1
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Takeuchi I, Kawamata R, Makino K. Effects of GGsTop ® on Collagen and Glutathione in the Oral Mucosa Using a Rat Model of 5-Fluorouracil-Induced Oral Mucositis. In Vivo 2021; 35:175-180. [PMID: 33402464 DOI: 10.21873/invivo.12246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 07/26/2020] [Accepted: 07/27/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM To evaluate the usefulness of GGsTop® for oral mucositis, a quantitative study focusing on oral mucosal tissues is necessary. In this study, we aimed to quantify collagen and glutathione using a rat model of 5-fluorouracil-induced oral mucositis. MATERIALS AND METHODS Changes in ulcer area and erythrocyte count were measured to confirm the usefulness of GGsTop® for oral mucositis. The effect of GGsTop on collagen was evaluated by observing oral mucosal tissue sections and measuring the collagen concentration in the tissues. The total glutathione concentration and the oxidized glutathione concentration were measured, and the concentration of the reduced form was calculated. RESULTS GGsTop® shortened the treatment period for oral mucositis without affecting the white blood cell count. In addition, GGsTop® promoted collagen production and alleviated oxidative stress conditions. CONCLUSION GGsTop affects collagen and glutathione in the treatment of oral mucositis.
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Affiliation(s)
- Issei Takeuchi
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan.,Center for Drug Delivery Research, Tokyo University of Science, Chiba, Japan
| | - Riko Kawamata
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan
| | - Kimiko Makino
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan; .,Center for Drug Delivery Research, Tokyo University of Science, Chiba, Japan
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2
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Suzuki H. γ-Glutamyltranspeptidase essential for the metabolism of γ-glutamyl compounds in bacteria and its application. Biosci Biotechnol Biochem 2021; 85:1295-1313. [DOI: 10.1093/bbb/zbab043] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 02/27/2021] [Indexed: 01/09/2023]
Abstract
ABSTRACT
The enzymatic characteristics of γ-glutamyltranspeptidase were elucidated. The catalytic nucleophile of the enzymatic reaction of Escherichia coli γ-glutamyltranspeptidase was identified as the Oγ of the N-terminal Thr-residue of the small subunit. It was demonstrated that the inactive precursor of γ-glutamyltranspeptidase is processed autocatalytically and intramolecularly into the active heterodimeric mature enzyme via an ester intermediate. The catalytic nucleophile of this processing reaction was identified as the same Oγ atom of the N-terminal Thr-residue of the small subunit. These results were also supported by the three-dimensional structures of the γ-glutamyl enzyme intermediate and of the precursor-mimicked T391A nonprocessable mutant enzyme. Applications of transpeptidation and hydrolysis activities of bacterial γ-glutamyltranspeptidases were developed. Using transpeptidation activity, efficient enzymatic production of useful γ-glutamyl compounds, such as prodrug for Parkinson's disease, theanine and kokumi compound, was enabled. Hydrolysis activity was used as glutaminase and the mutant enzymes gaining glutaryl-7-aminocephalosporanic acid acylase activity were isolated.
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Affiliation(s)
- Hideyuki Suzuki
- Division of Applied Biology, Kyoto Institute of Technology, Goshokaido-cho Matsugasaki Sakyo-ku, Kyoto, Japan
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3
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Abstract
The mercapturic acid pathway is a major route for the biotransformation of xenobiotic and endobiotic electrophilic compounds and their metabolites. Mercapturic acids (N-acetyl-l-cysteine S-conjugates) are formed by the sequential action of the glutathione transferases, γ-glutamyltransferases, dipeptidases, and cysteine S-conjugate N-acetyltransferase to yield glutathione S-conjugates, l-cysteinylglycine S-conjugates, l-cysteine S-conjugates, and mercapturic acids; these metabolites constitute a "mercapturomic" profile. Aminoacylases catalyze the hydrolysis of mercapturic acids to form cysteine S-conjugates. Several renal transport systems facilitate the urinary elimination of mercapturic acids; urinary mercapturic acids may serve as biomarkers for exposure to chemicals. Although mercapturic acid formation and elimination is a detoxication reaction, l-cysteine S-conjugates may undergo bioactivation by cysteine S-conjugate β-lyase. Moreover, some l-cysteine S-conjugates, particularly l-cysteinyl-leukotrienes, exert significant pathophysiological effects. Finally, some enzymes of the mercapturic acid pathway are described as the so-called "moonlighting proteins," catalytic proteins that exert multiple biochemical or biophysical functions apart from catalysis.
