Stanley B. Prusiner Biography (1942-)
Prusiner won the 1997 Nobel Prize in Physiology or Medicine for his ground-breaking, yet controversial, work on a type of protein particle, a prion, thathe hypothesized was responsible for a number of fatal neurodegenerative disorders, including Creutzfeldt-Jakob disease (CJD) and mad cow disease.
Prusiner was born on May 28, 1942, in Des Moines, Iowa. He earned his B.A., cum laude, at the University of Pennsylvania, in 1964, and then went onto receive an M.D. in 1968 from the same university. Prusiner then served his internship and residency at the prestigious University of California at SanFrancisco (UCSF) from 1968 to 1969, where he later served a residency in neurology. Prusiner soon became interested in neurodegenerative diseases. This interest was in part developed after one of his patients died of CJD, a disease of the cerebral cortex which leads to dementia and eventual death.
As a result of this experience, Prusiner learned that an entire category of diseases was yet to be elucidated. At the time, researchers thought many neurodegenerative diseases were caused by so-called slow viruses, which would takeyears and sometimes decades to incubate in the host. As early as 1967, a British team working at Hammersmith Hospital had proposed the existence of an infective agent that lacked nucleic acid in the sheep disease known as scrapie(so called because infected sheep tend to scrape the wool off their bodies).Their hypothesis grew out of the fact that when the genetic substance was destroyed in known infected material, extracts from the infected material were still able to spread the disease. This led to the conclusion that perhaps theinfective agents in such animal diseases as scrapie and kuru (a disease of the cannibalistic Fore people of New Guinea which had been traced to the ritualeating of the brains of departed relatives) were non-viral.
Prusiner combined a zeal for research with a disarming political sense to wingrants for the study of such diseases, including CJD, scrapie, kuru, fatal familial insomnia, and bovine spongiform encephalopathy (BSE), or mad cow disease. Over three decades, he managed to gain funding totaling 56 million dollars from the National Institutes of Health (NIH).
Expanding on work by British researchers as well as the NIH's Rocky MountainLaboratories, which had shown similarities between kuru and scrapie, Prusinerset up a research team at UCSF employing ultimately a quarter million mice infected with diseased brain matter in an attempt to isolate the infective agent in neurodegenerative diseases. Such research was laborious and time-consuming, for the incubation period in mice took upwards of 200 days. Early breakthroughs occurred when Prusiner switched from mice to hamsters, as the onset of illness in those animals would occur twice as fast. By 1981, Prusiner was able to conclude that a protein was the causative agent in these brain diseases, and he dubbed this agent the prion. Such proteins were resistant to any modification of nucleic acids. When he and his team added enzymes that destroynucleic acids in genes, they discovered that there was no reduction in the infective power of prions.
By 1992, Prusiner's research more clearly demonstrated the nature of the interaction between prion proteins. Prusiner showed that when the gene encoding for the prion protein in mice was destroyed, such mice (called prion knock-outmice) proved resistant to the diseases when injected with preparations of disease-causing prion protein. Later, when the prion gene was re-activated andthe same mice were injected with diseased matter, they again became susceptible to infection. Though the role of prion proteins is unclear, what has become clear is the close causative effect of prions in a variety of neural diseases.
The diseases which Prusiner studied are life-threatening to only a tiny fraction of the world's population--the annual death toll of CJD in the United States annually, for example, is about 225, less than the number of traffic fatalities in two days. However, as the Nobel committee noted, Prusiner's research could lead to new therapies for a larger array of neurological disorders such as Alzheimer's and Parkinson's disease, which may or may notbe caused by protein-based infective agents. In the case of prion-based diseases, Prusiner has suggested gene therapy to curtail the production of prionproteins and thus eliminate the spread of such diseases, as was done with hisprion knock-out mice.
July 2004: Prusiner and his colleagues at the University of California--San Francisco created the first synthetic prion protein and have shown thatthis protein alone can produce a deadly infection in mice similar to mad cowdisease. Their research was reported in an issue of Science. Source: New York Times, www.nytimes.com, July 30, 2004.