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Thomas CM, Salamat MKF, de Wolf C, McCutcheon S, Blanco ARA, Manson JC, Hunter N, Houston EF. Development of a sensitive real-time quaking-induced conversion (RT-QuIC) assay for application in prion-infected blood. PLoS One 2023; 18:e0293845. [PMID: 37917783 PMCID: PMC10621866 DOI: 10.1371/journal.pone.0293845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 10/18/2023] [Indexed: 11/04/2023] Open
Abstract
Efforts to prevent human-to-human transmission of variant Creutzfeldt-Jakob disease (vCJD) by contaminated blood would be aided by the development of a sensitive diagnostic test that could be routinely used to screen blood donations. As blood samples from vCJD patients are extremely rare, here we describe the optimisation of real-time quaking-induced conversion (RT-QuIC) for detection of PrPSc (misfolded prion protein, a marker of prion infection) in blood samples from an established large animal model of vCJD, sheep experimentally infected with bovine spongiform encephalopathy (BSE). Comparative endpoint titration experiments with RT-QuIC, miniaturized bead protein misfolding cyclic amplification (mb-PMCA) and intracerebral inoculation of a transgenic mouse line expressing sheep PrP (tgOvARQ), demonstrated highly sensitive detection of PrPSc by RT-QuIC in a reference sheep brain homogenate. Upon addition of a capture step with iron oxide beads, the RT-QuIC assay was able to detect PrPSc in whole blood samples from BSE-infected sheep up to two years before disease onset. Both RT-QuIC and mb-PMCA also demonstrated sensitive detection of PrPSc in a reference vCJD-infected human brain homogenate, suggesting that either assay may be suitable for application to human blood samples. Our results support the further development and evaluation of RT-QuIC as a diagnostic or screening test for vCJD.
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Affiliation(s)
- Charlotte M. Thomas
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - M. Khalid F. Salamat
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - Christopher de Wolf
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - Sandra McCutcheon
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - A. Richard Alejo Blanco
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - Jean C. Manson
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - Nora Hunter
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
| | - E. Fiona Houston
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
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Cazzaniga FA, De Luca CMG, Bistaffa E, Consonni A, Legname G, Giaccone G, Moda F. Cell-free amplification of prions: Where do we stand? PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:325-358. [PMID: 32958239 DOI: 10.1016/bs.pmbts.2020.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neurodegenerative diseases (NDs) such as Alzheimer's disease (AD), Parkinson's disease (PD), atypical parkinsonisms, frontotemporal dementia (FTLD) and prion diseases are characterized by the accumulation of misfolded proteins in the central nervous system (CNS). Although the cause for the initiation of protein aggregation is not well understood, these aggregates are disease-specific. For instance, AD is characterized by the intraneuronal accumulation of tau and extracellular deposition of amyloid-β (Aβ), PD is marked by the intraneuronal accumulation of α-synuclein, many FTLD are associated with the accumulation of TDP-43 while prion diseases show aggregates of misfolded prion protein. Hence, misfolded proteins are considered disease-specific biomarkers and their identification and localization in the CNS, collected postmortem, is required for a definitive diagnosis. With the development of two innovative cell-free amplification techniques named Protein Misfolding Cyclic Amplification (PMCA) and Real-Time Quaking-Induced Conversion (RT-QuIC), traces of disease-specific biomarkers were found in CSF and other peripheral tissues (e.g., urine, blood, and olfactory mucosa) of patients with different NDs. These techniques exploit an important feature shared by many misfolded proteins, that is their ability to interact with their normally folded counterparts and force them to undergo similar structural rearrangements. Essentially, RT-QuIC and PMCA mimic in vitro the same pathological processes of protein misfolding which occur in vivo in a very rapid manner. For this reason, they have been employed for studying different aspects of protein misfolding but, overall, they seem to be very promising for the premortem diagnosis of NDs.
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Affiliation(s)
- Federico Angelo Cazzaniga
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Unit of Neurology 5 and Neuropathology, Milan, Italy
| | | | - Edoardo Bistaffa
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Unit of Neurology 5 and Neuropathology, Milan, Italy
| | - Alessandra Consonni
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Milan, Italy
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore Di Studi Avanzati (SISSA), Trieste, Italy
| | - Giorgio Giaccone
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Unit of Neurology 5 and Neuropathology, Milan, Italy
| | - Fabio Moda
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Unit of Neurology 5 and Neuropathology, Milan, Italy.