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Affiliation(s)
- Patrick E Hanna
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - M W Anders
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
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4
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Milito A, Brancaccio M, Lisurek M, Masullo M, Palumbo A, Castellano I. Probing the Interactions of Sulfur-Containing Histidine Compounds with Human Gamma-Glutamyl Transpeptidase. Mar Drugs 2019; 17:md17120650. [PMID: 31757046 PMCID: PMC6949936 DOI: 10.3390/md17120650] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/11/2019] [Accepted: 11/18/2019] [Indexed: 02/07/2023] Open
Abstract
Gamma-glutamyl transpeptidase (GGT) is a cell surface enzyme involved in glutathione metabolism and maintenance of redox homeostasis. High expression of GGT on tumor cells is associated with an increase of cell proliferation and resistance against chemotherapy. GGT inhibitors that have been evaluated in clinical trials are too toxic for human use. We have previously identified ovothiols, 5(Nπ)-methyl-thiohistidines of marine origin, as non-competitive-like inhibitors of GGT that are more potent than the known GGT inhibitor, 6-diazo-5-oxo-l-norleucine (DON), and are not toxic for human embryonic cells. We extended these studies to the desmethylated form of ovothiol, 5-thiohistidine, and confirmed that this ovothiol derivative also acts as a non-competitive-like GGT inhibitor, with a potency comparable to ovothiol. We also found that both 5-thiohistidine derivatives act as reversible GGT inhibitors compared to the irreversible DON. Finally, we probed the interactions of 5-thiohistidines with GGT by docking analysis and compared them with the 2-thiohistidine ergothioneine, the physiological substrate glutathione, and the DON inhibitor. Overall, our results provide new insight for further development of 5-thiohistidine derivatives as therapeutics for GGT-positive tumors.
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Affiliation(s)
- Alfonsina Milito
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy; (A.M.); (M.B.); (A.P.)
| | - Mariarita Brancaccio
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy; (A.M.); (M.B.); (A.P.)
| | - Michael Lisurek
- Department of Computational Chemistry and Drug Design, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany;
| | - Mariorosario Masullo
- Department of Human Movement Sciences and Wellbeing, University of Naples “Parthenope”, 80133 Naples, Italy;
| | - Anna Palumbo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy; (A.M.); (M.B.); (A.P.)
| | - Immacolata Castellano
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy; (A.M.); (M.B.); (A.P.)
- Correspondence: ; Tel.: +39-081-5833206
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5
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Brancaccio M, Russo M, Masullo M, Palumbo A, Russo GL, Castellano I. Sulfur-containing histidine compounds inhibit γ-glutamyl transpeptidase activity in human cancer cells. J Biol Chem 2019; 294:14603-14614. [PMID: 31375562 DOI: 10.1074/jbc.ra119.009304] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/04/2019] [Indexed: 12/19/2022] Open
Abstract
γ-Glutamyl transpeptidase (GGT) is an enzyme located on the surface of cellular membranes and involved in GSH metabolism and maintenance of redox homeostasis. High GGT expression on tumor cells is associated with increased cell proliferation and resistance against chemotherapy. GGT inhibitors evaluated so far in clinical trials are too toxic for human use. In this study, using enzyme kinetics analyses, we demonstrate that ovothiols, 5(Nπ)-methyl thiohistidines of marine origin, act as noncompetitive inhibitors of GGT, with an apparent Ki of 21 μm, when we fixed the concentrations of the donor substrate. We found that these compounds are more potent than the known GGT inhibitor 6-diazo-5-oxo-l-norleucine and are not toxic toward human embryonic cells. In particular, cellular process-specific fluorescence-based assays revealed that ovothiols induce a mixed cell-death phenotype of apoptosis and autophagy in GGT-overexpressing cell lines, including human liver cancer and chronic B leukemic cells. The findings of our study provide the basis for further development of 5-thiohistidines as therapeutics for GGT-positive tumors and highlight that GGT inhibition is involved in autophagy.
