WRAP-based nanoparticles for siRNA delivery: a SAR study and a comparison with lipid-based transfection reagents

Abstract

Recently, we designed novel amphipathic cell-penetrating peptides, called WRAP, able to transfer efficiently siRNA molecules into cells. In order to gain more information about the relationship between amino acid composition, nanoparticle formation and cellular internalization of these peptides composed of only three amino acids (leucine, arginine and tryptophan), we performed a structure–activity relationship (SAR) study. First, we compared our WRAP1 and WRAP5 peptides with the C6M1 peptide also composed of the same three amino acids and showing similar behaviors in siRNA transfection. Afterwards, to further define the main determinants in the WRAP activity, we synthesized 13 new WRAP analogues harboring different modifications like the number and location of leucine and arginine residues, the relative location of tryptophan residues, as well as the role of the α-helix formation upon proline insertions within the native WRAP sequence. After having compared the ability of these peptides to form peptide-based nanoparticles (PBNs) using different biophysical methods and to induce a targeted gene silencing in cells, we established the main sequential requirements of the amino acid composition of the WRAP peptide. In addition, upon measuring the WRAP-based siRNA transfection ability into cells compared to several non-peptide transfection agents available on the markets, we confirmed that WRAP peptides induced an equivalent level of targeted gene silencing but in most of the cases with lower cell toxicity as clearly shown in clonogenic assays.

Membrane Internalization Mechanisms and Design Strategies of Arginine-Rich Cell-Penetrating Peptides

“…When the amount of arginine remains the same, but only the position of the arginine amino acids in the sequence is changed, will the function of the arginine-rich CPP change? The work of Konate et al [ 79 ] revealed the answers for us. To maintain the same charge number as the parental peptides, they created peptides with two more arginine residues at both ends but two fewer arginine residues in the middle of the sequence (Arg = 4 for W1, W5, W1-4R, and W5-4R).…”

Oleyl Conjugated Histidine-Arginine Cell-Penetrating Peptides as Promising Agents for siRNA Delivery

“…Few studies have been conducted lately to discover the role of arginine residues in lipid-based siRNA transfection agent. Recently, Konate et al conducted a comprehensive study in which they designed novel amphipathic cell-penetrating peptides, called WRAP, for siRNA transfection [54]. The current study is designed on the same lines to discover the lipid modified amphiphilic CPPs for efficient siRNA delivery.…”

Ongoing Clinical Trials of Nonviral siRNA Therapeutics

“…166,167 Compared to naked siRNA, it was demonstrated that WRAP siRNAs significantly silenced firefly luciferase in U87 cells. 168 Further optimizations on CPP nanoparticles have been developed for enhanced cellular uptake and tumor targeting capability. Ren et al developed a CPP conjugated to a LyP-1 ligand and a membrane translocating domain (TP) to selectively bind and be taken up by ovarian tumor cells expressing the surface receptor p32.…”

“…Tryptophan and arginine-rich amphipathic peptides (WRAP) have been explored for siRNA delivery. WRAPs are a 15- to 16-amino-acid sequence containing tryptophan, arginine, and leucine residues, forming an α-helical structure able to encapsulate siRNA. , Compared to naked siRNA, it was demonstrated that WRAP siRNAs significantly silenced firefly luciferase in U87 cells …”