title: Activity of stabilized short interfering RNA in a mouse model of hepatitis B virus replication.
abstract: To develop synthetic short interfering RNA (siRNA) molecules as therapeutic agents for systemic administration in vivo, chemical modifications were introduced into siRNAs targeted to conserved sites in hepatitis B virus (HBV) RNA. These modifications conferred significantly prolonged stability in human serum compared with unmodified siRNAs. Cell culture studies revealed a high degree of gene silencing after treatment with the chemically modified siRNAs. To assess activity of the stabilized siRNAs in vivo initially, an HBV vector-based model was used in which the siRNA and the HBV vector were codelivered via high-volume tail vein injection. More than a 3 log10 decrease in levels of serum HBV DNA and hepatitis B surface antigen, as well as liver HBV RNA, were observed in the siRNA-treated groups compared with the control siRNA-treated and saline groups. Furthermore, the observed decrease in serum HBV DNA was 1.5 log10 more with stabilized siRNA compared with unmodified siRNA, indicating the value of chemical modification in therapeutic applications of siRNA. In subsequent experiments, standard systemic intravenous dosing of stabilized siRNA 72 hours after injection of the HBV vector resulted a 0.9 log10 reduction of serum HBV DNA levels after 2 days of dosing. In conclusion, these experiments establish the strong impact that siRNAs can have on the extent of HBV infection and underscore the importance of stabilization of siRNA against nuclease degradation.
authors.affiliation: Sirna Therapeutics, Inc., Boulder, CO 80301, USA. morrisseyd@sirna.com
authors.forename: David V
authors.initials: DV
authors.lastname: Morrissey
authors.forename: Karin
authors.initials: K
authors.lastname: Blanchard
authors.forename: Lucinda
authors.initials: L
authors.lastname: Shaw
authors.forename: Kristi
authors.initials: K
authors.lastname: Jensen
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Lockridge
authors.forename: Brent
authors.initials: B
authors.lastname: Dickinson
authors.forename: James A
authors.initials: JA
authors.lastname: McSwiggen
authors.forename: Chandra
authors.initials: C
authors.lastname: Vargeese
authors.forename: Keith
authors.initials: K
authors.lastname: Bowman
authors.forename: Chris S
authors.initials: CS
authors.lastname: Shaffer
authors.forename: Barry A
authors.initials: BA
authors.lastname: Polisky
authors.forename: Shawn
authors.initials: S
authors.lastname: Zinnen
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D017124:Conserved Sequence; D004279:DNA, Viral / Q000097:blood; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D004355:Drug Stability; D020868:Gene Silencing; D018390:Gene Targeting; D016679:Genome, Viral; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000235:genetics / Q000502:physiology*; D006801:Humans; D051379:Mice; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000138:chemical synthesis / Q000737:chemistry / Q000502:physiology*; D012367:RNA, Viral / Q000097:blood; D014779:Virus Replication / Q000235:genetics*
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D034741:RNA, Small Interfering; D012367:RNA, Viral