title: Persistent interferon transgene expression by RNA interference-mediated silencing of interferon receptors.
abstract: BACKGROUND
  The in vivo half-life of interferons (IFNs) is very short, and its extension would produce a better therapeutic outcome in IFN-based therapy. Delivery of IFN genes is one solution for providing a sustained supply. IFNs have a variety of functions, including the suppression of transgene expression, through interaction with IFN receptors (IFNRs). This suppression could prevent IFNs from being expressed from vectors delivered. Silencing the expression of IFNAR and IFNGR, the receptors for type I and II IFNs, respectively, in cells expressing IFNs may prolong transgene expression of IFNs.
  
  
  METHODS
  Mouse melanoma B16-BL6 cells or mouse liver were selected as a site expressing IFNs (not a target for IFN gene therapy) and IFN-expressing plasmid DNA was delivered with or without small interfering RNA (siRNA) targeting IFNRs.
  
  
  RESULTS
  Transfection of B16-BL6 cells with siRNA targeting IFNAR1 subunit (IFNAR1) resulted in the reduced expression of IFNAR on the cell surface. This silencing significantly increased the IFN-beta production in cells that were transfected with IFN-beta-expressing plasmid DNA. Similar results were obtained with the combination of IFN-gamma and IFNGR. Co-injection of IFN-beta-expressing plasmid DNA with siRNA targeting IFNAR1 into mice resulted in sustained plasma concentration of IFN-beta.
  
  
  CONCLUSIONS
  These results provide experimental evidence that the RNAi-mediated silencing of IFNRs in cells expressing IFN, such as hepatocytes, is an effective approach for improving transgene expression of IFNs when their therapeutic target comprises cells other than those expressing IFNs.
authors.affiliation: Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Elin
authors.initials: E
authors.lastname: Vikman
authors.forename: Makiya
authors.initials: M
authors.lastname: Nishikawa
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ando
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Takakura
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D020868:Gene Silencing; D015316:Genetic Therapy; D005822:Genetic Vectors; D022781:Hepatocytes / Q000378:metabolism; D016899:Interferon-beta / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D008546:Melanoma, Experimental / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D051379:Mice; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D017471:Receptors, Interferon / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D019076:Transgenes / Q000502:physiology*
chemical_list: D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017471:Receptors, Interferon; D016899:Interferon-beta; D008156:Luciferases