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Identification of a homology-independent linchpin domain controlling mouse and bank vole prion protein conversion. PLoS Pathog 2020; 16:e1008875. [PMID: 32898162 PMCID: PMC7508373 DOI: 10.1371/journal.ppat.1008875] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 09/22/2020] [Accepted: 08/11/2020] [Indexed: 11/19/2022] Open
Abstract
Prions are unorthodox pathogens that cause fatal neurodegenerative diseases in humans and other mammals. Prion propagation occurs through the self-templating of the pathogenic conformer PrPSc, onto the cell-expressed conformer, PrPC. Here we study the conversion of PrPC to PrPSc using a recombinant mouse PrPSc conformer (mouse protein-only recPrPSc) as a unique tool that can convert bank vole but not mouse PrPC substrates in vitro. Thus, its templating ability is not dependent on sequence homology with the substrate. In the present study, we used chimeric bank vole/mouse PrPC substrates to systematically determine the domain that allows for conversion by Mo protein-only recPrPSc. Our results show that that either the presence of the bank vole amino acid residues E227 and S230 or the absence of the second N-linked glycan are sufficient to allow PrPC substrates to be converted by Mo protein-only recPrPSc and several native infectious prion strains. We propose that residues 227 and 230 and the second glycan are part of a C-terminal domain that acts as a linchpin for bank vole and mouse prion conversion. Prions are unconventional infectious agents that lack nucleic acids such as DNA and RNA, and the mechanism by which prions replicate is not fully understood. It has been established that a central feature of the replication mechanism involves the misfolding of a host protein (PrPC) into an infectious shape termed PrPSc, but it is unclear how this misfolding occurs. Interestingly, it has been observed that a particular animal species, the European bank vole, is unusually susceptible to prion infection and that this near-universal susceptibility is caused by the specific PrPC sequence of this protein. Here we use a powerful and unique biochemical system to determine the specific region of bank vole PrPC that is primarily responsible for its propensity to misfold into PrPSc. This critical region, which is located at the extreme C-terminal end of the protein, appears to act as a linchpin domain that normally stabilizes the shape of PrPC and thereby regulates its misfolding into PrPSc.
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McNulty EE, Nalls AV, Xun R, Denkers ND, Hoover EA, Mathiason CK. In vitro detection of haematogenous prions in white-tailed deer orally dosed with low concentrations of chronic wasting disease. J Gen Virol 2020; 101:347-361. [PMID: 31846418 PMCID: PMC7416609 DOI: 10.1099/jgv.0.001367] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/19/2019] [Indexed: 11/18/2022] Open
Abstract
Infectivity associated with prion disease has been demonstrated in blood throughout the course of disease, yet the ability to detect blood-borne prions by in vitro methods remains challenging. We capitalized on longitudinal pathogenesis studies of chronic wasting disease (CWD) conducted in the native host to examine haematogenous prion load by real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification. Our study demonstrated in vitro detection of amyloid seeding activity (prions) in buffy-coat cells harvested from deer orally dosed with low concentrations of CWD positive (+) brain (1 gr and 300 ng) or saliva (300 ng RT-QuIC equivalent). These findings make possible the longitudinal assessment of prion disease and deeper investigation of the role haematogenous prions play in prion pathogenesis.
