Presence and Seeding Activity of Pathological Prion Protein (PrPTSE) in Skeletal Muscles of White-Tailed Deer Infected with Chronic Wasting Disease

Abstract

Chronic wasting disease (CWD) is a contagious, rapidly spreading transmissible spongiform encephalopathy (TSE), or prion disease, occurring in cervids such as white tailed-deer (WTD), mule deer or elk in North America. Despite efficient horizontal transmission of CWD among cervids natural transmission of the disease to other species has not yet been observed. Here, we report for the first time a direct biochemical demonstration of pathological prion protein PrPTSE and of PrPTSE-associated seeding activity, the static and dynamic biochemical markers for biological prion infectivity, respectively, in skeletal muscles of CWD-infected cervids, i. e. WTD for which no clinical signs of CWD had been recognized. The presence of PrPTSE was detected by Western- and postfixed frozen tissue blotting, while the seeding activity of PrPTSE was revealed by protein misfolding cyclic amplification (PMCA). Semi-quantitative Western blotting indicated that the concentration of PrPTSE in skeletal muscles of CWD-infected WTD was approximately 2000-10000 -fold lower than in brain tissue. Tissue-blot-analyses revealed that PrPTSE was located in muscle-associated nerve fascicles but not, in detectable amounts, in myocytes. The presence and seeding activity of PrPTSE in skeletal muscle from CWD-infected cervids suggests prevention of such tissue in the human diet as a precautionary measure for food safety, pending on further clarification of whether CWD may be transmissible to humans.

Modified Protein Misfolding Cyclic Amplification Overcomes Real-Time Quaking-Induced Conversion Assay Inhibitors in Deer Saliva To Detect Chronic Wasting Disease Prions

“…PMCA has also been used to amplify and detect CWD prions in a variety of tissue types where other assays have failed, including in skeletal muscle and whole blood (21,22). In contrast, PMCA was unable to detect CWD prions in urine and saliva samples that induced infection in transgenic mouse bioassays (23).…”

Challenges in managing the risks of chronic wasting disease

“…Sampling with these tests is difficult and cumbersome in the wild (Gilch et al, 2011). The protein misfolding cyclic amplification (PMCA) assay can detect low levels of misfolded prions in tissues and body fluids (Sigurdson and Aguzzi, 2007;Johnson et al, 2012) and detects animals in the early stages of CWD pathogenesis (Daus et al, 2011;Haley et al, 2012). A high-throughput version of PMCA known as the real-time quaking induced conversion (RT-QuIC) can detect CWD prions in saliva , urine (John et al, 2013) and blood (Elder et al, 2013) in asymptomatic animals.…”

Disease Transmission by Misfolded Prion-Protein Isoforms, Prion-Like Amyloids, Functional Amyloids and the Central Dogma

“…PrP TSE does not only spread from cell to cell but also from individual to individual as it naturally occurs in scrapie and CWD [ 17 , 18 , 19 ]. Prions can exist as different strains similarly to bacteria or viruses.…”