Human Virus-Derived Small RNAs Can Confer Antiviral Immunity in Mammals

Publication date: 20 June 2017
Source:Immunity, Volume 46, Issue 6
Author(s): Yang Qiu, Yanpeng Xu, Yao Zhang, Hui Zhou, Yong-Qiang Deng, Xiao-Feng Li, Meng Miao, Qiang Zhang, Bo Zhong, Yuanyang Hu, Fu-Chun Zhang, Ligang Wu, Cheng-Feng Qin, Xi Zhou
RNA interference (RNAi) functions as a potent antiviral immunity in plants and invertebrates; however, whether RNAi plays antiviral roles in mammals remains unclear. Here, using human enterovirus 71 (HEV71) as a model, we showed HEV71 3A protein as an authentic viral suppressor of RNAi during viral infection. When the 3A-mediated RNAi suppression was impaired, the mutant HEV71 readily triggered the production of abundant HEV71-derived small RNAs with canonical siRNA properties in cells and mice. These virus-derived siRNAs were produced from viral dsRNA replicative intermediates in a Dicer-dependent manner and loaded into AGO, and they were fully active in degrading cognate viral RNAs. Recombinant HEV71 deficient in 3A-mediated RNAi suppression was significantly restricted in human somatic cells and mice, whereas Dicer deficiency rescued HEV71 infection independently of type I interferon response. Thus, RNAi can function as an antiviral immunity, which is induced and suppressed by a human virus, in mammals.

Graphical abstract

Teaser

It remains unclear if RNAi is an antiviral immunity in mammals. Qiu et al. demonstrate that a human enterovirus deficient in the RNAi suppression activity of 3A protein triggers virus-derived siRNA production, and this virus-induced RNAi response indeed plays antiviral roles in human somatic cells and mice.


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