title: Important role of phosphoramido linkage in imidazole-based dioleyl helper lipids for liposome stability and primary cell transfection.
abstract: BACKGROUND
  To optimize synthetic gene delivery systems, there is a need to develop more efficient lipid formulations. Most cationic lipid formulations contain 'helper' neutral lipids because of their ability to increase DNA delivery, in particular by improving endosomal escape of DNA molecules via the pH-buffering effect of protonatable groups and/or fusion with the lipid bilayer of endosomes.
  
  
  METHODS
  We evaluated the influence of the linker structure between the two oleyl chains in the helper lipid on transfection efficiency in cell lines, as well as in primary cells (hepatocytes/cardiomyocytes). We reported the synthesis of two new pH-buffering imidazole helper lipids characterized by a polar headgroup containing one (compound 6) or two (compound 5) imidazole groups and two oleyl chains linked by an amide group. We studied their association with the aminoglycoside lipidic derivative dioleylsuccinylparomomycin (DOSP), which contains two oleyl chains linked to the aminoglycoside polar headgroup via an amide function. We compared the morphology and transfection properties of such binary liposomes of DOSP/5 and DOSP/6 with those of liposomes combining DOSP with another imidazole-based dioleyl helper lipid (MM27) in which a phosphoramido group acts as a linker between the two oleyl chains and imidazole function.
  
  
  RESULTS
  The phosphoramido linker in the helper lipid induces a major difference in terms of morphology and resistance to decomplexation at physical pH for DOSP/helper lipid complexes.
  
  
  CONCLUSIONS
  This hybrid dioleyl linker composition of DOSP/MM27 led to higher transfection efficiency in cell lines and in primary cells compared to complexes with homogeneous dioleyl linker.
authors.affiliation: Unité INSERM UMR 1087, CNRS UMR 6291, Nantes, France.|Université de Nantes, l'institut du thorax, Nantes, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Mével
authors.affiliation: Unité INSERM UMR 1087, CNRS UMR 6291, Nantes, France.|Université de Nantes, l'institut du thorax, Nantes, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Haudebourg
authors.affiliation: Unité INSERM UMR 1087, CNRS UMR 6291, Nantes, France.|Université de Nantes, l'institut du thorax, Nantes, France.
authors.forename: Thibault
authors.initials: T
authors.lastname: Colombani
authors.affiliation: Unité INSERM UMR 1087, CNRS UMR 6291, Nantes, France.|Université de Nantes, l'institut du thorax, Nantes, France.
authors.forename: Pauline
authors.initials: P
authors.lastname: Peuziat
authors.affiliation: Unité INSERM UMR 1087, CNRS UMR 6291, Nantes, France.|Université de Nantes, l'institut du thorax, Nantes, France.|CBMN UMR-CNRS 5248 IECB, Université de Bordeaux 1-IPB, Pessac, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Dallet
authors.affiliation: Unité INSERM UMR 1087, CNRS UMR 6291, Nantes, France.|Université de Nantes, l'institut du thorax, Nantes, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Chatin
authors.affiliation: CBMN UMR-CNRS 5248 IECB, Université de Bordeaux 1-IPB, Pessac, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Lambert
authors.affiliation: UMR CNRS 6521, IFR 148 ScInBioS, Université de Bretagne Occidentale, Université Européenne de Bretagne, Brest, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Berchel
authors.affiliation: Unité INSERM 1078, IFR 148 ScInBioS, Université de Bretagne Occidentale, Université Européenne de Bretagne, Brest Cedex, France.|Service de Génétique Moléculaire et d'histocompatibilité, CHUR, Brest, France.
authors.forename: Tristan
authors.initials: T
authors.lastname: Montier
authors.affiliation: UMR CNRS 6521, IFR 148 ScInBioS, Université de Bretagne Occidentale, Université Européenne de Bretagne, Brest, France.
authors.forename: Paul-Alain
authors.initials: PA
authors.lastname: Jaffrès
authors.affiliation: Unité INSERM 1078, IFR 148 ScInBioS, Université de Bretagne Occidentale, Université Européenne de Bretagne, Brest Cedex, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Lehn
authors.affiliation: Unité INSERM UMR 1087, CNRS UMR 6291, Nantes, France.|Université de Nantes, l'institut du thorax, Nantes, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Pitard
mesh_terms: D000818:Animals; D002412:Cations / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D011992:Endosomes / Q000378:metabolism; D057809:HEK293 Cells; D022781:Hepatocytes; D006801:Humans; D007093:Imidazoles / Q000138:chemical synthesis / Q000737:chemistry*; D008055:Lipids / Q000138:chemical synthesis / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D032446:Myoblasts; D063088:Phosphoramides / Q000737:chemistry*; D061251:Primary Cell Culture; D051381:Rats; D014162:Transfection / Q000379:methods*
chemical_list: D002412:Cations; D007093:Imidazoles; D008055:Lipids; D008081:Liposomes; D063088:Phosphoramides; D004247:DNA
keywords: helper lipid; liposome; non viral vector; primary cell; transfection