linked glucuronide conjugate, O-(β-D-glucosidurony1)-2-hydroxyamino-9H-pyrido[2,3-b]indole (AαC-HN(2)-O-Gl). AαC-HN(2)-O-Gl is a biologically reactive metabolite and binds to calf thymus DNA (pH 5.0 or 7.0) to form the N-(deoxyguanosin-8-yl)-AαC adduct at 20-50-fold higher levels than the adduct levels formed with HONH-AαC. Major UGT isoforms were examined for their capacity to metabolize AαC and HONH-AαC. UGT1A4 was the most catalytically efficient enzyme (V(max)/K(m)) at forming AαC-N(2)-Gl (0.67 μl·min(-1)·mg of protein(-1)), and UGT1A9 was most catalytically efficient at forming AαC-HN-O-Gl (77.1 μl·min(-1)·mg of protein(-1)), whereas UGT1A1 was most efficient at forming AαC-HON(2)-Gl (5.0 μl·min(-1)·mg of protein(-1)). Human hepatocytes produced AαC-N(2)-Gl and AαC-HN(2)-O-Gl in abundant quantities, but AαC-HON(2)-Gl was a minor product. Thus, UGTs, usually important enzymes in the detoxication of many procarcinogens, serve as a mechanism of bioactivation of HONH-AαC.
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Affiliation(s)
- Yijin Tang
- From the Divisions of Environmental Health Sciences and
| | - David M. LeMaster
- Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, New York 12201
| | - Gwendoline Nauwelaërs
- the Institut National de la Santé et de la Recherche Médicale (INSERM), U.1085, Institut de Recherche Santé Environnement et Travail (IRSET), Université de Rennes 1, Fédération de Recherche BioSit de Rennes UMS 3480, F-35043 Rennes, France, and
- ANSES, Fougères Laboratory, Contaminant Toxicology Unit, La Haute Marche, BP 90203, 35 302 Fougères cedex, France
| | - Dan Gu
- From the Divisions of Environmental Health Sciences and
| | - Sophie Langouët
- the Institut National de la Santé et de la Recherche Médicale (INSERM), U.1085, Institut de Recherche Santé Environnement et Travail (IRSET), Université de Rennes 1, Fédération de Recherche BioSit de Rennes UMS 3480, F-35043 Rennes, France, and
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Effect of efavirenz on UDP-glucuronosyltransferase 1A1, 1A4, 1A6, and 1A9 activities in human liver microsomes. Molecules 2012; 17:851-60. [PMID: 22252501 PMCID: PMC6268312 DOI: 10.3390/molecules17010851] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 01/09/2012] [Accepted: 01/10/2012] [Indexed: 11/17/2022] Open
Abstract
Efavirenz is a non-nucleoside reverse transcriptase inhibitor used for the treatment of human immunodeficiency virus type 1 infections. Drug interactions of efavirenz have been reported due to in vitro inhibition of CYP2C9, CYP2C19, CYP3A4, and UDP-glucuronosyltransferase 2B7 (UGT2B7) and in vivo CYP3A4 induction. The inhibitory potentials of efavirenz on the enzyme activities of four major UDP-glucuronosyltransferases (UGTs), 1A1, 1A4, 1A6, and 1A9, in human liver microsomes were investigated using liquid chromatography-tandem mass spectrometry. Efavirenz potently inhibited UGT1A4-mediated trifluoperazine N-glucuronidation and UGT1A9-mediated propofol glucuronidation, with Ki values of 2.0 and 9.4 μM, respectively. [I]/Ki ratios of efavirenz for trifluoperazine N-glucuronidation and propofol glucuronidation were 6.5 and 1.37, respectively. Efavirenz also moderately inhibited UGT1A1-mediated 17β-estradiol 3-glucuronidation, with a Ki value of 40.3 μM, but did not inhibit UGT1A6-mediated 1-naphthol glucuronidation. Those in vitro results suggest that efavirenz should be examined for potential pharmacokinetic drug interactions in vivo due to strong inhibition of UGT1A4 and UGT1A9.
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Zhang H, Soikkeli A, Tolonen A, Rousu T, Hirvonen J, Finel M. Highly variable pH effects on the interaction of diclofenac and indomethacin with human UDP-glucuronosyltransferases. Toxicol In Vitro 2012; 26:1286-93. [PMID: 22265884 DOI: 10.1016/j.tiv.2012.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 01/04/2012] [Accepted: 01/06/2012] [Indexed: 11/30/2022]
Abstract
In vitro glucuronidation assays of diclofenac and indomethacin at pH 7.4 are biased by the instability of the glucuronides due to acyl migration. The extent of this acyl migration may be reduced significantly by performing the glucuronidation reaction at pH 6.0. Testing the human UDP-glucuronosyltransferases (UGTs) of subfamilies 1A, 2A and 2B at pH 7.4 revealed that UGT1A10, UGT2B7 and UGT2B17 are the most active enzymes in diclofenac glucuronidation, while the highest indomethacin glucuronidation rates (corrected for relative expression levels) were exhibited by UGT2A1, UGT1A10 and UGT2B7. Interestingly, lowering the reaction pH to 6.0 increased the activity of many UGTs, particularly UGT1A10, toward both drugs, even if the rate of 4-methylumbelliferone glucuronidation by UGT1A10 at pH 6.0 was significantly lower than at pH 7.4. On the other hand, UGT2B15 lost activity upon lowering the reaction pH to 6.0. UGT1A6 does not glucuronidate diclofenac and indomethacin. Nevertheless, both drugs inhibit the 1-naphthol glucuronidation activity of UGT1A6 and their inhibition was stimulated by lowering the reaction pH, yielding significantly lower IC(50) values at pH 6.0 than at pH 7.4. In conclusion, glucuronidation reactions pH affects their outcome in variable ways and could increase the toxicity of drugs that carry a carboxylic acid.
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Affiliation(s)
- Hongbo Zhang
- Center for Drug Research, University of Helsinki, Finland
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Höglund C, Sneitz N, Radominska-Pandya A, Laakonen L, Finel M. Phenylalanine 93 of the human UGT1A10 plays a major role in the interactions of the enzyme with estrogens. Steroids 2011; 76:1465-73. [PMID: 21846474 PMCID: PMC3188330 DOI: 10.1016/j.steroids.2011.07.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 07/28/2011] [Accepted: 07/29/2011] [Indexed: 10/17/2022]
Abstract
Little is currently known about the substrate binding site of the human UDP-glucuronosyltransferases (UGTs) and the structural elements that affect their complex substrate selectivity. In order to further understand and extend our earlier findings with phenylalanines 90 and 93 of UGT1A10, we have replaced each of them with Gly, Ala, Val, Leu, Ile or Tyr, and tested the activity of the resulting 12 mutants toward eight different substrates. Apart from scopoletin glucuronidation, the F90 mutants other than F90L were nearly inactive, while the F93 mutants' activity was strongly substrate dependent. Hence, F93L displayed high entacapone and 1-naphthol glucuronidation rates, whereas F93G, which was nearly inactive in entacapone glucuronidation, was highly active toward estradiol, estriol and even ethinylestradiol, a synthetic estrogen that is a poor substrate for the wild-type UGT1A10. Kinetic analyses of 4-nitrophenol, estradiol and ethinylestradiol glucuronidation by the mutants that catalyzed the respective reactions at considerable rates, revealed increased K(m) values for 4-nitrophenol and estradiol in all the mutants, whilst the K(m) values of F93G and F93A for ethinylestradiol were lower than in control UGT1A10. Based on the activity results and a new molecular model of UGT1A10, it is suggested that both F90 and F93 are located in a surface helix at the far end of the substrate binding site. Nevertheless, only F93 directly affects the selectivity of UGT1A10 toward large and rigid estrogens, particularly those with substitutions at the D ring. The effects of F93 mutations on the glucuronidation of smaller or less rigid substrates are indirect, however.
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Affiliation(s)
- Camilla Höglund
- Centre for Drug Research, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland
- Division of Pharmaceutical Chemistry, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland
| | - Nina Sneitz
- Centre for Drug Research, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland
- Division of Pharmaceutical Chemistry, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland
| | - Anna Radominska-Pandya
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA (A.R.-P.)
| | - Liisa Laakonen
- Centre for Drug Research, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland
| | - Moshe Finel
- Centre for Drug Research, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland
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Abstract
Inhibition of enzyme activity at high substrate concentrations, so-called "substrate inhibition," is commonly observed and has been recognized in drug metabolism reactions since the last decade. Although the importance of such "atypical" kinetics in vivo remains poorly understood, a substrate with substrate inhibition kinetics has been shown to unconventionally alter the metabolism of other substrates. In recent years, it is becoming increasingly evident that the mechanisms for substrate inhibition are highly complex, which are possibly contributed by multiple (at least two) binding sites within the enzyme protein, the formation of a ternary dead-end enzyme complex, and/or the ligand-induced changes in enzyme conformation. This review primarily discusses the mechanisms for substrate inhibition displayed by the important drug-metabolizing enzymes, such as cytochrome p450s, UDP-glucuronyltransferases, and sulfotransferases. Kinetic modeling of substrate inhibition in the absence or presence of a modifier is another central issue in this review because of its importance in the determination of kinetic parameters and in vitro/in vivo predictions.
