Tool For siRNA Delivery Research Articles

Development of Echo-Contrast Gas Entrapping Liposomes as Gene and siRNA Delivery Tool

Development of Echo-Contrast Gas Entrapping Liposomes as Gene and siRNA Delivery Tool

553. Development of Echo-Contrast Gas Entrapping Liposome as Gene and siRNA Delivery Tool

Background: Recently, ultrasound (US) has emerged as a unique method for the delivery of genes into cells and tissues, thus placing it as promising non-viral approach for gene delivery in the clinical settings. Echo-contrast gas entrapping microbubbles and US have been investigated with a view to improving the transfection efficiency of non-viral delivery systems for gene by cavitation. However, conventional microbubbles (Levovist, Optison, etc.) had some problems in stability and targeting ability.

Insight into the mechanism of the peptide-based gene delivery system MPG: implications for delivery of siRNA into mammalian cells.

The improvement of non-viral-based gene delivery systems is of prime importance for the future of gene and antisense therapies. We have previously described a peptide-based gene delivery system, MPG, derived from the fusion peptide domain of HIV-1 gp41 protein and the nuclear localisation sequence (NLS) of SV40 large T antigen. MPG forms stable non-covalent complexes with nucleic acids and improves their delivery. In the present work, we have investigated the mechanism through which MPG promotes gene delivery. We demonstrate that cell entry is independent of the endosomal pathway and that the NLS of MPG is involved in both electrostatic interactions with DNA and nuclear targeting. MPG/DNA particles interact with the nuclear import machinery, however, a mutation which affects the NLS of MPG disrupts these interactions and prevents nuclear delivery of DNA. Nevertheless, we show that this mutation yields a variant of MPG which is a powerful tool for delivery of siRNA into mammalian cells, enabling rapid release of the siRNA into the cytoplasm and promoting robust down-regulation of target mRNA. Taken together, these results support the potential of MPG-like peptides for therapeutic applications and suggest that specific variations in the sequence may yield carriers with distinct targeting features.