Reversible mode of binding of serum proteins to DOTAP/cholesterol lipoplexes: A possible explanation for intravenous lipofection efficiency

Dmitri Simberg, Aryeh Weiss, Yechezkel Barenholz

    Research output: Contribution to journalArticlepeer-review

    35 Scopus citations

    Abstract

    There are many indications that interaction of serum proteins with intravenously injected cationic lipoplexes disturbs lipofection in vitro and in vivo. However, transfection with certain lipid compositions such as N-[1-(2,3-dioleoyloxy)propyl]-N,N,N,-trimethylammonium chloride (DOTAP)/cholesterol appears to be more resistant to serum and more efficacious. We investigated the mechanism of interaction between fluorescently labeled lipoplexes of the above composition and fluorescently labeled serum proteins. Fluorescence resonance energy transfer measurements in vitro indicate that serum proteins interact instantly and closely with the DOTAP/cholesterol lipoplexes. In accord with this, preinjection of fluorescently labeled serum into mice before injection of lipoplexes showed an immediate association of proteins with lipoplexes. Serum proteins colocalized with the lipoplexes in the lung vasculature; however, they dissociated from the cationic lipid as soon as 1 hr postinjection, probably because of displacement of serum proteins from lipoplexes by extracellular proteoglycans. Indeed, this displacement was imitated by heparin, a typical glycosaminoglycan, and could be explained by the inability of weakly acidic serum proteins to neutralize the DOTAP/cholesterol electrical surface potential ψ0. The stability of the cationic lipid ψ0 in serum could be a key reason for the high lung association and transfection efficiency with this formulation.

    Original languageEnglish
    Pages (from-to)1087-1096
    Number of pages10
    JournalHuman Gene Therapy
    Volume16
    Issue number9
    DOIs
    StatePublished - Sep 2005

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