Department of Pharmacology, Toxicology, and Therapeutics, The University of Kansas Medical Center, Kansas City, Kansas 66160, USA.
Toxicol Sci. 2011 Jan;119(1):233-43. doi: 10.1093/toxsci/kfq327. Epub 2010 Oct 25.
Alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury causes tissue factor (TF)-dependent coagulation in mice, and TF deficiency reduces ANIT-induced liver injury. However, the mechanism whereby TF contributes to hepatotoxicity in this model is not known. Utilizing pharmacological and genetic strategies, we evaluated the contribution of fibrinogen and two distinct receptors for thrombin, protease-activated receptor-1 (PAR-1) and PAR-4, in a model of acute ANIT hepatotoxicity. ANIT administration (60 mg/kg, po) caused a marked induction of the genes encoding the three fibrinogen chains (α, β, and γ) in liver, an increase in plasma fibrinogen, and concurrent deposition of thrombin-cleaved fibrin in liver. Partial depletion of circulating fibrinogen with ancrod did not impact ANIT hepatotoxicity. However, complete fibrin(ogen) deficiency significantly reduced serum alanine aminotransferase activity and hepatocellular necrosis in ANIT-treated mice. ANIT-induced hepatocellular necrosis was similar in PAR-1(-/-) mice compared with PAR-1(+/+) mice. Interestingly, the progression of ANIT-induced hepatocellular necrosis was significantly reduced in PAR-4(-/-) mice and by administration of an inhibitory PAR-4 pepducin (P4Pal-10, 0.5 mg/kg, sc) to wild-type mice 8 h after ANIT treatment. Interestingly, a distinct lesion, parenchymal-type peliosis, was also observed in PAR-4(-/-) mice treated with ANIT and in mice that were given P4Pal-10 prior to ANIT administration. The results suggest that fibrin(ogen), but not PAR-1, contributes to the progression of ANIT hepatotoxicity in mice. Moreover, the data suggest a dual role for PAR-4 in ANIT hepatotoxicity, both mediating an early protection against peliosis and contributing to the progression of hepatocellular necrosis.
α-萘基异硫氰酸酯（ANIT）诱导的胆汁淤积性肝损伤可导致小鼠组织因子（TF）依赖性凝血，TF 缺乏可减轻 ANIT 诱导的肝损伤。然而，TF 如何促进该模型中的肝毒性尚不清楚。我们利用药理学和遗传学策略，评估了纤维蛋白原和两种不同的凝血酶受体，即蛋白酶激活受体-1（PAR-1）和 PAR-4，在急性 ANIT 肝毒性模型中的作用。给予 ANIT（60mg/kg，po）可显著诱导肝脏中三种纤维蛋白原链（α、β和γ）的基因表达，增加血浆纤维蛋白原，并在肝脏中同时沉积凝血酶切割的纤维蛋白。用Ancrod 部分耗尽循环纤维蛋白原不会影响 ANIT 的肝毒性。然而，完全纤维蛋白（原）缺乏可显著降低 ANIT 处理小鼠的血清丙氨酸氨基转移酶活性和肝细胞坏死。与 PAR-1(+/+)小鼠相比，PAR-1(-/-)小鼠的 ANIT 诱导的肝细胞坏死相似。有趣的是，在 PAR-4(-/-)小鼠中，以及在 ANIT 处理后 8 小时给予抑制性 PAR-4 pepducin（P4Pal-10，0.5mg/kg，sc）的野生型小鼠中，ANIT 诱导的肝细胞坏死的进展明显减少。有趣的是，在接受 ANIT 治疗的 PAR-4(-/-)小鼠中，以及在给予 P4Pal-10 之前接受 ANIT 治疗的小鼠中，也观察到了一种不同的病变，实质型血窦扩张。结果表明，纤维蛋白原（原）而不是 PAR-1，有助于小鼠 ANIT 肝毒性的进展。此外，数据表明 PAR-4 在 ANIT 肝毒性中具有双重作用，既介导对血窦扩张的早期保护，又有助于肝细胞坏死的进展。
