Treatment with an artificial, nontoxic prion protein (PrP) could substantially delay or even prevent the development of prion disease, according to a new study (Claudio Soto and colleagues) in a hamster model of prion disease. Researchers found that synthetic prions — dubbed ‘anti-prions’ — competed with pathogenic PrP to protect the animals against the disease.
Previous work suggested that different strains of prions compete with each other and cause distinct disease characteristics.
Strategy: To produce a new form of abnormal PrP that retains the ability to convert the normal PrP, but creates a product that is not toxic and does not cause disease.
Anti-prion: It converts the normal protein into an innocuous form so that normal protein is not available to be converted into the pathological form during prion infection.
They purified PrP from bacteria that were transfected with a plasmid containing the PrP gene, then denatured and annealed the protein to form anti-prion aggregates. They injected the anti-prions into hamsters that were infected with the pathogenic 263K strain of PrP. Animals treated with anti-prions at the same time as or prior to infection with 263K prions survived longer than control 263K‑infected animals. The anti-prions also completely prevented disease in a proportion of hamsters that were treated with low concentrations of 263K prions.
Furthermore, they found that the anti-prions could inhibit conversion of normal PrP to pathogenic PrP by 263K prions in vitro, supporting the theory that the anti-prions exert their effect by interfering with PrP replication.
“Similar agents could be produced to treat other more common neurodegenerative disorders such as Alzheimer and Parkinson disease.”