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Pristup J, Schaeffeler E, Arjune S, Hofmann U, Santamaria-Araujo JA, Leuthold P, Friedrich N, Nauck M, Mayr S, Haag M, Muerdter T, Marner FJ, Relling MV, Evans WE, Schwarz G, Schwab M. Molybdenum Cofactor Catabolism Unravels the Physiological Role of the Drug Metabolizing Enzyme Thiopurine S-Methyltransferase. Clin Pharmacol Ther 2022; 112:808-816. [PMID: 35538648 PMCID: PMC9474665 DOI: 10.1002/cpt.2637] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/04/2022] [Indexed: 12/14/2022]
Abstract
Therapy of molybdenum cofactor (Moco) deficiency has received US Food and Drug Administration (FDA) approval in 2021. Whereas urothione, the urinary excreted catabolite of Moco, is used as diagnostic biomarker for Moco-deficiency, its catabolic pathway remains unknown. Here, we identified the urothione-synthesizing methyltransferase using mouse liver tissue by anion exchange/size exclusion chromatography and peptide mass fingerprinting. We show that the catabolic Moco S-methylating enzyme corresponds to thiopurine S-methyltransferase (TPMT), a highly polymorphic drug-metabolizing enzyme associated with drug-related hematotoxicity but unknown physiological role. Urothione synthesis was investigated in vitro using recombinantly expressed human TPMT protein, liver lysates from Tpmt wild-type and knock-out (Tpmt-/- ) mice as well as human liver cytosol. Urothione levels were quantified by liquid-chromatography tandem mass spectrometry in the kidneys and urine of mice. TPMT-genotype/phenotype and excretion levels of urothione were investigated in human samples and validated in an independent population-based study. As Moco provides a physiological substrate (thiopterin) of TPMT, thiopterin-methylating activity was associated with TPMT activity determined with its drug substrate (6-thioguanin) in mice and humans. Urothione concentration was extremely low in the kidneys and urine of Tpmt-/- mice. Urinary urothione concentration in TPMT-deficient patients depends on common TPMT polymorphisms, with extremely low levels in homozygous variant carriers (TPMT*3A/*3A) but normal levels in compound heterozygous carriers (TPMT*3A/*3C) as validated in the population-based study. Our work newly identified an endogenous substrate for TPMT and shows an unprecedented link between Moco catabolism and drug metabolism. Moreover, the TPMT example indicates that phenotypic consequences of genetic polymorphisms may differ between drug- and endogenous substrates.
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Affiliation(s)
- Julika Pristup
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Elke Schaeffeler
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, 70376 Stuttgart, Germany
- Cluster of Excellence iFIT (EXC2180) "Image-Guided and Functionally Instructed Tumor Therapies", University of Tuebingen, 72076 Tuebingen, Germany
| | - Sita Arjune
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Ute Hofmann
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, 70376 Stuttgart, Germany
| | | | - Patrick Leuthold
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, 70376 Stuttgart, Germany
| | - Nele Friedrich
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, 17475 Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Greifswald, University Medicine, 17475 Greifswald, Germany
| | - Matthias Nauck
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, 17475 Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Greifswald, University Medicine, 17475 Greifswald, Germany
| | - Simon Mayr
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Mathias Haag
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, 70376 Stuttgart, Germany
| | - Thomas Muerdter
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, 70376 Stuttgart, Germany
| | - Franz-Josef Marner
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Mary V Relling
- Hematological Malignancies Program, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678, USA
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678, USA
| | - William E Evans
- Hematological Malignancies Program, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678, USA
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678, USA
| | - Guenter Schwarz
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Matthias Schwab
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, 70376 Stuttgart, Germany
- Cluster of Excellence iFIT (EXC2180) "Image-Guided and Functionally Instructed Tumor Therapies", University of Tuebingen, 72076 Tuebingen, Germany
- Departments of Clinical Pharmacology, Pharmacy and Biochemistry, University Tuebingen, 72076 Tuebingen, Germany
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