A Dual functioning 5’PPP-NS1shRNA that activates RIG-I antiviral pathway and suppresses influenza nonstructural protein 1

Abstract Retinoic acid-inducible gene-I (RIG-I) is a cytosolic pathogen sensor which is crucial against a number of viral infections. Many viruses have evolved to inhibit pathogen sensors to suppress host innate immune responses. In the case of influenza, nonstructural protein 1 (NS1) suppresses RIG-I function leading to viral replication, morbidity and mortality. We show that silencing NS1 with in vitro transcribed 5’-triphosphate containing NS1 shRNA designed using the conserved region of a number of Influenza viruses not only prevented NS1 expression but also induced RIG-I activation and type I interferon expression resulting in an anti-viral state leading to inhibition of influenza virus replication in vitro. In addition, administration of 5’PPP-NS1 shRNA in prophylactic and therapeutic settings resulted in significant inhibition of viral replication following viral challenge in vivo in mice with corresponding increases of RIG-I, IFN β and λ, as well as a decrease in NS1 expression.