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Inhibition of highly pathogenic PRRSV replication in MARC-145 cells by artificial microRNAs

Shuqi Xiao12, Qiwei Wang12, Jintao Gao12, Liangliang Wang12, Zuyong He12, Delin Mo12, Xiaohong Liu12 and Yaosheng Chen12*

Author Affiliations

1 State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, P. R. China

2 Pig Improving and Breeding Project Technology Research Exploitation Center of Guangdong, Guangzhou 510006, P. R. China

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Virology Journal 2011, 8:491  doi:10.1186/1743-422X-8-491

Published: 1 November 2011

Abstract

Background

Highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) has caused large economic losses in swine industry in recent years. However, current antiviral strategy could not effectively prevent and control this disease. In this research, five artificial microRNAs (amiRNAs) respectively targeted towards ORF5 (amirGP5-243, -370) and ORF6 (amirM-82, -217,-263) were designed and incorporated into a miRNA-based vector that mimics the backbone of murine miR-155 and permits high expression of amiRNAs in a GFP fused form mediated by RNA Pol II promoter CMV.

Results

It was found that amirGP5-370 could effectively inhibit H-PRRSV replication. The amirM-263-M-263, which was a dual pre-amiRNA expression cassette where two amirM-263s were chained, showed stronger virus inhibitory effects than single amirM-263. H-PRRSV replication was inhibited up to 120 hours in the MARC-145 cells which were stably transduced by recombinant lentiviruses (Lenti-amirGP5-370, -amirM-263-M-263). Additionally, efficacious dose of amirGP5-370 and amirM-263 expression did not trigger the innate interferon response.

Conclusions

Our study is the first attempt to suppress H-PRRSV replication in MARC-145 cells through vector-based and lentiviral mediated amiRNAs targeting GP5 or M proteins coding sequences of PRRSV, which indicated that artificial microRNAs and recombinant lentiviruses might be applied to be a new potent anti-PRRSV strategy.

Keywords:
Highly pathogenic PRRSV; RNAi; artificial miRNA; Lentivirus