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Affiliation(s)
- Mariarita Brancaccio
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
| | - Maria Russo
- Institute of Food Sciences, National Research Council, 83100 Avellino, Italy
| | - Mariorosario Masullo
- Department of Movement Sciences and Wellbeing, University of Naples "Parthenope," 80133 Naples, Italy
| | - Anna Palumbo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
| | - Gian Luigi Russo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy.,Institute of Food Sciences, National Research Council, 83100 Avellino, Italy
| | - Immacolata Castellano
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
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6
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Watanabe B, Tabuchi Y, Wada K, Hiratake J. Synthesis and evaluation of the inhibitory activity of the four stereoisomers of the potent and selective human γ-glutamyl transpeptidase inhibitor GGsTop. Bioorg Med Chem Lett 2017; 27:4920-4924. [PMID: 28985998 DOI: 10.1016/j.bmcl.2017.09.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 12/30/2022]
Abstract
2-Amino-4-{[3-(carboxymethyl)phenoxy](methoxy)phosphoryl}butanoic acid (GGsTop) is a potent, highly selective, nontoxic, and irreversible inhibitor of γ-glutamyl transpeptidase (GGT). GGsTop has been widely used in academic and medicinal research, and also as an active ingredient (Nahlsgen) in commercial anti-aging cosmetics. GGsTop consists of four stereoisomers due to the presence of two stereogenic centers, i.e., the α-carbon atom of the glutamate mimic (l/d) and the phosphorus atom (RP/SP). In this study, each stereoisomer of GGsTop was synthesized stereoselectively and their inhibitory activity against human GGT was evaluated. The l- and d-configurations of each stereoisomer were determined by a combination of a chiral pool synthesis and chiral HPLC analysis. The synthesis of the four stereoisomers of GGsTop used chiral synthetic precursors that were separated by chiral HPLC on a preparative scale. With respect to the configuration of the α-carbon atom of the glutamate mimic, the l-isomer (kon=174M-1s-1) was ca. 8-fold more potent than the d-isomer (kon=21.5M-1s-1). In contrast, the configuration of the phosphorus atom is critical for GGT inhibitory activity. Based on a molecular modeling approach, the absolute configuration of the phosphorus atom of the active GGsTop isomers was postulated to be SP. The SP-isomers inhibited human GGT (kon=21.5-174M-1s-1), while the RP-isomers were inactive even at concentrations of 0.1mM.
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Affiliation(s)
- Bunta Watanabe
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
| | - Yukiko Tabuchi
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kei Wada
- Department of Medical Sciences, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Jun Hiratake
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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7
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Watanabe B, Morikita T, Tabuchi Y, Kobayashi R, Li C, Yamamoto M, Koeduka T, Hiratake J. An improved synthesis of the potent and selective γ-glutamyl transpeptidase inhibitor GGsTop together with an inhibitory activity evaluation of its potential hydrolysis products. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.08.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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8
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Phosphonate-based irreversible inhibitors of human γ-glutamyl transpeptidase (GGT). GGsTop is a non-toxic and highly selective inhibitor with critical electrostatic interaction with an active-site residue Lys562 for enhanced inhibitory activity. Bioorg Med Chem 2016; 24:5340-5352. [PMID: 27622749 DOI: 10.1016/j.bmc.2016.08.050] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/25/2016] [Accepted: 08/27/2016] [Indexed: 11/22/2022]
Abstract
γ-Glutamyl transpeptidase (GGT, EC 2.3.2.2) that catalyzes the hydrolysis and transpeptidation of glutathione and its S-conjugates is involved in a number of physiological and pathological processes through glutathione metabolism and is an attractive pharmaceutical target. We report here the evaluation of a phosphonate-based irreversible inhibitor, 2-amino-4-{[3-(carboxymethyl)phenoxy](methoyl)phosphoryl}butanoic acid (GGsTop) and its analogues as a mechanism-based inhibitor of human GGT. GGsTop is a stable compound, but inactivated the human enzyme significantly faster than the other phosphonates, and importantly did not inhibit a glutamine amidotransferase. The structure-activity relationships, X-ray crystallography with Escherichia coli GGT, sequence alignment and site-directed mutagenesis of human GGT revealed a critical electrostatic interaction between the terminal carboxylate of GGsTop and the active-site residue Lys562 of human GGT for potent inhibition. GGsTop showed no cytotoxicity toward human fibroblasts and hepatic stellate cells up to 1mM. GGsTop serves as a non-toxic, selective and highly potent irreversible GGT inhibitor that could be used for various in vivo as well as in vitro biochemical studies.
