Prion seeding activity and infectivity in skin samples from patients with sporadic Creutzfeldt-Jakob disease

Abstract

Sporadic Creutzfeldt-Jakob disease (sCJD), the most common human prion disease, is transmissible through iatrogenic routes due to abundant infectious prions [misfolded forms of the prion protein (PrPSc)] in the central nervous system (CNS). Some epidemiological studies have associated sCJD risk with non-CNS surgeries. We explored the potential prion seeding activity and infectivity of skin from sCJD patients. Autopsy or biopsy skin samples from 38 patients [21 sCJD, 2 variant CJD (vCJD), and 15 non-CJD] were analyzed by Western blotting and real-time quaking-induced conversion (RT-QuIC) for PrPSc. Skin samples from two patients were further examined for prion infectivity by bioassay using two lines of humanized transgenic mice. Western blotting revealed dermal PrPSc in one of five deceased sCJD patients and one of two vCJD patients. However, the more sensitive RT-QuIC assay detected prion seeding activity in skin from all 23 CJD decedents but not in skin from any non-CJD control individuals (with other neurological conditions or other diseases) during blinded testing. Although sCJD patient skin contained ~103- to 105-fold lower prion seeding activity than did sCJD patient brain tissue, all 12 mice from two transgenic mouse lines inoculated with sCJD skin homogenates from two sCJD patients succumbed to prion disease within 564 days after inoculation. Our study demonstrates that the skin of sCJD patients contains both prion seeding activity and infectivity, which raises concerns about the potential for iatrogenic sCJD transmission via skin.

Detection of prions in skin punch biopsies of Creutzfeldt–Jakob disease patients

“…The RT‐QuIC test is currently mainly applied to cerebrospinal fluid (CSF) but attempts to adapt the assay to tissue sources that might be easier to collect or represent an alternative procedure in patients with contraindications to lumbar puncture are currently being pursued. Recently, Orrù et al detected prion‐seeding activity in post‐mortem skin samples of CJD patients with an overall sensitivity and specificity of 100% . In the present study, we aimed to validate the diagnostic accuracy of skin RT‐QuIC in another patient series including different disease subtypes and a few samples taken in vitam.…”

Human Tau Isoform Aggregation and Selective Detection of Misfolded Tau from Post-Mortem Alzheimer’s Disease Brains

“…RT-QuIC assay has been used for detection of seeding activities of misfolded proteins, first for prions and then for aSyn and tau in vitro (Atarashi et al, 2008;Orru et al, 2017;Groveman et al, 2018;Sano et al, 2018;Saijo et al, 2017;Kraus et al, 2019). To determine whether various recombinant wild-type human tau isoforms can be converted by the tau aggregate seeds from AD brain samples, we detected autopsied AD and non-AD brain samples from neuropathologically confirmed cadavers (Table 1).…”

“…RT-QuIC Analysis. Tau RT-QuIC assays were conducted as previously described with minor modifications (Orru et al, 2017;Saijo et al, 2017;Kraus et al, 2019;Wang et al, 2019). In brief, each recombinant tau isoform was thawed at room temperature and filtered with a 100 kDa spin column filter (Millipore) to remove unwanted tau aggregates.…”

“…Many protein misfolding diseases, such as AD and other tauopathies (Caughey & Lansbury, 2003), Parkinson's disease , type 2 diabetes , involve analogous pathological accumulation of disease-specific amyloidogenic protein in the form of self-seeding filaments or sub-filamentous deposits. Two methods to amplify misfolded proteins in vitro, the real-time quaking-induced conversion (RT-QuIC) assay and the protein misfolding cyclic amplification protocol (PMCA) are used for ultrasensitive detection in a number of neurodegenerative diseases, such as prion disease (Moda et al, 2014;Orru et al, 2017;Wang et al, 2019), Ab oligomers in AD (Salvadores et al, 2014), and a-synuclein in Parkinson's disease (Fairfoul et al, 2016;Shahnawaz et al, 2017;Groveman et al, 2018). Specifically for misfolded tau detection in AD and other tauopathies such as Pick's disease, detection of the prion-like tau seeding activities by RT-QuIC assays was successfully developed using engineered short fragments of tau or a mixture of tau fragments with mutations as a substrate (Saijo et al, 2017;Kraus et al, 2019).…”

Detection of Pathognomonic Biomarker PrPSc and the Contribution of Cell Free-Amplification Techniques to the Diagnosis of Prion Diseases

“…Given the generalized spread of prions throughout the body for certain prion strains and their presence in highly innervated tissues [266], skeletal muscle, and skin have been also tested for presence of prions. In skin, it seems to be associated to peripheral nerves rather than keratinocytes and has been detected by immunoblotting in scrapie-infected sheep [322], in patients with vCJD [323] and in sCJD patients by bioassay and RT-QuIC [324], and also by RT-QuIC in animal models infected with sCJD, even at pre-clinical stages [325]. Therefore, skin biopsy-based diagnostic test could be feasible soon.…”