Each year millions of chickens die from Newcastle disease virus (NDV) worldwide leading to severe economic and food losses. Current vaccination campaigns have limitations especially in developing countries, due to elevated costs, need of trained personnel for effective
vaccine administration, and functional cold chain network to maintain
vaccine viability. These problems have led to heightened interest in producing new
antiviral strategies, such as RNA interference (RNAi). RNAi methodology is capable of substantially decreasing viral replication at a cellular level, both in vitro and in vivo. In this study, we utilize
microRNA (
miRNA)-expressing constructs (a type of RNA interference) in an attempt to target and knockdown five NDV structural RNAs for
nucleoprotein (NP),
phosphoprotein (P),
matrix (M), fusion (F), and large (L)
protein genes. Immortalized chicken embryo fibroblast cells (DF-1) that transiently expressed
miRNA targeting NP
mRNA, showed increased resistance to NDV-induced cytopathic effects, as determined by cell count, relative to the same cells expressing
miRNA against alternative NDV
proteins. Upon
infection with NDV, DF-1 cells constitutively expressing the NP
miRNA construct had improved cell survival up to 48 h post
infection (h.p.i) and decreased viral yield up to 24 h.p.i. These results suggest that overexpression of the NP
miRNA in cells and perhaps live animal may provide resistance to NDV.