Characterization of Hepatic UDP-Glucuronosyltransferase Enzyme Abundance-Activity Correlations and Population Variability Using a Proteomics Approach and Comparison with Cytochrome P450 Enzymes

Abstract

The expression of ten major drug-metabolizing UDP-glucuronosyl transferase (UGT) enzymes in a panel of 130 human hepatic microsomal samples was measured using a LC-MS/MS-based approach. Simultaneously, ten cytochrome P450s and P450 reductase were also measured and activity-expression relationships assessed for comparison. The resulting data sets demonstrated that, with the exception of UGT2B17, 10 th -90 th percentiles of UGT expression spanned 3-to 8fold ranges. These ranges were small relative to ranges of reported mean UGT enzyme expression across different laboratories. We tested correlation of UGT expression with enzymatic activities using selective probe substrates. A high degree of abundance-activity correlation (rs > 0.6) was observed for UGT1As (1A1, 3, 4, 6) and CYPs. In contrast, protein abundance and activity did not correlate strongly for UGT1A9 and UGT2B enzymes (2B4, 7, 10, 15 and 17). Protein abundance was strongly correlated for UGTs 2B7, 2B10 and 2B15. We suggest a number of factors may contribute to these differences including incomplete selectivity of probe substrates, correlated expression of these UGT2B isoforms, and the impact of splice and This article has not been copyedited and formatted. The final version may differ from this version.

In silico modeling and simulation of organ‐on‐a‐chip systems to support data analysis and a priori experimental design

“…There is a large interindividual variability in the activities drug metabolizing enzymes due to the influences of age, sex, enzyme induction by drugs and foodstuffs, and genetic polymorphisms. Some individuals may completely lack expression of functional CYP2D6, 33 UGT2B10, 34 or FMO 35 due to genetic polymorphism. Expression levels of CYPs and UGTs have been seen to vary at least 10‐fold and frequently more than 100‐fold between different individuals 35 .…”

“…Some individuals may completely lack expression of functional CYP2D6, 33 UGT2B10, 34 or FMO 35 due to genetic polymorphism. Expression levels of CYPs and UGTs have been seen to vary at least 10‐fold and frequently more than 100‐fold between different individuals 35 . Individual donor variability was recently explored in commercially available batches of human hepatocytes by Horiuchi et al 36 …”

“…Expression levels of CYPs and UGTs have been seen to vary at least 10-fold and frequently more than 100-fold between different individuals. 35 Individual donor variability was recently explored in commercially available batches of human hepatocytes by Horiuchi et al 36 The problem of donor variability has been addressed in other ADME assays by pooling of donors to generate a "population average" preparation of cells or subcellular fractions. This has the benefit of enabling better comparison of results among experimental systems, facilitating extrapolation of the data, avoiding undue influence of genetic polymorphisms/other individual donor characteristics, and improving experiment to experiment reproducibility.…”

Contribution of UGT Enzymes to Human Drug Metabolism Stereoselectivity: A Case Study of Medetomidine, RO5263397, Propranolol, and Testosterone

“…RO5263397 displayed a metabolism profile similar to levomedetomidine but with somewhat higher metabolic stability and a greater extent of UGT2B10 selectivity (Badée et al, 2019;Milani et al, 2020;Takahashi et al, 2021). The intrinsic clearance of RO5263397 versus enantiomer RO5263396 was at least 36-fold higher.…”

Die Zukunft (Radio‐)‐isotopenmarkierter Verbindungen in Forschung und Entwicklung der modernen Lebenswissenschaften

“…Dank einer früh durchgeführten hADME-Studie konnte der Metabolit rechtzeitig identifiziert werden, was zur Sicherheit der Probanden in den klinischen Tests beitrug. [18] hADME-Studien können entweder nach herkömmlichen Methoden mit mäßigen Mengen an Radioaktivität und Detektion durch Flüssigszintillationszählung (LSC) oder mittels AMS-Technik mit sehr geringen Radioaktivitätsmengen durchgeführt werden. AMS ist die gleiche Technik, die für die C-14-Datierung in der Archäologie oder Geologie eingesetzt wird (Radiokarbonmethode).…”