title: Activation of the interferon system by short-interfering RNAs.
abstract: RNA interference (RNAi) is a powerful tool used to manipulate gene expression or determine gene function. One technique of expressing the short double-stranded (ds) RNA intermediates required for interference in mammalian systems is the introduction of short-interfering (si) RNAs. Although RNAi strategies are reliant on a high degree of specificity, little attention has been given to the potential non-specific effects that might be induced. Here, we found that transfection of siRNAs results in interferon (IFN)-mediated activation of the Jak-Stat pathway and global upregulation of IFN-stimulated genes. This effect is mediated by the dsRNA-dependent protein kinase, PKR, which is activated by 21-base-pair (bp) siRNAs and required for upregulation of IFN-beta in response to siRNAs. In addition, we show by using cell lines deficient in specific components mediating IFN action that the RNAi mechanism itself is independent of the interferon system. Thus, siRNAs have broad and complicating effects beyond the selective silencing of target genes when introduced into cells. This is of critical importance, as siRNAs are currently being explored for their potential therapeutic use.
authors.affiliation: Department of Cancer Biology, Lerner Research Institute, NB40, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195 USA.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Sledz
authors.forename: Michelle
authors.initials: M
authors.lastname: Holko
authors.forename: Michael J
authors.initials: MJ
authors.lastname: de Veer
authors.forename: Robert H
authors.initials: RH
authors.lastname: Silverman
authors.forename: Bryan R G
authors.initials: BR
authors.lastname: Williams
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004331:Drosophila melanogaster; D005057:Eukaryotic Cells / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral / Q000235:genetics; D020868:Gene Silencing / Q000276:immunology; D007369:Interferon Inducers / Q000009:adverse effects* / Q000378:metabolism; D007372:Interferons / Q000096:biosynthesis* / Q000235:genetics; D053613:Janus Kinase 1; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference / Q000276:immunology*; D012330:RNA, Double-Stranded / Q000235:genetics / Q000276:immunology*; D034741:RNA, Small Interfering / Q000009:adverse effects* / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics / Q000276:immunology; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology; D019892:eIF-2 Kinase / Q000235:genetics / Q000378:metabolism
chemical_list: D007369:Interferon Inducers; D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D012367:RNA, Viral; D007372:Interferons; D011505:Protein-Tyrosine Kinases; D053613:Janus Kinase 1; D019892:eIF-2 Kinase