No abstract

No abstract

For efficient transgene delivery and expression, internalized nucleic acids should quickly escape from cellular endosomes and lysosomes to avoid enzymatic destruction and degradation. Here, we report a novel strategy for safe and efficient endosomal/lysosomal escape of transgenes mediated by Pluronic L64, a neutral amphiphilic triblock copolymer. L64 enhanced the permeability of biomembranes by structural disturbance and pore formation in a concentration- and time-dependent manner. When applied at optimal concentration, it rapidly reached the endosome/lysosome compartments, where it facilitated escape of the transfection complex from the compartments and dissociation of the complex. Therefore, when applied properly, L64 not only significantly increased polyethylenimine- and liposome-mediated transgene expression, but also decreased the cytotoxicity occasioned by transfection process. Our studies revealed the function and mechanism of neutral amphiphilic triblock copolymer as potent mediator for safe and efficient gene delivery.

Hydrophilic-hydrophobic-hydrophilic triblock copolymers, such as Pluronic L64, P85, and P105, have attracted more attention due to their enhancement in muscular gene delivery. In the present study, a new kind of electroneutralized triblock copolymer, LPL, dendron G2(L-lysine-Boc)-PEG2k-dendron G2(L-lysine-Boc), was designed and investigated. This hydrophobic-hydrophilic-hydrophobic copolymer is composed of a structure reverse to that of L64, one of the most effective materials for intramuscular gene delivery so far. Our results showed that LPL exhibited good in vivo biocompatibility after intramuscular and intravenous administration. LPL mediated higher reporter gene expression than L64 in assays of β-galactosidase (LacZ), luciferase, and fluorescent protein E2-Crimson. Furthermore, LPL-mediated mouse growth hormone expression significantly accelerated mouse growth within the first 10 days. Altogether, LPL-mediated gene expression in skeletal muscle exhibits the potential of successful gene therapy. The current study also presented an innovative way to design and construct new electroneutralized triblock copolymers for safe and effective intramuscular gene delivery.

No abstract