Evaluation of Two Cationic Delivery Systems for siRNA

Abstract

Small interference RNA (siRNA) is an important research tool, and also has the potential for clinical application. RNA interference (RNAi) approaches allow degradation of selective mRNA coding for pathogenic or disease-related proteins. RNAi pathway can be taken advantage of by the delivery of chemically synthesized siRNA. To fully attain its potential a sufficient siRNA must be delivered to the cell's cytoplasm. Cellular delivery of polyanions such as siRNA, while a challenging problem, may be addressed by the use of cationic macromolecules, the two major classes being lipids and polymers. In this study we compared two model cationic vectors liposomes (lipoplexes) and polyethelyenimine (PEI) (polyplexes). Complexes of the cationic macromolecules and siRNA did not differ in terms of their cellular uptake as determined by flow cytometry. However, it was demonstrated that the lipoplexes decomplexed more easily than the polyplexes. Differences in the biological activity of the siRNA were observed using commercially available siTOX siRNA. Lipoplexes resulted in dose-dependent siRNA activity; to 76.4 +/- 5.9% cell death was seen 48 hours posttransfection using 80 nmol siTOX. In summary, the selection of delivery vector can have a profound impact on biological activity of siRNA molecules. siRNA decomplexation from the cationic vector might be an important factor in the future development of new vectors.

Fast degrading polyesters as siRNA nano-carriers for pulmonary gene therapy

“…In the case of Lipofectamine, no siRNA could be released from the lipoplexes with heparin. However, recent studies showed that lipoplexes decomplex more easily than polyplexes, which can be explained by their fusogenic properties with cell membranes leading to the release of the siRNA [39].…”

“…As mentioned above biodegradability is a key factor for long-term pulmonary application to avoid side-effects caused by accumulation [39][40][41]. The first breakthrough in pulmonary drug delivery was achieved with PLGA microparticles [42], due to their low toxicity and biodegradable character.…”

Enhanced Transfection Rates of Small-Interfering RNA Using Dioleylglutamide-Based Magnetic Lipoplexes

“…The intracellular delivery efficiency of cationic lipid-based nanoparticles can be affected by the type of cationic lipids used (Akinc et al, 2008), meaning that the selection of cationic lipids is critical for effective internalization of siRNA in magnetic lipoplexes. Moreover, as compared with polyplexes, lipoplexes were reported to decomplex more easily in the cells (Yadava et al, 2007). Since glutamic acid-derived cationic lipid DG was previously shown to help boost intracellular delivery of siRNA after 24 hours of incubation (Suh et al, 2009), we herein tested the magnetofection of DG-based cationic liposomes.…”

Effect of small interfering RNA 3'-end overhangs on chemosensitivity to thymidylate synthase inhibitors

“…Significant efforts have been placed, therefore, on developing nanoparticle technologies to facilitate siRNA cellular uptake. A wide range of molecules have been developed as delivery systems, and they include cationic lipids, carbon nanotubes, poly(lactic-coglycolic) acid (PLGA), polyethylenimine (PEI), peptides, dendrimers, and silicon and gold microparticles [5-11]. PEI has been used as an effective DNA plasmid delivery vehicle but has limited capacity for siRNA delivery [5,12].…”

“…A wide range of molecules have been developed as delivery systems, and they include cationic lipids, carbon nanotubes, poly(lactic-coglycolic) acid (PLGA), polyethylenimine (PEI), peptides, dendrimers, and silicon and gold microparticles [5-11]. PEI has been used as an effective DNA plasmid delivery vehicle but has limited capacity for siRNA delivery [5,12]. Recently, Bolcato-Bellemin and colleagues extended the 3' end of the siRNA creating longer complimentary overhangs of five or eight nucleotides, thereby allowing PEI to effectively deliver these siRNA molecules into cells [13].…”