PRION BASICS Why Prion Research?

With Canada being a leading beef producer and 70 per cent of Canada’s beef cattle being raised in Alberta, bovine spongiform encephalopathy (BSE) is a critical issue to Albertans.


The first case of BSE in Canada was in 1993, found in a beef cow that had been imported from the United Kingdom. Then, in May 2003, Canada’s first domestic case of BSE was discovered in an Alberta herd. Though the province had stringent testing in place for BSE prior to the 2003 case, further research was needed to understand and prevent this disease. However, the importance of prion research extends beyond BSE. The disposal of specified risk materials, the potential spread of chronic wasting disease and human prion diseases are also concerns and the work of prion researchers is important to Alberta’s economic well-being as well as human health.

 

 

BSE can have a devastating economic impact

  • When Canada’s first case of BSE was found in May 2003, international borders closed immediately and beef and cattle prices plummeted;
  • The BSE crisis in 2003 cost the Canadian economy $11 million per day while the borders were closed; and
  • Canada has made a strong recovery since 2003 largely due to the quality of science and surveillance done in Canada.
     

The challenge of specified risk materials (SRM)

  • SRM is material that has the potential to transmit BSE, such as the brain, spinal cord and other tissues of cattle;
  • Previously, SRM generated revenue, but that is no longer the case due to an enhanced feed ban that eliminates SRM from all animal feeds, pet foods and fertilizers; and
  • Research is being done to find new disposal methods and ways to use SRM valuably.
     

The potential spread of chronic wasting disease (CWD)

  • The first case in a wild deer in Alberta was found in 2005;
  • The potential spread from wild to farmed elk and deer poses economic concerns, particularly for farmers who trade in live elk and elk products; and
  • It also could impact herd size, hunting, tourism industries and the food and hunting practices of Aboriginal communities.
     

Prion diseases affect human health

  • Creutzfeldt-Jakob disease (CJD) affects one person per million per year. This is about 34 new cases in Canada annually;
  • Researchers are also investigating ways in which other proteins misfold in diseases like Alzheimer's and Parkinson’s. These other protein misfolding diseases have some basic similarities to prion diseases; and
  • The knowledge gained from studying prion diseases might aid research with regards to a cure or treatment for protein misfolding human neurodegenerative diseases.


 

Alberta is known globally for its research excellence in life sciences, and it was a logical step to build on existing resources and extend that excellence to prion research. Studying how and why proteins misfold and the genetics, diagnoses and treatments of prion diseases will have positive implications for both animal and human health issues.

What is a Prion?

A prion is an infectious prion protein that has misfolded. It is found in mammals and causes infectious diseases of the nervous system in humans and animals such as bovine spongiform encephalopathy in cattle and chronic wasting disease in cervids (deer, elk and moose).
 

Prion proteins also exist in a normal cellular form 

  • Prion proteins only become infectious and cause disease when misfolded
  • Normal prion protein is associated with the lipid layer of cell membranes. This makes prion proteins insoluble and therefore more difficult to study; and
  • The precise function of normal prion proteins is unknown, but they have been found to play a role in immune responses, cell to cell communications, the transport of copper (an essential nutrient) and the protection of cells from electro-chemical stress.
     

All proteins fold and can misfold, but not all misfolded proteins cause disease

  • Misfolded prions are different from other misfolded proteins as they can act as an infectious agent and transfer certain diseases within and across species; and
  • When proteins misfold the body normally gets rid of them. When prions misfold they begin to collect, converting their normal neighbouring prion proteins into misfolded ones. They form large clusters called fibrils, which accumulate in plaques.
     

Understanding the basic science of prion proteins, both in their normal cellular form and their infectious form, is the first step to understanding how they cause disease and developing therapies to combat prion diseases.