Degradation of the disease-associated prion protein by a serine protease from lichens.

PLoS ONE
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Abstract

The disease-associated prion protein (PrPTSE), the probable etiological agent of the transmissible spongiform encephalopathies (TSEs), is resistant to degradation and can persist in the environment. Lichens, mutualistic symbioses containing fungi, algae, bacteria and occasionally cyanobacteria, are ubiquitous in the environment and have evolved unique biological activities allowing their survival in challenging ecological niches. We investigated PrPTSE inactivation by lichens and found acetone extracts of three lichen species (Parmelia sulcata, Cladonia rangiferina and Lobaria pulmonaria) have the ability to degrade prion protein (PrP) from TSE-infected hamsters, mice and deer. Immunoblots measuring PrP levels and protein misfolding cyclic amplification indicated at least two logs of reductions in PrPTSE. Degradative activity was not found in closely related lichen species or in algae or a cyanobacterium that inhabit lichens. Degradation was blocked by Pefabloc SC, a serine protease inhibitor, but not inhibitors of other proteases or enzymes. Additionally, we found that PrP levels in PrPTSE-enriched preps or infected brain homogenates are also reduced following exposure to freshly-collected P. sulcata or an aqueous extract of the lichen. Our findings indicate that these lichen extracts efficiently degrade PrPTSE and suggest that some lichens could have potential to inactivate TSE infectivity on the landscape or be a source for agents to degrade prions. Further work to clone and characterize the protease, assess its effect on TSE infectivity and determine which organism or organisms present in lichens produce or influence the protease activity is warranted.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Degradation of the disease-associated prion protein by a serine protease from lichens.
Series title PLoS ONE
DOI 10.1371/journal.pone.0019836
Volume 6
Issue 5
Year Published 2011
Language English
Contributing office(s) National Wildlife Health Center
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title PLoS ONE
Country United States
State Michigan, Minnesota, Oregon, Wisconsin
Online Only (Y/N) N
Additional Online Files (Y/N) N