title: Physicochemical and Preclinical Evaluation of Spermine-Derived Surfactant Liposomes for in Vitro and in Vivo siRNA-Delivery to Liver Macrophages.
abstract: Herein we report on a liposomal system for siRNA delivery consisting of cholesterol (Chol), distearoylphosphatidylcholine (DSPC), and surfactant TF (1-hydroxy-50-amino-3,4,7,10,13,16,19,22-octaoxa-37,41,45-triaza-pentacontane), a novel spermine derivative (HO-EG8-C12-spermine) which has shown improved siRNA delivery to cells in vitro and in vivo. Predominantly single-walled liposomes with reproducible sizes and moderately broad size distributions were generated with an automated extrusion device. The liposomes remained stable when prepared in the presence of siRNA at N/P ratios of 17-34. However, when mixed with human serum in equal volumes, larger aggregates in the size range of several hundred nanometers were observed by dynamic light scattering. These larger aggregates could potentially limit prolonged in vivo applications. Aggregate formation could be reduced by the addition of a cholesterol-hyperbranched polyglycerol surfactant (hbPG) that sterically shields the liposomal surface against serum induced aggregation. In vitro experiments with murine macrophages utilizing macrophage-specific anti-CD68 siRNA loaded liposomes showed potent and sequence specific reduction of CD68 transcript levels without cytotoxicity. Experiments in mice using intravenous application of CW800 NHS ester labeled liposomes, near-infrared in vivo imaging, and fluorescent assisted cell sorting of inflammatory cells demonstrated an almost quantitative accumulation of these liposomes, with and without hbPG, in the liver and a specific knockdown of CD68 mRNA of up to 70% in liver resident macrophages. It was found that aggregate formation of TF liposomes in serum does not significantly affect in vivo siRNA delivery to these central inflammatory cells of the liver.
authors.affiliation: Max-Planck-Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Müller
authors.affiliation: Institute of Translational Immunology and Research Center for Immunotherapy (FZI), University Medical Center of the Johannes Gutenberg-University Mainz , Langenbeckstraße 1, 55131 Mainz, Germany.
authors.forename: Leonard
authors.initials: L
authors.lastname: Kaps
authors.affiliation: Institute of Translational Immunology and Research Center for Immunotherapy (FZI), University Medical Center of the Johannes Gutenberg-University Mainz , Langenbeckstraße 1, 55131 Mainz, Germany.|Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, Massachusetts 02215, United States.
authors.forename: Detlef
authors.initials: D
authors.lastname: Schuppan
authors.affiliation: Institute of Translational Immunology and Research Center for Immunotherapy (FZI), University Medical Center of the Johannes Gutenberg-University Mainz , Langenbeckstraße 1, 55131 Mainz, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Brose
authors.affiliation: Institute of Physical Chemistry , Jakob-Welder-Weg 11, 55099 Mainz, Germany.
authors.forename: Wenqiang
authors.initials: W
authors.lastname: Chai
authors.affiliation: Institute of Physical Chemistry , Jakob-Welder-Weg 11, 55099 Mainz, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Fischer
authors.affiliation: Institute of Organic Chemistry , Duesbergweg 10-14, 55128 Mainz, Germany.
authors.forename: Sophie
authors.initials: S
authors.lastname: Müller
authors.affiliation: Institute of Organic Chemistry , Duesbergweg 10-14, 55128 Mainz, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Frey
authors.affiliation: Institute of Physical Chemistry , Jakob-Welder-Weg 11, 55099 Mainz, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Schmidt
authors.affiliation: Max-Planck-Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Kristin
authors.initials: K
authors.lastname: Mohr
mesh_terms: D000818:Animals; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D002478:Cells, Cultured; D002784:Cholesterol / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry; D005434:Flow Cytometry; D008081:Liposomes / Q000737:chemistry*; D008099:Liver / Q000166:cytology*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008962:Models, Theoretical; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013096:Spermine / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D002784:Cholesterol; D004337:Drug Carriers; D008081:Liposomes; D010713:Phosphatidylcholines; D034741:RNA, Small Interfering; D013096:Spermine; D013501:Surface-Active Agents; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C010942:1,2-distearoyllecithin
keywords: CD68; in vivo; knockdown; liposome; plasma; siRNA delivery; stability