Biodegradable Nanoparticles of mPEG-PLGA-PLL Triblock Copolymers as Novel Non-Viral Vectors for Improving siRNA Delivery and Gene Silencing

Ming-Jie Zhu,You-Rong Duan,Ying Sun,Lian-Fang Du,Chun-Hui Wang,Jing Du,Pei-Feng Liu,Qiu-Sheng Shi

doi:10.3390/ijms13010516

Abstract

Degradation of mRNA by RNA interference is one of the most powerful and specific mechanisms for gene silencing. However, insufficient cellular uptake and poor stability have limited its usefulness. Here, we report efficient delivery of siRNA via the use of biodegradable nanoparticles (NPs) made from monomethoxypoly(ethylene glycol)-poly(lactic-co-glycolic acid)-poly-l-lysine (mPEG-PLGA-PLL) triblock copolymers. Various physicochemical properties of mPEG-PLGA-PLL NPs, including morphology, size, surface charge, siRNA encapsulation efficiency, and in vitro release profile of siRNA from NPs, were characterized by scanning electron microscope, particle size and zeta potential analyzer, and high performance liquid chromatography. The levels of siRNA uptake and targeted gene inhibition were detected in human lung cancer SPC-A1-GFP cells stably expressing green fluorescent protein. Examination of the cultured SPC-A1-GFP cells with fluorescent microscope and flow cytometry showed NPs loading Cy3-labeled siRNA had much higher intracellular siRNA delivery efficiencies than siRNA alone and Lipofectamine-siRNA complexes. The gene silencing efficiency of mPEG-PLGA-PLL NPs was higher than that of commercially available transfecting agent Lipofectamine while showing no cytotoxicity. Thus, the current study demonstrates that biodegradable NPs of mPEG-PLGA-PLL triblock copolymers can be potentially applied as novel non-viral vectors for improving siRNA delivery and gene silencing.

Highlights

Small interfering RNA is a promising biological strategy for treatment of diverse diseases, because of their superior ability to silence target genes in a specific manner
A novel Monomethoxypoly(ethylene glycol) (mPEG)-PLGA-PLL triblock copolymer was obtained by acidolysis of mPEG-PLGA-PZLL
The results measured by the Gel permeation chromatography (GPC) method showed that mPEG-PLGA-PLL triblock copolymer had a molecular weight of 11 kDa

Summary

Introduction

Small interfering RNA (siRNA) is a promising biological strategy for treatment of diverse diseases, because of their superior ability to silence target genes in a specific manner. It has been demonstrated that siRNA induces sequence-specific degradation of complementary mRNA, leading to knock down of a target protein in post-transcriptional level [1,2]. Various cationic polymers, peptides, and lipids have been extensively utilized to form nanosized polyelectrolyte complexes via electrostatic interactions with siRNA [5,6,7]. These polyelectrolyte complexes could protect siRNA from degradation by nucleases and facilitate cellular uptake of siRNA into target cells or tissues by an endocytic pathway [8−10]. Much effort has been dedicated to the development of efficient carrier materials that are non-toxic, biocompatible and biodegradable

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Conclusion