Recharging cationic DNA complexes with highly charged polyanions for in vitro and in vivo gene delivery

Abstract

The intravenous delivery of plasmid DNA complexed with either cationic lipids (CL) or polyethyleneimine (PEI) enables high levels of foreign gene expression in lung. However, these cationic DNA complexes cause substantial toxicity. The present study found that the inclusion of polyacrylic acid (pAA) with DNA/polycation and DNA/CL complexes prevented the serum inhibition of the transfection complexes in cultured cells. The mechanism mediating this increase seems to involve both particle size enlargement due to flocculation and electrostatic shielding from opsonizing serum proteins. The use of pAA also increased the levels of lung expression in mice in vivo substantially above the levels achieved with just binary complexes of DNA and linear PEI (lPEI) or CL and reduced their toxicity. Also, the use of a 'chaser' injection of pAA 30 min after injection of the ternary DNA/lPEI/pAA complexes further aided this effort to reduce toxicity while not affecting foreign gene expression. By optimizing the amount of pAA, lPEI, and DNA within the ternary complexes and using the 'chaser' injection, substantial levels of lung expression were obtained while avoiding adverse effects in lung or liver. These developments will aid the use of cationic DNA complexes in animals and for eventual human gene therapy.

Structure-dependent immunostimulatory effect of CpG oligodeoxynucleotides and their delivery system

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The role of counterions in the membrane-disruptive properties of pH-sensitive lysine-based surfactants

“…Moreover, recharging cationic complexes with anionic compounds has been reported as a promising method to overcome the adverse effects of cationic complexes [22].…”

A review of RGD-functionalized nonviral gene delivery vectors for cancer therapy

“…61 Therefore, it is needed to produce bio-inert hydrophilic polymers that can shield the positive surface charge in order to achieve in vivo stability. Trubetskoy et al 62 prepared ternary complexes with a negatively charged surface by adding small amount of polyanion, polyacrylic acid (PAA), to preformed pDNA/polycation complexes. These pDNA/PEI/PAA ternary complexes prevented serum inhibition for transfection in vitro and showed substantially higher gene expression in vivo than pDNA/PEI binary complexes.…”