title: Surface coating of siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers: enhanced gene silencing and reduced adverse effects in vitro.
abstract: Cationic vectors have demonstrated the potential to facilitate intracellular delivery of therapeutic oligonucleotides. However, enhanced transfection efficiency is usually associated with adverse effects, which also proves to be a challenge for vectors based on cationic peptides. In this study a series of proteolytically stable palmitoylated α-peptide/β-peptoid peptidomimetics with a systematically varied number of repeating lysine and homoarginine residues was shown to self-assemble with small interfering RNA (siRNA). The resulting well-defined nanocomplexes were coated with anionic lipids giving rise to net anionic liposomes. These complexes and the corresponding liposomes were optimized towards efficient gene silencing and low adverse effects. The optimal anionic liposomes mediated a high silencing effect, which was comparable to that of the control (cationic Lipofectamine 2000), and did not display any noticeable cytotoxicity and immunogenicity in vitro. In contrast, the corresponding nanocomplexes mediated a reduced silencing effect with a more narrow safety window. The surface coating with anionic lipid bilayers led to partial decomplexation of the siRNA-peptidomimetic nanocomplex core of the liposomes, which facilitated siRNA release. Additionally, the optimal anionic liposomes showed efficient intracellular uptake and endosomal escape. Therefore, these findings suggest that a more efficacious and safe formulation can be achieved by surface coating of the siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers.
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark. xianghui.zeng@sund.ku.dk camilla.foged@sund.ku.dk.
authors.forename: Xianghui
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Division of Immunology, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
authors.forename: Anne Marit
authors.initials: AM
authors.lastname: de Groot
authors.affiliation: Division of Immunology, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
authors.forename: Alice J A M
authors.initials: AJ
authors.lastname: Sijts
authors.affiliation: Division of Immunology, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
authors.forename: Femke
authors.initials: F
authors.lastname: Broere
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark. xianghui.zeng@sund.ku.dk camilla.foged@sund.ku.dk and Department of Pharmaceutics, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: Oude Blenke
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark. xianghui.zeng@sund.ku.dk camilla.foged@sund.ku.dk.
authors.forename: Stefano
authors.initials: S
authors.lastname: Colombo
authors.affiliation: Division of Immunology, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
authors.forename: Willem
authors.initials: W
authors.lastname: van Eden
authors.affiliation: Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Franzyk
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark. xianghui.zeng@sund.ku.dk camilla.foged@sund.ku.dk.
authors.forename: Hanne Mørck
authors.initials: HM
authors.lastname: Nielsen
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark. xianghui.zeng@sund.ku.dk camilla.foged@sund.ku.dk.
authors.forename: Camilla
authors.initials: C
authors.lastname: Foged
mesh_terms: D045744:Cell Line, Tumor; D020868:Gene Silencing; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry / Q000494:pharmacology; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry*; D057786:Peptidomimetics / Q000737:chemistry / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000737:chemistry / Q000494:pharmacology
chemical_list: D008051:Lipid Bilayers; D057786:Peptidomimetics; D034741:RNA, Small Interfering