Mounce Bryan C, Cesaro Teresa, Vlajnić Lea, Vidiņa Anna, Vallet Thomas, Weger-Lucarelli James, Passoni Gabriella, Stapleford Kenneth A, Levraud Jean-Pierre, Vignuzzi Marco
Institut Pasteur, Viral Populations and Pathogenesis Unit, CNRS UMR 3569, Paris, France.
Institut Pasteur, Macrophages and Development of Immunity Unit, CNRS UM3738, Paris, France.
J Virol. 2017 Jul 12;91(15). doi: 10.1128/JVI.00344-17. Print 2017 Aug 1.
Polyamines, which are small positively charge molecules present in all cells, play important roles in the replication of DNA and RNA viruses. Chikungunya virus (CHIKV) relies on polyamines for translation of the viral genome upon viral entry, and pharmacological depletion of polyamines limits viral replication. However, the potential development of antiviral resistance necessitates a better understanding of how polyamines function and can be targeted via compounds that alter polyamine levels. We have isolated CHIKV that is resistant to polyamine depletion and contains two mutations in the nonstructural protein 1 (nsP1)-coding region in combination with a mutation to the opal stop codon preceding nsP4. These mutations, in addition to promoting viral replication in polyamine-depleted cells, confer enhanced viral replication and The nsP1 mutations enhance membrane binding and methyltransferase activities, while the stop codon mutation allows increased downstream translation. These mutations, when combined, enhance viral fitness, but individual mutants are attenuated in mosquitoes. Together, our results suggest that CHIKV can evolve resistance to polyamine depletion and that pharmaceuticals targeting the polyamine biosynthetic pathway may be best used in combination with other established antivirals to mitigate the development of resistance. Chikungunya virus is a mosquito-borne virus that has infected millions worldwide. Its expansion into the Americas and rapid adaptation to new mosquito hosts present a serious threat to human health, which we can combat with the development of antiviral therapies as well as understanding how these viruses will mutate when exposed to antiviral therapies. Targeting polyamines, small positively charged molecules in the cell, may be a potential strategy against RNA viruses, including chikungunya virus. Here, we have described a virus that is resistant to polyamine depletion and has increased fitness in cells and in full organisms. Mutations in viral genome capping machinery, membrane binding activity, and a stop codon arise, and their altered activities enhance replication in the absence of polyamines. These results highlight strategies by which chikungunya virus can overcome polyamine depletion and emphasize continued research on developing improved antiviral therapies.
多胺是存在于所有细胞中的带正电荷的小分子，在DNA和RNA病毒的复制中发挥重要作用。基孔肯雅病毒（CHIKV）在病毒进入时依赖多胺来翻译病毒基因组，多胺的药理学耗竭会限制病毒复制。然而，抗病毒耐药性的潜在发展需要更好地了解多胺的功能以及如何通过改变多胺水平的化合物来靶向多胺。我们分离出了对多胺耗竭具有抗性的CHIKV，其在非结构蛋白1（nsP1）编码区域含有两个突变，并与nsP4之前的乳白终止密码子发生突变相结合。这些突变除了促进病毒在多胺耗竭的细胞中复制外，还赋予病毒增强的复制能力，并且nsP1突变增强了膜结合和甲基转移酶活性，而终止密码子突变则允许增加下游翻译。这些突变组合在一起时会增强病毒适应性，但单个突变体在蚊子中会减弱。总之，我们的结果表明CHIKV可以进化出对多胺耗竭的抗性，针对多胺生物合成途径的药物可能最好与其他已确立的抗病毒药物联合使用，以减轻耐药性的发展。基孔肯雅病毒是一种蚊媒病毒，已感染全球数百万人。它向美洲的扩张以及对新蚊子宿主的快速适应对人类健康构成严重威胁，我们可以通过开发抗病毒疗法以及了解这些病毒在接触抗病毒疗法时将如何突变来应对这一威胁。靶向细胞中带正电荷的小分子多胺可能是对抗包括基孔肯雅病毒在内的RNA病毒的潜在策略。在这里，我们描述了一种对多胺耗竭具有抗性且在细胞和完整生物体中适应性增强的病毒。病毒基因组封盖机制、膜结合活性和一个终止密码子发生突变，它们改变的活性增强了在缺乏多胺情况下的复制。这些结果突出了基孔肯雅病毒可以克服多胺耗竭的策略，并强调了继续开展研究以开发改进的抗病毒疗法的重要性。