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Affiliation(s)
- Erin E. McNulty
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Amy V. Nalls
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Randy Xun
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Nathaniel D. Denkers
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Edward A. Hoover
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Candace K. Mathiason
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
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Hannaoui S, Arifin MI, Chang SC, Yu J, Gopalakrishnan P, Doh-Ura K, Schatzl HM, Gilch S. Cellulose ether treatment in vivo generates chronic wasting disease prions with reduced protease resistance and delayed disease progression. J Neurochem 2019; 152:727-740. [PMID: 31553058 PMCID: PMC7078990 DOI: 10.1111/jnc.14877] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/17/2019] [Accepted: 09/19/2019] [Indexed: 12/19/2022]
Abstract
Chronic wasting disease (CWD) is a prion disease of free-ranging and farmed cervids that is highly contagious because of extensive prion shedding and prion persistence in the environment. Previously, cellulose ether compounds (CEs) have been shown to significantly extend the survival of mice inoculated with mouse-adapted prion strains. In this study, we used CEs, TC-5RW, and 60SH-50, in vitro and in vivo to assess their efficacy to interfere with CWD prion propagation. In vitro, CEs inhibited CWD prion amplification in a dose-dependent manner. Transgenic mice over-expressing elk PrPC (tgElk) were injected subcutaneously with a single dose of either of the CEs, followed by intracerebral inoculation with different CWD isolates from white tailed deer, mule deer, or elk. All treated groups showed a prolonged survival of up to more than 30 % when compared to the control group regardless of the CWD isolate used for infection. The extended survival in the treated groups correlated with reduced proteinase K resistance of prions. Remarkably, passage of brain homogenates from treated or untreated animals in tgElk mice resulted in a prolonged life span of mice inoculated with homogenates from CE-treated mice (of + 17%) even in the absence of further treatment. Besides the delayed disease onset upon passage in TgElk mice, the reduced proteinase K resistance was maintained but less pronounced. Therefore, these compounds can be very useful in limiting the spread of CWD in captive and wild-ranging cervids.
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Affiliation(s)
- Samia Hannaoui
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Maria Immaculata Arifin
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Sheng Chun Chang
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Jie Yu
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Preetha Gopalakrishnan
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Katsumi Doh-Ura
- Department of Neurochemistry, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Hermann M Schatzl
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Sabine Gilch
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
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Bernardi L, Bruni AC. Mutations in Prion Protein Gene: Pathogenic Mechanisms in C-Terminal vs. N-Terminal Domain, a Review. Int J Mol Sci 2019; 20:E3606. [PMID: 31340582 PMCID: PMC6678283 DOI: 10.3390/ijms20143606] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/07/2019] [Accepted: 07/15/2019] [Indexed: 12/21/2022] Open
Abstract
Inherited mutations in the Prion protein (PrP), encoded by the PRNP gene, have been associated with autosomal dominant neurodegenerative disorders, such as Creutzfeldt-Jacob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), and Fatal Familial Insomnia (FFI). Notably, PRNP mutations have also been described in clinical pictures resembling other neurodegenerative diseases, such as frontotemporal dementia. Regarding the pathogenesis, it has been observed that these point mutations are located in the C-terminal region of the PRNP gene and, currently, the potential significance of the N-terminal domain has largely been underestimated. The purpose of this report is to review and provide current insights into the pathogenic mechanisms of PRNP mutations, emphasizing the differences between the C- and N-terminal regions and focusing, in particular, on the lesser-known flexible N-terminal, for which recent biophysical evidence has revealed a physical interaction with the globular C-terminal domain of the cellular prion protein (PrPC).
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Affiliation(s)
- Livia Bernardi
- Regional Neurogenetic Centre, ASP Catanzaro, 88046 Lamezia Terme (CZ), Italy
| | - Amalia C Bruni
- Regional Neurogenetic Centre, ASP Catanzaro, 88046 Lamezia Terme (CZ), Italy.
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Modified Protein Misfolding Cyclic Amplification Overcomes Real-Time Quaking-Induced Conversion Assay Inhibitors in Deer Saliva To Detect Chronic Wasting Disease Prions. J Clin Microbiol 2018; 56:JCM.00947-18. [PMID: 29950332 DOI: 10.1128/jcm.00947-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 06/18/2018] [Indexed: 01/19/2023] Open
Abstract
Chronic wasting disease (CWD), a fatal neurodegenerative prion disease of cervids, has spread across North America and has been detected in The Republic of Korea, Finland, and Norway. CWD appears to spread by horizontal transmission, and prions shed in saliva, feces, and urine are thought to contribute. However, studies investigating the rapid spread of CWD have been hampered by assay inhibitors and a lack of consistent and sensitive means to detect the relatively low levels of prions in these samples. Here we show that saliva frequently contains an inhibitor of the real-time quaking-induced conversion assay (RT-QuIC) and that the inhibitor is a member of the mucin family. To circumvent the inhibitor, we developed a modified protein misfolding cyclic amplification (PMCA) method to amplify CWD prions in saliva that were undetectable or ambiguous by RT-QuIC. Our results reinforce the impact of saliva in horizontal CWD transmission and highlight the importance of detection optimization.