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9
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Juillerat-Jeanneret L, Flohr A, Schneider M, Walter I, Wyss JC, Kumar R, Golshayan D, Aebi JD. Targeted γ-Secretase Inhibition To Control the Notch Pathway in Renal Diseases. J Med Chem 2015; 58:8097-109. [DOI: 10.1021/acs.jmedchem.5b00912] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lucienne Juillerat-Jeanneret
- Transplantation
Center, Department of Medicine, Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne (UNIL), CH-1011 Lausanne, Switzerland
- University
Institute of Pathology, Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne (UNIL), CH-1011 Lausanne, Switzerland
| | - Alexander Flohr
- Medicinal
Chemistry, Roche Pharma Research and Early Development (pRED), Roche
Innovation Center Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland
| | - Manfred Schneider
- Medicinal
Chemistry, Roche Pharma Research and Early Development (pRED), Roche
Innovation Center Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland
| | - Isabelle Walter
- Medicinal
Chemistry, Roche Pharma Research and Early Development (pRED), Roche
Innovation Center Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland
| | - Jean-Christophe Wyss
- Transplantation
Center, Department of Medicine, Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne (UNIL), CH-1011 Lausanne, Switzerland
| | - Rajesh Kumar
- Transplantation
Center, Department of Medicine, Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne (UNIL), CH-1011 Lausanne, Switzerland
| | - Dela Golshayan
- Transplantation
Center, Department of Medicine, Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne (UNIL), CH-1011 Lausanne, Switzerland
| | - Johannes D. Aebi
- Medicinal
Chemistry, Roche Pharma Research and Early Development (pRED), Roche
Innovation Center Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland
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10
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Terzyan SS, Burgett AWG, Heroux A, Smith CA, Mooers BHM, Hanigan MH. Human γ-Glutamyl Transpeptidase 1: STRUCTURES OF THE FREE ENZYME, INHIBITOR-BOUND TETRAHEDRAL TRANSITION STATES, AND GLUTAMATE-BOUND ENZYME REVEAL NOVEL MOVEMENT WITHIN THE ACTIVE SITE DURING CATALYSIS. J Biol Chem 2015; 290:17576-86. [PMID: 26013825 DOI: 10.1074/jbc.m115.659680] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Indexed: 12/31/2022] Open
Abstract
γ-Glutamyl transpeptidase 1 (GGT1) is a cell surface, N-terminal nucleophile hydrolase that cleaves glutathione and other γ-glutamyl compounds. GGT1 expression is essential in cysteine homeostasis, and its induction has been implicated in the pathology of asthma, reperfusion injury, and cancer. In this study, we report four new crystal structures of human GGT1 (hGGT1) that show conformational changes within the active site as the enzyme progresses from the free enzyme to inhibitor-bound tetrahedral transition states and finally to the glutamate-bound structure prior to the release of this final product of the reaction. The structure of the apoenzyme shows flexibility within the active site. The serine-borate-bound hGGT1 crystal structure demonstrates that serine-borate occupies the active site of the enzyme, resulting in an enzyme-inhibitor complex that replicates the enzyme's tetrahedral intermediate/transition state. The structure of GGsTop-bound hGGT1 reveals its interactions with the enzyme and why neutral phosphonate diesters are more potent inhibitors than monoanionic phosphonates. These structures are the first structures for any eukaryotic GGT that include a molecule in the active site covalently bound to the catalytic Thr-381. The glutamate-bound structure shows the conformation of the enzyme prior to release of the final product and reveals novel information regarding the displacement of the main chain atoms that form the oxyanion hole and movement of the lid loop region when the active site is occupied. These data provide new insights into the mechanism of hGGT1-catalyzed reactions and will be invaluable in the development of new classes of hGGT1 inhibitors for therapeutic use.
