Abstract:Prion diseases are associated with the conformational conversion of the cellular prion protein (PrPC) into the pathological scrapie isoform (PrPSc) in the brain. Both the in vivo and in vitro conversion of PrPC into PrPSc is significantly inhibited by differences in amino acid sequence between the two molecules. Using protein misfolding cyclic amplification (PMCA), we now report that the recombinant full-length human PrP (rHuPrP23-231) (that is unglycosylated and lacks the glycophosphatidylinositol anchor) is … Show more
“…TgNN6h mice express human PrP-129M with the two N-linked glycosylation sites mutated to eliminate glycosylation (24), whereas TgWV mice express wild-type human PrP-129V (25). We observed that TgNN6h and TgWV mice were susceptible to sCJDMM2 or sCJDVV2 prion strains, respectively, after an intracerebral inoculation of 129 polymorphism-matched sCJD brain homogenates; this was confirmed by Western blotting (fig.…”
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.
“…In fact, some studies support the view that anchorless versions of PrP C either directly inhibit the conversion to PrP Sc or at least are less efficiently converted compared to membrane-anchored forms. 43, Fitting to this model, impaired production of shed PrP C in our ADAM10 cKO mice (possibly in connection with increased PrP C surface levels) resulted in increased PrP Sc formation 39 , whereas overexpression of ADAM10 leads to decreased production of PrP Sc . 34 Further support for this model might come from bank voles: this animal model has raised attention in prion research due to its high susceptibility to different sources of prions.…”
Section: Inhibition Of Prp Sc Formation By Shed Prp?mentioning
Proteolytic processing regulates key processes in health and disease. The cellular prion protein (PrP(C)) is subject to at least 3 cleavage events, α-cleavage, β-cleavage and shedding. In contrast to α- and β-cleavage where there is an ongoing controversy on the identity of relevant proteases, the metalloprotease ADAM10 represents the only relevant PrP sheddase. Here we focus on the roles that ADAM10-mediated shedding of PrP(C) and its pathogenic isoform (PrP(Sc)) might play in regulating their physiological and pathogenic functions, respectively. As revealed by our recent study using conditional ADAM10 knockout mice (Altmeppen et al., 2015), shedding of PrP seems to be involved in key processes of prion diseases. These aspects and several open questions arising from them are discussed. Increased knowledge on this topic can shed new light on prion diseases and other neurodegenerative conditions as well.
“…In agreement with this result, recombinant PrP reduces prion conversion in vitro by binding to PrP res and preventing PrP res /PrP C interactions. 6 Third, PrPC1 produced after PrP C α-cleavage is not a substrate for prion conversion. In contrast, PrPC1 acts as a dominant-negative inhibitor of PrP res mediated-conversion suggesting that an incomplete PrP C molecule at the cell surface can trap PrP res into a non-convertible complex.…”
Section: Secreted Forms Of Prp C In Prion Diseasesmentioning
“…PrP C is composed of an unstructured N-terminal domain and a structured C-terminal domain with three α-helices and two short β-sheets. 5 Both domain are essential for efficient conversion of PrP C into PrP res 6,7 . PrP C has a dual function in prion diseases.…”
Section: Secreted Forms Of Prp C In Prion Diseasesmentioning
“…Furthermore, PMCA has been used by several groups to determine the involvement of other cofactors, such as divalent metal cations and polyanions, in the conversion of cellular to infectious prion proteins (96,195). Lastly, PMCA has been applied as a method to rapidly assay molecules that may inhibit the conversion of PrP C to PrP Sc (221,222).…”
Section: Protein Misfolding Cyclic Amplification (Pmca)mentioning
SUMMARYSince the term protein was first coined in 1838 and protein was discovered to be the essential component of fibrin and albumin, all cellular proteins were presumed to play beneficial roles in plants and mammals. However, in 1967, Griffith proposed that proteins could be infectious pathogens and postulated their involvement in scrapie, a universally fatal transmissible spongiform encephalopathy in goats and sheep. Nevertheless, this novel hypothesis had not been evidenced until 1982, when Prusiner and coworkers purified infectious particles from scrapie-infected hamster brains and demonstrated that they consisted of a specific protein that he called a “prion.” Unprecedentedly, the infectious prion pathogen is actually derived from its endogenous cellular form in the central nervous system. Unlike other infectious agents, such as bacteria, viruses, and fungi, prions do not contain genetic materials such as DNA or RNA. The unique traits and genetic information of prions are believed to be encoded within the conformational structure and posttranslational modifications of the proteins. Remarkably, prion-like behavior has been recently observed in other cellular proteins—not only in pathogenic roles but also serving physiological functions. The significance of these fascinating developments in prion biology is far beyond the scope of a single cellular protein and its related disease.
scite is a Brooklyn-based startup that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.