Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8675, Japan.
Arch Toxicol. 2019 Jun;93(6):1573-1584. doi: 10.1007/s00204-019-02454-1. Epub 2019 Apr 16.
Early hepatocyte death occurs in most liver injury cases and triggers liver inflammation, which in combination with other risk factors leads to the development of liver disease. However, the pathogenesis of early phase hepatocyte death remains poorly understood. Here, C57BL/6J mice were treated with the hepatotoxic drug flucloxacillin (FLUX) and the toll-like receptor 9 agonist CpG oligodeoxynucleotide (ODN) to reproduce the early phase of drug-induced hepatotoxicity and investigate its pathogenesis. C57BL/6J mice were treated with FLUX (100 mg/kg, gavage) alone or in combination with ODN (40 μg/mouse, intraperitoneally). Plasma alanine aminotransferase (ALT) level was measured as a marker of hepatotoxicity. FLUX or ODN alone was insufficient to induce ALT elevation, whereas combination treatment with FLUX and ODN increased ALT levels 24 h after FLUX treatment and upregulated Fas ligand in natural killer T (NKT) cells and Fas in hepatocytes. FLUX induced mitochondrial permeability transition (MPT), and pretreatment with ODN sensitized mitochondria to FLUX-induced MPT. The increase in ALT levels induced by ODN and FLUX co-treatment was suppressed in Fas ligand (gld/gld)-deficient mice and in mice deficient in a component of MPT pore opening (cyclophilin D-knockout mice). These results suggested that ODN activated the Fas/Fas ligand-mediated pathway in NKT cells and hepatocytes, which may predispose to FLUX-induced mitochondrial dysfunction and lead to early phase hepatocyte apoptosis. Taken together, these findings elucidate a potentially novel mechanism underlying drug-induced early phase hepatocyte death related to the Fas/Fas ligand death receptor pathway and mitochondrial dysfunction.
早期肝细胞死亡发生在大多数肝损伤病例中，并引发肝脏炎症，这与其他风险因素一起导致肝病的发展。然而，早期肝细胞死亡的发病机制仍知之甚少。在这里，使用肝毒性药物氟氯西林（FLUX）和 Toll 样受体 9 激动剂 CpG 寡脱氧核苷酸（ODN）处理 C57BL/6J 小鼠，以重现药物诱导的肝毒性的早期阶段，并研究其发病机制。用 FLUX（100mg/kg，灌胃）单独或与 ODN（40μg/只，腹腔内注射）联合处理 C57BL/6J 小鼠。血浆丙氨酸氨基转移酶（ALT）水平被用作肝毒性的标志物。FLUX 或 ODN 单独处理不足以诱导 ALT 升高，而 FLUX 和 ODN 联合处理在 FLUX 处理后 24 小时增加 ALT 水平，并上调自然杀伤 T（NKT）细胞中的 Fas 配体和肝细胞中的 Fas。FLUX 诱导线粒体通透性转换（MPT），而 ODN 预处理使线粒体对 FLUX 诱导的 MPT 敏感。在 Fas 配体（gld/gld）缺陷型小鼠和 MPT 孔开放成分（亲环素 D 敲除小鼠）缺陷型小鼠中，ODN 和 FLUX 共同处理诱导的 ALT 水平升高受到抑制。这些结果表明，ODN 激活了 NKT 细胞和肝细胞中的 Fas/Fas 配体介导的途径，这可能使 FLUX 诱导的线粒体功能障碍和早期肝细胞凋亡易于发生。总之，这些发现阐明了 Fas/Fas 配体死亡受体途径和线粒体功能障碍与药物诱导的早期肝细胞死亡相关的潜在新机制。