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Affiliation(s)
- Simon S Terzyan
- From the Macromolecular Crystallography Laboratory, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Anthony W G Burgett
- the Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019
| | - Annie Heroux
- the Energy Sciences Directorate/Photon Science Division, Brookhaven National Laboratory, Upton, New York 11973
| | - Clyde A Smith
- the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025
| | - Blaine H M Mooers
- the Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| | - Marie H Hanigan
- the Department of Cell Biology, University of Oklahoma Health Sciences Center, Stanton L. Young Biomedical Research Center, Oklahoma City, Oklahoma 73104
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11
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Tuzova M, Jean JC, Hughey RP, Brown LAS, Cruikshank WW, Hiratake J, Joyce-Brady M. Inhibiting lung lining fluid glutathione metabolism with GGsTop as a novel treatment for asthma. Front Pharmacol 2014; 5:179. [PMID: 25132819 PMCID: PMC4116799 DOI: 10.3389/fphar.2014.00179] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 07/14/2014] [Indexed: 12/29/2022] Open
Abstract
Asthma is characterized by airway inflammation. Inflammation is associated with oxidant stress. Airway epithelial cells are shielded from this stress by a thin layer of lung lining fluid (LLF) which contains an abundance of the antioxidant glutathione. LLF glutathione metabolism is regulated by γ-glutamyl transferase (GGT). Loss of LLF GGT activity in the mutant GGTenu1 mouse causes an increase in baseline LLF glutathione content which is magnified in an IL-13 model of allergic airway inflammation and protective against asthma. Normal mice are susceptible to asthma in this model but can be protected with acivicin, a GGT inhibitor. GGT is a target to treat asthma but acivicin toxicity limits clinical use. GGsTop is a novel GGT inhibitor. GGsTop inhibits LLF GGT activity only when delivered through the airway. In the IL-13 model, mice treated with IL-13 and GGsTop exhibit a lung inflammatory response similar to that of mice treated with IL-13 alone. But mice treated with IL-13 and GGsTop show attenuation of methacholine-stimulated airway hyper-reactivity, inhibition of Muc5ac and Muc5b gene induction, decreased airway epithelial cell mucous accumulation and a fourfold increase in LLF glutathione content compared to mice treated with IL-13 alone. Mice treated with GGsTop alone are no different from that of mice treated with saline alone, and show no signs of toxicity. GGsTop could represent a valuable pharmacological tool to inhibit LLF GGT activity in pulmonary disease models. The associated increase in LLF glutathione can protect lung airway epithelial cells against oxidant injury associated with inflammation in asthma.
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Affiliation(s)
- Marina Tuzova
- The Pulmonary Center, Boston University School of Medicine Boston, MA, USA
| | - Jyh-Chang Jean
- The Pulmonary Center, Boston University School of Medicine Boston, MA, USA
| | - Rebecca P Hughey
- Department of Medicine, University of Pittsburgh Pittsburgh, PA, USA
| | - Lou Ann S Brown
- Department of Pediatrics, Emory University School of Medicine Atlanta, GA, USA
| | | | - Jun Hiratake
- Institute for Chemical Research, Kyoto University Kyoto, Japan
| | - Martin Joyce-Brady
- The Pulmonary Center, Boston University School of Medicine Boston, MA, USA
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12
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Balakrishna S, Prabhune AA. Gamma-glutamyl transferases: A structural, mechanistic and physiological perspective. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s11515-014-1288-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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13
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Nakajima M, Watanabe B, Han L, Shimizu BI, Wada K, Fukuyama K, Suzuki H, Hiratake J. Glutathione-analogous peptidyl phosphorus esters as mechanism-based inhibitors of γ-glutamyl transpeptidase for probing cysteinyl-glycine binding site. Bioorg Med Chem 2013; 22:1176-94. [PMID: 24411479 DOI: 10.1016/j.bmc.2013.12.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 12/06/2013] [Accepted: 12/07/2013] [Indexed: 12/29/2022]
Abstract
