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Volume 4

Nano Research & Applications

ISSN: 2471-9838

Page 29


August 16-18, 2018 | Dublin, Ireland




Edition of International Conference on

Nanopharmaceutics and Advanced Drug Delivery



Nano Congress for

Future Advancements

Nano Congress 2018


Nano Drug Delivery 2018

August 16-18, 2018

Simon C W Richardson et al., Nano Res Appl 2018, Volume 4

DOI: 10.21767/2471-9838-C3-014

Attenuated protein toxins as intracellular nucleic acid delivery fibromyalgia and chronic pain vectors

Simon C W Richardson


Benedita Kac

University of Greenwich, UK


any protein toxins have evolved to access a variety of relatively inaccessible intracellular compartments in order to exert

virulence. Counted among this number are proteins such as ricin toxin, shiga toxin, diphtheria toxin and anthrax toxin.

These proteins display diverse architecture ranging from AB5 to AB configurations and depending upon the specific B chain

in question, entertain a number of strategies from direct membrane penetration to utilizing retrograde trafficking pathways

to access a plethora of intracellular compartments including the cytosol. Typically the A chain will exhibit catalytic activity

proportional to both cellular intoxication and virulence. However given the facile nature of protein recombination, attenuation

is relatively simple. Here we describe the ability of attenuated anthrax toxin (ATx) to manipulate endocytic cargo sorting for the

purposes of drug delivery, traversing intracellular compartmental boundaries for nucleic acid delivery. We report not only the

efficiency with which siRNA and antisense effectors are delivered but also the mechanisms they utilize to traverse the barriers

responsible for intracellular compartmentalization. Attenuated Atx:ASO complexes had transfection efficiency approximately

equivalent to Nucleofection®. In HeLa cells, at 200 pmol ASO expression of the target gene was 5.4±2.0% relative to an untreated

control after 24 h. Using 200 pmol ASOs, Nucleofection® reduced Synt5 expression to 8.1±2.1% after 24 h. PA:LFn-GAL4:ASO

transfection of non- or terminally-differentiated THP-1 cells and Vero cells resulted in 35.2±19.1%, 36.4±1.8% and 22.9±6.9%

(respectively) target gene expression after treatment with 200 pmol of ASO and demonstrated versatility. Nucleofection® with

Stealth RNAi™ siRNA reduced HeLa Synt5 levels to 4.6±6.1% whereas treatment with the PA:LFn-PKR:siRNA resulted in

8.5±3.4% Synt5 expression after 24 h (HeLa cells). These data underscore the tractability of this approach to both antisense and

siRNA delivery.

Recent Publications

1. P D Dyer et al. (2016) An

in vitro

evaluation of epigallocatechin gallate (eGCG) as a biocompatible inhibitor of ricin

toxin, Biochim. Biophys. Acta. 1860(7):1541-1550. Doi:10.1016/j.bbagen.2016.03.024.

2. P D Dyer et al. (2015) Disarmed anthrax toxin delivers antisense oligonucleotides and siRNA with high efficiency and

low toxicity. Journal of Controlled Release. 220(PtA):316-328. Doi:10.1016/j.jconrel.2015.10.054.

3. S A Shorter et al. (2017) The potential of toxin-based drug delivery systems for enhanced nucleic acid therapeutic

delivery. Expert Opinion on Drug Delivery. 14(5):685-696. Doi:10.1080/17425247.2016.1227781.

4. S A Shorter et al. (2017) Green fluorescent protein (GFP): is seeing believing and is that enough? Journal of Drug

Targeting. 25(9-10):809-817. Doi:10.1080/1061186X.2017.1358725.

5. MWPettit et al. (2014) Construction and physiochemical characterization of a multi-composite, potential oral vaccine

delivery system (VDS). International Journal of Pharmaceutics. 468(1-2):264-271. Doi:10.1016/j.ijpharm.2014.03.046.


Simon C W Richardson is a Founder, Director and CSO at Intracellular Delivery Solutions Ltd, and Reader (Associate Professor) in Membrane Trafficking and

Drug Delivery, at the University of Greenwich, UK. The driving theme behind his research is the intracellular delivery of antisense and RNAi to the cytosol. He is

currently leading the Cell Biology Research Cluster within the Faculty of Engineering and Science, located at the Medway campus. His lab is currently working

with several technologies based upon attenuated virulence factors that have very low

in vitro

toxicity profiles (and are minimally disruptive to the cell), and very

high efficiency intracellular delivery profiles. We are also examining several methodologies to modulate protein stability and intracellular trafficking to aid the oral

delivery of vaccines.

[email protected]