title: Multifunctional, self-assembling anionic peptide-lipid nanocomplexes for targeted siRNA delivery.
abstract: Formulations of cationic liposomes and polymers readily self-assemble by electrostatic interactions with siRNA to form cationic nanoparticles which achieve efficient transfection and silencing in vitro. However, the utility of cationic formulations in vivo is limited due to rapid clearance from the circulation, due to their association with serum proteins, as well as systemic and cellular toxicity. These problems may be overcome with anionic formulations but they provide challenges of self-assembly and transfection efficiency. We have developed anionic, siRNA nanocomplexes utilizing anionic PEGylated liposomes and cationic targeting peptides that overcome these problems. Biophysical measurements indicated that at optimal ratios of components, anionic PEGylated nanocomplexes formed spherical particles and that, unlike cationic nanocomplexes, were resistant to aggregation in the presence of serum, and achieved significant gene silencing although their non-PEGylated anionic counterparts were less efficient. We have evaluated the utility of anionic nanoparticles for the treatment of neuronal diseases by administration to rat brains of siRNA to BACE1, a key enzyme involved in the formation of amyloid plaques. Silencing of BACE1 was achieved in vivo following a single injection of anionic nanoparticles by convection enhanced delivery and specificity of RNA interference verified by 5' RACE-PCR and Western blot analysis of protein.
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK. Electronic address: a.tagalakis@ucl.ac.uk.
authors.forename: Aristides D
authors.initials: AD
authors.lastname: Tagalakis
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Do Hyang D
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Functional Neurosurgery Research Group, School of Clinical Sciences, AMBI Labs, University of Bristol, Southmead Hospital, Bristol, BS10 5NB, UK.
authors.forename: Alison S
authors.initials: AS
authors.lastname: Bienemann
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Mustafa M
authors.initials: MM
authors.lastname: Munye
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Luisa
authors.initials: L
authors.lastname: Saraiva
authors.affiliation: UCL School of Pharmacy, 29-39 Brunswick Square, London, WC1N 1AX, UK.
authors.forename: David
authors.initials: D
authors.lastname: McCarthy
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Zixiu
authors.initials: Z
authors.lastname: Du
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Conrad A
authors.initials: CA
authors.lastname: Vink
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Ruhina
authors.initials: R
authors.lastname: Maeshima
authors.affiliation: Functional Neurosurgery Research Group, School of Clinical Sciences, AMBI Labs, University of Bristol, Southmead Hospital, Bristol, BS10 5NB, UK.
authors.forename: Edward A
authors.initials: EA
authors.lastname: White
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Kenth
authors.initials: K
authors.lastname: Gustafsson
authors.affiliation: Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Hart
mesh_terms: D053829:Amyloid Precursor Protein Secretases / Q000235:genetics*; D000818:Animals; D000838:Anions / Q000737:chemistry; D016282:Aspartic Acid Endopeptidases / Q000235:genetics*; D001921:Brain / Q000378:metabolism; D001927:Brain Diseases / Q000235:genetics / Q000628:therapy; D002460:Cell Line; D015316:Genetic Therapy; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D008297:Male; D053758:Nanoparticles / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D014162:Transfection / Q000379:methods
chemical_list: D000838:Anions; D008055:Lipids; D008081:Liposomes; D034741:RNA, Small Interfering; D011092:Polyethylene Glycols; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509281:Bace1 protein, rat
keywords: Anionic liposome; Gene silencing; Gene therapy; Nanoparticle; Targeted; siRNA