Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France.
Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France
J Virol. 2020 Apr 16;94(9). doi: 10.1128/JVI.02145-19.
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. 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.
微小 RNA（miRNAs）是通过调节靶基因的表达而起作用的小调节 RNA。除了在细胞中维持基本生理功能外，miRNAs 还可以调节病毒感染。它们可以通过靶向病毒来源的 RNA 直接作用，也可以通过靶向宿主 mRNA 间接作用，这对病毒可能产生正向或负向的结果。在这里，我们进行了基于荧光的 miRNA 全基因组筛选，以鉴定参与人类细胞中 arbovirus 感染调节的细胞 miRNA。我们鉴定出了 16 个 miRNA 对表达绿色荧光蛋白（GFP）的辛德毕斯病毒（SINV）表现出正向作用，其中包括许多神经元特异性的 miRNA，如 miR-124。我们证实，miR-124 的过表达既增加了 SINV 结构蛋白的翻译，也增加了病毒的产生，而这种效应是由其种子序列介导的。我们进一步证明，SINV 基因组具有 miR-124 的结合位点。miR-124 的抑制以及沉默突变以破坏病毒 RNA 中的该结合位点都消除了正向调节。我们还证明，miR-124 的抑制降低了 SINV 在人类分化神经元细胞中的感染。最后，我们表明，miR-124 的前病毒效应在其他甲病毒中是保守的，因为它的抑制降低了人类细胞中基孔肯雅病毒（CHIKV）的产生。总的来说，我们的工作扩展了宿主 miRNAs 通过与病毒 RNA 的直接结合对病毒周期的正向调节的范围，并为细胞 miRNA 作为 arbovirus 感染调节剂的作用提供了新的见解。节肢动物传播（arbo）病毒是一类病原体的一部分，这些病原体通过昆虫传播到它们的最终宿主。由于气候变化，这些昆虫（如蚊子）的一些栖息地正在转移，从而促进了病毒流行的出现。在与 arbovirus 感染相关的病理中，脑膜炎和脑炎等神经系统疾病代表着重大的健康负担。通过全基因组 miRNA 筛选，我们鉴定出神经元 miR-124 是 Sindbis 和基孔肯雅病毒的正向调节剂。我们还表明，这种效应部分是直接的，从而为治疗 arbovirus 感染开辟了新的途径。