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Affiliation(s)
- Baojian Wu
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Texas, USA.
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Manevski N, Moreolo PS, Yli-Kauhaluoma J, Finel M. Bovine serum albumin decreases Km values of human UDP-glucuronosyltransferases 1A9 and 2B7 and increases Vmax values of UGT1A9. Drug Metab Dispos 2011; 39:2117-29. [PMID: 21856742 DOI: 10.1124/dmd.111.041418] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The human UDP-glucuronosyltransferase (UGT) enzymes UGT1A9 and UGT2B7 play important roles in the hepatic glucuronidation of many drugs. The presence of bovine serum albumin (BSA) during in vitro assays was recently reported to lower the K(m) values of both these UGTs for their aglycone substrates without affecting the corresponding V(max) values. Nonetheless, using the specific substrates entacapone and zidovudine (AZT) for UGT1A9 and UGT2B7, respectively, and using an improved ultrafiltration method for measuring drug binding to BSA and to biological membranes, we found that the presence of BSA during the glucuronidation reaction leads to a large increase in the V(max) value of UGT1A9, in addition to lowering its K(m) value. On the other hand, in the case of UGT2B7, our results agree with the previously described effect of BSA, namely lowering the K(m) value without a large effect on the enzyme's V(max) value. The unexpected BSA effect on UGT1A9 was independent of the expression system because it was found in a recombinant enzyme that was expressed in baculovirus-infected insect cells as well as in the native enzyme in human liver microsomes. Moreover, the effect of BSA on the kinetics of 4-methylumbelliferone glucuronidation by recombinant UGT1A9 was similar to its effect on entacapone glucuronidation. Contrary to the aglycone substrates, the effect of BSA on the apparent K(m) of UGT1A9 for the cosubstrate UDP-α-D-glucuronic acid was nonsignificant. Our findings call for further investigations of the BSA effects on different UGTs and the inhibitors that it may remove.
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Affiliation(s)
- Nenad Manevski
- Division of Pharmaceutical Chemistry, and Centre for Drug Research, Faculty of Pharmacy, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland
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Wu B, Kulkarni K, Basu S, Zhang S, Hu M. First-pass metabolism via UDP-glucuronosyltransferase: a barrier to oral bioavailability of phenolics. J Pharm Sci 2011; 100:3655-81. [PMID: 21484808 DOI: 10.1002/jps.22568] [Citation(s) in RCA: 214] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/10/2011] [Accepted: 03/10/2011] [Indexed: 12/11/2022]
Abstract
Glucuronidation mediated by UDP-glucuronosyltransferases (UGTs) is a significant metabolic pathway that facilitates efficient elimination of numerous endobiotics and xenobiotics, including phenolics. UGT genetic deficiency and polymorphisms or inhibition of glucuronidation by concomitant use of drugs are associated with inherited physiological disorders or drug-induced toxicities. Moreover, extensive glucuronidation can be a barrier to oral bioavailability as the first-pass glucuronidation (or premature clearance by UGTs) of orally administered agents usually results in the poor oral bioavailability and lack of efficacies. This review focused on the first-pass glucuronidation of phenolics including natural polyphenols and pharmaceuticals. The complexity of UGT-mediated metabolism of phenolics is highlighted with species-, gender-, organ- and isoform-dependent specificity, as well as functional compensation between UGT1A and 2B subfamily. In addition, recent advances are discussed with respect to the mechanisms of enzymatic actions, including the important properties such as binding pocket size and phosphorylation requirements.
