title: Delivery of siRNA using ternary complexes containing branched cationic peptides: the role of peptide sequence, branching and targeting.
abstract: Ternary nanocomplexes, composed of bifunctional cationic peptides, lipids and siRNA, as delivery vehicles for siRNA have been investigated. The study is the first to determine the optimal sequence and architecture of the bifunctional cationic peptide used for siRNA packaging and delivery using lipopolyplexes. Specifically three series of cationic peptides of differing sequence, degrees of branching and cell-targeting sequences were co-formulated with siRNA and vesicles prepared from a 1 : 1 molar ratio of the cationic lipid DOTMA and the helper lipid, DOPE. The level of siRNA knockdown achieved in the human alveolar cell line, A549-luc cells, in both reduced serum and in serum supplemented media was evaluated, and the results correlated to the nanocomplex structure (established using a range of physico-chemical tools, namely small angle neutron scattering, transmission electron microscopy, dynamic light scattering and zeta potential measurement); the conformational properties of each component (circular dichroism); the degree of protection of the siRNA in the lipopolyplex (using gel shift assays) and to the cellular uptake, localisation and toxicity of the nanocomplexes (confocal microscopy). Although the size, charge, structure and stability of the various lipopolyplexes were broadly similar, it was clear that lipopolyplexes formulated from branched peptides containing His-Lys sequences perform best as siRNA delivery agents in serum, with protection of the siRNA in serum balanced against efficient release of the siRNA into the cytoplasm of the cell.
authors.affiliation: Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, Waterloo Campus, London SE1 9NH, UK.
authors.forename: Laila
authors.initials: L
authors.lastname: Kudsiova
authors.affiliation: Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK. a.b.tabor@ucl.ac.uk.
authors.forename: Katharina
authors.initials: K
authors.lastname: Welser
authors.affiliation: Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK. a.b.tabor@ucl.ac.uk.
authors.forename: Frederick
authors.initials: F
authors.lastname: Campbell
authors.affiliation: Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK. a.b.tabor@ucl.ac.uk.
authors.forename: Atefeh
authors.initials: A
authors.lastname: Mohammadi
authors.affiliation: Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK. a.b.tabor@ucl.ac.uk.
authors.forename: Natalie
authors.initials: N
authors.lastname: Dawson
authors.affiliation: Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, Waterloo Campus, London SE1 9NH, UK.
authors.forename: Lili
authors.initials: L
authors.lastname: Cui
authors.affiliation: Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK. a.b.tabor@ucl.ac.uk.
authors.forename: Helen C
authors.initials: HC
authors.lastname: Hailes
authors.affiliation: Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, Waterloo Campus, London SE1 9NH, UK.
authors.forename: M Jayne
authors.initials: MJ
authors.lastname: Lawrence
authors.affiliation: Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK. a.b.tabor@ucl.ac.uk.
authors.forename: Alethea B
authors.initials: AB
authors.lastname: Tabor
mesh_terms: D000595:Amino Acid Sequence; D002412:Cations; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D000067493:Dynamic Light Scattering; D024202:Electrophoretic Mobility Shift Assay; D005453:Fluorescence; D055785:Gene Knockdown Techniques; D018014:Gene Transfer Techniques; D006801:Humans; D008081:Liposomes / Q000378:metabolism / Q000648:ultrastructure; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D033363:Neutron Diffraction; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D053838:Scattering, Small Angle; D044967:Serum / Q000378:metabolism; D055672:Static Electricity
chemical_list: D002412:Cations; D008081:Liposomes; D010455:Peptides; D034741:RNA, Small Interfering