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Endogenous Brain Lipids Inhibit Prion Amyloid Formation In Vitro. J Virol 2017; 91:JVI.02162-16. [PMID: 28202758 DOI: 10.1128/jvi.02162-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 02/08/2017] [Indexed: 01/22/2023] Open
Abstract
The normal cellular prion protein (PrPC) resides in detergent-resistant outer membrane lipid rafts in which conversion to the pathogenic misfolded form is believed to occur. Once misfolding occurs, the pathogenic isoform polymerizes into highly stable amyloid fibrils. In vitro assays have demonstrated an intimate association between prion conversion and lipids, specifically phosphatidylethanolamine, which is a critical cofactor in the formation of synthetic infectious prions. In the current work, we demonstrate an alternative inhibitory function of lipids in the prion conversion process as assessed in vitro by real-time quaking-induced conversion (RT-QuIC). Using an alcohol-based extraction technique, we removed the lipid content from chronic wasting disease (CWD)-infected white-tailed deer brain homogenates and found that lipid extraction enabled RT-QuIC detection of CWD prions in a 2-log10-greater concentration of brain sample. Conversely, addition of brain-derived lipid extracts to CWD prion brain or lymph node samples inhibited amyloid formation in a dose-dependent manner. Subsequent lipid analysis demonstrated that this inhibitory function was restricted to the polar lipid fraction in brain. We further investigated three phospholipids commonly found in lipid membranes, phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol, and found all three similarly inhibited RT-QuIC. These results demonstrating polar-lipid, and specifically phospholipid, inhibition of prion-seeded amyloid formation highlight the diverse roles lipid constituents may play in the prion conversion process.IMPORTANCE Prion conversion is likely influenced by lipid interactions, given the location of normal prion protein (PrPC) in lipid rafts and lipid cofactors generating infectious prions in in vitro models. Here, we use real-time quaking-induced conversion (RT-QuIC) to demonstrate that endogenous brain polar lipids can inhibit prion-seeded amyloid formation, suggesting that prion conversion is guided by an environment of proconversion and anticonversion lipids. These experiments also highlight the applicability of RT-QuIC to identify potential therapeutic inhibitors of prion conversion.
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Hwang S, Greenlee JJ, Nicholson EM. Use of bovine recombinant prion protein and real-time quaking-induced conversion to detect cattle transmissible mink encephalopathy prions and discriminate classical and atypical L- and H-Type bovine spongiform encephalopathy. PLoS One 2017; 12:e0172391. [PMID: 28225797 PMCID: PMC5321280 DOI: 10.1371/journal.pone.0172391] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 02/03/2017] [Indexed: 12/15/2022] Open
Abstract
Prions are amyloid-forming proteins that cause transmissible spongiform encephalopathies through a process involving conversion from the normal cellular prion protein to the pathogenic misfolded conformation (PrPSc). This conversion has been used for in vitro assays including serial protein misfolding amplification and real-time quaking induced conversion (RT-QuIC). RT-QuIC can be used for the detection of prions in a variety of biological tissues from humans and animals. Extensive work has been done to demonstrate that RT-QuIC is a rapid, specific, and highly sensitive prion detection assay. RT-QuIC uses recombinant prion protein to detect minute amounts of PrPSc. RT-QuIC has been successfully used to detect PrPSc from different prion diseases with a variety of substrates including hamster, human, sheep, bank vole, bovine and chimeric forms of prion protein. However, recombinant bovine prion protein has not been used to detect transmissible mink encephalopathy (TME) or to differentiate types of bovine spongiform encephalopathy (BSE) in samples from cattle. We evaluated whether PrPSc from TME and BSE infected cattle can be detected with RT-QuIC using recombinant bovine prion proteins, and optimized the reaction conditions to specifically detect cattle TME and to discriminate between classical and atypical BSE by conversion efficiency. We also found that substrate composed of the disease associated E211K mutant protein can be effective for the detection of TME in cattle and that wild type prion protein appears to be a practical substrate to discriminate between the different types of BSEs.
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Affiliation(s)
- Soyoun Hwang
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States of America
| | - Justin J. Greenlee
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States of America
| | - Eric M. Nicholson
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States of America
- * E-mail:
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