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Affiliation(s)
- Baojian Wu
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas 77030, USA
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41
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Regioselective glucuronidation of flavonols by six human UGT1A isoforms. Pharm Res 2011; 28:1905-18. [PMID: 21472492 DOI: 10.1007/s11095-011-0418-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 03/04/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE Glucuronidation is a major barrier to flavonoid bioavailability; understanding its regiospecificity and reaction kinetics would greatly enhance our ability to model and predict flavonoid disposition. We aimed to determine the regioselective glucuronidation of four model flavonols using six expressed human UGT1A isoforms (UGT1A1, 1A3, 1A7, 1A8, 1A9, 1A10). METHODS In vitro reaction kinetic profiles of six UGT1A-mediated metabolism of four flavonols (all with 7-OH group) were characterized; kinetic parameters (K(m), V(max) and CL(int) = V(max)/K(m)) were determined. RESULTS UGT1A1 and 1A3 regioselectively metabolized the 7-OH group, whereas UGT1A7, 1A8, 1A9 and 1A10 preferred to glucuronidate the 3-OH group. UGT1A1 and 1A9 were the most efficient conjugating enzymes with K(m) values of ≤1 μM and relative catalytic efficiency ratios of ≥5.5. Glucuronidation by UGT1As displayed surprisingly strong substrate inhibition. In particular, K(si) values (substrate inhibition constant) were less than 5.4 μM for UGT1A1-mediated metabolism. CONCLUSION UGT1A isoforms displayed distinct positional preferences between 3-OH and 7-OH of flavonols. Differentiated kinetic properties between 3-O- and 7-O- glucuronidation suggested that (at least) two distinct binding modes within the catalytic domain were possible. The existence of multiple binding modes should provide better "expert" knowledge to model and predict UGT1A-mediated glucuronidation.
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Soikkeli A, Kurkela M, Hirvonen J, Yliperttula M, Finel M. Fluorescence-based high-throughput screening assay for drug interactions with UGT1A6. Assay Drug Dev Technol 2011; 9:496-502. [PMID: 21438674 DOI: 10.1089/adt.2010.0349] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The increasing awareness and the rising importance of UDP-glucuronosyltransferases (UGTs) in the pharmacokinetics of drugs have evoked a need to develop more powerful tools for studying the role of UGTs in the metabolism of drug candidates. To this end, we have developed a fluorescent high-throughput screening assay for screening potential inhibitors and/or substrates for recombinant human UGTs-here, for the UGT1A6. The assay is based on the increase in fluorescence intensity when 1-naphthol is glucuronidated. The formation of the highly fluorescent product, 1-naphthylglucuronide, is followed at excitation wavelengths of 295 and 300 nm with fixed emission (335 nm) in real time directly from the reaction mixture. A probe concentration of 5 μM with 2.5 μg of total protein in phosphate buffer at pH 7.4 with 5% dimethyl sulfoxide resulted in optimal linearity and acceptable signal separation (signal-to-base, 3.0) for the probe reaction. The interactions of test compounds with the enzyme are detected as lower rate of 1-naphthylglucuronide formation and thus lower rate of fluorescence increase. The success of the assay was first demonstrated with the known UGT1A6 substrates 4-hydroxyindole and scopoletin (Z' factor ≥0.5) and later with nonsteroidal anti-inflammatory drugs and salicylate derivatives. Diclofenac, 5-methylsalicylic acid, 5-bromosalicylic acid, 5-chlorosalicylic acid, and 5-fluorosalicylic acid decreased the probe glucuronidation rate at 500 μM by >50%. Further, the results gained with the high-throughput screening assay correlated well with the results obtained, in parallel, with the reference high-performance liquid chromatography method.
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Affiliation(s)
- Anne Soikkeli
- Division of Pharmaceutical Technology, University of Helsinki,Viikinkaari 5E, Helsinki, Finland.
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Kaivosaari S, Finel M, Koskinen M. N-glucuronidation of drugs and other xenobiotics by human and animal UDP-glucuronosyltransferases. Xenobiotica 2011; 41:652-69. [PMID: 21434773 DOI: 10.3109/00498254.2011.563327] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Metabolic disposition of drugs and other xenobiotics includes glucuronidation reactions that are catalyzed by the uridine diphosphate glucuronosyltransferases (UGTs). The most common glucuronidation reactions are O- and N-glucuronidation and in this review, we discuss both, while the emphasis is on N-glucuronidation. Interspecies difference in glucuronidation is another central issue in this review due to its importance in drug development. Accordingly, the available data on glucuronidation in different animals comes mainly from the species that are used in preclinical studies to assess the safety of drugs under development. Both O- and N-glucuronidation reactions are chemically diverse. Different O-glucuronidation reactions are described and discussed, and many drugs that undergo such reactions are indicated. The compounds that undergo N-glucuronidation include primary aromatic amines, hydroxylamines, amides, tertiary aliphatic amines, and aromatic N-heterocycles. The interspecies variability in N-glucuronidation is particularly high, above all when it comes to aliphatic tertiary amines and aromatic N-heterocycles. The N-glucuronidation rates in humans are typically much higher than in animals, largely due to the activity of two enzymes, the extensively studied UGT1A4, and the more recently identified as a main player in N-glucuronidation, UGT2B10. We discuss both enzymes and review the findings that revealed the role of UGT2B10 in N-glucuronidation.
