Advancements in Medical Technology in Viral and Prionic InfectionsAubrey Lewis1, Ruchi Patel1, Zach Pipkin2, David Rash1

1Biological Sciences, 2Textiles

abstractInfectious agents such as viruses and prions spread through organ systems via multiple pathways. Viruses attack the body by replicating themselves inside of the cells of living organisms, while prions are misfolded proteins that can result in neurological damage. Many research efforts are dedicated to understanding these diseases, as well as establishing new treatment methods with better technology. While antiviral drugs and injections are effective, viral resistance still remains an issue. With prionic diseases, treatment is currently being focused on slowing down disease progression by diminishing the rate of replication with the use of various chemicals. An example of a technology that is being used to improve treatment methods includes nanomedicine, which allows for devices to be built at a molecular scale in order to target harmful cells. Recently, scientists have developed silver nanoparticles containing antiviral activity against the H1N1 influenza A virus. Researchers have also found gold nanoparticles to show curing effects on prion-infected cells. In addition to nanotechnology, light-emitting polymer technology could soon replace the need for harmful chemical treatments and surgery. In the future, scientists could possibly implement technologies such as luminescent conjugated polymers as anti-prion compounds. With these newer technologies, methods currently used in treating diseases such as viruses and prions should be greatly improved in the near future.

backgroundViruses: Viruses are infectious agents with high mutation rates and methods of natural selection, meaning they can evolve and replicate very quickly, making treatment more difficult.

Methods & ResultsA chitosan solution was prepared in the lab by mixing various solutions and Ag NP composites. The Ag NP composites were developed in various sizes in order to observe the effect of size on Ag NP’s antiviral activity. Human influenza A virus was obtained and viral suspension was added to the Ag NP/Ch composite Antiviral activity was calcualated.1

Gold nanoparticles were coated with oppositely charged polyelectrolytes and tested to see if they could have any potential inhibition of prion protein aggregation effects and prevent prion conversion and replication in mice.2

Researchers suggest that luminescent conjugated polymers (LCPs) may possess antiprion properties. In order to test this hypothesis, mice were cerebrally inoculated with a strain of prion diseases and injected with LCP.3

DISCUSSION

REFERENCES1. Mori Y, Ono T, Miyahira Y, Nguyen VQ, Matsui T, Ishihara M. Antiviral activity of silver nanoparticle/chitosan composites against H1N1 influenza A virus. Nanoscale research letters [Internet]. 2013 January;8(1):93. Available from: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3606407&tool=pmcentrez&rendertype=abstract

2. Margalith I, Suter C, Ballmer B, Schwarz P, Tiberi C, Sonati T, Falsig J, Nyström S, Hammarström P, Aslund A, et al. Polythiophenes inhibit prion propagation by stabilizing prion protein (PrP) aggregates. The Journal of biological chemistry [Internet]. 2012 June 1 [cited 2014 March 19];287(23):18872–87. Available from: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3365923&tool=pmcentrez&rendertype=abstract

3. Ai Tran HN, Sousa F, Moda F, Mandal S, Chanana M, Vimercati C, Morbin M, Krol S, Tagliavini F, Legname G. A novel class of potential prion drugs: preliminary in vitro and in vivo data for multilayer coated gold nanoparticles. Nanoscale [Internet]. 2010 December [cited 2014 March 20];2(12):2724–32. Available from: http://www.ncbi.nlm.nih.gov/pubmed/20944860

Prions: Prions are infectious protein particles that cause neurological disease in the brains of host organisms by causing the misfold of healthy proteins that aggregate to form porous legions in the brain, thereby inhibiting neural communication. There is no cure for prion diseases but there is much work being done with yeast cells, synthetic chemicals, and nanoparticles.

Nanomedicine: Over time, nanomedicine has allowed for scientists and researchers to develop many mechanisms including drug delivery systems. In addition to many other uses, large surface area ratio of the nanoparticles enable them to add functionalities by attaching molecules such as ligands to the surface.

Polymers: Polymer science has great potential benefit for future textile, biological, and medical applications. Polymers are useful and interesting molecules in medicine, science, and production due to their unique chemical and physical properties as well as their (generally) low cost of production.

