title: Noninvasive imaging of lipid nanoparticle-mediated systemic delivery of small-interfering RNA to the liver.
abstract: Mouse models with liver-specific expression of firefly luciferase were developed that enable a noninvasive and longitudinal assessment of small-interfering RNA (siRNA)-mediated gene silencing in hepatocytes of live animals via bioluminescence imaging. Using these models, a set of lipid nanoparticles (LNPs) with different compositions of cationic lipids, polyethylene glycol (PEG), and cholesterol, were tested for their abilities in delivering a luciferase siRNA to the liver via systemic administration. A dose-dependent luciferase knockdown by LNP/siRNA assemblies was measured by in vivo bioluminescence imaging, which correlated well with the results from parallel ex vivo analyses of luciferase mRNA and protein levels in the liver. RNA interference (RNAi)-mediated target silencing was further confirmed by the detection of RNAi-specific target mRNA cleavage. A single dose of LNP02L at 3 mg/kg (siRNA) caused 90% reduction of luciferase expression and the target repression lasted for at least 10 days. With identical components, LNPs containing 2% PEG are more potent than those with 5.4% PEG. Our results demonstrate that these liver-luciferase mouse models provide a powerful tool for a high-throughput evaluation of hepatic delivery platforms by noninvasive imaging and that the molar ratio of PEG lipid can affect the efficacy of LNPs in silencing liver targets via systemic administration.
authors.affiliation: Department of RNA Therapeutics, Merck Research Laboratories, West Point, Pennsylvania 19486, USA. weikang_tao@merck.com
authors.forename: Weikang
authors.initials: W
authors.lastname: Tao
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Davide
authors.forename: Mingmei
authors.initials: M
authors.lastname: Cai
authors.forename: Guo-Jun
authors.initials: GJ
authors.lastname: Zhang
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: South
authors.forename: Andrea
authors.initials: A
authors.lastname: Matter
authors.forename: Bruce
authors.initials: B
authors.lastname: Ng
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.forename: Laura
authors.initials: L
authors.lastname: Sepp-Lorenzino
mesh_terms: D000818:Animals; D005455:Fluorescent Antibody Technique; D020868:Gene Silencing / Q000502:physiology; D008055:Lipids / Q000737:chemistry*; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008156:Luciferases / Q000235:genetics; D051379:Mice; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics*
chemical_list: D008055:Lipids; D034741:RNA, Small Interfering; D008156:Luciferases