Synthesis of a novel series of cationic lipids that can act as efficient gene delivery vehicles through systematic heterocyclic substitution of cholesterol derivatives

Abstract

The synthesis of a series of novel cationic lipids through the systematic substitution of cholesterol derivatives that could greatly enhance the delivery and expression of plasmid DNA in vitro and in vivo is described. Two of the newly synthesized lipids, designated as NCC4 and NCC10, were chosen to be studied in detail and gave much higher levels of gene expression than that which could be obtained with some of the conventional cationic polymers and cationic liposomes.

Non-Viral Gene Delivery Systems Based on Cholesterol Cationic Lipids: Structure-Activity Relationships

“…In the case of monocationic lipids there is a single reference that the in vivo result corresponded to the in vitro one (Ding et al, 2008) and positively charged lipoplexes are significantly more effective than negatively charged ones. Other investigations revealed that the best TE in vivo corresponds to a low N/P ratio, small size of lipoplexes, and negative ξ-potential (Hattori et al, 2007;Gao & Hui, 2001). It is noteworthy when considering polycationic lipids, that lipoplexes that have a total negative charge and small size (200-300 nm) are optimal for both in vitro and in vivo transfection.…”

“…It was found that heterocyclic cationic lipids containing imidazolinium (Solodin et al, 1995) or pyridinium polar heads (Ilies et al, 2006) reveal a higher TE and a reduced level of cytotoxicity in comparison with the classical transfectants. To study the influence of this type of heterocyclic polar head on the TE, the cholesterol-based lipids containing heterocyclic amine connected to the cholesterol residue via urethane (4a-f, 6a), ether (5a-5h) and ester linkers (6b-f) were synthesized (Gao & Hui, 2001;Bajaj et al, 2008c;Medvedeva et al, 2009). The study of the transfection activity for the lipids 4a-f revealed that liposomes 4c/DOPE and 4f/DOPE displayed the highest TE, which from 3 to 6-fold exceeded the TE of DC-Chol (1а)/DOPE and Lipofectamine 2000 (Gao & Hui, 2001).…”

“…To study the influence of this type of heterocyclic polar head on the TE, the cholesterol-based lipids containing heterocyclic amine connected to the cholesterol residue via urethane (4a-f, 6a), ether (5a-5h) and ester linkers (6b-f) were synthesized (Gao & Hui, 2001;Bajaj et al, 2008c;Medvedeva et al, 2009). The study of the transfection activity for the lipids 4a-f revealed that liposomes 4c/DOPE and 4f/DOPE displayed the highest TE, which from 3 to 6-fold exceeded the TE of DC-Chol (1а)/DOPE and Lipofectamine 2000 (Gao & Hui, 2001). The serum (from 1 to 10%) have no effect on cells transfection mediated by these cationic liposomes at different N/P ratios.…”

“…The significant transfection activity attained was attributed to an improved cell binding and uptake of the lipoplexes promoted by the presence of cholesterol (Crook et al, 1998) and/or better stability of the lipoplex in serum (Simberg et al, 2003). In 1991, Gao et al reported the synthesis and application of the cholesterol-based cationic lipid 3-β-[N-(N′,N′-dimethylaminoethyl)carbamoyl]-cholesterol (DC-Chol, 1a), which was combined with DOPE to transfect mammalian cells (Gao & Huang, 1991 (Zhdanov et al, 1998;Gao & Hui, 2001;Geall et al, 2000;Percot et al, 2004;Ding et al, 2008;Medvedeva et al, 2009;Maslov et al, 2010). The cationic amphiphiles containing cholesterol as a hydrophobic residue possess a high transfection activity and a low toxicity, finding use in the studies of both the structure-activity relationships and membrane fusion mechanisms Kearns et al, 2008).…”

On the disulfide‐linker strategy for designing efficacious cationic transfection lipids: an unexpected transfection profile

“…Such complex transfection pathway makes rational design of efficient cationic transfection lipids an arduous task. A number of recent structure-activity investigations [21][22][23][24], including our own [25][26][27][28][29][30], have thrown significant new insights into the various architectural elements of cationic lipids necessary for overcoming the above mentioned cellular barriers involved in lipofection process.…”