pH-Triggered Nanoparticle Mediated Delivery of siRNA to Liver Cells in Vitro and in Vivo

Abstract

Recently, we reported for the first time the development of pH-triggered nanoparticles for the functional delivery of small interfering RNA (siRNA) to liver for treatment of hepatitis B virus infections in vivo. Here, we report on systematic formulation and biophysical studies of three different pH-triggered nanoparticle formulations looking for ways to improve on the capabilities of our previous nanoparticle system. We demonstrate how pH-triggered, PEGylated siRNA nanoparticles stable with respect to aggregation in 80% serum can still release siRNA payload at pH 5.5 within 30 min. This capability allows functional delivery to cultured murine hepatocyte cells in vitro, despite a high degree of PEGylation (5 mol %). We also demonstrate that pH-triggered, PEGylated siRNA nanoparticles typically enter cells by clathrin-coated pit endocytosis, but functional delivery requires membrane fusion events (fusogenicity). Biodistribution studies indicate that >70% of our administered nanoparticles are found in liver hepatocytes, post intravenous administration. Pharmacodynamic experiments show siRNA delivery to murine liver effecting maximum knockdown 48 h post administration from a single dose, while control (nontriggered) nanoparticles require 96 h and two doses to demonstrate the same effect. We also describe an anti-hepatitis C virus (HCV) proof-of-concept experiment indicating the possibility of RNAi therapy for HCV infections using pH-triggered, PEGylated siRNA nanoparticles.

Synthetic Nucleic Acid Delivery Systems: Present and Perspectives

“…[253][254][255][256] The majority of these technologies targeted the liver, with the lipoplexes being 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 88 MEND, formulated as YSK05 67b/Chol/PEG 2000 -DMG 107 70/70/3 mol ratio with a diameter of ~50 nm, suppressed HCV replication for two weeks 257 (Entry 1 of Table S2). Similar strategies have been used by other teams for HCV and HBV therapies 172,174 (Entries 2, 3 of Table S2). …”

MicroRNAs and Drug Resistance in Prostate Cancers

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Lipid-Based Nanoparticles in Cancer Diagnosis and Therapy

“…Such nanoparticles are designed for high levels of stability in biological fluid from points of administration to target cells whereupon they become triggered for the controlled release of therapeutic agent payload(s) by changes in local endogenous conditions (such as in pH, t 1/2 , enzyme, redox state, and temperature status), [42–46, 65] or through application of an external/exogenous stimulus (Wright M. et al, 2013, papers in preparation and submission). While much of previous work on this topic has revolved around change(s) in local endogenous conditions [42–46, 65], the development of appropriate exogenous stimuli looks to be a real growth area for the future. In principle, all ABC/ABCD nanoparticles could be triggered to exhibit physical property change(s) through interaction with light, ultrasound, radiofrequency, and thermal radiation from defined sources.…”