Amphiphilic Block Copolymers Promote Gene Delivery In Vivo to Pathological Skeletal Muscles

Abstract

We reported that amphiphilic block copolymers hold promise as nonviral vectors for the delivery of plasmid DNA, ranging from 4.7 to 6.2 kb, to healthy muscle for the production of local or secreted proteins. To evaluate the efficiency of these vectors to deliver large plasmid DNA molecules to pathological muscles, plasmid DNAs of various lengths were complexed with Lutrol or poloxamine 304 and injected intramuscularly into dystrophic muscles. Lutrol-DNA and poloxamine 304-DNA complexes promoted gene transfer into muscles of the naturally occurring mouse model for DMD (mdx) in a dose- and plasmid DNA size-dependent manner. For small plasmid DNAs encoding reporter genes, this improvement over naked DNA was smaller in mdx than in the wild-type control strain. By contrast, Lutrol enabled us to deliver the large plasmid (16.1 kb) encoding the rod-deleted dystrophin in mdx mouse muscle, whereas the same amount of naked DNA did not lead to dystrophin expression, under the same experimental conditions. Lutrol-treated mdx mice showed the production of dystrophin in large numbers of muscle fibers. More importantly, we also found that expressing dystrophin with Lutrol led to restoration of the dystrophin-associated protein complex. Thus, we conclude that block copolymers constitute a novel class of vectors for the delivery of large plasmid DNA not only to healthy muscles but also to pathological muscle tissues.

Relationships between the physicochemical properties of an amphiphilic triblock copolymers/DNA complexes and their intramuscular transfection efficiency

“…Thereby we aimed to draw correlations between their physicochemical properties and their transfection efficiency, which is of crucial importance for the development of nonviral vectors. In our previous works, we have reported that mixing DNA with PE6400 block copolymer or Lutrol ® increased either reporter and therapeutic genes expression in skeletal or cardiac muscles and in lungs, including the corresponding pathological tissues such as Duchenne Muscular Distrophy muscles and cystic fibrosis lungs (10,12,13). Proofs of PEO-PPO-PEO-based formulations effectiveness have also been reported by Lemieux et al (8) who have used mixture of L61 and F127 to transfect muscle.…”

Physicochemical Parameters of Non-Viral Vectors that Govern Transfection Efficiency

“…These observations prompted researchers to explore and define new breakthrough approaches for in vivo gene transfer. In this context, others polymers displaying few or no charges have been recently developed and appear very promising to transfect efficiently and safely various organs in vivo after loco-regional administration in muscle and heart [52][53][54][55][56][57], lung [58] and eyes [59]. These block polymers consisting of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) exhibit amphiphilic properties in aqueous solutions, because PPO homopolymer phase-separates from water at relative low temperature, whereas POE is well soluble in water.…”

Neue Behandlungsansätze bei erblich bedingten Myopathien

“…Genmutationen, die zu einem Verlust des codierenden Proteins führen -jedoch nicht zu einem neuen toxischen Produkt -sind theoretisch einer Genersatztherapie zugänglich. Das zu ersetzende Gen kann hierfür mittels "nackter" DNA [37], DNA komplexiert mit kationischen Polymeren als Träger [38] oder mittels viraler Vektoren [39,40] in den Empfängerorganismus, im Speziellen in das Muskelgewebe, geschleust werden (• " Abb. 3).…”