Publications by authors named "Juan María Torres"

79 Publications

TREM2 expression in the brain and biological fluids in prion diseases.

Acta Neuropathol 2021 Apr 21. Epub 2021 Apr 21.

Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), L'Hospitalet de Llobregat, Spain.

Triggering receptor expressed on myeloid cells 2 (TREM2) is an innate immune cell surface receptor that regulates microglial function and is involved in the pathophysiology of several neurodegenerative diseases. Its soluble form (sTREM2) results from shedding of the TREM2 ectodomain. The role of TREM2 in prion diseases, a group of rapidly progressive dementias remains to be elucidated. In the present study, we analysed the expression of TREM2 and its main sheddase ADAM10 in the brain of sporadic Creutzfeldt-Jakob disease (sCJD) patients and evaluated the role of CSF and plasma sTREM2 as a potential diagnostic marker of prion disease. Our data indicate that, compared to controls, TREM2 is increased in sCJD patient brains at the mRNA and protein levels in a regional and subtype dependent fashion, and expressed in a subpopulation of microglia. In contrast, ADAM10 is increased at the protein, but not the mRNA level, with a restricted neuronal expression. Elevated CSF sTREM2 is found in sCJD, genetic CJD with mutations E200K and V210I in the prion protein gene (PRNP), and iatrogenic CJD, as compared to healthy controls (HC) (AUC = 0.78-0.90) and neurological controls (AUC = 0.73-0.85), while CSF sTREM2 is unchanged in fatal familial insomnia. sTREM2 in the CSF of cases with Alzheimer's disease, and multiple sclerosis was not significantly altered in our series. CSF sTREM2 concentrations in sCJD are PRNP codon 129 and subtype-related, correlate with CSF 14-3-3 positivity, total-tau and YKL-40, and increase with disease progression. In plasma, sTREM2 is increased in sCJD compared with HC (AUC = 0.80), displaying positive correlations with plasma total-tau, neurofilament light, and YKL-40. We conclude that comparative study of TREM2 in brain and biological fluids of prion diseases reveals TREM2 to be altered in human prion diseases with a potential value in target engagement, patient stratification, and disease monitoring.
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http://dx.doi.org/10.1007/s00401-021-02296-1DOI Listing
April 2021

Classical scrapie in small ruminants is caused by at least four different prion strains.

Vet Res 2021 Apr 15;52(1):57. Epub 2021 Apr 15.

Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos, Madrid, Spain.

The diversity of goat scrapie strains in Europe has recently been studied using bioassays in a wide collection of rodent models, resulting in the classification of classical scrapie into four different categories. However, the sole use of the first passage does not lead to isolate adaptation and identification of the strains involved and might therefore lead to misclassification of some scrapie isolates. Therefore, this work reports the complete transmission study of a wide collection of goat transmissible spongiform encephalopathy (TSE) isolates by intracranial inoculation in two transgenic mouse lines overexpressing either small ruminant (TgGoat-ARQ) or bovine (TgBov) PrP. To compare scrapie strains in sheep and goats, sheep scrapie isolates from different European countries were also included in the study. Once the species barrier phenomenon was overcome, an accurate classification of the isolates was attained. Thus, the use of just two rodent models allowed us to fully differentiate at least four different classical scrapie strains in small ruminants and to identify isolates containing mixtures of strains. This work reinforces the idea that classical scrapie in small ruminants is a prion disease caused by multiple different prion strains and not by a single strain, as is the case for epidemic classical bovine spongiform encephalopathy (BSE-C). In addition, the clear dissimilarity between the different scrapie strains and BSE-C does not support the idea that classical scrapie is the origin of epidemic BSE-C.
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http://dx.doi.org/10.1186/s13567-021-00929-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8048364PMC
April 2021

PMCA-generated prions from the olfactory mucosa of patients with Fatal Familial Insomnia cause prion disease in mice.

Elife 2021 04 14;10. Epub 2021 Apr 14.

Fondazione IRCCS Istituto Neurologico Carlo Besta, Division of Neurology 5 and Neuropathology, Milan, Italy.

Background: Fatal Familial Insomnia (FFI) is a genetic prion disease caused by the D178N mutation in the prion protein gene (PRNP) in coupling phase with methionine at PRNP 129. In 2017, we have shown that the olfactory mucosa (OM) collected from FFI patients contained traces of PrPSc detectable by Protein Misfolding Cyclic Amplification (PMCA).

Methods: In this work, we have challenged PMCA-generated products obtained from OM and brain homogenate of FFI patients in BvPrP-Tg407 transgenic mice expressing the bank vole prion protein to test their ability to induce prion pathology.

Results: All inoculated mice developed mild spongiform changes, astroglial activation, and PrPSc deposition mainly affecting the thalamus. However, their neuropathological alterations were different from those found in the brain of BvPrP-Tg407 mice injected with raw FFI brain homogenate.

Conclusions: Although with some experimental constraints, we show that PrPSc present in OM of FFI patients is potentially infectious.

Funding: This work was supported in part by the Italian Ministry of Health (GR-2013-02355724 and Ricerca Corrente), MJFF, ALZ, Alzheimer's Research UK and the Weston Brain Institute (BAND2015), and Euronanomed III (SPEEDY) to FM; by the Spanish Ministerio de Economía y Competitividad (grant AGL2016-78054-R [AEI/FEDER, UE]) to JMT and JCE; AM-M was supported by a fellowship from the INIA (FPI-SGIT-2015-02).
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http://dx.doi.org/10.7554/eLife.65311DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8064759PMC
April 2021

Two distinct conformers of PrP type 1 of sporadic Creutzfeldt-Jakob disease with codon 129VV genotype faithfully propagate in vivo.

Acta Neuropathol Commun 2021 03 25;9(1):55. Epub 2021 Mar 25.

Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.

Current classifications of sporadic Creutzfeldt-Jakob disease (sCJD) identify five subtypes associated with different disease phenotypes. Most of these histopathological phenotypes (histotypes) co-distribute with distinct pairings of methionine (M)/valine (V) genotypes at codon 129 of the prion protein (PrP) gene and the type (1 or 2) of the disease-associated PrP (PrP). Types 1 and 2 are defined by the molecular mass (~ 21 kDa and ~ 19 kDa, respectively) of the unglycosylated isoform of the proteinase K-resistant PrP (resPrP). We recently reported that the sCJDVV1 subtype (129VV homozygosity paired with PrP type 1, T1) shows an electrophoretic profile where the resPrP unglycosylated isoform is characterized by either one of two single bands of ~ 20 kDa (T1) and ~ 21 kDa (T1), or a doublet of ~ 21-20 kDa (T1). We also showed that T1 and T1 in sCJDVV have different conformational features but are associated with indistinguishable histotypes. The presence of three distinct molecular profiles of T1 is unique and raises the issue as to whether T1 and T1 represent distinct prion strains. To answer this question, brain homogenates from sCJDVV cases harboring each of the three resPrP profiles, were inoculated to transgenic (Tg) mice expressing the human PrP-129M or PrP-129V genotypes. We found that T1 and T1 were faithfully replicated in Tg129V mice. Electrophoretic profile and incubation period of mice challenged with T1 resembled those of mice inoculated with T1 and T1, respectively. As in sCJDVV1, Tg129V mice challenged with T1 and T1 generated virtually undistinguishable histotypes. In Tg129M mice, T1 was not replicated while T1 and T1 generated a ~ 21-20  kDa doublet after lengthier incubation periods. On second passage, Tg129M mice incubation periods and regional PrP accumulation significantly differed in T1 and T1 challenged mice. Combined, these data indicate that T1 and T1 resPrP represent distinct human prion strains associated with partially overlapping histotypes.
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http://dx.doi.org/10.1186/s40478-021-01132-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7995586PMC
March 2021

Allelic Interference in Prion Replication Is Modulated by the Convertibility of the Interfering PrP and Other Host-Specific Factors.

mBio 2021 03 16;12(2). Epub 2021 Mar 16.

Centro de Investigación en Sanidad Animal (CISA-INIA), Madrid, Spain

Early studies in transgenic mouse lines have shown that the coexpression of endogenous murine prion protein (PrP) and transgenic PrP from another species either inhibits or allows the propagation of prions, depending on the infecting prion strain and interacting protein species. The way whereby this phenomenon, so-called "interference," is modulated remains to be determined. In this study, different transgenic mouse lines were crossbred to produce mice coexpressing bovine and porcine PrP, bovine and murine PrP, or murine and porcine PrP These animals and their respective hemizygous controls were inoculated with several prion strains from different sources (cattle, mice, and pigs) to examine the effects of the simultaneous presence of PrP from two different species. Our results indicate interference with the infection process, manifested as extended survival times and reduced attack rates. The interference with the infectious process was reduced or absent when the potentiality interfering PrP species was efficiently converted by the inoculated agent. However, the propagation of the endogenous murine PrP was favored, allowing us to speculate that host-specific factors may disturb the interference caused by the coexpression of an exogenous second PrP Prion propagation can be interfered with by the expression of a second prion protein in the host. In the present study, we investigated prion propagation in a host expressing two different prion protein genes. Our findings indicate that the ability of the second prion protein to interfere with prion propagation is related to the transmissibility of the prion in the host expressing only the interfering prion protein. The interference detected occurs in a prion strain-dependent manner. Interestingly, a bias favoring the propagation of the murine PrP allele has been observed. These results open the door to future studies in order to determine the role of host factors other than the PrP amino acid sequence in the interference in prion propagation.
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http://dx.doi.org/10.1128/mBio.03508-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8092304PMC
March 2021

Wide distribution of prion infectivity in the peripheral tissues of vCJD and sCJD patients.

Acta Neuropathol 2021 03 2;141(3):383-397. Epub 2021 Feb 2.

UMR INRA ENVT 1225, Interactions Hôtes Agents Pathogènes, Ecole Nationale Vétérinaire de Toulouse, 23 Chemin des Capelles, 31076, Toulouse, France.

Sporadic Creutzfeldt-Jakob disease (sCJD) is the commonest human prion disease, occurring most likely as the consequence of spontaneous formation of abnormal prion protein in the central nervous system (CNS). Variant Creutzfeldt-Jakob disease (vCJD) is an acquired prion disease that was first identified in 1996. In marked contrast to vCJD, previous investigations in sCJD revealed either inconsistent levels or an absence of PrP in peripheral tissues. These findings contributed to the consensus that risks of transmitting sCJD as a consequence of non-CNS invasive clinical procedures were low. In this study, we systematically measured prion infectivity levels in CNS and peripheral tissues collected from vCJD and sCJD patients. Unexpectedly, prion infectivity was detected in a wide variety of peripheral tissues in sCJD cases. Although the sCJD infectivity levels varied unpredictably in the tissues sampled and between patients, these findings could impact on our perception of the possible transmission risks associated with sCJD.
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http://dx.doi.org/10.1007/s00401-021-02270-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7882550PMC
March 2021

Met -Glu residues in human PrP β2-α2 loop account for evolutionary resistance to prion infection.

Neuropathol Appl Neurobiol 2021 Jun 22;47(4):506-518. Epub 2020 Dec 22.

Centro de Investigación en Sanidad Animal (INIA-CISA), Madrid, Spain.

Aims: The amino acid sequence of prion protein (PrP) is a key determinant in the transmissibility of prion diseases. While PrP sequence is highly conserved among mammalian species, minor changes in the PrP amino acid sequence may confer alterations in the transmissibility of prion diseases. Classical bovine spongiform encephalopathy (C-BSE) is the only zoonotic prion strain reported to date causing variant Creutzfeldt-Jacob disease (vCJD) in humans, although experimental transmission points to atypical L-BSE and some classical scrapie isolates as also zoonotic. The precise molecular elements in the human PrP sequence that limit the transmissibility of prion strains such as sheep/goat scrapie or cervid chronic wasting disease (CWD) are not well known.

Methods: The transmissibility of a panel of diverse prions from different species was compared in transgenic mice expressing either wild-type human PrP (MDE-HuTg340) or a mutated human PrP harbouring Val -Gln amino acid changes (VDQ-HuTg372) in the β2-α2 loop instead of Met -Glu wild-type variants.

Results: VDQ-HuTg372 mice were more susceptible to prions than MDE-HuTg340 mice in a strain-dependent manner.

Conclusions: Met -Glu amino acid residues present in wild-type human PrP are molecular determinants that limit the propagation of most prion strains assayed in the human PrP context.
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http://dx.doi.org/10.1111/nan.12676DOI Listing
June 2021

Transgenic mouse models for the study of prion diseases.

Prog Mol Biol Transl Sci 2020 11;175:147-177. Epub 2020 Sep 11.

Centro de Investigación en Sanidad Animal (CISA-INIA), Madrid, Spain. Electronic address:

Prions are unique agents that challenge the molecular biology dogma by transmitting information on the protein level. They cause neurodegenerative diseases that lack of any cure or treatment called transmissible spongiform encephalopathies. The function of the normal form of the prion protein, the exact mechanism of prion propagation between species as well as at the cellular level and neuron degeneration remains elusive. However, great amount of information known for all these aspects has been achieved thanks to the use of animal models and more precisely to transgenic mouse models. In this chapter, the main contributions of these powerful research tools in the prion field are revised.
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http://dx.doi.org/10.1016/bs.pmbts.2020.08.007DOI Listing
September 2020

MicroRNA Alterations in a Tg501 Mouse Model of Prion Disease.

Biomolecules 2020 06 15;10(6). Epub 2020 Jun 15.

Laboratorio de Genética Bioquímica (LAGENBIO), Facultad de Veterinaria, University of Zaragoza, 50013 Zaragoza, Spain.

MicroRNAs (miRNAs) may contribute to the development and pathology of many neurodegenerative diseases, including prion diseases. They are also promising biomarker candidates due to their stability in body fluids. We investigated miRNA alterations in a Tg501 mouse model of prion diseases that expresses a transgene encoding the goat prion protein (). Tg501 mice intracranially inoculated with mouse-adapted goat scrapie were compared with age-matched, mock inoculated controls in preclinical and clinical stages. Small RNA sequencing from the cervical spinal cord indicated that miR-223-3p, miR-151-3p, and miR-144-5p were dysregulated in scrapie-inoculated animals before the onset of symptoms. In clinical-stage animals, 23 significant miRNA alterations were found. These miRNAs were predicted to modify the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways including prion disease, extracellular matrix interactions, glutaminergic synapse, axon guidance, and transforming growth factor-beta signaling. MicroRNAs miR-146a-5p (up in cervical spinal cord) and miR-342-3p (down in cervical spinal cord, cerebellum and plasma), both indicated in neurodegenerative diseases earlier, were verified by quantitative real-time polymerase chain reaction (qRT-PCR). Minimal changes observed before the disease onset suggests that most miRNA alterations observed here are driven by advanced prion-associated pathology, possibly limiting their use as diagnostic markers. However, the results encourage further mechanistic studies on miRNA-regulated pathways involved in these neurodegenerative conditions.
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http://dx.doi.org/10.3390/biom10060908DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7355645PMC
June 2020

Prions from Sporadic Creutzfeldt-Jakob Disease Patients Propagate as Strain Mixtures.

mBio 2020 06 16;11(3). Epub 2020 Jun 16.

UMR INRA ENVT 1225, Interactions Hôte Agent Pathogène, Ecole Nationale Vétérinaire de Toulouse, Toulouse, France

Sporadic Creutzfeldt-Jakob disease (sCJD) cases are currently classified according to the methionine/valine polymorphism at codon 129 of the gene and the proteinase K-digested abnormal prion protein (PrP) isoform identified by Western blotting (type 1 or type 2). Converging evidence led to the view that MM/MV1, VV/MV2, and VV1 and MM2 sCJD cases are caused by distinct prion strains. However, in a significant proportion of sCJD patients, both type 1 and type 2 PrP were reported to accumulate in the brain, which raised questions about the diversity of sCJD prion strains and the coexistence of two prion strains in the same patient. In this study, a panel of sCJD brain isolates ( = 29) that displayed either a single or mixed type 1/type 2 PrP were transmitted into human-PrP-expressing mice (tgHu). These bioassays demonstrated that two distinct prion strains (M1 and V2) were associated with the development of sCJD in MM1/MV1 and VV2/MV2 patients. However, in about 35% of the investigated VV and MV cases, transmission results were consistent with the presence of both M1 and V2 strains, including in patients who displayed a "pure" type 1 or type 2 PrP The use of a highly sensitive prion amplification technique that specifically probes the V2 strain revealed the presence of the V2 prion in more than 80% of the investigated isolates, including isolates that propagated as a pure M1 strain in tgHu. These results demonstrate that at least two sCJD prion strains can be present in a single patient. sCJD occurrence is currently assumed to result from spontaneous and stochastic formation of a misfolded PrP nucleus in the brains of affected patients. This original nucleus then recruits and converts nascent PrP into PrP, leading to the propagation of prions in the patient's brain. Our study demonstrates the coexistence of two prion strains in the brains of a majority of the 23 sCJD patients investigated. The relative proportion of these sCJD strains varied both between patients and between brain areas in a single patient. These findings strongly support the view that the replication of an sCJD prion strain in the brain of a patient can result in the propagation of different prion strain subpopulations. Beyond its conceptual importance for our understanding of prion strain properties and evolution, the sCJD strain mixture phenomenon and its frequency among patients have important implications for the development of therapeutic strategies for prion diseases.
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http://dx.doi.org/10.1128/mBio.00393-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7298703PMC
June 2020

Radical Change in Zoonotic Abilities of Atypical BSE Prion Strains as Evidenced by Crossing of Sheep Species Barrier in Transgenic Mice.

Emerg Infect Dis 2020 06;26(6):1130-1139

Classical bovine spongiform encephalopathy (BSE) is the only zoonotic prion disease described to date. Although the zoonotic potential of atypical BSE prions have been partially studied, an extensive analysis is still needed. We conducted a systematic study by inoculating atypical BSE isolates from different countries in Europe into transgenic mice overexpressing human prion protein (PrP): TgMet, TgMet/Val, and TgVal. L-type BSE showed a higher zoonotic potential in TgMet mice than classical BSE, whereas Val-PrP variant was a strong molecular protector against L-type BSE prions, even in heterozygosis. H-type BSE could not be transmitted to any of the mice. We also adapted 1 H- and 1 L-type BSE isolate to sheep-PrP transgenic mice and inoculated them into human-PrP transgenic mice. Atypical BSE prions showed a modification in their zoonotic ability after adaptation to sheep-PrP producing agents able to infect TgMet and TgVal, bearing features that make them indistinguishable of sporadic Creutzfeldt-Jakob disease prions.
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http://dx.doi.org/10.3201/eid2606.181790DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7258450PMC
June 2020

Crossing Species Barriers Relies on Structurally Distinct Prion Assemblies and Their Complementation.

Mol Neurobiol 2020 Jun 1;57(6):2572-2587. Epub 2020 Apr 1.

Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France.

Prion replication results from the autocatalytic templated assisted conversion of the host-encoded prion protein PrP into misfolded, polydisperse PrP conformers. Structurally distinct PrP conformers can give rise to multiple prion strains. Within and between prion strains, the biological activity (replicative efficacy and specific infectivity) of PrP assemblies is size dependent and thus reflects an intrinsic structural heterogeneity. The contribution of such PrP heterogeneity across species prion adaptation, which is believed to be based on fit adjustment between PrP template(s) and host PrP, has not been explored. To define the structural-to-fitness PrP landscape, we measured the relative capacity of size-fractionated PrP assemblies from different prion strains to cross mounting species barriers in transgenic mice expressing foreign PrP. In the absence of a transmission barrier, the relative efficacy of the isolated PrP assemblies to induce the disease is like the efficacy observed in the homotypic context. However, in the presence of a transmission barrier, size fractionation overtly delays and even abrogates prion pathogenesis in both the brain and spleen tissues, independently of the infectivity load of the isolated assemblies. Altering by serial dilution PrP assembly content of non-fractionated inocula aberrantly reduces their specific infectivity, solely in the presence of a transmission barrier. This suggests that synergy between structurally distinct PrP assemblies in the inoculum is requested for crossing the species barrier. Our data support a mechanism whereby overcoming prion species barrier requires complementation between structurally distinct PrP assemblies. This work provides key insight into the "quasispecies" concept applied to prions, which would not necessarily rely on prion substrains as constituent but on structural PrP heterogeneity within prion population.
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http://dx.doi.org/10.1007/s12035-020-01897-3DOI Listing
June 2020

Mixtures of prion substrains in natural scrapie cases revealed by ovinised murine models.

Sci Rep 2020 03 19;10(1):5042. Epub 2020 Mar 19.

Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, Facultad de Veterinaria, Instituto Agroalimentario de Aragón - IA2 (Universidad de Zaragoza - CITA), 50013, Zaragoza, Spain.

Phenotypic variability in prion diseases, such as scrapie, is associated to the existence of prion strains, which are different pathogenic prion protein (PrP) conformations with distinct pathobiological properties. To faithfully study scrapie strain variability in natural sheep isolates, transgenic mice expressing sheep cellular prion protein (PrP) are used. In this study, we used two of such models to bioassay 20 scrapie isolates from the Spain-France-Andorra transboundary territory. Animals were intracerebrally inoculated and survival periods, proteinase K-resistant PrP (PrP) banding patterns, lesion profiles and PrP distribution were studied. Inocula showed a remarkable homogeneity on banding patterns, all of them but one showing 19-kDa PrP. However, a number of isolates caused accumulation of 21-kDa PrP in TgShp XI. A different subgroup of isolates caused long survival periods and presence of 21-kDa PrP in Tg338 mice. It seemed that one major 19-kDa prion isoform and two distinct 21-kDa variants coexisted in source inocula, and that they could be separated by bioassay in each transgenic model. The reason why each model favours a specific component of the mixture is unknown, although PrP expression level may play a role. Our results indicate that coinfection with more than one substrain is more frequent than infection with a single component.
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http://dx.doi.org/10.1038/s41598-020-61977-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7081250PMC
March 2020

Correlation between Bioassay and Protein Misfolding Cyclic Amplification for Variant Creutzfeldt-Jakob Disease Decontamination Studies.

mSphere 2020 Jan 29;5(1). Epub 2020 Jan 29.

Pathogenesis and Control of Chronic Infections, Etablissement Français du Sang, INSERM, Université de Montpellier, Montpellier, France

To date, approximately 500 iatrogenic Creutzfeldt-Jakob disease cases have been reported worldwide, most of them resulting from cadaveric dura mater graft and from the administration of prion-contaminated human growth hormone. The unusual resistance of prions to decontamination processes, their large tissue distribution, and the uncertainty about the prevalence of variant Creutzfeldt-Jakob disease (vCJD) in the general population lead to specific recommendations regarding identification of tissue at risk and reprocessing of reusable medical devices, including the use of dedicated treatment for prion inactivation. We previously described an assay, called Surf-PMCA, which allowed us to classify prion decontamination treatments according to their efficacy on vCJD prions by monitoring residual seeding activity (RSA). Here, we used a transgenic mouse line permissive to vCJD prions to study the correlation between the RSA measured and the infectivity. Implantation in mouse brains of prion-contaminated steel wires subjected to different decontamination procedures allows us to demonstrate a good concordance between RSA measured by Surf-PMCA () and residual infectivity (). These experiments emphasize the strength of the Surf-PMCA method as a rapid and sensitive assay for the evaluation of prion decontamination procedures and also confirm the lack of efficacy of several marketed reagents on vCJD prion decontamination. Creutzfeldt-Jakob diseases are neurodegenerative disorders for which transmission linked to medical procedures have been reported in hundreds of patients. As prion diseases, they are characterized by an unusual resistance to conventional decontamination processes. Moreover, their large tissue distribution and the ability of prions to attach to many surfaces raised the risk of transmission in health care facilities. It is therefore of major importance that decontamination procedures applied to medical devices before their reprocessing are thoroughly validated for prion inactivation. We previously described an assay, which allowed us to classify accurately prion decontamination treatments according to their efficacy on variant Creutzfeldt-Jakob disease. The significance of this study is in demonstrating the concordance between previous results and infectivity studies in transgenic mice. Furthermore, commercial reagents currently used in hospitals were tested by both protocols, and we observed that most of them were ineffective on human prions.
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http://dx.doi.org/10.1128/mSphere.00649-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6992370PMC
January 2020

Porcine Prion Protein as a Paradigm of Limited Susceptibility to Prion Strain Propagation.

J Infect Dis 2021 Mar;223(6):1103-1112

Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos, Madrid, Spain.

Although experimental transmission of bovine spongiform encephalopathy (BSE) to pigs and transgenic mice expressing pig cellular prion protein (PrPC) (porcine PrP [PoPrP]-Tg001) has been described, no natural cases of prion diseases in pig were reported. This study analyzed pig-PrPC susceptibility to different prion strains using PoPrP-Tg001 mice either as animal bioassay or as substrate for protein misfolding cyclic amplification (PMCA). A panel of isolates representatives of different prion strains was selected, including classic and atypical/Nor98 scrapie, atypical-BSE, rodent scrapie, human Creutzfeldt-Jakob-disease and classic BSE from different species. Bioassay proved that PoPrP-Tg001-mice were susceptible only to the classic BSE agent, and PMCA results indicate that only classic BSE can convert pig-PrPC into scrapie-type PrP (PrPSc), independently of the species origin. Therefore, conformational flexibility constraints associated with pig-PrP would limit the number of permissible PrPSc conformations compatible with pig-PrPC, thus suggesting that pig-PrPC may constitute a paradigm of low conformational flexibility that could confer high resistance to the diversity of prion strains.
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http://dx.doi.org/10.1093/infdis/jiz646DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8006416PMC
March 2021

Characterization of goat prions demonstrates geographical variation of scrapie strains in Europe and reveals the composite nature of prion strains.

Sci Rep 2020 01 8;10(1):19. Epub 2020 Jan 8.

Wageningen BioVeterinary Research, Lelystad, the Netherlands.

Bovine Spongiform Encephalopathy (BSE) is the only animal prion which has been recognized as a zoonotic agent so far. The identification of BSE in two goats raised the need to reliably identify BSE in small ruminants. However, our understanding of scrapie strain diversity in small ruminants remains ill-defined, thus limiting the accuracy of BSE surveillance and spreading fear that BSE might lurk unrecognized in goats. We investigated prion strain diversity in a large panel of European goats by a novel experimental approach that, instead of assessing the neuropathological profile after serial transmissions in a single animal model, was based on the direct interaction of prion isolates with several recipient rodent models expressing small ruminants or heterologous prion proteins. The findings show that the biological properties of scrapie isolates display different patterns of geographical distribution in Europe and suggest that goat BSE could be reliably discriminated from a wide range of biologically and geographically diverse goat prion isolates. Finally, most field prion isolates showed composite strain features, with discrete strain components or sub-strains being present in different proportions in individual goats or tissues. This has important implications for understanding the nature and evolution of scrapie strains and their transmissibility to other species, including humans.
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http://dx.doi.org/10.1038/s41598-019-57005-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6949283PMC
January 2020

The emergence of classical BSE from atypical/Nor98 scrapie.

Proc Natl Acad Sci U S A 2019 Dec 16. Epub 2019 Dec 16.

UMR Institut National de la Recherche Agronomique (INRA)/École Nationale Vétérinaire de Toulouse (ENVT) 1225, Interactions Hôtes Agents Pathogènes, 31076 Toulouse, France;

Atypical/Nor98 scrapie (AS) is a prion disease of small ruminants. Currently there are no efficient measures to control this form of prion disease, and, importantly, the zoonotic potential and the risk that AS might represent for other farmed animal species remains largely unknown. In this study, we investigated the capacity of AS to propagate in bovine PrP transgenic mice. Unexpectedly, the transmission of AS isolates originating from 5 different European countries to bovine PrP mice resulted in the propagation of the classical BSE (c-BSE) agent. Detection of prion seeding activity in vitro by protein misfolding cyclic amplification (PMCA) demonstrated that low levels of the c-BSE agent were present in the original AS isolates. C-BSE prion seeding activity was also detected in brain tissue of ovine PrP mice inoculated with limiting dilutions (endpoint titration) of ovine AS isolates. These results are consistent with the emergence and replication of c-BSE prions during the in vivo propagation of AS isolates in the natural host. These data also indicate that c-BSE prions, a known zonotic agent in humans, can emerge as a dominant prion strain during passage of AS between different species. These findings provide an unprecedented insight into the evolution of mammalian prion strain properties triggered by intra- and interspecies passage. From a public health perspective, the presence of c-BSE in AS isolates suggest that cattle exposure to small ruminant tissues and products could lead to new occurrences of c-BSE.
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http://dx.doi.org/10.1073/pnas.1915737116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936354PMC
December 2019

Transgenic mouse models expressing human and macaque prion protein exhibit similar prion susceptibility on a strain-dependent manner.

Sci Rep 2019 10 30;9(1):15699. Epub 2019 Oct 30.

Centro de Investigación en Sanidad Animal (INIA-CISA), 28130, Valdeolmos, Madrid, Spain.

Cynomolgus macaque has been used for the evaluation of the zoonotic potential of prion diseases, especially for classical-Bovine Spongiform Encephalopathy (classical-BSE) infectious agent. PrP amino acid sequence is considered to play a key role in the susceptibility to prion strains and only one amino acid change may alter this susceptibility. Macaque and human-PrP sequences have only nine amino acid differences, but the effect of these amino acid changes in the susceptibility to dissimilar prion strains is unknown. In this work, the transmissibility of a panel of different prions from several species was compared in transgenic mice expressing either macaque-PrP (TgMac) or human-PrP (Hu-Tg340). Similarities in the transmissibility of most prion strains were observed suggesting that macaque is an adequate model for the evaluation of human susceptibility to most of the prion strains tested. Interestingly, TgMac were more susceptible to classical-BSE strain infection than Hu-Tg340. This differential susceptibility to classical-BSE transmission should be taken into account for the interpretation of the results obtained in macaques. It could notably explain why the macaque model turned out to be so efficient (worst case model) until now to model human situation towards classical-BSE despite the limited number of animals inoculated in the laboratory experiments.
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http://dx.doi.org/10.1038/s41598-019-52155-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6821920PMC
October 2019

RNA editing alterations define manifestation of prion diseases.

Proc Natl Acad Sci U S A 2019 09 6;116(39):19727-19735. Epub 2019 Sep 6.

Neurodegenerative Diseases Research Group, Department of Pharmacy, School of Health Sciences, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;

Prion diseases are fatal neurodegenerative disorders caused by misfolding of the normal prion protein into an infectious cellular pathogen. Clinically characterized by rapidly progressive dementia and accounting for 85% of human prion disease cases, sporadic Creutzfeldt-Jakob disease (sCJD) is the prevalent human prion disease. Although sCJD neuropathological hallmarks are well-known, associated molecular alterations are elusive due to rapid progression and absence of preclinical stages. To investigate transcriptome alterations during disease progression, we utilized tg340-129MM mice infected with postmortem material from sCJD patients of the most susceptible genotype (MM1 subtype), a sCJD model that faithfully recapitulates the molecular and pathological alterations of the human disease. Here we report that transcriptomic analyses from brain cortex in the context of disease progression, reveal epitranscriptomic alterations (specifically altered RNA edited pathway profiles, eg., ER stress, lysosome) that are characteristic and possibly protective mainly for preclinical and clinical disease stages. Our results implicate regulatory epitranscriptomic mechanisms in prion disease neuropathogenesis, whereby RNA-editing targets in a humanized sCJD mouse model were confirmed in pathological human autopsy material.
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http://dx.doi.org/10.1073/pnas.1803521116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6765247PMC
September 2019

Thermostability as a highly dependent prion strain feature.

Sci Rep 2019 08 6;9(1):11396. Epub 2019 Aug 6.

Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos, Madrid, Spain.

Prion diseases are caused by the conversion of physiological PrP into the pathogenic misfolded protein PrP, conferring new properties to PrP that vary upon prion strains. In this work, we analyze the thermostability of three prion strains (BSE, RML and 22L) that were heated at 98 °C for 2 hours. PrP resistance to proteinase K (PrP), residual infectivity by mouse bioassay and in vitro templating activity by protein misfolding cyclic amplification (PMCA) were studied. Heated strains showed a huge loss of PrP and a radically different infectivity loss: RML was the most thermolabile strain (6 to 7 log10 infectivity loss), followed by 22L (5 log10) while BSE was the most thermostable strain with low or null infectivity reduction showing a clear dissociation between PrP and infectivity. These results indicate that thermostability is a strain-specific feature, measurable by PMCA and mouse bioassay, and a great tool to distinguish prion strains.
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http://dx.doi.org/10.1038/s41598-019-47781-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684573PMC
August 2019

Nonpathogenic Heterologous Prions Can Interfere with Prion Infection in a Strain-Dependent Manner.

J Virol 2018 12 27;92(24). Epub 2018 Nov 27.

Centro de Investigación en Sanidad Animal, CISA-INIA, Madrid, Spain

Co-occurrence of different prion strains into the same host has been recognized as a natural phenomenon for several sporadic Creutzfeldt-Jakob disease (sCJD) patients and natural scrapie cases. The final outcome of prion coinfection is not easily predictable. In addition to the usual factors that influence prion conversion, the replication of one strain may entail positive or negative consequences to the other. The main aim of this study was to gain insights into the prion coinfection and interference concepts and their potential therapeutic implications. Here, different mouse models were challenged with several combinations of prion strains coupled on the basis of the lengths of their incubation periods and the existence/absence of a species barrier in the tested animal model. We found that nontransmissible strains can interfere the replication of fully transmissible strains when there is a species transmission barrier involved, as happened with the combination of a mouse (22L) and a human (sCJD) strain. However, this phenomenon seems to be strain dependent, since no interference was observed when the human strain coinoculated was vCJD. For the other combinations tested in this study, the results suggest that both strains replicate independently without effect on the replication of one over the other. It is common that the strain with more favorable conditions (e.g., a higher speed of disease development or the absence of a species barrier) ends being the only one detectable at the terminal stage of the disease. However, this does not exclude the replication of the least favored strain, leading to situations of the coexistence of prion strains. As a general conclusion, the outcome of prion coinfection is strongly dependent on the strain combination and the model utilized and is therefore difficult to predict. The coexistence of several prion strains may remain undetected if one of the strains has more favorable conditions to replicate in the host. The use of several models (such as a transgenic mouse expressing PrP from different species) to analyze field prion isolates is recommended to avoid this situation. The inference effect exerted by nonreplicative prion strains should be considered an interesting tool to advance in new therapeutic strategies for treating prion diseases; it may even be a proper therapeutic strategy.
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http://dx.doi.org/10.1128/JVI.01086-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6258938PMC
December 2018

Epigenetic Control of the Notch and Eph Signaling Pathways by the Prion Protein: Implications for Prion Diseases.

Mol Neurobiol 2019 Mar 11;56(3):2159-2173. Epub 2018 Jul 11.

INSERM UMR 1124, 75006, Paris, France.

Among the ever-growing number of self-replicating proteins involved in neurodegenerative diseases, the prion protein PrP remains the most infamous for its central role in transmissible spongiform encephalopathies (TSEs). In these diseases, pathogenic prions propagate through a seeding mechanism, where normal PrP molecules are converted into abnormally folded scrapie isoforms termed PrP. Since its discovery over 30 years ago, much advance has contributed to define the host-encoded cellular prion protein PrP as a critical relay of prion-induced neuronal cell demise. A current consensual view is that the conversion of PrP into PrP in neuronal cells diverts the former from its normal function with subsequent molecular alterations affecting synaptic plasticity. Here, we report that prion infection is associated with reduced expression of key effectors of the Notch pathway in vitro and in vivo, recapitulating changes fostered by the absence of PrP. We further show that both prion infection and PrP depletion promote drastic alterations in the expression of a defined set of Eph receptors and their ephrin ligands, which represent important players in synaptic function. Our data indicate that defects in the Notch and Eph axes can be mitigated in response to histone deacetylase inhibition in PrP-depleted as well as prion-infected cells. We thus conclude that infectious prions cause a loss-of-function phenotype with respect to Notch and Eph signaling and that these alterations are sustained by epigenetic mechanisms.
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http://dx.doi.org/10.1007/s12035-018-1193-7DOI Listing
March 2019

Both murine host and inoculum modulate expression of experimental variant Creutzfeldt-Jakob disease.

J Gen Virol 2018 Mar;99(3):422-433

U.S. Food and Drug Administration, Center for Biologics Evaluation and Research, Office of Blood Research and Review, Department of Emerging and Transfusion Transmitted Diseases, Laboratory of Bacterial and Transmissible Spongiform Encephalopathy Agents, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA.

Transmissible spongiform encephalopathies (TSEs) are infections that are experimentally transmissible to laboratory animals. TSE agents (prions) can be serially passaged in the same animal species. The susceptibility of mice to infection with specific TSE agents can be unpredictable and must be established empirically. We challenged wild-type C57BL/6 and RIIIS/J mice and transgenic mice overexpressing bovine prion protein (TgBo110) with a human brain infected with variant Creutzfeldt-Jakob disease (vCJD) agent and pooled brains of macaques experimentally infected with human vCJD agent (first-passage macaque vCJD). The human vCJD brain yielded a wide range of infectivity titres in different mouse models; TgBo110 mice were the most sensitive. In contrast, infectivity titres of macaque vCJD brain were similar in all three murine models. The brains of RIIIS/J mice infected with both human and macaque vCJD had mild or no vacuolation, while infected C57BL/6 and TgBo110 mice had spongiform degeneration with vacuolation. Abnormal prion protein (PrP) extracted from the brains of vCJD-infected TgBo110 mice displayed different glycosylation profiles and had greater resistance to denaturation by guanidine hydrochloride than PrP from infected wild-type mice or from either inoculum. Those histopathological features of TSE and physical properties of PrP in mice with experimental vCJD were intrinsic to the host, even though we also observed differences between wild-type mice infected with either agent, suggesting a modulatory effect of the inoculum. This study compared three widely used mouse models infected with two different vCJD inocula. The results show that the host plays a major role in manifestations of experimental TSEs.
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http://dx.doi.org/10.1099/jgv.0.001017DOI Listing
March 2018

Regional and subtype-dependent miRNA signatures in sporadic Creutzfeldt-Jakob disease are accompanied by alterations in miRNA silencing machinery and biogenesis.

PLoS Pathog 2018 01 22;14(1):e1006802. Epub 2018 Jan 22.

Department of Neurology, University Medical School, Göttingen, Germany.

Increasing evidence indicates that microRNAs (miRNAs) are contributing factors to neurodegeneration. Alterations in miRNA signatures have been reported in several neurodegenerative dementias, but data in prion diseases are restricted to ex vivo and animal models. The present study identified significant miRNA expression pattern alterations in the frontal cortex and cerebellum of sporadic Creutzfeldt-Jakob disease (sCJD) patients. These changes display a highly regional and disease subtype-dependent regulation that correlates with brain pathology. We demonstrate that selected miRNAs are enriched in sCJD isolated Argonaute(Ago)-binding complexes in disease, indicating their incorporation into RNA-induced silencing complexes, and further suggesting their contribution to disease-associated gene expression changes. Alterations in the miRNA-mRNA regulatory machinery and perturbed levels of miRNA biogenesis key components in sCJD brain samples reported here further implicate miRNAs in sCJD gene expression (de)regulation. We also show that a subset of sCJD-altered miRNAs are commonly changed in Alzheimer's disease, dementia with Lewy bodies and fatal familial insomnia, suggesting potential common mechanisms underlying these neurodegenerative processes. Additionally, we report no correlation between brain and cerebrospinal fluid (CSF) miRNA-profiles in sCJD, indicating that CSF-miRNA profiles do not faithfully mirror miRNA alterations detected in brain tissue of human prion diseases. Finally, utilizing a sCJD MM1 mouse model, we analyzed the miRNA deregulation patterns observed in sCJD in a temporal manner. While fourteen sCJD-related miRNAs were validated at clinical stages, only two of those were changed at early symptomatic phase, suggesting that the miRNAs altered in sCJD may contribute to later pathogenic processes. Altogether, the present work identifies alterations in the miRNA network, biogenesis and miRNA-mRNA silencing machinery in sCJD, whereby contributions to disease mechanisms deserve further investigation.
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http://dx.doi.org/10.1371/journal.ppat.1006802DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5794191PMC
January 2018

YKL-40 in the brain and cerebrospinal fluid of neurodegenerative dementias.

Mol Neurodegener 2017 Nov 10;12(1):83. Epub 2017 Nov 10.

Department of Neurology, University Medical School, Göttingen, Germany.

Background: YKL-40 (also known as Chitinase 3-like 1) is a glycoprotein produced by inflammatory, cancer and stem cells. Its physiological role is not completely understood but YKL-40 is elevated in the brain and cerebrospinal fluid (CSF) in several neurological and neurodegenerative diseases associated with inflammatory processes. Yet the precise characterization of YKL-40 in dementia cases is missing.

Methods: In the present study, we comparatively analysed YKL-40 levels in the brain and CSF samples from neurodegenerative dementias of different aetiologies characterized by the presence of cortical pathology and disease-specific neuroinflammatory signatures.

Results: YKL-40 was normally expressed in fibrillar astrocytes in the white matter. Additionally YKL-40 was highly and widely expressed in reactive protoplasmic cortical and perivascular astrocytes, and fibrillar astrocytes in sporadic Creutzfeldt-Jakob disease (sCJD). Elevated YKL-40 levels were also detected in Alzheimer's disease (AD) but not in dementia with Lewy bodies (DLB). In AD, YKL-40-positive astrocytes were commonly found in clusters, often around β-amyloid plaques, and surrounding vessels with β-amyloid angiopathy; they were also distributed randomly in the cerebral cortex and white matter. YKL-40 overexpression appeared as a pre-clinical event as demonstrated in experimental models of prion diseases and AD pathology. CSF YKL-40 levels were measured in a cohort of 288 individuals, including neurological controls (NC) and patients diagnosed with different types of dementia. Compared to NC, increased YKL-40 levels were detected in sCJD (p < 0.001, AUC = 0.92) and AD (p < 0.001, AUC = 0.77) but not in vascular dementia (VaD) (p > 0.05, AUC = 0.71) or in DLB/Parkinson's disease dementia (PDD) (p > 0.05, AUC = 0.70). Further, two independent patient cohorts were used to validate the increased CSF YKL-40 levels in sCJD. Additionally, increased YKL-40 levels were found in genetic prion diseases associated with the PRNP-D178N (Fatal Familial Insomnia) and PRNP-E200K mutations.

