Prions - An Overview
The Prion
In the late 1960s, radiation biologist Tikvah Alper observed that the infectious agent of the transmissible spongiform encephalopathies (TSE) was much smaller than a virus, and physicist J.S. Griffith introduced the theory that TSE could be propagated through protein conformation. This theory was developed to explain the discovery that the mysterious infectious agent causing the neurodegenerative diseases such as scrapie (in sheep and goats) and Creutzfeldt-Jakob disease (in humans) was sensitive to agents that disrupt proteins but resisted ultraviolet radiation, which acts to break down nucleic acids present in viruses and all living things.
However, it wasn’t until the 1980s that Stanley Prusiner and his team at the University of California in San Francisco were able to successfully purify this infectious material, a significant scientific milestone that changed the dogma of infectious agents entirely. Dr. Prusiner aptly named this infectious agent “prion” (pronounced pree-on), short for proteinaceous infectious particle (-on by analogy to virion, a viral particle).
Prions are now known to be composed of an altered host protein, appropriately named the prion protein (PrP). PrP is a normal cell membrane protein expressed throughout the body in healthy people and animals. It has been proposed that normal PrP can become misfolded in disease in such a manner that it provides a guide or template for the refolding of neighboring normal PrP. Once infectious prions are introduced to the brain, all of the normal PrP can become converted to the abnormal infectious form by this “template directed misfolding” mechanism.
Prion Diseases
Prion diseases are fatal, transmissible diseases associated with a sponge-like degeneration of brain tissue in humans and animals. In animals, the most common of these diseases include scrapie (in sheep and goats), bovine spongiform encephalopathy (BSE in cattle, also known as mad cow disease), and chronic wasting disease (CWD in deer and elk). Some examples of prion diseases in humans include fatal and sporadic familial insomnia, Creutzfeldt-Jakob disease (CJD) and its many varieties, and Kuru. Investigations continue into the potential link of prion diseases to other neurodegenerative disorders such as Alzheimer’s disease.
Economic Impact to Canada
In May 2003, Canada’s cattle industry reeled when a confirmed case of BSE was discovered in Alberta. Overnight, the world’s borders closed to Canadian cattle. Canada’s economic loss stemming from this first BSE diagnosis is estimated at over $6 billion. The crisis left in its trail a heightened awareness about food safety, surveillance measures, and health issues.
Responding to the Need
PrioNet was born out of the federal government’s goal to overcome the impacts caused by prion diseases in Canada.
PrioNet capitalizes on strengths in basic, applied, and social science research to help solve the various problems associated with prion diseases. PrioNet supports multidisciplinary projects, provides training and networking opportunities, facilitates the transfer of research results to industrial receptors, and promotes knowledge exchange about prions and prion diseases.
PrioNet’s activities are developing strategies for a sustained, rational approach to mitigate, and ultimately control, prion diseases in Canada. Last Updated: 5/18/2010 1:36:45 PM
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