State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
University of Chinese Academy of Sciences, Beijing, China.
J Virol. 2022 Feb 23;96(4):e0177821. doi: 10.1128/JVI.01778-21. Epub 2021 Dec 15.
RNA interference (RNAi) functions as the major host antiviral defense in insects, while less is understood about how to utilize antiviral RNAi in controlling viral infection in insects. Enoxacin belongs to the family of synthetic antibacterial compounds based on a fluoroquinolone skeleton that has been previously found to enhance RNAi in mammalian cells. In this study, we show that enoxacin efficiently inhibited viral replication of C virus (DCV) and cricket paralysis virus (CrPV) in cultured cells. Enoxacin promoted the loading of Dicer-2-processed virus-derived small interfering RNA (siRNA) into the RNA-induced silencing complex, thereby enhancing the antiviral RNAi response in infected cells. Moreover, enoxacin treatment elicited RNAi-dependent protective efficacy against DCV or CrPV challenge in adult fruit flies. In addition, enoxacin also inhibited the replication of flaviviruses, including dengue virus and Zika virus, in mosquito cells in an RNAi-dependent manner. Together, our findings demonstrate that enoxacin can enhance RNAi in insects, and enhancing RNAi by enoxacin is an effective antiviral strategy against diverse viruses in insects, which may be exploited as a broad-spectrum antiviral agent to control the vector transmission of arboviruses or viral diseases in insect farming. RNAi has been widely recognized as one of the most broadly acting and robust antiviral mechanisms in insects. However, the application of antiviral RNAi in controlling viral infections in insects is less understood. Enoxacin is a fluoroquinolone compound that was previously found to enhance RNAi in mammalian cells, while its RNAi-enhancing activity has not been assessed in insects. Here, we show that enoxacin treatment inhibited viral replication of DCV and CrPV in cells and adult fruit flies. Enoxacin promoted the loading of Dicer-generated virus-derived siRNA into the Ago2-incorporated RNA-induced silencing complex and in turn strengthened the antiviral RNAi response in the infected cells. Moreover, enoxacin displayed effective RNAi-dependent antiviral effects against flaviviruses, such as dengue virus and Zika virus, in mosquito cells. This study is the first to demonstrate that enhancing RNAi by enoxacin elicits potent antiviral effects against diverse viruses in insects.
RNA 干扰 (RNAi) 是昆虫主要的抗病毒防御机制，而如何利用抗病毒 RNAi 来控制昆虫中的病毒感染则知之甚少。依诺沙星属于基于氟喹诺酮骨架的合成抗菌化合物家族，先前已发现它能增强哺乳动物细胞中的 RNAi。在本研究中，我们表明依诺沙星能有效抑制培养细胞中 C 病毒 (DCV) 和蟋蟀麻痹病毒 (CrPV) 的复制。依诺沙星促进了 Dicer-2 加工的病毒衍生小干扰 RNA (siRNA) 载入 RNA 诱导沉默复合物，从而增强了感染细胞中的抗病毒 RNAi 反应。此外，依诺沙星处理还能引发对成年果蝇中 DCV 或 CrPV 攻击的 RNAi 依赖性保护效力。此外，依诺沙星还能以 RNAi 依赖性方式抑制蚊细胞中的黄病毒（包括登革热病毒和寨卡病毒）的复制。总之，我们的研究结果表明依诺沙星可以增强昆虫中的 RNAi，并且通过依诺沙星增强 RNAi 是一种针对昆虫中多种病毒的有效抗病毒策略，可将其作为一种广谱抗病毒剂来控制虫媒病毒或昆虫养殖中病毒病的传播。RNAi 已被广泛认为是昆虫中最广泛作用和最强大的抗病毒机制之一。然而，在昆虫中利用抗病毒 RNAi 来控制病毒感染的应用还不太了解。依诺沙星是一种氟喹诺酮化合物，先前发现它能增强哺乳动物细胞中的 RNAi，但其在昆虫中的 RNAi 增强活性尚未得到评估。在这里，我们表明依诺沙星处理抑制了 DCV 和 CrPV 在细胞和成年果蝇中的复制。依诺沙星促进了 Dicer 产生的病毒衍生 siRNA 载入 Ago2 结合的 RNA 诱导沉默复合物，并进而增强了感染细胞中的抗病毒 RNAi 反应。此外，依诺沙星在蚊细胞中对黄病毒（如登革热病毒和寨卡病毒）显示出有效的 RNAi 依赖性抗病毒作用。本研究首次证明，通过依诺沙星增强 RNAi 可引发昆虫中多种病毒的强大抗病毒作用。
