Significant inhibition of Tembusu virus envelope and NS5 gene using an adenovirus-mediated short hairpin RNA delivery system

Tembusu virus (TMUV) is a mosquito-borne flavivirus, which was first isolated in the tropics during the 1970s. Recently, a disease characterized by ovarian haemorrhage and neurological symptoms was observed in ducks in China, which threatens poultry production. However, there is no suitable vaccination strategy or effective antiviral drugs to combat TMUV infections. Consequently, there is an urgent need to develop a new anti-TMUV therapy. In this study, we report an efficient short hairpin RNA (shRNA) delivery strategy for the inhibition of TMUV production using an adenovirus vector system. Using specifically designed shRNAs based on the E and NS5 protein genes of TMUV, the vector-expressed viral genes, TMUV RNA replication and infectious virus production were downregulated at different levels in Vero cells, where the shRNA (NS52) was highly effective in inhibiting TMUV. Using the human adenovirus type 5 shRNA delivery system, the recombinant adenovirus (rAd-NS52) inhibited TMUV multiplication with high efficiency. Furthermore, the significant dose-dependent inhibition of viral RNA copies induced by rAd-NS52 was found in TMUV-infected cells, which could last for at least 96h post infection. Our results indicated that the adenovirus-mediated delivery of shRNAs could play an active role in future TMUV antiviral therapeutics.