Time of detection of prions in the brain by nanoscale liquid chromatography coupled to tandem mass spectrometry is comparable to animal bioassay

Authors: Silva, Christopher - Chris; Onisko, Bruce; Dynin, Irina; Erickson-Beltran, Melissa; REQUENA, JESUS - University Of Santiago De Compostela

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2021
Publication Date: 2/15/2021
Citation: Silva, C.J., Onisko, B.C., Dynin, I.A., Erickson-Beltran, M.L., Requena, J.R. 2021. Time of detection of prions in the brain by nanoscale liquid chromatography coupled to tandem mass spectrometry is comparable to animal bioassay. Journal of Agricultural and Food Chemistry. 69(7):2279-2286. https://doi.org/10.1021/acs.jafc.0c06241.
DOI: https://doi.org/10.1021/acs.jafc.0c06241

Interpretive Summary: Prions are infectious proteins that are responsible for such agriculturally important diseases as bovine spongiform encephalopathy (BSE) in domestic cattle, scrapie in sheep and goats or chronic wasting disease (CWD) in farmed and wild deer, elk, and related animals (cervids). Prions replicate by inducing a normal cellular prion to adopt the prion conformation or shape. Prion-infected animals contain molecules with both the prion shape and the normal cellular prion shape. To detect the prions, the normal cellular prion protein needs to be removed. The prion shape is resistant to digestion by a protein (proteinase K), but the normal cellular prion protein is not. Proteinase K digestion removes the cellular prion protein, leaving behind a truncated prion form referred to as PrP 27-30. Mass spectrometry was used to quantify the amount of PrP 27-30 in the brains of animals over a 14-week period after they were peripherally infected with prions. PrP 27-30 was detectable after 4 weeks of incubation. These results are consistent with what other researchers found when they used the more sensitive but much more labor and time-intensive bioassay. These results indicate that mass spectrometry detects the presence of prions in an animal’s brain at a time when they are detectable by bioassay, but before they are detectable by immunohistochemical techniques or well before the animals show clinical signs.

Technical Abstract: Detection of prions in asymptomatic animals is an important goal of prion research. We used mass spectrometry to determine the amount of PrP 27-30 present in the brains of hamsters challenged (ip) with the Sc237 strain of hamster-adapted scrapie. Four animals were used per weekly time point for weeks 1-14 post inoculation. PrP 27-30 was detectable in some animals as early as 2 weeks post inoculation. After four weeks, PrP 27-30 was detected in all of the inoculated animals. These results are consistent with those observed in other ip challenged animals that were bioassayed. These results show that the sensitivity of mass spectrometric-based detection of PrP 27-30 is comparable to detection by bioassay.