非酒精性脂肪肝致OAT2、ENT1表达下调改变恩替卡韦抗HBV药效研究

Non-alcoholic fatty liver disease (NAFLD) and chronic hepatitis B are the two major liver diseases in the world. In addition to weight management to improve glycolipid metabolism, antiviral therapy is still predominated in patients with hepatitis B complicated by NAFLD. However, the mechanism by which NAFLD affects the efficacy of antivirals against hepatitis B virus (HBV) remains unclear. Entecavir (ETV) is a first-line antiviral drug against HBV, which is positively charged at physiological conditions and relies on the transporter into hepatocytes. Our previous studies indicated that organic anion transporter (OAT) 2 and equilibrative nucleotide transporter (ENT) 1 play a major role in the uptake of ETV by hepatocytes, whereas the expression of mOat2 and mEnt1 in the liver of mouse NAFLD model was repressed. Based on these results, we will demonstrate the effect of NAFLD on the efficacy of ETV both in vitro and in vivo, and elucidate the mechanism of hepatic uptake of ETV mediated by transporter. The aim of this project is to explore the mechanism of decreased efficacy of ETV in NAFLD by clarifying the expression changes of hepatic OAT2 and ENT1 that further affect the ETV distribution in liver. The information obtained in this study may provide a basis for the use of ETV in patients with hepatitis B complicated by NAFLD.

非酒精性脂肪肝（NAFLD）和慢性乙型肝炎是全球两大主要肝病。目前，合并NAFLD的乙肝患者，除控制体重改善糖脂代谢外，仍以抗病毒药物治疗为主，但NAFLD状态下抗乙肝药物药效变化的机制研究尚不明确。恩替卡韦（ETV）是最主要抗乙肝药物，体内以离子形式存在，依赖转运体进入肝细胞发挥药效。我们的前期研究结果提示肝脏有机阴离子转运体（OAT）2和平衡性核苷转运体（ENT）1在肝细胞摄取ETV中发挥主要作用，且NAFLD模型小鼠肝脏mOat2、mEnt1表达下调。本项目将在此基础上，从细胞和整体动物水平证实NAFLD对ETV药效的影响，多角度阐明转运体介导的ETV肝摄取机制，通过研究NAFLD对肝OAT2、ENT1表达的调控进而改变ETV肝组织分布及药代动力学，探究NAFLD影响ETV药效的机制。本研究为提高合并NAFLD慢性乙型肝炎患者的ETV药效提供理论依据与指导。

非酒精性脂肪肝（NAFLD）和慢性乙型肝炎是全球流行的主要肝病。对于合并NAFLD的乙肝患者，抗病毒药物治疗仍是其主要治疗手段，但NAFLD状态下抗乙肝药物药效变化及其分子机制研究尚不明确。恩替卡韦（ETV）是最主要的治疗慢性乙型肝炎的药物，因极性较大，无法通过被动扩散进入肝细胞，转运体介导的主动转运是ETV发挥药效的关键。本项目系统阐释了转运体介导的ETV肝脏摄取分子机制，发现有机阴离子转运体2（OAT2）和平衡型核酸转运体1（ENT1）是介导ETV肝脏摄取的主要转运体，其表达或活性的改变影响ETV的肝细胞内浓度和体外抗HBV活性。此外，细胞水平上，棕榈酸刺激HepG2细胞后减少ETV在细胞内的积聚。高脂饲料喂养（HFD）的小鼠ETV的血浆暴露水平显著高于对照组，HFD小鼠肝脏OAT2蛋白表达显著下调，但ETV在两组小鼠肝脏的分布不变，提示NAFLD减少OAT2介导的ETV肝摄取可能被血浆ETV暴露增多所抵消，因此，NAFLD可能对ETV抗病毒疗效影响较小。本研究为ETV肝脏发挥抗病毒作用提供分子基础，为基于OAT2、ENT1的ETV相关药物药物相互作用预测提供基础，也为临床慢性乙型肝炎合并NAFLD患者的合理用药提供支持。