title: Development of lipid nanoparticle formulations of siRNA for hepatocyte gene silencing following subcutaneous administration.
abstract: Recently developed lipid nanoparticle (LNP) formulations of siRNA have proven to be effective agents for hepatocyte gene silencing following intravenous administration with at least three LNP-siRNA formulations in clinical trials. The aim of this work was to develop LNP-siRNA systems for hepatocyte gene silencing that can be administered subcutaneously (s.c.). Three parameters were investigated, namely LNP size, residence time of the polyethylene glycol (PEG)-lipid coating and the influence of hepatocyte-specific targeting ligands. LNP sizes were varied over the range of 30 to 115 nm in diameter and PEG-lipid that dissociates rapidly (PEG-DMG) and slowly (PEG-DSG) were employed. In mice, results show that large (~80 nm) LNP exhibited limited accumulation in the liver and poor Factor VII (FVII) gene silencing at 1mg siRNA/kg body weight. Conversely, small (~30 nm) LNP systems showed maximal liver accumulation yet still had minimal activity. Interestingly, intermediate size (~45 nm) LNP containing PEG-DSG exhibited nearly equivalent liver accumulation as the smaller systems following s.c. administration but reduced FVII levels by 80% at 1mg siRNA/kg body weight. Smaller systems (~35 nm diameter) containing either PEG-DMG or PEG-DSG were less active; however addition of 0.5 mol.% of a GalNAc-PEG lipid to these smaller systems improved activity to levels similar to that observed for the ~45 nm diameter systems. In summary, this work shows that appropriately designed LNP-siRNA systems can result in effective hepatocyte gene silencing following s.c administration.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T 1Z3.
authors.forename: Sam
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T 1Z3.
authors.forename: Yuen Yi C
authors.initials: YY
authors.lastname: Tam
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T 1Z3.
authors.forename: Paulo J C
authors.initials: PJ
authors.lastname: Lin
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T 1Z3.
authors.forename: Alex K K
authors.initials: AK
authors.lastname: Leung
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T 1Z3; Acuitas Therapeutics, 2714 West 31st Avenue, Vancouver, British Columbia, Canada, V6L 2A1.
authors.forename: Ying K
authors.initials: YK
authors.lastname: Tam
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada, V6T 1Z3. Electronic address: pieterc@mail.ubc.ca.
authors.forename: Pieter R
authors.initials: PR
authors.lastname: Cullis
mesh_terms: D000818:Animals; D002626:Chemistry, Pharmaceutical; D016503:Drug Delivery Systems; D005167:Factor VII / Q000494:pharmacology; D005260:Female; D020868:Gene Silencing / Q000187:drug effects*; D022781:Hepatocytes / Q000187:drug effects*; D055104:Infusions, Subcutaneous; D008055:Lipids / Q000737:chemistry*; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology*; D014018:Tissue Distribution
chemical_list: D008055:Lipids; D034741:RNA, Small Interfering; D005167:Factor VII
keywords: Drug delivery; Lipid nanoparticles; Liposomes; Nanomedicine; Subcutaneous administration; siRNA