Unidad de Medicina Molecular, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, 02008 Albacete, Spain.
ZOOVIR, Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28040 Madrid, Spain.
Viruses. 2021 May 12;13(5):896. doi: 10.3390/v13050896.
Arthropod-borne flaviviruses, such as Zika virus (ZIKV), Usutu virus (USUV), and West Nile virus (WNV), are a growing cause of human illness and death around the world. Presently, no licensed antivirals to control them are available and, therefore, search for broad-spectrum antivirals, including host-directed compounds, is essential. The PI3K/Akt pathway controls essential cellular functions involved in cell metabolism and proliferation. Moreover, Akt has been found to participate in modulating replication in different viruses including the flaviviruses. In this work we studied the interaction of flavivirus NS5 polymerases with the cellular kinase Akt. In vitro NS5 phosphorylation experiments with Akt showed that flavivirus NS5 polymerases are phosphorylated and co-immunoprecipitate by Akt. Polymerase activity assays of Ala- and Glu-generated mutants for the Akt-phosphorylated residues also indicate that Glu mutants of ZIKV and USUV NS5s present a reduced primer-extension activity that was not observed in WNV mutants. Furthermore, treatment with Akt inhibitors (MK-2206, honokiol and ipatasertib) reduced USUV and ZIKV titers in cell culture but, except for honokiol, not WNV. All these findings suggest an important role for Akt in flavivirus replication although with specific differences among viruses and encourage further investigations to examine the PI3K/Akt/mTOR pathway as an antiviral potential target.
虫媒黄病毒，如寨卡病毒（ZIKV）、乌苏图病毒（USUV）和西尼罗河病毒（WNV），是目前全球导致人类疾病和死亡的一个日益严重的原因。目前，尚无针对这些病毒的许可抗病毒药物，因此，寻找广谱抗病毒药物，包括宿主定向化合物，是至关重要的。PI3K/Akt 通路控制着细胞代谢和增殖所涉及的基本细胞功能。此外，已经发现 Akt 参与调节不同病毒（包括黄病毒）的复制。在这项工作中，我们研究了黄病毒 NS5 聚合酶与细胞激酶 Akt 的相互作用。体外 Akt 与 NS5 的磷酸化实验表明，黄病毒 NS5 聚合酶可被 Akt 磷酸化并共免疫沉淀。针对 Akt 磷酸化残基的 Ala 和 Glu 突变体的聚合酶活性测定也表明，ZIKV 和 USUV NS5 的 Glu 突变体的引物延伸活性降低，而 WNV 突变体则没有观察到这种情况。此外，Akt 抑制剂（MK-2206、厚朴酚和 ipatasertib）处理可降低细胞培养物中的 USUV 和 ZIKV 滴度，但 honokiol 除外，对 WNV 则没有影响。所有这些发现表明 Akt 在黄病毒复制中起着重要作用，尽管不同病毒之间存在特定差异，并鼓励进一步研究 PI3K/Akt/mTOR 通路作为抗病毒的潜在靶点。
