Cationic Amphiphiles with Fatty Acyl Chain Asymmetry of Coconut Oil Deliver Genes Selectively to Mouse Lung

Abstract

Recent structure-activity studies have revealed a dramatic influence of hydrophobic chain asymmetry in enhancing gene delivery efficacies of synthetic cationic amphiphiles (Nantz, M. H. et al. Mol. Pharmaceutics2010, 7, 786-794; Koynova, R. et al. Mol. Pharmaceutics2009, 6, 951-958). The present findings demonstrate for the first time that such a transfection enhancing influence of asymmetric hydrocarbon chains observed in pure synthetic cationic amphiphiles also works for cationic amphiphiles designed with natural, asymmetric fatty acyl chains of a food-grade oil. Herein, we demonstrate that cationic amphiphiles designed with the natural fatty acyl chain asymmetry of food-grade coconut oil are less cytotoxic and deliver genes selectively to mouse lung. Despite lauroyl chains being the major fatty acyl chains of coconut oil, both the in vitro and In vivo gene transfer efficiencies of such cationic amphiphiles were found to be remarkably superior (>4-fold) to those of their pure dilauroyl analogue. Mechanistic studies involving the technique of fluorescence resonance energy transfer (FRET) revealed higher biomembrane fusibility of the cationic liposomes of the coconut amphiphiles than that of the symmetric dilauroyl analogue. AFM study revealed pronounced fusogenic nonlamellar structures of the liposomes of coconut amphiphiles. Findings in the FRET and cellular uptake study, taken together, support the notion that the higher cellular uptake resulting from the more fusogenic nature of the liposomes of coconut amphiphiles 1 are likely to play a dominant role in making the coconut amphiphiles transfection competent.

Green Transfection: Cationic Lipid Nanocarrier System Derivatized from Vegetable Fat, Palmstearin Enhances Nucleic Acid Transfections

“… 20 Our prior findings convincingly demonstrated that cationic lipids prepared using a mixture of fatty acids derived from coconut oil impart membrane fusion and enhance gene-delivery efficacies. 20 However, the major limitation with cationic lipids derivatized from coconut oil is the reproducibility of the same composition because of a large variation in the fatty acyl chain lengths, which ranges from C6:0 to C18:2 (batch to batch variation). To overcome the limitation, we have developed a cationic lipid pool from palmstearin, which has less variation as compared to coconut oil.…”

“… 17 − 19 Taking cues from these findings, we further demonstrated that the hydrophobic chain asymmetry that originated from food-grade coconut oil enhanced the transfection properties of the liposomal system by greater than 4-fold and was found to be safer, when compared with its symmetric lauric acid (C12) analogue. 20 However, greater variation in the chain lengths of the fatty acyl chains from coconut oil, which ranges from C6 to C18:2, makes it difficult to maintain the uniform composition from batch to batch.…”

Asymmetric 1-alkyl-2-acyl phosphatidylcholine: A helper lipid for enhanced non-viral gene delivery

“…Wang et al reported the enhanced gene transfer mediated by the combination of dilauroyl (C12 chain) and dioleoyl (C18 chain) homologues of O-ethylphosphatidylcholine in contrast to the poor transfection ability of the individual cationic lipid (Wang and MacDonald, 2004). There are also increasing interest in designing asymmetric cationic lipids to improve transfection efficiency (Chandrashekhar et al, 2011; Koynova et al, 2009; Nantz et al, 2010). Some fusogenic cationic lipids can mediate efficient transfection without helper lipids (Cherezov et al, 2002; Koynova et al, 2009).…”

Effects of heterocyclic-based head group modifications on the structure–activity relationship of tocopherol-based lipids for non-viral gene delivery

“…Cationic liposomes (SUVs) were prepared by the lipid hydration method as described before (30,31). Small unilamellar liposomes were formulated from 1:1 (mole ratio) mixture of each of the differently modified cationic tocopherol lipid and co-lipid DOPE (1, 2-dioleoyl-snglycero-3-phosphoethanolamine).…”