Introduction

Scientists have found that amphiphilic copolymer polycyanocrylate nanoparticles that are PEGylated diffuse more efficiently through the blood-brain barrier than non-PEGylated nanoparticles. PEGylation can provide water solubility to hydrophobic drugs and proteins.

Hypothesis

We hypothesize that PEGylated polycyanoacrylate nanoparticles may serve as a vector for astemizole delivery in bovine models for treatment of bovine spongiform encephalopathy.

Research Design

In our proposition, the drug astemizole is carried by a hydrophobic polycyanocrylate particle core which is surrounded by the hydrophilic PEG part. Astemizole was chosen as the experimental drug in this study because it is an antihistamine drug that has been shown to cross the blood brain barrier in order to bind with protein folds related to prion diseases, and is a current focus of prion treatment research. We plan on infecting three groups of female cattle (aged 12 years, similar body weight) with Bovine Spongiform Encephalopathy (BSE). The experiment will be conducted when the three groups are at an intermediate stage of the disease; in other words, non-clinical symptoms will be observed. One group of cattle will be the control group and will receive no treatment for their BSE. The next group will receive the drug astemizole through a non-PEGylated nanoparticle to assess how quickly the drug works without the aid of polyethylene glycol polymer chains expediting its cross of the blood-brain barrier. The final group will receive both the anti-prion drug astemizole and the PEGylated nanoparticles to see how quickly the drug works with the help of an amphiphilic copolymer nanoparticle. The presence of the astemizole as well as whether or not the nanoparticles are PEGylated or not represent the independent variables. The dependent variable is the number of dense plaque fiber buildups caused by prion protein aggregates. These will be counted in a sample of brain tissue from each cow after it is euthanized after a time period of six months.

• Antiviral activity of the Ag NP/Ch increased with the increasing amount of Ag NPs, though stronger antiviral activity was generally observed from smaller sized Ag NPs.

• Chitosan treatment alone did not exhibit antiviral activity

• Overall, this suggests Ag NPs are essential for antiviral activity of the composites.

Fig. 2: Survival Time: This graph describes the survival time among the three different treatment groups used in the experiment

In vivo, only 2A-treated animals showed a significant increase of survival time when compared with controls. However, treatment with nanoparticles 5S was not as effective.

Fig. 1: Effect of the nanoparticles on fibril formation and ASA lag phase compared between different molecular devices: Graph A shows the results from the SpectraMax M5 molecular device. Graph B shows the results from the Gemini EM instruments.

In Graph A, 2A and 5S, used in concentrations of 50 pM and 200 pM respectively, both prolonged the “lag phase” by around 5–15 hours, which shows results of a much slower kinetics than the control which is found in Graph B.In vitro, these gold nanoparticles directly interacted with PrP and prevented it from converting into the pathogenic PrPSc-like form.

Figure A – PrPC is in a reversible thermodynamic equilibrium with PrP*, which aggregates into amyloid fibrils PrPSc. When the fibrils reach a certain length, fragmentation occurs, which allows for the newly formed ends of the fragments to now act as sites for further fibril growth.

Figure B – The antiprion activity of the LCPs seems to be based on interactions with PrPSc aggregates, possibly enhancing compactness. LCP coated PrPSc embed preexisting prions and even PrPC. The higher compactness of the PTAA treated aggregates ultimately causes less fragmentation reducing the number of particles that can replicate.

RML control miceNanogold 2A treated miceNanogold 5S treated mice

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RESEARCH PROPOSAL

• Viral and prionic infections affect global health and developing better understanding of these diseases as well as perfecting sciences like nanomedicine and polymer science will shed light on improved and novel treatment options.

• Although science is still trying to solve many questions related to prionic diseases and is currently working on understanding these diseases, the main focus lies in targeting prion proteins without harming the normal neural proteins.

Future Work:• The biggest problem that scientists are experiencing is that when attempting to

denature prionic proteins, they also denature normal proteins that are needed to live.

• Since many individuals that are affected with prion diseases live in rural areas, it would be difficult to provide the treatment. The treatment would also need to be fairly inexpensive to help everyone infected with prions.

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