A new amphipathic, amino-acid-pairing (AAP) peptide as siRNA delivery carrier: physicochemical characterization and in vitro uptake.
RNA interference has emerged as a powerful tool in biological and pharmaceutical research; however, the enzymatic degradation and polyanionic nature of short interfering RNAs (siRNAs) lead to their poor cellular uptake and eventual biological effects. Among nonviral delivery systems, cell-penetrating peptides have been recently employed to improve the siRNA delivery efficiency. Here we introduce an 18-mer amphipathic, amino-acid-pairing peptide, C6, as an siRNA delivery carrier. Peptide C6 adopted a helical structure upon coassembling with siRNA. The C6-siRNA coassembly showed a size distribution between 50 and 250 nm, confirmed by dynamic light scattering and atomic force microscopy. The C6-siRNA interaction enthalpy and stoichiometry were 8.8 kJ·mol(-1) and 6.5, respectively, obtained by isothermal titration calorimetry. A minimum C6/siRNA molar ratio of 10:1 was required to form stable coassemblies/complexes, indicated by agarose gel shift assay and fluorescence spectroscopy. Peptide C6 showed lower toxicity and higher efficiency in cellular uptake of siRNA compared with Lipofectamine 2000. Fluorescence microscopy images also confirmed the localization of C6-siRNA complexes in the cytoplasm using Cy3-labeled siRNAs. These results indicate high capabilities of C6 in forming safe and stable complexes with siRNA and enhancing its cellular uptake.
Department of Chemical Engineering, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Mousa
M
Jafari
Wen
W
Xu
Sheva
S
Naahidi
Baoling
B
Chen
P
P
Chen
D000818:Animals; D016466:CHO Cells; D002232:Carbocyanines / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D057846:Cell-Penetrating Peptides / Q000737:chemistry*; D006224:Cricetinae; D003412:Cricetulus; D004337:Drug Carriers / Q000737:chemistry* / Q000633:toxicity; D008055:Lipids / Q000737:chemistry; D010316:Particle Size; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics; D014162:Transfection
D002232:Carbocyanines; D057846:Cell-Penetrating Peptides; D004337:Drug Carriers; D008055:Lipids; C086724:Lipofectamine; D034741:RNA, Small Interfering; C089187:cyanine dye 3