SXL and CJC research proposal for F08 20.109 click here for more information

The Diseases

Normal prion proteins (often denoted as PRP^C) can undergo a conformation change (often denoted as PRP^SC) to become a different isomer. This Prion conformational change is believed to cause many transmissible spongiform encephalopathies or TSEs which the CDC defines on their website define as " a family of rare progressive neuodegenerative disorders that affect both humans and animals". Some of these diseases include kuru, mad cow disease, and Creutzfeldt-Jakob Disease or CJD. While these diseases are rare they are extremely infective. It is believed that this prion can be passed to other other organisms through blood transfusions and consuming protein with this isoform. Additionally these prions are excreted and can remain infective once it leaves an organism. These diseases often have periods of time in which they incubate in the body and do not show any symptoms. Sometimes this incubation can be as short as a few months and sometimes it can be as long as decades.

The Prion protein

While the prion protein has been studied extensively during the last decade especially in Europe, there is still much unknown about how the prion protein works and why a conformational change is so dramatic in affected an organism. However, the PRP^SC form of the prion appears to aggregate and form clumps or plaques on neuron tissue which after a long enough time causes dementia and loss of motor control.

The Problem

People infected with the conformational change of prion protein often do not know if they have it until it progresses and late symptoms of neuodegenrative properties appear. One of the few ways to test for presence of this conformation during the incubated time of this folded protein is through invasive procedures that require a biopsy of brain or of neuron cells. While these prions exist in blood, urine, or fluids of the eye, they have such a low concentration it is almost impossible to detect presence of misfolded prions. Recently, a procedure known as PMCA was discovered that allows the concentration of prions with the wrong conformation to be amplified. This procedure has open the doorway to exploring noninvasive tests to determine if someone has a good chance of having the disease.

Our Goal

We would like to design and test an assay that uses this PMCA method and improves the efficiency of 80% in detecting PRP^SC prion protein found by Gonzalez-Romero et. al. If the assay appear promising, we will test it further and hopefully down the road we can introduce this assay or test as a common and easy indicator that could be conducted by a hospital to examine if a person does or does not have this form of prion protein folding before outward symptoms are shown. While we are using the PMCA method, our assay will not use a western blot testing for partial proteinase K resistance. Our initial plan is to use plasminogen binding property of PRP^SC conformational prions to help discriminate between different conformations of prion protein and improve upon this procedure to give more reliable results. However, right now we are also considering possibly using a suspected relationship between deubiquitylation and prion protein aggregation of the PRP^SC conformation and the suspected relationship between copper homeostasis and the prion to help discriminate different isomer conformations.

Papers and Resources

Plasminogen binds to disease-associated prion protein of multiple species

Dection of infectious prions in urine

Non-invasive, ultra-sensitive, high-throughput assays to quantify rare biomarkers in the blood

A Pitfall in Diagnosis of Human Prion Diseases Using Detection of Protease-resistant Prion Protein in Urine

Immunoglobulins in Urine of Hamsters with Scrapie

The risk of transmission of variant Creutzfeldt–Jakob disease via contact lenses and ophthalmic devices

Prions and the proteasome

UV-Light Exposed Prion Protein Fails to Form Amyloid Fibrils

Regulation of Prion Gene Expression by Transcription Factors SP1 and MTF-1