A chicken microRNA expressing LaSota targets Newcastle disease virus phosphoprotein and impacts interferon expression

Newcastle disease (ND), a major cause of economic loss in the poultry industry worldwide, is caused by outbreaks of virulent avian paramyxovirus type 1(APMV-1) virus. We previously demonstrated that chicken miRNA-27b-5p (gga-miR-27b-5p) can regulate the APMV-1 phosphoprotein (P) and alter viral replication. In this study, the LaSota vaccine strain of APMV-1 was used as a backbone to express the chicken pre-miRNA-27b and expected to increase intra-cellular levels of both gga-miR-27b-5p and gga-miR-27b-3p. This novel recombinant virus, rLS-miR-27b, was rescued, propagated in embryonating chicken eggs (ECEs) and did not exhibit toxicity in ECEs. Expression of both gga-miR-27b-5p and gga-miR-27b-3p was increased significantly relative to controls. An inverse correlation was observed between increased expression of gga-miR-27b-5p and reduced APMV-1 P transcripts. Additionally, increased expression of interferons (alpha, beta and lambda) and interferon stimulated gene MX1 was observed. Suppression of P did not alter the P:V ratio in rLS-27b virus infected cells. These data support the observation that miR-27b-5p expression alters viral transcriptional kinetics in cell culture without affecting overall progeny virus yield in ECEs and could be utilized to improve current APMV-1 vaccines.