More than 3 years since the last Zika virus (ZIKV) outbreak in Brazil, researchers are still deciphering the molecular mechanisms of neurovirulence and vertical transmission, as well as the best way to control spread of ZIKV, a flavivirus. The use of pesticides was the main strategy of mosquito control during the last ZIKV outbreak. We used vesicular stomatitis virus (VSV) tagged with green fluorescent protein (GFP) as our prototypical virus to study the impact of insecticide pyriproxyfen (PPF). VZV-GFP infected and uninfected Jurkat, HeLa and trophoblast cells were treated with PPF and compared to untreated cells (control). Cell viability was determined by the MTT assay. Cell morphology, presence of extracellular vesicles (EVs), virus infection/GFP expression as well as active mitochondrial levels/localization were examined by confocal microscopy. PPF, which was used to control mosquito populations in Brazil prior to the ZIKV outbreak, enhances VSV replication and has cell membrane-altering properties in the presence of virus. PPF causes enhanced viral replication and formation of large EVs, loaded with virus as well as mitochondria. Treatment of trophoblasts or HeLa cells with increasing concentrations of PPF does not alter cell viability, however, it proportionately increases Jurkat cell viability. Increasing concentrations of PPF followed by VSV infection does not interfere with HeLa cell viability. Both Jurkats and trophoblasts show proportionately increased cell death with increased concentrations of PPF in the presence of virus. We hypothesize that PPF disrupts the lipid microenvironment of mammalian cells, thereby interfering with pathways of viral replication. PPF lowers viability of trophoblasts and Jurkats in the presence of VSV, implying that the combination renders immune system impairment in infected individuals as well as enhanced vulnerability of fetuses towards viral vertical transmission. We hypothesize that similar viruses such as ZIKV may be vertically transmitted via EV-to-cell contact when exposed to PPF, thereby bypassing immune detection. The impact of pesticides on viral replication must be fully investigated before large scale use in future outbreaks of mosquito borne viruses.

中文翻译：

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吡虫啉对病毒行为的影响：对农药诱导的毒力和传播机制的影响。

自巴西上一次寨卡病毒（ZIKV）爆发以来已有3年多的时间，研究人员仍在研究神经毒力和垂直传播的分子机制，以及控制黄病毒ZIKV传播的最佳方法。在上一次ZIKV爆发期间，农药的使用是控制蚊子的主要策略。我们使用标记有绿色荧光蛋白（GFP）的水泡性口炎病毒（VSV）作为我们的原型病毒来研究杀虫剂吡ip昔芬（PPF）的影响。将VZV-GFP感染和未感染的Jurkat，HeLa和滋养细胞用PPF处理，并与未处理的细胞（对照）进行比较。通过MTT测定法确定细胞活力。共聚焦显微镜检查细胞形态，细胞外囊泡（EVs）的存在，病毒感染/ GFP表达以及线粒体活性水平/定位。在ZIKV爆发之前，PPF被用来控制巴西的蚊子种群，它增强了VSV复制，并在存在病毒时具有改变细胞膜的特性。PPF导致病毒复制增强和大型EV的形成，并携带病毒和线粒体。用增加的PPF浓度处理滋养细胞或HeLa细胞不会改变细胞活力，但是，它会成比例地增加Jurkat细胞活力。PPF浓度增加，随后VSV感染，不会干扰HeLa细胞的生存能力。在病毒存在下，Jurkats和滋养细胞都显示出随着PPF浓度的增加而增加的细胞死亡。我们假设PPF破坏了哺乳动物细胞的脂质微环境，从而干扰了病毒复制的途径。在存在VSV的情况下，PPF降低了滋养细胞和Jurkats的活力，这意味着该组合可导致感染个体的免疫系统受损，并增强胎儿对病毒垂直传播的脆弱性。我们假设当暴露于PPF时，类似病毒（例如ZIKV）可能会通过EV与细胞的接触而垂直传播，从而绕过了免疫检测。在未来的蚊子传播病毒大规模使用之前，必须充分研究农药对病毒复制的影响。我们假设，当暴露于PPF时，类似病毒（例如ZIKV）可能会通过EV与细胞的接触而垂直传播，从而绕过了免疫检测。在未来的蚊子传播病毒大规模使用之前，必须充分研究农药对病毒复制的影响。我们假设，当暴露于PPF时，类似病毒（例如ZIKV）可能会通过EV与细胞的接触而垂直传播，从而绕过了免疫检测。在未来的蚊子传播病毒大规模使用之前，必须充分研究农药对病毒复制的影响。