MicroRNAs (miRNAs) are small regulatory RNAs which act by modulating the expression of target genes. In addition to their role in maintaining essential physiological functions in the cell, miRNAs can also regulate viral infections. They can do so directly by targeting RNAs of viral origin or indirectly by targeting host mRNAs, and this can result in a positive or negative outcome for the virus. Here, we performed a fluorescence-based miRNA genome-wide screen in order to identify cellular miRNAs involved in the regulation of arbovirus infection in human cells. We identified 16 miRNAs showing a positive effect on Sindbis virus (SINV) expressing green fluorescent protein (GFP), among which were a number of neuron-specific ones such as miR-124. We confirmed that overexpression of miR-124 increases both SINV structural protein translation and viral production and that this effect is mediated by its seed sequence. We further demonstrated that the SINV genome possesses a binding site for miR-124. Both inhibition of miR-124 and silent mutations to disrupt this binding site in the viral RNA abolished positive regulation. We also proved that miR-124 inhibition reduces SINV infection in human differentiated neuronal cells. Finally, we showed that the proviral effect of miR-124 is conserved in other alphaviruses, as its inhibition reduces chikungunya virus (CHIKV) production in human cells. Altogether, our work expands the panel of positive regulation of the viral cycle by direct binding of host miRNAs to the viral RNA and provides new insights into the role of cellular miRNAs as regulators of alphavirus infection.IMPORTANCE Arthropod-borne (arbo) viruses are part of a class of pathogens that are transmitted to their final hosts by insects. Because of climate change, the habitat of some of these insects, such as mosquitoes, is shifting, thereby facilitating the emergence of viral epidemics. Among the pathologies associated with arbovirus infection, neurological diseases such as meningitis and encephalitis represent a significant health burden. Using a genome-wide miRNA screen, we identified neuronal miR-124 as a positive regulator of the Sindbis and chikungunya alphaviruses. We also showed that this effect was in part direct, thereby opening novel avenues to treat alphavirus infections.

中文翻译：

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基于高通量荧光的屏幕将神经元MicroRNA miR-124鉴定为Alphavirus感染的阳性调节剂。

微小RNA（miRNA）是小的调节性RNA，通过调节靶基因的表达起作用。除了在细胞中维持基本生理功能方面，miRNA还可以调节病毒感染。他们可以直接靶向病毒来源的RNA，也可以间接靶向宿主mRNA，从而对病毒产生阳性或阴性结果。在这里，我们进行了基于荧光的miRNA全基因组筛选，以鉴定参与人细胞中虫媒病毒感染调控的细胞miRNA。我们鉴定了16个对表达绿色荧光蛋白（GFP）的Sindbis病毒（SINV）表现出积极作用的miRNA，其中包括许多神经元特异性的miRNA，例如miR-124。我们证实，miR-124的过表达增加了SINV结构蛋白的翻译和病毒的产生，并且这种效应是由其种子序列介导的。我们进一步证明了SINV基因组具有miR-124的结合位点。对miR-124的抑制和破坏病毒RNA中该结合位点的沉默突变都废除了阳性调控。我们还证明了miR-124抑制可减少人类分化神经元细胞中的SINV感染。最后，我们证明了miR-124的前病毒作用在其他alpha病毒中是保守的，因为它的抑制作用减少了人类细胞中的基孔肯雅病毒（CHIKV）产生。共，通过将宿主miRNA与病毒RNA直接结合，我们的工作扩展了对病毒周期的积极调控，并提供了对细胞miRNA作为α病毒感染调节剂的作用的新见解。重要节肢动物传播的（arbo）病毒是病毒的一部分。一类由昆虫传播到最终宿主的病原体。由于气候变化，其中一些昆虫（例如蚊子）的栖息地正在转移，从而促进了病毒流行的出现。在与虫媒病毒感染相关的病理中，脑膜炎和脑炎等神经系统疾病构成了严重的健康负担。使用全基因组的miRNA筛选，我们确定神经元miR-124为Sindbis和基孔肯雅α病毒的阳性调节剂。我们还表明，这种影响部分是直接的，