Human UGT2B7 is the major isoform responsible for the glucuronidation of clopidogrel carboxylate
Human UGT2B7 is the major isoform responsible for the glucuronidation of clopidogrel carboxylate
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人 UGT2B7 是负责羧酸氯吡格雷葡萄糖醛酸化的主要亚型
DOI：
10.1002/bdd.2117
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发表时间：
2018-02-01
影响因子：
2.1
通讯作者：
Xie, Hong-Guang
中科院分区：
文献类型：
--
作者：
Ji, Jin-Zi;Huang, Bei-Bei;Xie, Hong-Guang
氯吡格雷主要被羧酸酯酶1水解为氯吡格雷羧酸(CCA)，随后CCA被尿苷二磷酸-葡萄糖醛酸基转移酶(UGT)葡萄糖醛酸化为氯吡格雷酰基葡萄糖醛酸化物(CAG)；然而，迄今为止，CCA 葡萄糖醛酸化的 UGT 同工酶仍未得到鉴定。在这项研究中，利用汇集的人肝微粒体 (HLM) 和 7 种人重组 UGT (rUGT) 亚型筛选了 CCA 的葡萄糖醛酸化。结果表明，rUGT2B7 对 CCA 葡萄糖醛酸化表现出最高的催化活性，平均 V-max 值为 120.9pmol/min/mg 蛋白质，比其他测试的 rUGT 亚型高 3 至 12 倍。根据相对活性因子方法，rUGT2B7 对 CCA 葡萄糖醛酸化的相对贡献估计为 58.6%，rUGT1A9 的贡献较小（3%）。此外，CCA 的葡萄糖醛酸化遵循 Michaelis-Menten 动力学，对于混合的 HLM 和 rUGT2B7，平均 K-m 值分别为 372.9M 和 296.4M，显示出对两者相似的亲和力。对于 HLM 和 rUGT2B7，叠氮胸苷和吉非贝齐（已充分表征的 UGT2B7 底物）以浓度依赖性方式显着抑制 CAG 的形成，或者以时间依赖性方式被氟康唑（典型的 UGT2B7 选择性抑制剂）显着抑制。此外，CCA 以浓度依赖性方式抑制 HLM 和 rUGT2B7 的叠氮胸苷葡萄糖醛酸化（几乎完全由 UGT2B7 催化），表明 CCA 是 UGT2B7 的底物。这些结果表明UGT2B7是人肝脏中催化氯吡格雷葡萄糖醛酸化的主要酶，并且氯吡格雷与UGT2B7的其他底物药物之间存在药物相互作用的潜力。
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-max value of 120.9pmol/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-m value of 372.9M and 296.4M 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.