Use of Dithiodiglycolic Acid as a Tether for Cationic Lipids Decreases the Cytotoxicity and Increases Transgene Expression of Plasmid DNA in Vitro

Abstract

Two major barriers that limit cationic lipids in gene delivery are low transfection efficiency and toxicity. In the present studies, we used dithiodiglycolic acid as a new tether for the polar and hydrophobic domains of a cationic lipid, cholesteryl hemidithiodiglycolyl tris(aminoethyl)amine (CHDTAEA). We compared the transfection activity and toxicity of CHDTAEA with its nondisulfide analogue and cholesteryl N-(dimethylaminoethyl) carbamate (DC-Chol). The liposomes of CHDTAEA had more than 2 orders of magnitude greater transfection activity than DC-Chol in CHO cells and 7 times greater transfection activity in SKnSH cells. CHDTAEA also demonstrated much less toxicity than the other two lipids. Dithiodiglycolic acid may act as an excellent linker in the application of cationic lipid syntheses.

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

“…Based on such similar lipoplex size range and the same mono-cationic nature of both lipids 1 and 2, the endocytotic cellular uptake efficiencies for the lipoplexes 1 and 2 are unlikely to be dramatically different. Interestingly, the cellular uptake of plasmid DNA complexed with a transfection efficient cholesterol-based disulfide-linker containing cationic lipid has been reported earlier to be even less than that of lipoplexes prepared from the corresponding non-disulfide transfection-inefficient counterpart [32]. Thus, correlating cellular uptake efficiency and transfection efficacies are not that straightforward.…”

“…Towards this end, Tang and Hughes pioneered the use of the disulfide bond as the linker functionality of cationic transfection lipids [31,32]. The rationale behind this elegant approach was to ensure collapsing of the lipid:DNA complex inside the cell cytoplasm after reduction of the disulfide-linker by the intracellular glutathione pool.…”

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

“…Previously, it was demonstrated that the transfection of the plasmid DNA by the glycerolipids containing disulfide bonds was higher compared to the transfection activity of its non-disulfide analogue (Tang & Hughes, 1998). Lipid 8a containing cholesterol, was synthesized and its activity to mediate DNA transfer was compared with the activity of both non-disulfide analogue 8b and DC-Chol (1a) (Tang & Hughes, 1999). In the presence of glutathione (10 mM) a 50% DNA release from the complex with liposomes 8а/DOPE was observed, while the lipoplexes formed by lipid 8b did not release DNA.…”

Rationally Designed Synthetic Vectors for Gene Delivery

“…In our laboratory, we have synthesized a disulfide linker-containing cationic lipid (cholesteryl hemidithiodiglycolyl tris(aminoethyl) amine; CHDTAEA; Fig. 4G) that takes advantage of the high intracellular reductive environment [114]. This can decrease the toxicity while not sacrificing the stability of liposomes in aqueous media [114,115].…”

“…4G) that takes advantage of the high intracellular reductive environment [114]. This can decrease the toxicity while not sacrificing the stability of liposomes in aqueous media [114,115]. Such lipids are selectively stable outside cells, but once internalized can be reduced by intracellular reductive substances such as glutathione.…”