title: Helper-dependent adenovirus-mediated short hairpin RNA expression in the liver activates the interferon response.
abstract: The use of RNA interference has proven to be an effective means to study the function of genes. Constitutive synthesis of small interfering RNA molecules can be accomplished with the use of viral vectors expressing short hairpin RNA (shRNA). Binding of shRNA to the target mRNA promotes transcript degradation. So far, little is known about the effects that shRNA induce in vivo. To determine the feasibility of using helper-dependent adenoviral vectors for expression of shRNA in liver, we have designed an shRNA construct to mouse fabp5 (fatty acid-binding protein 5). Intravenous administration of this vector resulted in approximately 75% silencing of fabp5. Increasing the dose of vector did not result in higher levels of silencing, indicating that there is a threshold for the level of knockdown that can be achieved. Synthesis of high levels of shRNA molecules did not alter the levels of cellular micro-RNA, such as miR-122 and let-7a, suggesting that the exportin-5 pathway was not affected. However, high level shRNA expression resulted in activation of the interferon response. Thus, an important consideration when using shRNA-based vectors in vivo is to closely monitor signs of interferon-stimulated gene expression, since a narrow window exists between gene silencing efficacy and nonspecific effects.
authors.affiliation: Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Witting
authors.forename: Matthew
authors.initials: M
authors.lastname: Brown
authors.forename: Romil
authors.initials: R
authors.lastname: Saxena
authors.forename: Sarah
authors.initials: S
authors.lastname: Nabinger
authors.forename: Núria
authors.initials: N
authors.lastname: Morral
mesh_terms: D000818:Animals; D000229:Dependovirus; D050556:Fatty Acid-Binding Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D020868:Gene Silencing / Q000502:physiology; D006801:Humans; D007372:Interferons / Q000096:biosynthesis* / Q000235:genetics; D028884:Karyopherins / Q000096:biosynthesis / Q000235:genetics; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D020871:RNA Stability; D016372:RNA, Antisense / Q000096:biosynthesis* / Q000235:genetics; D014161:Transduction, Genetic
chemical_list: C082667:Fabp5 protein, mouse; D050556:Fatty Acid-Binding Proteins; D028884:Karyopherins; D035683:MicroRNAs; D009363:Neoplasm Proteins; D016372:RNA, Antisense; C499175:Xpo5 protein, mouse; D007372:Interferons