Type I Interferons Impede Short Hairpin RNA-Mediated RNAi via Inhibition of Dicer-Mediated Processing to Small Interfering RNA.

ABSTRACT: RNAi by short hairpin RNA (shRNA) is a powerful tool not only for studying gene functions in various organisms, including mammals, but also for the treatment of severe disorders. However, shRNA-expressing vectors can induce type I interferon (IFN) expression by activation of innate immune responses, leading to off-target effects and unexpected side effects. Several strategies have been developed to prevent type I IFN induction. On the other hand, it has remained unclear whether type I IFNs have effects on shRNA-mediated RNAi. Here, we show that the type I IFNs significantly inhibit shRNA-mediated RNAi. Treatment with recombinant human IFN-? significantly inhibited shRNA-mediated knockdown of target genes, while it did not inhibit small interfering RNA (siRNA)-mediated knockdown. Following treatment with IFN-?, increased and decreased copy numbers of shRNA and its processed form, respectively, were found in the cells transfected with shRNA-expressing plasmids. Dicer protein levels were not altered by IFN-?. These results indicate that type I IFNs inhibit shRNA-mediated RNAi via inhibition of dicer-mediated processing of shRNA to siRNA. Our findings should provide important clues for efficient RNAi-mediated knockdown of target genes in both basic researches and clinical gene therapy.

SUBMITTER: Machitani M 

PROVIDER: S-EPMC5363498 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature