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Herbal drug-induced liver injury has been reported worldwide and gained global attention. Thousands of hepatic sinusoidal obstruction syndrome (HSOS) cases have been reported after consumption of herbal medicines and preparations containing pyrrolizidine alkaloids (PAs), which are natural phytotoxins globally distributed. And herbal medicines, such as Gynura japonica, are the current leading cause of PA-induced HSOS. The present study aimed to reveal the mechanism underlying the hepatotoxicity of seneciphylline (Seph), a main PA in G. japonica. Results showed that Seph induced severe liver injury through apoptosis in mice (70 mg/kg Seph, orally) and primary mouse and human hepatocytes (5–50 μM Seph). Further research uncovered that Seph induced apoptosis by disrupting mitochondrial homeostasis, inducing mitochondrial depolarization, mitochondrial membrane potential (MMP) loss, and cytochrome c (Cyt c) release and activating c-Jun N-terminal kinase (JNK). The Seph-induced apoptosis in hepatocytes could be alleviated by Mdivi-1 (50 μM, a dynamin-related protein 1 inhibitor), as well as SP600125 (25 μM, a specific JNK inhibitor) and ZVAD-fmk (50 μM, a general caspase inhibitor). Moreover, the Seph-induced MMP loss in hepatocytes was also rescued by Mdivi-1. In conclusion, Seph induced liver toxicity via activating mitochondrial-mediated apoptosis in mice and primary hepatocytes. Our results provide further information on Seph detoxification and herbal medicines containing Seph such as G. japonica.     

千里光菲灵碱诱导MEK/ERK1/2介导的宫颈癌细胞自噬效应

探讨千里光菲灵碱对人宫颈癌HeLa、Caski细胞增殖、自噬的影响及其可能的作用机制。MTT法检测千里光菲灵碱对HeLa、Caski细胞增殖的影响;免疫荧光法检测GFP-LC3/HeLa和GFP-LC3/Caski两种细胞内自噬体的形成情况;免疫印迹法检测千里光菲灵碱对自噬相关蛋白表达的影响;荧光共定位法检测自噬体与溶酶体的融合情况;建立荷宫颈癌HeLa、Caski细胞移植瘤裸鼠模型,检测千里光菲灵碱对移植瘤生长的抑制作用。结果显示,千里光菲灵碱呈时间和剂量依赖性抑制HeLa、Caski两种宫颈癌细胞的增殖;千里光菲灵碱可诱导HeLa、Caski细胞内自噬体的形成和LC3-II蛋白的增加及P62蛋白的减少,表明千里光菲灵碱可诱导HeLa、Caski细胞发生自噬;与单药千里光菲灵碱相比,千里光菲灵碱联合自噬下游抑制剂氯喹(CQ)显著增加了LC3-II及P62的蛋白表达,同时荧光共定位显示千里光菲灵碱诱导的自噬体可与溶酶体实现共定位,表明千里光菲灵碱可诱导完整自噬流;与单药千里光菲灵碱相比,千里光菲灵碱联合自噬上游抑制3-甲基腺嘌呤(3MA)剂显著增加了LC3-II的蛋白表达,显著降低了HeLa、Caski细胞的存活率,表明抑制自噬可增强千里光菲灵碱对宫颈癌细胞增殖的抑制作用;与单药千里光菲灵碱相比,千里光菲灵碱联合MEK抑制剂显著降低了P-ERK1/2的蛋白表达,减少了自噬体的形成,表明千里光菲灵碱诱导的HeLa、Caski细胞自噬依赖于MEK/ERK1/2途径;另外,千里光菲灵碱可显著抑制宫颈癌细胞裸鼠皮下移植瘤的生长。