Amphiphilic Peptides for Efficient siRNA Delivery.

Saghar Mozaffari,Parvin Mahdipoor,Robert Lamboy,Ryley Hall,Melissa Coyle,Keykavous Parang,Hamidreza Montazeri Aliabadi,Farideh Amirrad,Emira Bousoik,Abdulaziz Alasmari

doi:10.3390/polym11040703

Saghar Mozaffari, Parvin Mahdipoor + Show 8 more

Open Access

https://doi.org/10.3390/polym11040703

Copy DOI

Journal: Polymers	Publication Date: Apr 17, 2019
Citations: 19	License type: CC BY 4.0

Affiliation: Chapman University, Target (United States)

Abstract

A number of amphiphilic cyclic peptides—[FR]4, [WR]5, and [WK]5—containing hydrophobic and positively-charged amino acids were synthesized by Fmoc/tBu solid-phase peptide methods and evaluated for their efficiency in intracellular delivery of siRNA to triple-negative breast cancer cell lines, MDA-MB-231 and MDA-MB-468, in the presence and absence of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). Among the peptides, [WR]5, which contains alternate tryptophan (W) and arginine (R) residues, was found to be the most efficient in the delivery of siRNA by improving the delivery by more than 3-fold when compared to other synthesized cyclic peptides that were not efficient. The data also showed that co-formulation of [WR]5 with lipid DOPE significantly enhanced the efficiency of siRNA delivery by up to ~2-fold compared to peptide alone. Based on the data indicating the efficiency of [WR]5 in siRNA delivery, peptides containing arginine residues on the ring and tryptophan residues on the side chain, [R6K]W6 and [R5K]W5, were also evaluated, and demonstrated improved delivery of siRNA. The presence of DOPE again enhanced the siRNA delivery in most cases. [WR]5, [R5K]W5, and [R6K]W6 did not show any significant toxicity in MDA-MB-231, MDA-MB-468, and AU565 WT cells at N/P ratios of 20:1 or less, in the presence and absence of DOPE. Silencing of kinesin spindle protein (KSP) and Janus kinase 2 (JAK2) was evaluated in MDA-MB-231 cells in the presence of the peptides. The addition of DOPE significantly enhanced the silencing efficiency for all selected peptides. In conclusion, peptides containing tryptophan and arginine residues were found to enhance siRNA delivery and to generate silencing of targeted proteins in the presence of DOPE.

Highlights

Post-transcriptional regulation of protein expression is an important intracellular mechanism that relies on the interference of non-coding RNAs (RNAi) and a protein complex containing Argonaute protein (AGO) and cofactors [1]
Human AGO protein subfamily consists of AGO1, 2, 3, and 4 and bind to microRNAs and small interfering RNAs [2]. siRNA would lose one of the strands, and the guide strand is incorporated into AGO-containing protein complex
After the protected linear peptide formation was confirmed by matrix-assisted laser desorption/ionization (MALDI) mass spectroscopy resin

Summary

Introduction

Post-transcriptional regulation of protein expression is an important intracellular mechanism that relies on the interference of non-coding RNAs (RNAi) and a protein complex containing Argonaute protein (AGO) and cofactors [1]. The guide strand directs the RISC complex to the target mRNA, and the binding of the guide strand to the mRNA (based on complementary sequences) will trigger the cleavage and degradation of mRNA, which is known as “silencing” [3]. This intracellular mechanism has been the inspiration for different exogenous. Throughout the last two decades, efficient non-viral siRNA delivery strategies have been pursued, which include different physical approaches [4]. The use of physical strategies can be highly effective in siRNA delivery to a small population of cells [5]; these approaches can jeopardize the integrity of cellular membrane and are restricted as in vitro investigational tools [6]

Methods

Results

Conclusion