Bovine spongiform encephalopathy

What were Stanley Prusiner’s contributions to neuroscience?

Answer: Stanley Prusiner is a neurologist and Nobel Prize winner who discovered and described prions. 

stanley prusiner prion neuroscience

In the 1980s, Stanley Prusiner, an American neurologist, was interested in studying the neurodegenerative disorder bovine spongiform encephalopathy (BSE) and the related human condition, Creutzfeldt-Jakob disease. In specific, he identified that a misfolded proteinaceous agent was able to cause the infection, so he coined the portmanteau prion. In 1997, he and his coworkers won the Nobel Prize in Physiology or Medicine for their work. 

Dr. Prusiner did biochemical research that led to the isolation of the protein disease causing agent. Much of his biochemistry work was done at the University of California San Francisco, and was inspired by a female patient of his who had Creutzfeldt-Jakob disease. The disease was unusual compared to other conditions that were well documented, since it did not elicit a significant immune response, as one would expect from an infection. 

Prusiner published his work in 1982. Initially, much of his research was criticized by the scientific community, who were skeptical of the existence of these agents. Prior to his publication describing prions, the community had believed that only viruses, bacteria and fungi were the causes of diseases, so Prusiner’s research had been groundbreaking.

Prions are particularly scary since they are almost indestructible. For example, they deform at high temperatures as many proteins do (denaturation), but prions often reform into their pathogenic shape after returning to lowered temperatures. Additionally, they are able of self-replication, interacting with harmless proteins to turn them into disease causing agents.

Related prion diseases

Today, prions are known to cause a variety of diseases, almost all of them are incurable, irreversible, and deadly. 

The most well known prion diseases are bovine spongiform encephalopathy (Mad Cow disease) and the human equivalent, Creutzfeldt-Jakob disease. Mad Cow disease causes highly unusual behaviors and difficulty sleeping. Mad Cow disease is easily transmissible between cattle because they were often fed meat and bone meal that came from other cattle who had died from the disease. Pathologically, the brains of the infected cattle had very large holes in the tissue, which is why the disease was described as producing a “sponge-like” appearance - hence, spongiform. Because of major outbreak of the disease in the United Kingdom in the early 90s, government policy had enforced many changes in slaughterhouse laws that led to containing the spread of the disease. For example, they regulated how to properly and safely dispose of tissue from infected animals, especially the trigeminal nerve and other specific parts of nervous tissue that are known to house high densities of prions. 

sheep scrapie prion disease

Scrapie is another prion disease that is found in sheep and goats. Another central nervous system disorder, scrapie mostly resides in the brain and affects the coordination of the animals. It gets its namesake from the observation that the infected animals experience severe itching, causing them to scrape their fur up against whatever they can find. As far as we know, the disease cannot be transmissible to humans. 

In humans, prions can also cause diseases. A prion disease can lead to a very rare condition called fatal familial insomnia, or FFI. As the name describes, the disease causes people to have severe difficulty sleeping, which worsens into insomnia that causes people to stay awake for several nights in a row. In fatal familial insomnia, it was found that the disease causes damage to the thalamus, producing similar holes in the brain as in BSE. Generally, FFI is incurable and lethal within a year from presentation of symptoms.

Kuru is a well-characterized disease that is found among the Fore people of Papua New Guinea. Kuru is a central nervous system disease that causes patients to shake uncontrollably, a lack of coordination, and eventually death. Kuru has sprung up among cannibals in the country, especially among women and children, who were given brains to eat from the recently deceased. As it turns out, the prions that cause kuru live in the brain and they are able to replicate once ingested.