The Importance of Poly(ethylene glycol) and Lipid Structure in Targeted Gene Delivery to Lymph Nodes by Lipid Nanoparticles.

Danijela Zukancic,Azizah Algarni,Hareth Al-Wassiti,Emily H Pilkington,Estelle J A Suys,Nghia P Truong

doi:10.3390/pharmaceutics12111068

Danijela Zukancic, Azizah Algarni + Show 4 more

Open Access

https://doi.org/10.3390/pharmaceutics12111068

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Abstract

Targeted delivery of nucleic acids to lymph nodes is critical for the development of effective vaccines and immunotherapies. However, it remains challenging to achieve selective lymph node delivery. Current gene delivery systems target mainly to the liver and typically exhibit off-target transfection at various tissues. Here we report novel lipid nanoparticles (LNPs) that can deliver plasmid DNA (pDNA) to a draining lymph node, thereby significantly enhancing transfection at this target organ, and substantially reducing gene expression at the intramuscular injection site (muscle). In particular, we discovered that LNPs stabilized by 3% Tween 20, a surfactant with a branched poly(ethylene glycol) (PEG) chain linking to a short lipid tail, achieved highly specific transfection at the lymph node. This was in contrast to conventional LNPs stabilized with a linear PEG chain and two saturated lipid tails (PEG-DSPE) that predominately transfected at the injection site (muscle). Interestingly, replacing Tween 20 with Tween 80, which has a longer unsaturated lipid tail, led to a much lower transfection efficiency. Our work demonstrates the importance of PEGylation in selective organ targeting of nanoparticles, provides new insights into the structure–property relationship of LNPs, and offers a novel, simple, and practical PEGylation technology to prepare the next generation of safe and effective vaccines against viruses or tumours.

Highlights

Gene therapy has received considerable interest since the 2006 Nobel prize in medicine [1]
We found that lipid nanoparticles (LNPs) with 1.5% Tween 20 exhibited reduced transfection efficiency when compared to 1.5% poly(ethylene glycol) (PEG)-DSPE LNPs, but their gene expression in the muscle was higher than LNPs stabilized by 3% PEG-DSPE and Tween 80
We report an innovative PEGylation method using Tween 20 to improve targeted gene delivery of LNPs to the lymph nodes after intramuscular administration

Summary

Introduction

Gene therapy has received considerable interest since the 2006 Nobel prize in medicine [1]. Nucleic acids such as small interfering RNA (siRNA), messenger RNA (mRNA) or plasmid DNA (pDNA) are introduced into cells to degrade targeted genes or trigger the production of proteins such as antigens [2,3]. Translation of gene therapies to the clinic remains limited due to challenges associated with in vivo gene delivery [8]. Nucleic acids have molecular weights below the cut off of glomerular filtration by the kidney and are excreted rapidly when entering the systemic circulation [9]. Nucleic acids are prone to degradation by enzymes and negatively charged, which limits their uptake in target tissues and cells [9]. Considerable efforts have been directed toward developing new gene delivery technologies to overcome these significant challenges [10]

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