Autophagy inhibition due to thymidine analogues as novel mechanism leading to hepatocyte dysfunction and lipid accumulation
Autophagy inhibition due to thymidine analogues as novel mechanism leading to hepatocyte dysfunction and lipid accumulation
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DOI：
10.1097/qad.0b013e32835804f9
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发表时间：
2012-10-23
期刊：
影响因子：
3.8
通讯作者：
Behrens, Georg M. N.
中科院分区：
文献类型：
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作者：
Stankov, Metodi V.;Panayotova-Dimitrova, Diana;Behrens, Georg M. N.
目的：核苷类逆转录酶抑制剂（NRTI）长期暴露可导致微泡性脂肪变性。我们假设胸苷类似物可能会干扰肝细胞中的自噬，这是一种与细胞存活和肝细胞脂质代谢调节有关的溶酶体降解途径。设计：使用HepG2和HUH7细胞系和原代人肝细胞，我们对NRTI介导的自噬作用进行了全面分析。采用荧光显微镜、电镜、免疫印迹和流式细胞术分析齐多夫定（ZDV）、司他夫定（d4T）和拉米夫定（3TC）对细胞自噬的影响。对肝细胞自噬的影响与细胞活力、线粒体功能障碍和细胞内脂质积聚有关。结果：ZDV和d4T，但不是3TC，以剂量依赖性和时间依赖性方式显著抑制组成性自噬活性和刺激性自噬活性。在治疗药物浓度下抑制自噬导致功能障碍的线粒体的积累、增加的ROS产生、增加的凋亡、减少的增殖和增加的细胞内脂质积累。这些NRTI的影响可以很容易地通过药理学和遗传抑制肝细胞自噬。结论：我们的数据表明，胸苷类似物抑制肝细胞自噬，这反过来又导致增加ROS的产生，脂质积累和肝功能障碍。这种新的机制可能导致HIV感染患者的非酒精性脂肪肝。(C)2012威科健康垂直酒吧Lippincott威廉姆斯& Wilkins
Objectives: Prolonged nucleoside reverse transcriptase inhibitors (NRTI) exposure can lead to microvesicular steatosis. We hypothesized that thymidine analogues might interfere with autophagy in hepatocytes, a lysosomal degradation pathway implicated in cell survival and regulation of hepatocyte lipid metabolism.Design: Using HepG2 and HUH7 cell lines and primary human hepatocytes, we performed a comprehensive analysis of NRTI-mediated effects on autophagy.Methods: The impact of zidovudine (ZDV), stavudine (d4T) and lamivudine (3TC) on constitutive and induced autophagy was analyzed by fluorescent and electron microscopy, western blotting and flow cytometry. Effects on hepatocyte autophagy were correlated to cellular viability, mitochondrial dysfunction and intracellular lipid accumulation.Results: ZDV and d4T, but not 3TC, significantly inhibited both constitutive as well as stimulated autophagic activity in a dose-dependent and time-dependent manner. Inhibition of autophagy at therapeutic drug concentrations led to accumulation of dysfunctional mitochondria, increased ROS production, increased apoptosis, decreased proliferation and increased intracellular lipid accumulation. These NRTI effects could be readily resembled by pharmacological and genetic inhibition of hepatocyte autophagy.Conclusion: Our data suggest that thymidine analogues inhibit autophagy in hepatocytes, which in turn leads to increased ROS production, lipid accumulation and hepatic dysfunction. This novel mechanism could contribute to nonalcoholic fatty liver disease in HIV-infected patients. (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins