Branched Amphiphilic Cationic Oligopeptides Form Peptiplexes with DNA: A Study of Their Biophysical Properties and Transfection Efficiency

Abstract

Over the past decade, peptides have emerged as a new family of potential carriers in gene therapy. Peptides are easy to synthesize and quite stable. Additionally, sequences shared by the host proteome are not expected to be immunogenic or trigger inflammatory responses, which are commonly observed with viral approaches. We recently reported on a new class of branched amphiphilic peptide capsules (BAPCs) that self-assemble into extremely stable nanospheres. These capsules are capable of retaining and delivering alpha-emitting radionuclides to cells. Here we report that, in the presence of double stranded plasmid DNA, BAPCs are unable to form. Instead, depending of the peptide/DNA ratios, the peptides either coat the plasmid surface forming nanofibers (high peptide to DNA ratio) or condense the plasmid into nanometer-sized compacted structures (at low peptide to DNA ratios). Different gene delivery efficiencies are observed for the two types of assemblies. The compacted nanometer-sized structures display much higher transfection efficiencies in HeLa cells. This level of transfection is greater than that observed for a lipid-based reagent when the total number of viable transfected cells is taken into account.

Prospects, challenges and current status of RNAi through insect feeding

“…Nanoparticles can be made up of various molecules such as cationic polymers, peptides, sugars, lipids, and metals, and their applications are quite diverse . During RNAi through feeding, nanoparticles can act as molecular carriers and promote translocation of dsRNA across the gut epithelial cell membranes . Nanoparticles can also shield and protect nucleic acids from nuclease degradation inside the gut.…”

Incorporating 131I into a PAMAM (G5.0) dendrimer-conjugate: design of a theranostic nanosensor for medullary thyroid carcinoma

“…Thus, the complete surgical resection of all tumour tissue is difficult or impossible. 4 With advances in molecular biology, numerous researchers focus on targeted therapies and biological therapies of MTC. 2,5,6 Compared to the large antibody molecules, small peptides are advantageous, because they can avoid macromolecular protein immunogenicity, slow clearance, and other shortcomings.…”

Organization and Structure of Branched Amphipathic Oligopeptide Bilayers

“…S6). 11 If the BAP bilayer is semi-permeable to water, the flux of water into or out of the dye-filled capsules will change the internal Eosin Y concentration and lead to changes in the fluorescence intensity. To normalize for batch to batch variations with Eosin Y encapsulation from different experiments, we only examine the relative fluorescence intensity change when diluted in hyper- or hypo-tonic solutions with respect to the reference BAPCs that were diluted into isotonic solutions (see Methods for details).…”

“…Both peptides bis(Ac-FLIVIGSII)-K-K 4 and bis(Ac-FLIVI)-K-K 4 were synthesized as described previously 8,9,11 using solid phase peptide chemistry. They were dissolved individually into 2,2,2-trifluoroethanol and absorbance of phenylalanine was taken to determine the concentration.…”

“…8, 9 The resulting BAP capsules (BAPCs) have diameters ranging from 20 nm to 2 µm depending on the assembly and annealing temperatures. 11 BAPCs have several attractive properties as a potential delivery vesicle. They can encapsulate macromolecules, up to ~12 kDa proteins and have long intracellular life-time (> 2 weeks) after uptake.…”