Targeting Cellular Squalene Synthase, an Enzyme Essential for Cholesterol Biosynthesis, Is a Potential Antiviral Strategy against Hepatitis C Virus
Targeting Cellular Squalene Synthase, an Enzyme Essential for Cholesterol Biosynthesis, Is a Potential Antiviral Strategy against Hepatitis C Virus
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DOI：
10.1128/jvi.03385-14
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发表时间：
2014-12
影响因子：
5.4
通讯作者：
Kyoko Saito;Yoshitaka Shirasago;Tetsuro Suzuki;H. Aizaki;K. Hanada;T. Wakita;M. Nishijima;M. Fukasawa
中科院分区：
文献类型：
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作者：
Kyoko Saito;Yoshitaka Shirasago;Tetsuro Suzuki;H. Aizaki;K. Hanada;T. Wakita;M. Nishijima;M. Fukasawa
丙型肝炎病毒（HCV）利用宿主膜胆固醇及其代谢产生子代病毒。在这里，我们研究了靶向细胞角鲨烯合成酶（SQS）对丙型肝炎病毒产生的影响，SQS是第一个用于胆固醇生物合成的酶。通过使用HCV JFH-1株和人肝癌huh -7.5.1衍生细胞，我们发现SQS抑制剂YM-53601和zaragozic acid A在HCV感染细胞中降低病毒RNA、蛋白质和子代产量，但不影响细胞活力。同样，小干扰RNA （siRNA）介导的SQS敲低导致HCV产生显著减少，证实了该酶是抗病毒靶点。一项代谢标记研究表明，YM-53601在抗病毒浓度下抑制胆固醇和胆固醇酯的生物合成。与m -53601不同，胆固醇酯化抑制剂Sandoz 58-035没有表现出抗病毒作用，这表明在HCV的产生中，胆固醇的生物合成比胆固醇酯的生物合成更重要。YM-53601抑制JFH-1亚基因组复制子的瞬时复制和JFH-1伪颗粒的进入，表明至少抑制病毒RNA的复制和进入有助于药物的抗病毒作用。总的来说，我们的发现强调了胆固醇生物合成途径在HCV产生中的重要性，并暗示SQS是HCV抗病毒策略的潜在靶点。丙型肝炎病毒（HCV）在整个病毒生命周期中与宿主胆固醇及其代谢密切相关。然而，靶向胆固醇生物合成酶对丙型肝炎病毒产生的影响尚不完全清楚。我们发现角鲨烯合成酶是第一个致力于胆固醇生物合成的酶，对丙型肝炎病毒的产生很重要，我们提出这种酶是潜在的抗丙型肝炎病毒靶点。我们提供的证据表明，在HCV生产中，游离胆固醇的合成比酯化胆固醇的合成更重要，强调了HCV生产对游离胆固醇的显著依赖性。我们的研究结果也为细胞内胆固醇库及其生物合成在HCV生命周期中的作用提供了新的见解。
ABSTRACT Hepatitis C virus (HCV) exploits host membrane cholesterol and its metabolism for progeny virus production. Here, we examined the impact of targeting cellular squalene synthase (SQS), the first committed enzyme for cholesterol biosynthesis, on HCV production. By using the HCV JFH-1 strain and human hepatoma Huh-7.5.1-derived cells, we found that the SQS inhibitors YM-53601 and zaragozic acid A decreased viral RNA, protein, and progeny production in HCV-infected cells without affecting cell viability. Similarly, small interfering RNA (siRNA)-mediated knockdown of SQS led to significantly reduced HCV production, confirming the enzyme as an antiviral target. A metabolic labeling study demonstrated that YM-53601 suppressed the biosynthesis of cholesterol and cholesteryl esters at antiviral concentrations. Unlike YM-53601, the cholesterol esterification inhibitor Sandoz 58-035 did not exhibit an antiviral effect, suggesting that biosynthesis of cholesterol is more important than that of cholesteryl esters for HCV production. YM-53601 inhibited transient replication of a JFH-1 subgenomic replicon and entry of JFH-1 pseudoparticles, suggesting that at least suppression of viral RNA replication and entry contributes to the antiviral effect of the drug. Collectively, our findings highlight the importance of the cholesterol biosynthetic pathway in HCV production and implicate SQS as a potential target for antiviral strategies against HCV. IMPORTANCE Hepatitis C virus (HCV) is known to be closely associated with host cholesterol and its metabolism throughout the viral life cycle. However, the impact of targeting cholesterol biosynthetic enzymes on HCV production is not fully understood. We found that squalene synthase, the first committed enzyme for cholesterol biosynthesis, is important for HCV production, and we propose this enzyme as a potential anti-HCV target. We provide evidence that synthesis of free cholesterol is more important than that of esterified cholesterol for HCV production, highlighting a marked free cholesterol dependency of HCV production. Our findings also offer a new insight into a role of the intracellular cholesterol pool that is coupled to its biosynthesis in the HCV life cycle.