γ-Glutamyl transpeptidase (GGT) catalyzing the cleavage of γ-glutamyl bond of glutathione and its S-conjugates is involved in a number of physiological and pathological processes through glutathione homeostasis. Defining its Cys-Gly binding site is extremely important not only in defining the physiological function of GGT, but also in designing specific and effective inhibitors for pharmaceutical purposes. Here we report the synthesis and evaluation of a series of glutathione-analogous peptidyl phosphorus esters as mechanism-based inhibitors of human and Escherichia coli GGTs to probe the structural and stereochemical preferences in the Cys-Gly binding site. Both enzymes were inhibited strongly and irreversibly by the peptidyl phosphorus esters with a good leaving group (phenoxide). Human GGT was highly selective for l-aliphatic amino acid such as l-2-aminobutyrate (l-Cys mimic) at the Cys binding site, whereas E. coli GGT significantly preferred l-Phe mimic at this site. The C-terminal Gly and a l-amino acid analogue at the Cys binding site were necessary for inhibition, suggesting that human GGT was highly selective for glutathione (γ-Glu-l-Cys-Gly), whereas E. coli GGT are not selective for glutathione, but still retained the dipeptide (l-AA-Gly) binding site. The diastereoisomers with respect to the chiral phosphorus were separated. Both GGTs were inactivated by only one of the stereoisomers with the same stereochemistry at phosphorus. The strict recognition of phosphorus stereochemistry gave insights into the stereochemical course of the catalyzed reaction. Ion-spray mass analysis of the inhibited E. coli GGT confirmed the formation of a 1:1 covalent adduct with the catalytic subunit (small subunit) with concomitant loss of phenoxide, leaving the peptidyl moiety that presumably occupies the Cys-Gly binding site. The peptidyl phosphonate inhibitors are highly useful as a ligand for X-ray structural analysis of GGT for defining hitherto unidentified Cys-Gly binding site to design specific inhibitors.
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Affiliation(s)
- Mado Nakajima
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Bunta Watanabe
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Liyou Han
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Bun-Ichi Shimizu
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kei Wada
- Organization for Promotion of Tenure Track, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Keiichi Fukuyama
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Hideyuki Suzuki
- Division of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Jun Hiratake
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
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14
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Synthesis of 5-amino-2-aminoalkyl-1,3-oxazol-4-ylphosphonic acid derivatives and their use in the preparation of phosphorylated peptidomimetics. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.05.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Hu X, Legler PM, Khavrutskii I, Scorpio A, Compton JR, Robertson KL, Friedlander AM, Wallqvist A. Probing the donor and acceptor substrate specificity of the γ-glutamyl transpeptidase. Biochemistry 2012; 51:1199-212. [PMID: 22257032 DOI: 10.1021/bi200987b] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
γ-Glutamyl transpeptidase (GGT) is a two-substrate enzyme that plays a central role in glutathione metabolism and is a potential target for drug design. GGT catalyzes the cleavage of γ-glutamyl donor substrates and the transfer of the γ-glutamyl moiety to an amine of an acceptor substrate or water. Although structures of bacterial GGT have revealed details of the protein-ligand interactions at the donor site, the acceptor substrate site is relatively undefined. The recent identification of a species-specific acceptor site inhibitor, OU749, suggests that these inhibitors may be less toxic than glutamine analogues. Here we investigated the donor and acceptor substrate preferences of Bacillus anthracis GGT (CapD) and applied computational approaches in combination with kinetics to probe the structural basis of the enzyme's substrate and inhibitor binding specificities and compare them with human GGT. Site-directed mutagenesis studies showed that the R432A and R520S variants exhibited 6- and 95-fold decreases in hydrolase activity, respectively, and that their activity was not stimulated by the addition of the l-Cys acceptor substrate, suggesting an additional role in acceptor binding and/or catalysis of transpeptidation. Rat GGT (and presumably HuGGT) has strict stereospecificity for L-amino acid acceptor substrates, while CapD can utilize both L- and D-acceptor substrates comparably. Modeling and kinetic analysis suggest that R520 and R432 allow two alternate acceptor substrate binding modes for L- and D-acceptors. R432 is conserved in Francisella tularensis, Yersinia pestis, Burkholderia mallei, Helicobacter pylori and Escherichia coli, but not in human GGT. Docking and MD simulations point toward key residues that contribute to inhibitor and acceptor substrate binding, providing a guide to designing novel and specific GGT inhibitors.
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Affiliation(s)
- Xin Hu
- Biotechnology HPC Software Applications Institute, Telemedicine and Advanced Technology Research Center, US Army Medical Research and Materiel Command, Fort Detrick, Maryland 21702, United States.
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Joyce-Brady M, Hiratake J. Inhibiting Glutathione Metabolism in Lung Lining Fluid as a Strategy to Augment Antioxidant Defense. ACTA ACUST UNITED AC 2011; 7:71-78. [PMID: 22485086 PMCID: PMC3319921 DOI: 10.2174/157340811796575308] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 03/25/2011] [Accepted: 04/08/2011] [Indexed: 12/22/2022]
Abstract
Glutathione is abundant in the lining fluid that bathes the gas exchange surface of the lung. On the one hand glutathione in this extracellular pool functions in antioxidant defense to protect cells and proteins in the alveolar space from oxidant injury; on the other hand, it functions as a source of cysteine to maintain cellular glutathione and protein synthesis. These seemingly opposing functions are regulated through metabolism by gamma-glutamyl transferase (GGT, EC 2.3.2.2). Even under normal physiologic conditions, lung lining fluid (LLF) contains a concentrated pool of GGT activity exceeding that of whole lung by about 7-fold and indicating increased turnover of glutathione at the epithelial surface of the lung. With oxidant stress LLF GGT activity is amplified even further as glutathione turnover is accelerated to meet the increased demands of cells for cysteine. Mouse models of GGT deficiency confirmed this biological role of LLF GGT activity and revealed the robust expansiveness and antioxidant capacity of the LLF glutathione pool in the absence of metabolism. Acivicin, an irreversible inhibitor of GGT, can be utilized to augment LLF fluid glutathione content in normal mice and novel GGT inhibitors have now been defined that provide advantages over acivicin. Inhibiting LLF GGT activity is a novel strategy to selectively augment the extracellular LLF glutathione pool. The enhanced antioxidant capacity can maintain lung epithelial cell integrity and barrier function under oxidant stress.
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Affiliation(s)
- Martin Joyce-Brady
- The Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA
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Williams K, Cullati S, Sand A, Biterova EI, Barycki JJ. Crystal structure of acivicin-inhibited gamma-glutamyltranspeptidase reveals critical roles for its C-terminus in autoprocessing and catalysis. Biochemistry 2010; 48:2459-67. [PMID: 19256527 DOI: 10.1021/bi8014955] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Helicobacter pylori gamma-glutamyltranspeptidase (HpGT) is a general gamma-glutamyl hydrolase and a demonstrated virulence factor. The enzyme confers a growth advantage to the bacterium, providing essential amino acid precursors by initiating the degradation of extracellular glutathione and glutamine. HpGT is a member of the N-terminal nucleophile (Ntn) hydrolase superfamily and undergoes autoprocessing to generate the active form of the enzyme. Acivicin is a widely used gamma-glutamyltranspeptidase inhibitor that covalently modifies the enzyme, but its precise mechanism of action remains unclear. The time-dependent inactivation of HpGT exhibits a hyperbolic dependence on acivicin concentration with k(max) = 0.033 +/- 0.006 s(-1) and K(I) = 19.7 +/- 7.2 microM. Structure determination of acivicin-modified HpGT (1.7 A; R(factor) = 17.9%; R(free) = 20.8%) demonstrates that acivicin is accommodated within the gamma-glutamyl binding pocket of the enzyme. The hydroxyl group of Thr 380, the catalytic nucleophile in the autoprocessing and enzymatic reactions, displaces chloride from the acivicin ring to form the covalently linked complex. Within the acivicin-modified HpGT structure, the C-terminus of the protein becomes ordered with Phe 567 positioned over the active site. Substitution or deletion of Phe 567 leads to a >10-fold reduction in enzymatic activity, underscoring its importance in catalysis. The mobile C-terminus is positioned by several electrostatic interactions within the C-terminal region, most notably a salt bridge between Arg 475 and Glu 566. Mutational analysis reveals that Arg 475 is critical for the proper placement of the C-terminal region, the Tyr 433 containing loop, and the proposed oxyanion hole.
