title: Enhanced endosomal/lysosomal escape by distearoyl phosphoethanolamine-polycarboxybetaine lipid for systemic delivery of siRNA.
abstract: Cationic liposome based siRNA delivery system has improved the efficiencies of siRNA. However, cationic liposomes are prone to be rapidly cleared by the reticuloendothelial system (RES). Although modification of cationic liposomes with polyethylene glycol (PEG) could prolong circulation lifetime, PEG significantly inhibits siRNA entrapment efficiency, cellular uptake and endosomal/lysosomal escape process, resulting in low gene silencing efficiency of siRNA. In this study, we report the synthesis of zwitterionic polycarboxybetaine (PCB) based distearoyl phosphoethanolamine-polycarboxybetaine (DSPE-PCB) lipid for cationic liposome modification. The DSPE-PCB20 cationic liposome/siRNA complexes (lipoplexes) show an excellent stability in serum medium. The siRNA encapsulation efficiency of DSPE-PCB20 lipoplexes could reach 92% at N/P ratio of 20/1, but only 73% for DSPE-PEG lipoplexes. The zeta potential of DSPE-PCB20 lipoplexes is 8.19±0.53mV at pH 7.4, and increases to 24.6±0.87mV when the pH value is decreased to 4.5, which promotes the endosomal/lysosomal escape of siRNA. The DSPE-PCB20 modification could enhance the silencing efficiency of siRNA by approximately 20% over the DSPE-PEG 2000 lipoplexes at the same N/P ratio in vitro. Furthermore, DSPE-PCB20 lipoplexes could efficiently mediate the down-regulation of Apolipoprotein B (ApoB) mRNA in the liver and consequently decrease the total cholesterol in the serum in vivo, suggesting therapeutic potentials for siRNA delivery in hypercholesterolemia-related diseases.
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Laboratory of Nucleic Acid Technology, Institute of Molecular Medicine, Peking University, Beijing 100871, PR China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Cheng
authors.affiliation: Laboratory of Nucleic Acid Technology, Institute of Molecular Medicine, Peking University, Beijing 100871, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Jiang
authors.affiliation: Laboratory of Nucleic Acid Technology, Institute of Molecular Medicine, Peking University, Beijing 100871, PR China.
authors.forename: Yuanyu
authors.initials: Y
authors.lastname: Huang
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Weipeng
authors.initials: W
authors.lastname: Cao
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Ma
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: fydai@home.ipe.ac.cn.
authors.forename: Fengying
authors.initials: F
authors.lastname: Dai
authors.affiliation: CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: liangxj@nanoctr.cn.
authors.forename: Xingjie
authors.initials: X
authors.lastname: Liang
authors.affiliation: Laboratory of Nucleic Acid Technology, Institute of Molecular Medicine, Peking University, Beijing 100871, PR China. Electronic address: liangz@pku.edu.cn.
authors.forename: Zicai
authors.initials: Z
authors.lastname: Liang
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: xzhang@home.ipe.ac.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001055:Apolipoproteins B / Q000235:genetics; D001622:Betaine / Q000737:chemistry*; D002470:Cell Survival; D011992:Endosomes / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008081:Liposomes; D008099:Liver / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000008:administration & dosage*
chemical_list: D001055:Apolipoproteins B; D008081:Liposomes; D010714:Phosphatidylethanolamines; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C038089:1,2-distearoylphosphatidylethanolamine; D001622:Betaine; D011092:Polyethylene Glycols; D008156:Luciferases
keywords: Cationic liposomes; Endosomal/lysosomal escape; Polycarboxybetaine; pH-sensitive; siRNA delivery