Human UGT2B7 is the major isoform responsible for the glucuronidation of clopidogrel carboxylate

Abstract

Clopidogrel is predominantly hydrolyzed to clopidogrel carboxylic acid (CCA) by carboxylesterase 1, and subsequently CCA is glucuronidated to clopidogrel acyl glucuronide (CAG) by uridine diphosphate-glucuronosyltransferases (UGTs); however, the UGT isoenzymes glucuronidating CCA remain unidentified to date. In this study, the glucuronidation of CCA was screened with pooled human liver microsomes (HLMs) and 7 human recombinant UGT (rUGT) isoforms. Results indicated that rUGT2B7 exhibited the highest catalytical activity for the CCA glucuronidation as measured with a mean V value of 120.9 pmol/min/mg protein, 3- to 12-fold higher than that of the other rUGT isoforms tested. According to relative activity factor approach, the relative contribution of rUGT2B7 to CCA glucuronidation was estimated to be 58.6%, with the minor contributions (3%) from rUGT1A9. Moreover, the glucuronidation of CCA followed Michaelis-Menten kinetics with a mean K value of 372.9 μM and 296.4 μM for pooled HLMs and rUGT2B7, respectively, showing similar affinity for both. The formation of CAG was significantly inhibited by azidothymidine and gemfibrozil (well-characterized UGT2B7 substrates) in a concentration-dependent manner, or by fluconazole (a typical UGT2B7-selective inhibitor) in a time-dependent manner, for both HLMs and rUGT2B7, respectively. In addition, CCA inhibited azidothymidine glucuronidation (catalyzed almost exclusively by UGT2B7) by HLMs and rUGT2B7 in a concentration-dependent manner, indicating that CCA is a substrate of UGT2B7. These results reveal that UGT2B7 is the major enzyme catalyzing clopidogrel glucuronidation in the human liver, and that there is the potential for drug-drug interactions between clopidogrel and the other substrate drugs of UGT2B7.

Quantitative characterization of UDP-glucuronosyltransferase 2B17 in human liver and intestine and its role in testosterone first-pass metabolism

“…In summary, we characterized UGT2B17 in first-pass effect organs, whose role in drug metabolism remains understudied and underappreciated. For example, while one study showed UGT2B17 to be one of the main isoforms responsible for clopidogrel acyl glucuronide (CAG) formation [47], another study did not include this isoform and hence concluded that UGT2B7 forms CAG [48]. In addition, TRT has recently come under scrutiny due to reports of possible increased cardiovascular events, and the risks and benefits of TRT still remain contentious among practitioners [14,49–51].…”

Clopidogrel Increases Dasabuvir Exposure With or Without Ritonavir, and Ritonavir Inhibits the Bioactivation of Clopidogrel

“…About 90% of clopidogrel is hydrolyzed by the polymorphic carboxylesterase 1 (CES1) to a pharmacologically inactive carboxylic acid metabolite, [13][14][15] which is further glucuronized to an acyl-b-D-glucuronide metabolite by uridine 5 0 -diphospho-glucuronosyltransferase (UGT) 2B enzymes. 16,17 The bioactivation of clopidogrel to the pharmacologically active cis-5-thiol metabolite is susceptible to changes in CYP2C19 activity, 18,19 but also CYP3A contributes to clopidogrel activation. For example, grapefruit juice, an inhibitor of CYP3A4 in the gut wall, has impaired the bioactivation of clopidogrel and consequently the inhibition of platelet aggregation.…”

“…Clopidogrel is a prodrug, activated in two steps. About 90% of clopidogrel is hydrolyzed by the polymorphic carboxylesterase 1 (CES1) to a pharmacologically inactive carboxylic acid metabolite, which is further glucuronized to an acyl‐ β ‐D‐glucuronide metabolite by uridine 5′‐diphospho‐glucuronosyltransferase (UGT) 2B enzymes . The bioactivation of clopidogrel to the pharmacologically active cis ‐5‐thiol metabolite is susceptible to changes in CYP2C19 activity, but also CYP3A contributes to clopidogrel activation.…”

Mrp3 Transports Clopidogrel Acyl Glucuronide from the Hepatocytes into Blood

“…CLP-C Is Not an Mrp3 Substrate. Although it is an intermediate metabolite of clopidogrel, CLP-C is glucuronidated to CLP-G principally by UGT2B7 (Ji et al, 2018). In this study, the liver-to-plasma ratio of CLP-C in Abcc3 KO mice was approximately 37% of that in WT mice (Fig.…”