Gene Delivery Using Ternary Lipopolyplexes Incorporating Branched Cationic Peptides: The Role of Peptide Sequence and Branching

Abstract

Cationic peptide sequences, whether linear, branched, or dendritic, are widely used to condense and protect DNA in both polyplex and lipopolyplex gene delivery vectors. How these peptides behave within these particles and the consequences this has on transfection efficiency remain poorly understood. We have compared, in parallel, a complete series of cationic peptides, both branched and linear, coformulated with plasmid DNA to give polyplexes, or with plasmid DNA and the cationic lipid, DOTMA, mixed with 50% of the neutral helper lipid, DOPE, to give lipopolyplexes, and correlated the transfection efficiencies of these complexes to their biophysical properties. Lipopolyplexes formulated from branched Arg-rich peptides, or linear Lys-rich peptides, show the best transfection efficiencies in an alveolar epithelial cell line, with His-rich peptides being relatively ineffective. The majority of the biophysical studies (circular dichroism, dynamic light scattering, zeta potential, small angle neutron scattering, and gel band shift assay) indicated that all of the formulations were similar in size, surface charge, and lipid bilayer structure, and longer cationic sequences, in general, gave better transfection efficiencies. Whereas lipopolyplexes formulated from branched Arg-containing peptides were more effective than those formulated from linear Arg-containing sequences, the reverse was true for Lys-containing sequences, which may be related to differences in DNA condensation between Arg-rich and Lys-rich peptides observed in the CD studies.

Cargo-Free Nanoparticles Containing Cationic Lipids Induce Reactive Oxygen Species and Cell Death in HepG2 Cells

“…10,11) In addition to siRNA, DOTMA-containing particles have been used for gene delivery vectors as lipo(poly) plexes or polyplexes. 12) These gene delivery methods using DOTMA-NPs have been shown to effectively stimulate the immune response for carcinoma treatment and are, therefore, promising for clinical applications. 13) ROS are considered so-called "double-edged sword" in cells.…”

Gene delivery from supercharged coiled-coil protein and cationic lipid hybrid complex

“…5). For effective gene delivery, the particle size is critical [35] and the ternary lipoproteoplex reveals a more uniform particle size leading to enhanced transfection.…”

“…Recently, lipopolyplexes composed of a cationic lipid and cationic peptide-based ternary complex have been introduced to enhance transfection of nucleic acids [28–34]. While lipopolyplexes have been successfully employed for gene delivery, it depends on the development of branched systems carrying a net positive charge [35]; in such cases, identifying optimal branching, charge and sequence will require various synthetic design strategies.…”

Synthetic vectors for gene delivery: An overview of their evolution depending on routes of administration.

“…Moreover, lipopolyplexes with linear Lys-containing sequences are more effective than the lipopolyplexes with branched Lys-containing peptides. This can be explained by differences observed in the formation of DNA complexes between Arg-rich and Lys-rich peptides [27]. The structure of the peptide sequence also influences formation of complexes with NA.…”