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Affiliation(s)
- Sanna Kaivosaari
- Research and Development, Orion Corporation Orion Pharma, Espoo, Finland
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Zhang H, Tolonen A, Rousu T, Hirvonen J, Finel M. Effects of cell differentiation and assay conditions on the UDP-glucuronosyltransferase activity in Caco-2 cells. Drug Metab Dispos 2010; 39:456-64. [PMID: 21098645 DOI: 10.1124/dmd.110.036582] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cell differentiation increases UDP-glucuronosyltransferase (UGT) gene expression in Caco-2 cells. Glucuronidation of 13 UGT substrates, 1-naphthol, diclofenac, epitestosterone, estradiol, ethinylestradiol, indomethacin, oxazepam, R- and S-propranolol, propofol, testosterone, trifluoperazine, and zidovudine, were studied to derive a broad view on the effect of cell differentiation on the glucuronidation activities of different human UGTs. In parallel, the glucuronidation of these compounds in human liver microsomes (HLM) and human intestinal microsomes (HIM) was analyzed. Because many of the substrates are highly lipophilic, the effects of dimethyl sulfoxide (DMSO) concentrations in the reaction mixture on glucuronidation rates were tested, as well as the effect of alamethicin, a pore-forming peptide. Large differences were observed in the effects of DMSO and alamethicin between recombinant UGTs and Caco-2 cells and HLM and HIM, and, therefore, the activity assays were performed under multiple conditions. Regardless of the assay conditions, however, the results clearly indicated that although differentiation increases glucuronidation activity, the rates in Caco-2 cells are mostly very low, much lower than those in either HLM or HIM. One clear exception was observed: substrates of UGT1A6, such as 1-naphthol, were glucuronidated at very high rates in both undifferentiated and differentiated Caco-2 cells. It may thus be concluded that Caco-2 cells, even differentiated ones, do not provide a good model system to assess first-pass drug glucuronidation in the intestine.
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Affiliation(s)
- Hongbo Zhang
- Centre for Drug Research, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
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Wu B, Morrow JK, Singh R, Zhang S, Hu M. Three-dimensional quantitative structure-activity relationship studies on UGT1A9-mediated 3-O-glucuronidation of natural flavonols using a pharmacophore-based comparative molecular field analysis model. J Pharmacol Exp Ther 2010; 336:403-13. [PMID: 21068207 DOI: 10.1124/jpet.110.175356] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glucuronidation is often recognized as one of the rate-determining factors that limit the bioavailability of flavonols. Hence, design and synthesis of more bioavailable flavonols would benefit from the establishment of predictive models of glucuronidation using kinetic parameters [e.g., K(m), V(max), intrinsic clearance (CL(int)) = V(max)/K(m)] derived for flavonols. This article aims to construct position (3-OH)-specific comparative molecular field analysis (CoMFA) models to describe UDP-glucuronosyltransferase (UGT) 1A9-mediated glucuronidation of flavonols, which can be used to design poor UGT1A9 substrates. The kinetics of recombinant UGT1A9-mediated 3-O-glucuronidation of 30 flavonols was characterized, and kinetic parameters (K(m), V(max), CL(int)) were obtained. The observed K(m), V(max), and CL(int) values of 3-O-glucuronidation ranged from 0.04 to 0.68 μM, 0.04 to 12.95 nmol/mg/min, and 0.06 to 109.60 ml/mg/min, respectively. To model UGT1A9-mediated glucuronidation, 30 flavonols were split into the training (23 compounds) and test (7 compounds) sets. These flavonols were then aligned by mapping the flavonols to specific common feature pharmacophores, which were used to construct CoMFA models of V(max) and CL(int), respectively. The derived CoMFA models possessed good internal and external consistency and showed statistical significance and substantive predictive abilities (V(max) model: q(2) = 0.738, r(2) = 0.976, r(pred)(2) = 0.735; CL(int) model: q(2) = 0.561, r(2) = 0.938, r(pred)(2) = 0.630). The contour maps derived from CoMFA modeling clearly indicate structural characteristics associated with rapid or slow 3-O-glucuronidation. In conclusion, the approach of coupling CoMFA analysis with a pharmacophore-based structural alignment is viable for constructing a predictive model for regiospecific glucuronidation rates of flavonols by UGT1A9.
