Biophysical properties of CDAN/DOPE-analogue lipoplexes account for enhanced gene delivery
| Autor: | Michael R. Jorgensen, Andrew D. Miller, Wayne S. Price, Ayesha Ahmad, Steven Fletcher |
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| Rok vydání: | 2008 |
| Předmět: |
Liposome
Chemistry Spectrum Analysis Organic Chemistry Static Electricity Rational design Cationic polymerization Biophysics Gene Transfer Techniques Lipid bilayer fusion Transfection Gene delivery Endocytosis Biochemistry Lipids Biophysical Phenomena X-Ray Diffraction Molecular Medicine lipids (amino acids peptides and proteins) Cationic liposome Molecular Biology |
| Zdroj: | Chembiochem : a European journal of chemical biology. 9(3) |
| ISSN: | 1439-7633 |
| Popis: | mediated plasmid DNA (pDNA) delivery and the clarification of specific physical and biochemical barriers encountered along the delivery pathway is necessary for the rational design of optimal synthetic cationic liposome vectors. These range from the biophysical aspects underlying the design and self-assembly properties of cationic liposome–pDNA complex (lipoplex; LD) particles to the different biological impediments that need to be overcome before gene expression can occur. [7–11] Cationic lipids are needed to ensure the formation of LD particles by pDNA condensation, as well as for efficient cell binding of LD particles and intracellular trafficking of pDNA post-intracellular delivery by endocytosis. [12] Furthermore, one of the most commonly used neutral, bioavailable co-lipids in cationic liposomes, dioleoyl l-a-phosphatidylethanolamine (DOPE), has been incorporated because of its associated fusogenic properties that may contribute towards efficient endosome-breakout (endosomolysis) and intracellular trafficking of pDNA. [6, 13–20] These fusogenic effects are associated with a preference for Typically, cationic liposomes are formulated from the combination of a synthetic cationic lipid (cytofectin) and a neutral, biologically available co-lipid. However, the use of cationic liposome formulations to mediate gene delivery to cells is hampered by a paradox. Cationic lipids, such as N 1 -cholesteryloxycarbonyl-3-7-diazanonane-1,9-diamine (CDAN), are needed to ensure the formation of cationic liposome-DNA (lipoplex, LD) particles by plasmid DNA (pDNA) condensation, as well as for efficient cell binding of LD particles and intracellular trafficking of pDNA post-intracellular delivery by endocytosis. However, the same cationic lipids can exhibit toxicity, and also promote LD particle colloidal instability, leading to aggregation. This results from electrostatic interactions with anionic agents in biological fluids, particularly in vivo. One of the most commonly used neutral, bioavailable co-lipids, dioleoyl l-a-phosphatidylethanolamine (DOPE), has been incorporated into many cationic liposome formulations owing to its fusogenic characteristics that are associated with a preference for the inverted hexagonal (HII) phase—a phase typical of membrane– membrane fusion events. However, these same fusogenic characteristics also destabilize LD particles substantially with respect to aggregation, in vitro and especially in vivo. Therefore, there is a real need to engineer more stable cationic liposome systems with lower cellular toxicity. We hypothesize that one way to achieve this goal should be to find the means to reduce the mol fraction of cationic lipid in cationic liposomes without impairing the overall transfection efficiency, by replacing DOPE with an alternative co-lipid with fusogenic properties “tuned” with a greater preference for the more stable lamellar phases than DOPE is able to achieve. Herein, we document the syntheses of triple bond variants of DOPE, and their formulation into a range of low charge, low cationic lipid containing LD systems. The first indications are that our hypothesis is correct in vitro. |
| Databáze: | OpenAIRE |
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