Highly infectious prions are not directly neurotoxic

Area of Science:

• Neuroscience
• Molecular Biology
• Infectious Diseases

Background:

• Prions cause fatal neurodegenerative diseases in humans and animals.
• These diseases involve misfolded prion protein assemblies.
• Prions are assumed to be directly neurotoxic.

Purpose of the Study:

• To directly test the neurotoxicity of pure infectious prions.
• To investigate the relationship between prion infectivity and toxicity.
• To explore the mechanisms underlying prion-induced neurodegeneration.

Main Methods:

• Development of methods for obtaining exceptionally pure prions from mouse brain.
• Correlation of defined prion structures with infectivity.
• Testing the toxicity of pure prions on cultured neurons.
• Treatment of prion homogenates with sodium lauroylsarcosine.

Main Results:

• Exceptionally pure, intact infectious prions demonstrated no direct neurotoxicity.
• Brain homogenates from prion-infected mice were highly toxic to neurons.
• Sodium lauroylsarcosine treatment eliminated toxicity without affecting prion infectivity.

Conclusions:

• Prion infectivity and neurotoxicity can be mechanistically uncoupled.
• The direct neurotoxic effect of prions is questionable.
• This research opens new avenues for understanding and treating prion diseases.