Cited by 634RNA Interference and Gene DeliveryLipid Membrane Structure and BehaviorNanoparticle-Based Drug Delivery

Mechanism of oligonucleotide release from cationic liposomes.

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Zelphati, O, Szoka, F C·1996·Proceedings of the National Academy of Sciences

Abstract

We propose a mechanism for oligonucleotide (ODN) release from cationic lipid complexes in cells that accounts for various observations on cationic lipid-nucleic acid-cell interactions. Fluorescent confocal microscopy of cells treated with rhodamine-labeled cationic liposome/ fluorescein-labeled ODN (F-ODN) complexes show the F-ODN separates from the lipid after internalization and enters the nucleus leaving the fluorescent lipid in cytoplasmic structures. ODN displacement from the complex was studied by fluorescent resonance energy transfer. Anionic liposome compositions (e.g., phosphatidylserine) that mimic the cytoplasmic facing monolayer of the cell membrane released ODN from the complex at about a 1:1 (-/+) charge ratio. Release was independent of ionic strength and pH. Physical separation of the F-ODN from monovalent and multivalent cationic lipids was confirmed by gel electrophoresis. Fluid but not solid phase anionic liposomes are required, whereas the physical state of the cationic lipids does not effect the release. Water soluble molecules with a high negative linear charge density, dextran sulfate, or heparin also release ODN. However, ATP, spermidine, spermine, tRNA, DNA, polyglutamic acid, polylysine, bovine serum albumin, or histone did not release ODN, even at 100-fold charge excess (-/+). Based upon these results, we propose that the complex, after internalization by endocytosis, induces flip-flop of anionic lipids from the cytoplasmic facing monolayer. Anionic lipids laterally diffuse into the complex and form a charged neutralized ion-pair with the cationic lipids. This leads to displacement of the ODN from the cationic lipid and its release into the cytoplasm.

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Crossref · 10.1073/pnas.93.21.11493

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Authors
Zelphati, O., & Szoka, F. C.
Affiliations
University of California, San Francisco (US)
Venue
Proceedings of the National Academy of Sciences
Published
1996-10-15
Volume
93
Issue
21
Pages
11493-11498
ISSN
  • 0027-8424 (ISSN-L)
  • 1091-6490
OpenAlex
W2018116983
Cited by
634
References
22
Citations by year
2026: 10 · 2025: 12 · 2024: 14 · 2023: 9 · 2022: 9 · 2021: 16 · 2020: 15 · 2019: 26 · 2018: 19 · 2017: 17 · 2016: 21 · 2015: 14 · 2014: 20 · 2013: 24 · 2012: 27
FWCI
8.46
Type
journal article
Language
en
Open access
Locations
  • Proceedings of the National Academy of Sciences (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health (5r01dk046052-07, 5r01gm030163-11)
  • National Institute of General Medical Sciences (GM30163)
  • National Institute of Diabetes and Digestive and Kidney Diseases (DK-46052)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › RNA Interference and Gene Delivery
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Lipid Membrane Structure and Behavior
  • Physical Sciences › Materials Science › Biomaterials › Nanoparticle-Based Drug Delivery
Keywords
cationic liposomes, anionic liposomes, phosphatidylserine, lipid flip-flop, endocytosis, nuclear delivery, charge ratio, ion pairing, lipid lateral diffusion, dextran sulfate, heparin, nucleic acid delivery
MeSH terms
Base Sequence, Cell Membrane, DNA, Endocytosis, Energy Transfer, Hydrogen-Ion Concentration, Liposomes, Models, Biological, Oligodeoxyribonucleotides, Osmolar Concentration, RNA, Transfer, Serum Albumin, Bovine, Spectrometry, Fluorescence, Spermidine, Spermine, Structure-Activity Relationship, Thionucleotides, Microscopy, Confocal

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