The Role of the Equilibrative Nucleoside Transporter 1 (ENT1) in Transport and Metabolism of Ribavirin by Human and Wild-Type or Ent1(-/-) Mouse Erythrocytes
The Role of the Equilibrative Nucleoside Transporter 1 (ENT1) in Transport and Metabolism of Ribavirin by Human and Wild-Type or Ent1(-/-) Mouse Erythrocytes
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DOI：
10.1124/jpet.108.145854
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发表时间：
2009-04-01
影响因子：
3.5
通讯作者：
Unadkat, Jashvant D.
中科院分区：
文献类型：
--
作者：
Endres, Christopher J.;Moss, Aaron M.;Unadkat, Jashvant D.
极性核苷类药物利巴韦林是慢性丙型肝炎病毒感染的一线治疗药物。人平衡核苷转运蛋白（ENT） 1将利巴韦林转运到红细胞中磷酸化。这些磷酸化的代谢物在红细胞中积累并产生限制剂量的溶血性贫血。在这里，我们检测了利巴韦林在体外和体外的转运和代谢的红细胞分离的人与小鼠的ent1缺失。Ent1（+/+）小鼠红细胞对利巴韦林（2.4 μ M）的摄取（1044 +/- 255 amol/ μ g/10 s）显著高于Ent1（-/-）小鼠（76.48 +/- 11.20 amol/ μ g/10 s）。结果显示，[H-3]利巴韦林可饱和转运（K-m为382 +/- 75.1 μ M）进入Ent1（+/+）小鼠红细胞。我们发现，在小鼠和人红细胞中，经过[h -3]利巴韦林转运（2.5 μ M）和8小时的代谢过程，利巴韦林在红细胞中的浓度迅速（60 s内）达到平衡。然而，利巴韦林的总放射性主要归因于其磷酸化代谢物单磷酸利巴韦林和三磷酸利巴韦林。我们的研究结果使我们能够估计利巴韦林的运输、扩散和代谢清除，并预测利巴韦林磷酸盐在小鼠和人类红细胞中的体内积累。我们对长期给予利巴韦林的红细胞中的利巴韦林的建模表明，利巴韦林在细胞内的积累依赖于ENT1/ ENT1运输和细胞内磷酸化的速率以及磷酸化代谢物的降解。我们预测Ent1（+/+）和Ent1（-/-）小鼠将成为研究Ent1对利巴韦林体内药代动力学和毒性贡献的良好模型。
The polar nucleoside drug ribavirin is front-line treatment for chronic hepatitis C virus infection. The human equilibrative nucleoside transporter (ENT) 1 transports ribavirin into erythrocytes where it is phosphorylated. These phosphorylated metabolites accumulate in the erythrocytes and produce doselimiting hemolytic anemia. Here, we examined the in vitro and ex vivo transport and metabolism of ribavirin by erythrocytes isolated from humans and Ent1-null mice. Ribavirin (2.4 mu M) uptake was significantly higher (1044 +/- 255 amol/mu g/10 s) into erythrocytes from Ent1(+/+) mice compared with that from Ent1(-/-) mice (76.48 +/- 11.20 amol/mu g/10 s). Our results showed a saturable (K-m of 382 +/- 75.1 mu M) transport of [H-3]ribavirin into erythrocytes from Ent1(+/+) mice. We found that ribavirin concentration rapidly (within 60 s) reached equilibrium in erythrocytes using a time course of [H-3] ribavirin transport (2.5 mu M) and metabolism in mouse and human erythrocytes for 8 h. However, total radioactivity of ribavirin was predominantly attributed to the phosphorylated metabolites ribavirin monophosphate and ribavirin triphosphate. Our findings allow us to estimate ribavirin transport, diffusion, and metabolic clearance and to predict in vivo accumulation of ribavirin phosphates in erythrocytes of both mice and humans. Our modeling of ribavirin in erythrocytes on long-term administration of ribavirin suggests that the accumulation of ribavirin inside the cells is dependent on ENT1/Ent1 transport and the rates of intracellular phosphorylation and the degradation of the phosphorylated metabolites. We predict that Ent1(+/+) and Ent1(-/-) mice will serve as excellent models to investigate the contribution of Ent1 to the pharmacokinetics and toxicity of ribavirin in vivo.