title: A pH-sensitive fusogenic peptide facilitates endosomal escape and greatly enhances the gene silencing of siRNA-containing nanoparticles in vitro and in vivo.
abstract: Previously, we developed a multifunctional envelope-type nano device (MEND) for efficient delivery of both pDNA and siRNA. Modification of a MEND with polyuethylene glycol, i.e., PEGylation, is a potential strategy for in vivo delivery of MENDs to tumor tissue. However, PEGylation also inhibits both uptake and endosomal escape of MENDs. To overcome these limitations, we developed a PEG-peptide-DOPE (PPD) that can be cleaved in a matrix metalloproteinase (MMP)-rich environment. In this study, to further improve the silencing activity of encapsulated siRNA, we modified the PPD-MEND with a pH-sensitive fusogenic GALA peptide (GALA/PPD-MEND). First, we determined the GALA and PPD content that would optimize the synergistic functions of GALA and PPD. The most efficient gene silencing activity was achieved when GALA and either conventional PEG-lipid or PPD were used to modify the MEND at a molar ratio of 1:1. In this case, the silencing activity was comparable to that achieved when using a MEND that had not been modified with PEG (unmodified MEND). Furthermore, in vivo topical administration revealed that optimized PPD/GALA-MENDa resulted in more efficient gene silencing compared with unmodified MENDs. Collectively, data demonstrate that introduction of both of a pH-sensitive fusogenic GALA peptide and PPD into the MEND facilitates nanoparticle endosomal escape, thereby enhancing the efficiency of siRNA delivery and gene silencing.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan. harasima@pharm.hokudai.ac.jp
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hatakeyama
authors.forename: Erika
authors.initials: E
authors.lastname: Ito
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Akita
authors.forename: Motoi
authors.initials: M
authors.lastname: Oishi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nagasaki
authors.forename: Shiroh
authors.initials: S
authors.lastname: Futaki
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Harashima
mesh_terms: D000818:Animals; D020868:Gene Silencing; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D053758:Nanoparticles / Q000737:chemistry*; D009369:Neoplasms / Q000628:therapy; D010455:Peptides / Q000737:chemistry*; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000627:therapeutic use
chemical_list: D010455:Peptides; D010714:Phosphatidylethanolamines; D034741:RNA, Small Interfering; C066951:GALA peptide; D011092:Polyethylene Glycols