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In vitro and in vivo delivery of siRNA via VIPER polymer system to lung cells
- Feldmann, Daniel P., Cheng, Yilong, Kandil, Rima, Xie, Yuran, Mohammadi, Mariam, Harz, Hartmann, Sharma, Akhil, Peeler, David J., Moszczynska, Anna, Leonhardt, Heinrich, Pun, Suzie H., Merkel, Olivia M.
- Journal of controlled release 2018 v.276 pp. 50-58
- cations, composite polymers, cultured cells, flow cytometry, gene silencing, lungs, melittin, messenger RNA, mice, microscopy, plasmids, quantitative polymerase chain reaction, reverse transcriptase polymerase chain reaction, small interfering RNA, transfection
- The block copolymer VIPER (virus-inspired polymer for endosomal release) has been reported to be a promising novel delivery system of DNA plasmids both in vitro and in vivo. VIPER is comprised of a polycation segment for condensation of nucleic acids as well as a pH-sensitive segment that exposes the membrane lytic peptide melittin in acidic environments to facilitate endosomal escape. The objective of this study was to investigate VIPER/siRNA polyplex characteristics, and compare their in vitro and in vivo performance with commercially available transfection reagents and a control version of VIPER lacking melittin. VIPER/siRNA polyplexes were formulated and characterized at various charge ratios and shown to be efficiently internalized in cultured cells. Target mRNA knockdown was confirmed by both flow cytometry and qRT-PCR and the kinetics of knockdown was monitored by live cell spinning disk microscopy, revealing knockdown starting by 4 h post-delivery. Intratracheal instillation of VIPER particles formulated with sequence specific siRNA to the lung of mice resulted in a significantly more efficient knockdown of GAPDH compared to treatment with VIPER particles formulated with scrambled sequence siRNA. We also demonstrated using pH-sensitive labels that VIPER particles experience less acidic environments compared to control polyplexes. In summary, VIPER/siRNA polyplexes efficiently deliver siRNA in vivo resulting in robust gene silencing (>75% knockdown) within the lung.