Dexamethasone-induced methylprednisolone hemisuccinate hydrolase: Its identification as a member of the rat carboxylesterase 2 family and its unique existence in plasma
Dexamethasone-induced methylprednisolone hemisuccinate hydrolase: Its identification as a member of the rat carboxylesterase 2 family and its unique existence in plasma
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DOI：
10.1016/j.bcp.2005.01.017
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发表时间：
2005-04-15
影响因子：
5.8
通讯作者：
Chiba, K
中科院分区：
文献类型：
--
作者：
Furihata, T;Hosokawa, M;Chiba, K
羧酸酯酶（CES）在许多酯类药物的代谢中发挥着重要作用。在本研究中，我们鉴定并表征了大鼠肝微粒体中地塞米松诱导的甲基泼尼松龙半琥珀酸（MPHS）水解酶。腹腔注射地塞米松导致 MPHS 水解酶活性水平显着增加，同时诱导特定的 CES 同工酶。由于诱导的 CES 同工酶的生化特征与大鼠 CES RL4 的生化特征非常相似，因此我们假设它们是相同的酶。纳米电喷雾电离串联质谱分析结果表明，地塞米松诱导的 CES 同工酶和 CES RL4 均具有与大鼠 CES2 同工酶 AB010635 相同的肽片段，支持了我们的假设。此外，逆转录聚合酶链式反应结果显示，地塞米松处理的肝脏中ABO10635 mRNA的量高于对照肝脏。为了证实ABO10635编码地塞米松诱导的CES同工酶，进行了cDNA克隆，并使用杆状病毒介导的表达系统在SO细胞中表达获得的cDNA。重组CES蛋白可以水解MPHS并表现出与CES RL4相似的生化特性。总的来说，结果表明肝微粒体中地塞米松诱导的 MPHS 水解酶是大鼠 CES2 同工酶。有趣的是，结果还表明，这种大鼠CES2同工酶存在于血浆中，并且这种蛋白质的量会因地塞米松而增加。这些发现与上述发现一起，为酯类药物的药代动力学和药效学研究以及CESs的研究提供了重要信息。 (c) 2005 Elsevier Inc. 保留所有权利。
Carboxylesterases (CESs) play important roles in the metabolism of many ester-drugs. In the present study, we identified and characterized dexamethasone-induced methylprednisolone hemisuccinate (MPHS) hydrolase in rat liver microsomes. Intraperitoneal injection of dexamethasone resulted in a significant increase in the level of MPHS hydrolase activity accompanied by induction of a specific CES isozyme. Since the biochemical characteristics of the induced CES isozyme were very similar to those of rat CES RL4, we hypothesized that these were the same enzymes. The results of nano-electrospray ionization tandem mass spectrometry analysis revealed that both dexamethasone-induced CES isozyme and CES RL4 possessed identical peptide fragments to those of AB010635, a rat CES2 isozyme, supporting our hypothesis. Furthermore, the results of reverse transcription-polymerase chain reaction showed that the amount of ABO10635 mRNA in dexamethasone-treated liver was greater than that in control liver. To confirm that ABO10635 encodes dexamethasone-induced CES isozyme, cDNA cloning was performed and the obtained cDNA was expressed in SO cells by using a baculovirus-mediated expression system. The recombinant CES protein could hydrolyze MPHS and exhibited biochemical characteristics similar to those of CES RL4. Collectively, the results indicated that dexamethasone-induced MPHS hydrolase in liver microsomes is a rat CES2 isozyme. Interestingly, the results also showed that this rat CES2 isozyme exists in plasma and that the amount of this protein is increased by dexamethasone. These findings, together with the findings described above, provide important information for the study of phramacokinetics and pharmacodynamics of ester-drugs as well as for the study of CESs. (c) 2005 Elsevier Inc. All rights reserved.