State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing, 210009, China.
State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing, 210009, China.
J Ethnopharmacol. 2022 Oct 28;297:115577. doi: 10.1016/j.jep.2022.115577. Epub 2022 Jul 22.
Psoraleae Fructus (PF), a traditional Chinese medicine, has long been used to treat diseases such as cancer, osteoporosis and leukoderma. Psoralen and isopsoralen are main bioactive ingredients of PF with anti-tumor, anti-inflammatory, estrogen-like neuroprotection, etc., meanwhile they are also representative hepatotoxic components of PF. Hepatic CYP1A2 has been reported to be the important metabolic enzymes involved in psoralen and isopsoralen-induced hepatotoxicity. However, the relationship between the hepatotoxicity and CYP1A2 expression, and the underlying mechanism of regulating CYP1A2 expression remain unclear.
The aim of this study was to explore the associated mechanism between psoralen or isopsoralen induced hepatotoxicity and activated aryl hydrocarbon receptor (AhR)-mediated transcriptional induction of CYP1A2 in vitro and in vivo.
Psoralen and isopsoralen at different doses were treated on HepG2 cells (10, 25, 50, 100, 200 μM for 2, 12, 24, 36, 48 h) and mice (20, 80, 160 mg/kg for 3, 7, 14 days) for different time, to assess the correlation of induced hepatotoxicity and CYP1A2 mRNA and protein expression in vivo and in vitro, as well as the effect on CYP1A2 enzyme activity evaluated by phenacetin metabolism. In addition, the potential mechanism of the regulation of CYP1A2 expression mediated by AhR was explored through nucleocytoplasmic shuttling, immunofluorescence, cellular thermal shift assay and molecular docking, etc. RESULTS: Psoralen and isopsoralen induced cytotoxicity in HepG2 cells, and hepatomegaly, biochemicals disorder and tissue pathological impairment in mice, respectively in dose- and time-dependent manners. Simultaneously accompanied with elevated levels of CYP1A2 mRNA and protein in the same trend, and the CYP1A2 activity was remarkably inhibited in vitro but significantly elevated overall in vivo. Besides, psoralen and isopsoralen bound to AhR and activated translocation of AhR from the cytoplasm to the nucleus, leading to the transcriptional induction of target gene CYP1A2.
Hepatotoxicities in HepG2 cells and mice aroused by psoralen and isopsoralen were related to the induction of CYP1A2 expression and activity, whose underlying mechanism might be psoralen or isopsoralen activated AhR translocation and induced increase of CYP1A2 transcriptional expression. Hopefully, these finding are conductive to propose an alert about the combined usage of psoralen or isopsoralen and AhR ligands or CYP1A2 substrates in clinical practice.
补骨脂（PF）作为一种传统中药，长期以来一直用于治疗癌症、骨质疏松症和白癜风等疾病。补骨脂素和异补骨脂素是 PF 的主要生物活性成分，具有抗肿瘤、抗炎、雌激素样神经保护等作用，同时也是 PF 代表性的肝毒性成分。肝 CYP1A2 已被报道为参与补骨脂素和异补骨脂素诱导肝毒性的重要代谢酶。然而，肝毒性与 CYP1A2 表达之间的关系以及调节 CYP1A2 表达的潜在机制尚不清楚。
本研究旨在探讨补骨脂素或异补骨脂素诱导的肝毒性与体外和体内芳基烃受体（AhR）激活介导的 CYP1A2 转录诱导之间的关联机制。
用不同剂量的补骨脂素和异补骨脂素（10、25、50、100、200μM，2、12、24、36、48h）处理 HepG2 细胞和小鼠（20、80、160mg/kg，3、7、14d），以评估体内和体外诱导的肝毒性与 CYP1A2mRNA 和蛋白表达的相关性，以及通过对乙酰氨基酚代谢评估 CYP1A2 酶活性的影响。此外，通过核质穿梭、免疫荧光、细胞热转移测定和分子对接等方法探讨 AhR 介导的 CYP1A2 表达调节的潜在机制。
补骨脂素和异补骨脂素以剂量和时间依赖性方式诱导 HepG2 细胞毒性，并在小鼠中诱导肝肿大、生化紊乱和组织病理损伤。同时，CYP1A2mRNA 和蛋白水平呈相同趋势升高，体外 CYP1A2 活性显著抑制，而整体体内活性显著升高。此外，补骨脂素和异补骨脂素与 AhR 结合并激活 AhR 从细胞质向细胞核的易位，导致靶基因 CYP1A2 的转录诱导。
补骨脂素和异补骨脂素在 HepG2 细胞和小鼠中引起的肝毒性与 CYP1A2 表达和活性的诱导有关，其潜在机制可能是补骨脂素或异补骨脂素激活 AhR 易位并诱导 CYP1A2 转录表达增加。希望这些发现有助于在临床实践中提出关于补骨脂素或异补骨脂素与 AhR 配体或 CYP1A2 底物联合使用的警示。