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Affiliation(s)
- Baojian Wu
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas 77030, USA
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Lehtonen P, Sten T, Aitio O, Kurkela M, Vuorensola K, Finel M, Kostiainen R. Glucuronidation of racemic O-desmethyltramadol, the active metabolite of tramadol. Eur J Pharm Sci 2010; 41:523-30. [DOI: 10.1016/j.ejps.2010.08.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 08/17/2010] [Accepted: 08/18/2010] [Indexed: 01/27/2023]
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Liu Y, Ramírez J, House L, Ratain MJ. The UGT1A1*28 polymorphism correlates with erlotinib's effect on SN-38 glucuronidation. Eur J Cancer 2010; 46:2097-103. [PMID: 20580994 DOI: 10.1016/j.ejca.2010.04.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 04/21/2010] [Accepted: 04/23/2010] [Indexed: 11/16/2022]
Abstract
The combination of irinotecan and erlotinib has been evaluated in clinical trials, although toxicity has been significant. We aimed to investigate the effect of erlotinib on SN-38 glucuronidation and the association between UGT1A polymorphisms and SN-38 glucuronidation activity in the presence of erlotinib. The inhibitory effect of erlotinib on SN-38 glucuronidation was determined by measuring the formation rates for SN-38 glucuronide, using recombinant human UGT1A1, pooled human liver microsomes (HLMs) and 52 Caucasian liver microsomes in the absence or presence of erlotinib. Inhibition kinetic studies were conducted. AUC ratios were used to predict the risk of potential drug-drug interactions (DDI) in vivo. Our data showed that erlotinib exhibited potent non-competitive inhibition against SN-38 glucuronidation in pooled HLMs and UGT1A1. Using the physiological and pharmacokinetic parameters obtained from the literature, we estimated the in vivo concentrations of unbound erlotinib available for UGT1A1 active site and thus the AUC ratios of SN-38 were also quantitatively predicted. It is estimated that erlotinib administered at 50mg/day or higher doses may result in at least a 24% increase in SN-38 AUC. Significant correlations were observed between SN-38 glucuronidation activity in the presence of erlotinib and UGT1A1*28 in 52 Caucasian liver microsomes. Our results suggest that erlotinib is a potent inhibitor of SN-38 glucuronidation via UGT1A1 inhibition. The coadministration of erlotinib with irinotecan may result in clinically significant DDI. UGT1A1*28 polymorphism correlates with erlotinib's effect on SN-38 glucuronidation. The present findings shed light on the development and optimisation of combinations involving irinotecan and erlotinib.
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Affiliation(s)
- Yong Liu
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
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48
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Aprile S, Del Grosso E, Grosa G. Identification of the human UDP-glucuronosyltransferases involved in the glucuronidation of combretastatin A-4. Drug Metab Dispos 2010; 38:1141-6. [PMID: 20375181 DOI: 10.1124/dmd.109.031435] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The stilbenic compound (Z)-combretastatin A-4 (CA-4) has been described as a potent tubulin polymerization inhibitor. In vivo, CA-4 binds to tubulin and inhibits microtubule depolymerization, which results in morphological changes in proliferating endothelial cells. Combretastatin A-4 prodrug phosphate is a leading vascular disrupting agent and is currently being evaluated in multiple clinical trials as a treatment for solid tumors. The aim of this study was to identify and characterize the UDP-glucuronosyltransferase (UGT) isoforms involved in CA-4 glucuronidation by incubation with human liver microsomes and a panel of nine liver-expressed recombinant UGT Supersomes (1A1, 1A3, 1A4, 1A6, 1A9, 2B4, 2B7, 2B15, and 2B17). As we observed, the high rate of formation of CA-4 glucuronide (V(max) = 12.78 +/- 0.29 nmol/min/mg protein) and the low K(m) (6.98 +/- 0.65 microM) denoted that UGT1A9 was primarily responsible for the in vitro glucuronidation of CA-4. UGT1A6 was also a significant contributor to CA-4 glucuronidation (V(max) = 3.95 +/- 0.13 nmol/min/mg protein and S(50) = 44.80 +/- 3.54 microM). Furthermore, we demonstrated that the kinetics of CA-4 glucuronidation with liver microsomes but also with a panel of recombinant UGTs is atypical as it fits two different models: the substrate inhibition and also the sigmoidal kinetic model. Finally, experiments conducted to inhibit the glucuronosyltransferase activity in the human liver microsomes assay showed that phenylbutazone, trifluoperazine, propofol, and 1-naphthol effectively inhibited CA-4 glucuronidation.
