A Humanized UGT1 Mouse Model Expressing the UGT1A1*28 Allele for Assessing Drug Clearance by UGT1A1-Dependent Glucuronidation
A Humanized UGT1 Mouse Model Expressing the UGT1A1*28 Allele for Assessing Drug Clearance by UGT1A1-Dependent Glucuronidation
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DOI：
10.1124/dmd.109.030130
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发表时间：
2010-05-01
影响因子：
3.9
通讯作者：
Stevens, Jeffrey C.
中科院分区：
文献类型：
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作者：
Cai, Hongliang;Nguyen, Nghia;Stevens, Jeffrey C.
表达人 UDP-葡萄糖醛酸基转移酶 (UGT) 1 位点的人源化小鼠已在 Ugt1 缺失的背景下开发出来，作为模型来改善对人 UGT1A 依赖性药物清除的预测。使用表达吉尔伯特 UGT1A1*28 等位基因的野生型和人源化 UGT1 小鼠 [Tg(UGT1(A1)*(28)) Ugt1(-/-) 小鼠] 比较三种探针药物的酶动力学参数（K-m 和 V-max）和药代动力学特性。充分表征的 UGT1A1 底物 7-乙基-10-羟基喜树碱 (SN-38)，与野生型和苯巴比妥治疗的动物相比，静脉注射后 Tg(UGT1(A1)*(28)) Ugt1(-/-) 小鼠的母体药物暴露（类似于 3 倍增加）和清除（类似于 3 倍减少）显示出最大差异。相反，在 Tg(UGT1(A1)*(28)) Ugt1(-/-) 小鼠中，UGT2B7 底物 (-)-17-allyl-4, 5 alpha-epoxy-3, 14-diHydroxymorphinan-6-one（纳洛酮）的清除率没有改变。此外，被认为是 UGT1A1 主要底物的 1-(4-氟苯基)3(R)-[3-(4-氟苯基)3(S)-羟丙基]-4(S)-(4-羟苯基)-2-氮杂环丁酮 (ezetimibe, Zetia; Merck & Co., Whitehouse Station, NJ) 的药代动力学参数显示出对 UGT1A1 指导的葡萄糖醛酸化作用的依赖性很小甚至没有。使用野生型和 Tg(UGT1(A1)*(28)) Ugt1(-/-) 小鼠制备的肝微粒体评估 SN-38、依折麦布和纳洛酮的酶动力学参数，显示出与体内药代动力学数据一致的模式。对于 SN-38 葡萄糖醛酸化，与野生型小鼠制备的微粒体相比，Tg(UGT1(A1)*(28)) Ugt1(-/-) 小鼠肝微粒体中的 Vmax 降低了 5 倍，与苯巴比妥处理的 Tg(UGT1(A1)*(28)) Ugt1(-/-) 小鼠相比，Vmax 降低了 10 倍。这些差异与使用从基因型为 UGT1A1*1 或 UGT1A1*28 的个体分离的 HLM 进行的 SN-38 葡萄糖醛酸化活性一致。对于依折麦布和纳洛酮，Vmax 的差异很小。因此，Tg(UGT1(A1)*(28)) Ugt1(-/-)小鼠可以作为药代动力学模型，进一步研究UGT1A1表达对药物代谢的影响。
Humanized mice that express the human UDP-glucuronosyltransferase (UGT) 1 locus have been developed in a Ugt1-null background as a model to improve predictions of human UGT1A-dependent drug clearance. Enzyme kinetic parameters (K-m and V-max) and pharmacokinetic properties of three probe drugs were compared using wild-type and humanized UGT1 mice that express the Gilbert's UGT1A1*28 allele [Tg(UGT1(A1)*(28)) Ugt1(-/-) mice]. The well characterized substrate for UGT1A1, 7-ethyl-10-hydroxycamptothecin (SN-38), showed the greatest difference in parent drug exposure (similar to 3-fold increase) and clearance (similar to 3-fold decrease) in Tg(UGT1(A1)*(28)) Ugt1(-/-) mice after intravenous administration compared with wild-type and phenobarbital-treated animals. In contrast, the clearance of the UGT2B7 substrate (-)-17-allyl-4, 5 alpha-epoxy-3, 14-dihydroxymorphinan-6-one (naloxone) was not altered in Tg(UGT1(A1)*(28)) Ugt1(-/-) mice. In addition, pharmacokinetic parameters with 1-(4-fluorophenyl)3(R)-[3-(4-fluorophenyl)3(S)-hydroxypropyl]-4(S)-(4-hydroxyphenyl)-2-azetidinone (ezetimibe, Zetia; Merck & Co., Whitehouse Station, NJ), considered to be a major substrate for UGT1A1, showed small to no dependence on UGT1A1-directed glucuronidation. Enzyme kinetic parameters assessed for SN-38, ezetimibe, and naloxone using liver microsomes prepared from wild-type and Tg(UGT1(A1)*(28)) Ugt1(-/-) mice showed patterns consistent with the in vivo pharmacokinetic data. For SN-38 glucuronidation, Vmax decreased 5-fold in Tg(UGT1(A1)*(28)) Ugt1(-/-) mouse liver microsomes compared with microsomes prepared from wild-type mice, and decreased 10-fold compared with phenobarbital-treated Tg(UGT1(A1)*(28)) Ugt1(-/-) mice. These differences are consistent with SN-38 glucuronidation activities using HLMs isolated from individuals genotyped as UGT1A1*1 or UGT1A1*28. For ezetimibe and naloxone the differences in Vmax were minimal. Thus, Tg(UGT1(A1)*(28)) Ugt1(-/-) mice can serve as a pharmacokinetic model to further investigate the effects of UGT1A1 expression on drug metabolism.