Novel neutral imidazole-lipophosphoramides for transfection assays

Abstract

New helper lipids, possessing an imidazole polar head, have been synthesized and included in formulations for transfection assays; these new helper lipids can improve the transfection by a factor of up to 100 compared to the use of DOPE as co-lipid.

Enhancement of dendritic cells transfection in vivo and of vaccination against B16F10 melanoma with mannosylated histidylated lipopolyplexes loaded with tumor antigen messenger RNA

“…16,21 O,O-dioleyl-N-[3N-(N-methylimidazolium iodide)propylene] phosphoramidate (lipid 1) and O,Odioleyl-N-histamine phosphoramidate (lipid 2) were synthesized as described (Supplementary Figure S1). 18,19 β-Dmannopyranosyl-N-dodecylhexadecanamide (Man-lipid) was synthesized as described. 22 Plasmids pTG11033 [pCMV-Luc; 9514 base pairs (bp), a gift from Transgène S.A., Strasbourg, France] and pCMV-EGFP (5310 bp) were pDNA encoding the luciferase gene of Photinus pyralis (firefly luciferase, FLuc) and the EGFP under control of a cytomegalovirus promoter, respectively.…”

“…16 Recently, we have designed new imidazole/imidazolium binary liposomes (termed Lip100) made with a cationic [O,O-dioleyl-N-(3N-(N-methylimidazolium iodide)propylene) phosphoramidate)], lipid 1, and a neutral [O, O-dioleyl-N-histamine phosphoramidate], co-lipid 2, in a molar ratio of 1:1 (Supplementary Figure S1, found in the online version of this article). 18,19 Lipid 1 possesses an N-methylimidazolium polar head conferring a permanent positive charge used for nucleic acid DNA condensation. The imidazole group of co-lipid 2 is not alkylated on the nitrogen atoms and can acquire a cationic charge when the pH of the medium drops below pH 6 favoring the endosome destabilization and nucleic acids delivery in the cytosol.…”

New Lipo-Phosphoramidates for Gene Delivery

“…The incorporation of this motif into the structure of a lipophosphoramide led us to synthesize imidazole-lipophosphoramidates as exemplified by lipid 3. 9 This compound is easily obtained by an Atherton-Todd reaction that involves both dioleylphosphite and histamine. The formulation of the lipid 3 in association with the cationic lipid 4 10 ( Figure 2) produces a supramolecular assembly that is characterized by its capacity to compact pDNA and to transfect cells efficiently (in vitro assays).…”

Neutral Liposomes and DNA Transfection

“…With this modified geometry a new intermolecular packing is realized, able to induce an increase of the phase transition at the physiological conditions. The achievements just shown were based on the concept to modify DOPE: a different approach to the search for more efficient helpers has been realized by synthesizing completely new lipids characterized by the presence of an imidazole polar head (Mével et al, 2008). These lipophosphoramides are neutral at physiological pH: the protonation occurring in the acidic compartments of the cell, namely the endosomes, induces fusion of liposomes with endosomes and structural changes that favour the release of DNA in the cytosol.…”