Catalpol coordinately regulates phase I and II detoxification enzymes of Triptolide through CAR and NRF2 pathways to reduce Triptolide-induced hepatotoxicity
Catalpol coordinately regulates phase I and II detoxification enzymes of Triptolide through CAR and NRF2 pathways to reduce Triptolide-induced hepatotoxicity
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梓醇通过 CAR 和 NRF2 途径协调调节雷公藤甲素 I 相和 II 相解毒酶，降低雷公藤甲素诱导的肝毒性
DOI：
10.1016/j.biopha.2020.110379
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发表时间：
2020-09-01
影响因子：
7.5
通讯作者：
Zhou, Xueping
中科院分区：
文献类型：
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作者：
Fu, Ling;Zhou, Lingling;Zhou, Xueping
雷公藤甲素(TP)作为雷公藤(TW)的主要成分，在发挥治疗作用时可引起明显的肝损伤。然而，在我们之前的研究中，地黄 (RG) 的主要活性成分梓醇 (CAT) 被证明可以提高 TP 的药物清除率并减轻 TP 引起的肝毒性。因此本研究旨在探讨TP解毒过程中I、II相代谢酶和核受体的作用，分析CAT减轻肝毒性的机制。为此，我们的研究中选择了SD大鼠和人肝细胞系L-02和HepG2细胞，并用TP或TP和CAT的组合进行处理。分析CAT对TP解毒的影响，评价I相代谢酶细胞色素P450 3A2/4（CYP3A2/4）和II相代谢酶UDP-葡萄糖醛酸基转移酶1A6（UGT1A6）的作用及其相关核受体调节。结果发现TP抑制CYP3A2/4的转录。并且通过组成型雄甾烷受体（CAR）途径，CAT不仅显着改变了这种抑制作用，增加了CYP3A2/4的表达，还增加了CYP2C9的表达，这两者都是TP的I相解毒酶。并且通过基因沉默实验，证实了这种调控是CAR依赖性的。我们还发现，CAR沉默后，CAT仍能继续发挥一定的保护作用，TP的II相解毒酶UGT1A6被显着诱导。这与核因子红细胞2相关因子2（NRF2）通路的转录调控增强密切相关。总之，我们的结果表明，当CAR被强烈抑制时，CAT可以通过CAR途径诱导TP的I期解毒酶CYP3A2/4和CYP2C9，并通过NRF2途径诱导TP的II期解毒酶UGT1A6。而CAT的这种协调调控可能是CAT提高TP代谢转化、降低TP肝毒性作用的重要来源。
Triptolide (TP), as the main component of Tripterygium Wilfordii (TW), can induce obvious liver injury when exerting the therapeutic effect. However, in our previous study, Catalpol (CAT), the main active ingredient of Rehmannia Glutinosa (RG), was shown to increase the drug clearance rate of TP and to attenuate TP-induced hepatotoxicity. Thus the present study aims to address the roles of phase I and II metabolic enzymes and the nuclear receptors in the detoxification process of TP, to analyze the mechanism of CAT reducing hepatotoxicity. For this purpose, SD rats and human liver cell line L-02 and HepG2 cells were selected, and treated with TP or the combination of TP and CAT in our study. Then the effect of CAT on detoxification of TP was analyzed, and the roles of phase I metabolic enzymes cytochrome P450 3A2/4 (CYP3A2/4) and phase II metabolic enzyme UDP-glucuronosyltransferase 1A6 (UGT1A6) and their related nuclear receptor regulations were evaluated. It was found that TP inhibited the transcription of CYP3A2/4. And through the constitutive androstane receptor (CAR) pathway, CAT not only significantly changed this inhibition and increased the expression of CYP3A2/4 but also increased the expression of CYP2C9, both of which are phase I detoxification enzymes of TP. And with the gene-silenced experiment, it was confirmed that this regulation was CAR-dependent. We also found that CAT could continue to exert a certain protective effect after CAR was silenced, with UGT1A6, the phase II detoxification enzyme of TP, significantly induced. And this was closely related to the enhanced transcriptional regulation of the nuclear factor erythroid 2-related factor 2 (NRF2) pathway. In conclusion, our results reveal that CAT can induce TP's phase I detoxification enzymes CYP3A2/4 and CYP2C9 through the CAR pathway, and induce TP's phase II detoxification enzyme UGT1A6 via the NRF2 pathway when CAR is strongly inhibited. And this coordinate regulation of CAT may be an important source of the effect for CAT to increase TP metabolic conversion and reduce TP hepatotoxicity.