Stanley Prusiner at the SGM: Prion Biology and Diseases
Monday, April 6th, 2009
Stanley Prusiner was awarded the first ever SGM Prize Medal (to a microbiologist of international standing whose work has had a far-reaching impact beyond microbiology) at the SGM Spring meeting at Harrogate on 1st April 2009. MicrobiologyBytes was there and this is a summary of his Prize lecture.
Prions are infectious proteins which multiply by binding to a host cell protein and converting it into insolubile fibrils (“amyloid“). Prions are associated with infectious, inherited and sporadic diseases – a feature unique to these entities. Tikvah Alper was the first person to identify prions in the 1960s, but when Prusiner started working on them in 1974, at first he didn’t believe the protein-only hypothesis. After eight years of failing to be able to identify any nucleic acid associated with them, in 1982 he changed his mind and invented the name prion (“pree-on”).
In prion diseases, the cellular form of the protein, PrPc, is converted into a disease-associated form, PrPSc. If prions really are infectious proteins, PrPSc produced in bacteria should be able to cause disease – and it does. It is also possible to produce synthetic amyloids with different biological properties – essentially strains of the protein.
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Quinacrine cures cultured cells of prions. In mice, the drug increases survival time of infected animals by up to 20%, but recently concluded clinical trials in humans have shown little effect. Prusiner’s group have found that quinacrine does work in stationary phase cells – such as those in the brain. Future trials of anti-prion (or amyloid) drugs need to be carried out in stationary cells. The latest assay uses genetically-modified mice which express luciferase when glial cells are disturbed. The resulting luminescence can be detected in the brains of live mice, and signs of disease can be recorded even before any neurological symptoms appear. This is up to eight times faster than waiting for the mice to die and examining their brains, and only requires one tenth of the animals. Prusiner hopes to use this approach to study Alzheimer’s and Parkinson’s disease, which also involve brain injury and amyloid deposits.
Stanley Prusiner’s take home message to all the students present was: it’s important to be lucky! But as Robin Weiss, SGM President, pointed out, Pasteur said: Fortune favours the prepared mind!
Related:
- Alzheimer’s Disease and Prions
- The Origin of BSE
- What the heck are prions for?
- Drugs for treatment of prion infections
- What drove the cow mad? Lessons from a fish