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Affiliation(s)
- Kristin Williams
- Department of Biochemistry, University of Nebraska, 1901 Vine Street, Lincoln, Nebraska 68588-0664, USA
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King JB, West MB, Cook PF, Hanigan MH. A novel, species-specific class of uncompetitive inhibitors of gamma-glutamyl transpeptidase. J Biol Chem 2009; 284:9059-65. [PMID: 19203993 DOI: 10.1074/jbc.m809608200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of gamma-glutamyl transpeptidase (GGT) in tumors contributes to resistance to radiation and chemotherapy. GGT is inhibited by glutamine analogues that compete with the substrate for the gamma-glutamyl binding site. However, the glutamine analogues that have been evaluated in clinical trials are too toxic for use in humans. We have used high throughput screening to evaluate small molecules for their ability to inhibit GGT and have identified a novel class of inhibitors that are not glutamine analogues. These compounds are uncompetitive inhibitors, binding the gamma-glutamyl enzyme complex. OU749, the lead compound, has an intrinsic K(i) of 17.6 microm. It is a competitive inhibitor of the acceptor glycyl-glycine, which indicates that OU749 occupies the acceptor site while binding to the gamma-glutamyl substrate complex. OU749 is more than 150-fold less toxic than the GGT inhibitor acivicin toward dividing cells. Inhibition of GGT by OU749 is species-specific, inhibiting GGT isolated from human kidney with 7-10-fold greater potency than GGT isolated from rat or mouse kidney. OU749 does not inhibit GGT from pig cells. Human GGT expressed in mouse fibroblasts is inhibited by OU749 similarly to GGT from human cells, which indicates that the species specificity is determined by differences in the primary structure of the protein rather than species-specific, post-translational modifications. These studies have identified a novel class of inhibitors of GGT, providing the basis for further development of a new group of therapeutics that inhibit GGT by a mechanism distinct from the toxic glutamine analogues.
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Affiliation(s)
- Jarrod B King
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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Vergauwen B, Dudycz LW, Dansercoer A, Devreese B. A direct spectrophotometric gamma-glutamyltransferase inhibitor screening assay targeting the hydrolysis-only mode. Biochem Biophys Res Commun 2009; 380:591-6. [PMID: 19285006 DOI: 10.1016/j.bbrc.2009.01.129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 01/23/2009] [Indexed: 10/21/2022]
Abstract
Gamma-glutamyltransferase (GGT, E.C. 2.3.2.2) catalyzes the hydrolysis and transpeptidation of extracellular glutathione. Due to its central role in maintaining mammalian glutathione homeostasis, GGT is now believed to be a valuable drug target for a variety of life-threatening diseases, such as cancer. Unfortunately, however, effective tools for screening GGT inhibitors are still lacking. We report here the synthesis and evaluation of an alpha-phenylthio-containing glutathione peptide mimic that eliminates thiophenol upon GGT-catalyzed hydrolysis of the gamma-glutamyl peptide bond. The concurrent, real-time spectrophotometric quantification of the released thiophenol using Ellman's reagent creates a GGT assay format that is simple, robust, and highly sensitive. The versatility of the assay has been demonstrated by its application to the kinetic characterization of equine kidney GGT, and enzyme inhibition assays. The ability of the glutathione mimic to behave as an excellent donor substrate (exhibiting Michaelis-Menten kinetics with a K(m) of 11.3+/-0.5 microM and a k(cat) of 90.1+/-0.8 nmol mg(-1)min(-1)), coupled to the assay's ability to study the hydrolysis-only mode of the GGT-catalyzed reaction, make our approach amenable to high-throughput drug screening platforms.
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Affiliation(s)
- Bjorn Vergauwen
- Laboratory for Protein Biochemistry and Biomolecular Engineering, Ghent University, 9000 Ghent, Belgium.
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Petrini M, Shaikh RR. Synthesis of indolylalkylphosphonates and 3-(1-diphenylphosphinoalkyl) indoles by reaction of 3-(1-arylsulfonylalkyl) indoles with phosphorus derivatives. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.07.077] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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