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Affiliation(s)
- Silvio Aprile
- Dipartimento di Scienze Chimiche, Alimentari, Farmaceutiche e Farmacologiche and Drug and Food Biotechnology Center, Università degli Studi del Piemonte Orientale A. Avogadro, 28100 Novara, Italy.
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Sneitz N, Bakker CT, de Knegt RJ, Halley DJJ, Finel M, Bosma PJ. Crigler-Najjar syndrome in The Netherlands: identification of four novel UGT1A1 alleles, genotype-phenotype correlation, and functional analysis of 10 missense mutants. Hum Mutat 2010; 31:52-9. [PMID: 19830808 DOI: 10.1002/humu.21133] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Crigler-Najjar syndrome (CN), caused by deficiency of UGT isoform 1A1 (UGT1A1), is characterized by severe unconjugated hyperbilirubinemia. In this study we have analyzed 19 CN patients diagnosed in The Netherlands (18) and in Belgium (1), and have identified 14 different UGT1A1 mutations, four of which are novel. Two mutations were present in several unrelated patients, suggesting the presence of two founder effects in The Netherlands. In addition, we show linkage of the UGT1A1 *28 promoter polymorphism (rs5719145insTA) to three structural mutations. Functional studies of partial active UGT1A1 mutants are limited. Therefore, we performed in vitro studies to determine the functional activity of seven missense mutants identified in this study and of three reported previously. In addition to bilirubin, we also determined their activity toward eight other UGT1A1 substrates. We demonstrate that five mutants have residual activity that, depending on the substrate, varies from not detectable to 94% of wild-type UGT1A1 activity. The identification of four novel pathogenic mutations and the analysis of residual activity of 10 UGT1A1 missense mutants are useful for clinical diagnosis, and provides new insights in enzyme activity, whereas the identification of two founder mutations will speed up genetic counseling for newly identified CN patients in The Netherlands.
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Affiliation(s)
- Nina Sneitz
- Centre for Drug Research, University of Helsinki, Finland
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50
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Laakkonen L, Finel M. A molecular model of the human UDP-glucuronosyltransferase 1A1, its membrane orientation, and the interactions between different parts of the enzyme. Mol Pharmacol 2010; 77:931-9. [PMID: 20215562 DOI: 10.1124/mol.109.063289] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vertebrate UDP-glucuronosyltransferases (UGTs) are membrane-bound enzymes of the endoplasmic reticulum that process both endogenous and exogenous substrates. The human UGTs are well known biologically, but biophysical understanding is scarce, largely because of problems in purification. The one resolved crystal structure covers the C-terminal domain of the human UGT2B7. Here, we present a homology model of the complete monomeric human UGT1A1, the enzyme that catalyzes bilirubin glucuronidation. The enzyme can be seen as composed of four different domains: two large ones, the N- and C-terminal domains, and two small ones, the "envelope" helices and the transmembrane segment that includes the cytoplasmic tail. The hydrophobic core of the N-terminal domain and the two envelope helices that connect the large domains are shown to be structurally well conserved even among distant homologs and can thus be modeled with good certainty according to plant and bacterial structures. We consider alternative solutions for the highly variable N-terminal regions that probably contribute to substrate binding. The bilirubin binding site, known pathological mutations in UGT1A1, and other specific residues have been examined in the context of the model with regard to available experimental data. A putative orientation of the protein relative to the membrane has been derived from the location of predicted N-glycosylation sites. The model presents extensive interactions between the N- and C-terminal domains, the two envelope helices, and the membrane. Together, these interactions could allow for a concerted large-scale conformational change during catalysis.
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Affiliation(s)
- Liisa Laakkonen
- Centre for Drug Research, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
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