Boost of serum resistance and storage stability in cationic polyprenyl-based lipofection by helper lipids compositions

Lipofection is a widely used molecular biology technique and one of the most promising non-viral gene therapy strategies. However, one of the main drawbacks of using cationic lipids-based lipoplexes in DNA/RNA delivery is serum-associated inhibition of transfection. We have addressed this issue using PTAI (trimethylpolyprenylammonium iodides)-based lipofection model. To overcome serum-sensitivity we used 100 different formulations based on different PTAI, various helper lipids compositions, lipoplex surface modifications with polyethylene glycol (PEG), and precondensation of DNA with poly-L-lysine (PLL). Multicomponent helper lipids compositions boosted serum resistance and largely improved long-term storage of PTAI-based reagents. This was observed, in particular, for PTAI with longer isoprenoid chains. Additionally, our PTAI-based carriers were efficient for DNA and RNA delivery and safe for human red blood cells (RBC). Moreover, a broad array of the modifications used resulted in an important observation - a diverse susceptibility of various cell types to different compositions was noted. Overall, our results show that helper lipids composition mediates efficient serum-resistant DNA/RNA lipofection. Additionally, multicomponent PTAI-based reagents are promising gene delivery carriers both, at the cellular and organismal level.

Efficient and non-toxic gene delivery by anionic lipoplexes based on polyprenyl ammonium salts and their effects on cell physiology

BACKGROUND

One of the major challenges limiting the development of gene therapy is an absence of efficient and safe gene carriers. Among the nonviral gene delivery methods, lipofection is considered as one of the most promising. In the present study, a set of cationic polyprenyl derivatives [trimethylpolyprenylammonium iodides (PTAI)] with different lengths of polyprenyl chains (from 7, 8 and 11 to 15 isoprene units) was suggested as a component of efficient DNA vehicles.

METHODS

Optimization studies were conducted for PTAI in combination with co-lipid dioleoylphosphatidylethanolamine on DU145 human prostate cancer cells using: size and zeta potential measurements, confocal microscopy, the fluorescein diacetate/ethidium bromide test, cell counting, time-lapse monitoring of cell movement, gap junctional intercellular coupling analysis, antimicrobial activity assay and a red blood cell hemolysis test.

RESULTS

The results obtained show that the lipofecting activity of PTAI allows effective transfection of plasmid DNA complexed in negatively-charged lipoplexes of 200-500 nm size into cells without significant side effects on cell physiology (viability, proliferation, morphology, migration and gap junctional intercellular coupling). Moreover, PTAI-based vehicles exhibit a potent bactericidal activity against Staphylococcus aureus and Escherichia coli. The developed anionic lipoplexes are safe towards human red blood cell membranes, which are not disrupted in their presence.

CONCLUSIONS

The developed carriers constitute a group of promising lipofecting agents of a new type that can be utilized as effective lipofecting agents in vitro and they are also an encouraging basis for in vivo applications.