Conclusions: Our results unequivocally demonstrate that in neurodegenerative dementias, YKL-40 is a disease-specific marker of neuroinflammation showing its highest levels in prion diseases. Therefore, YKL-40 quantification might have a potential for application in the evaluation of therapeutic intervention in dementias with a neuroinflammatory component.
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http://dx.doi.org/10.1186/s13024-017-0226-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5681777PMC
November 2017

Protective Effect of Val-PrP against Bovine Spongiform Encephalopathy but not Variant Creutzfeldt-Jakob Disease.

Emerg Infect Dis 2017 09;23(9):1522-1530

Bovine spongiform encephalopathy (BSE) is the only known zoonotic prion that causes variant Creutzfeldt-Jakob disease (vCJD) in humans. The major risk determinant for this disease is the polymorphic codon 129 of the human prion protein (Hu-PrP), where either methionine (Met) or valine (Val) can be encoded. To date, all clinical and neuropathologically confirmed vCJD cases have been Met homozygous, with the exception of 1 recently reported Met/Val heterozygous case. Here, we found that transgenic mice homozygous for Val Hu-PrP show severely restricted propagation of the BSE prion strain, but this constraint can be partially overcome by adaptation of the BSE agent to the Met Hu-PrP. In addition, the transmission of vCJD to transgenic mice homozygous for Val Hu-PrP resulted in a prion with distinct strain features. These observations may indicate increased risk for vCJD secondary transmission in Val Hu-PrP-positive humans with the emergence of new strain features.
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http://dx.doi.org/10.3201/eid2309.161948DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5572891PMC
September 2017

Infectivity in bone marrow from sporadic CJD patients.

J Pathol 2017 11 22;243(3):273-278. Epub 2017 Sep 22.

UMR INRA ENVT 1225, Interactions Hôtes Agents Pathogènes, Ecole Nationale Vétérinaire de Toulouse, France.

Prion infectivity was recently identified in the blood of both sporadic and variant Creutzfeldt-Jakob disease (CJD) patients. In variant CJD (vCJD), the widespread distribution of prions in peripheral tissues of both asymptomatic and symptomatic patients is likely to explain the occurrence of the observed prionaemia. However, in sporadic CJD (sCJD), prion infectivity is described to be located principally in the central nervous system. In this study, we investigated the presence of prion infectivity in bone marrow collected after death in patients affected with different sCJD agents. Bioassays in transgenic mice expressing the human prion protein revealed the presence of unexpectedly high levels of infectivity in the bone marrow from seven out of eight sCJD cases. These findings may explain the presence of blood-borne infectivity in sCJD patients. They also suggest that the distribution of prion infectivity in peripheral tissues in sCJD patients could be wider than currently believed, with potential implications for the iatrogenic transmission risk of this disease. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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http://dx.doi.org/10.1002/path.4954DOI Listing
November 2017

Altered Ca homeostasis induces Calpain-Cathepsin axis activation in sporadic Creutzfeldt-Jakob disease.

Acta Neuropathol Commun 2017 04 27;5(1):35. Epub 2017 Apr 27.

Department of Neurology, University Medical Center Göttingen, and German Center for Neurodegenerative Diseases (DZNE), Robert Koch Strasse 40, 37075, Göttingen, Germany.

Sporadic Creutzfeldt-Jakob disease (sCJD) is the most prevalent form of human prion disease and it is characterized by the presence of neuronal loss, spongiform degeneration, chronic inflammation and the accumulation of misfolded and pathogenic prion protein (PrP). The molecular mechanisms underlying these alterations are largely unknown, but the presence of intracellular neuronal calcium (Ca) overload, a general feature in models of prion diseases, is suggested to play a key role in prion pathogenesis.Here we describe the presence of massive regulation of Ca responsive genes in sCJD brain tissue, accompanied by two Ca-dependent processes: endoplasmic reticulum stress and the activation of the cysteine proteases Calpains 1/2. Pathogenic Calpain proteins activation in sCJD is linked to the cleavage of their cellular substrates, impaired autophagy and lysosomal damage, which is partially reversed by Calpain inhibition in a cellular prion model. Additionally, Calpain 1 treatment enhances seeding activity of PrP in a prion conversion assay. Neuronal lysosomal impairment caused by Calpain over activation leads to the release of the lysosomal protease Cathepsin S that in sCJD mainly localises in axons, although massive Cathepsin S overexpression is detected in microglial cells. Alterations in Ca homeostasis and activation of Calpain-Cathepsin axis already occur at pre-clinical stages of the disease as detected in a humanized sCJD mouse model.Altogether our work indicates that unbalanced Calpain-Cathepsin activation is a relevant contributor to the pathogenesis of sCJD at multiple molecular levels and a potential target for therapeutic intervention.
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http://dx.doi.org/10.1186/s40478-017-0431-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5408381PMC
April 2017

Molecular Alterations in the Cerebellum of Sporadic Creutzfeldt-Jakob Disease Subtypes with DJ-1 as a Key Regulator of Oxidative Stress.

Mol Neurobiol 2018 01 14;55(1):517-537. Epub 2016 Dec 14.

Department of Neurology, University Medical Center Goettingen (UMG) and German Center for Neurodegenerative Diseases (DZNE) Goettingen, Robert-Koch-Str., 40, 37075, Goettingen, Germany.

Cerebellar damage and granular and Purkinje cell loss in sporadic Creutzfeldt-Jakob disease (sCJD) highlight a critical involvement of the cerebellum during symptomatic progression of the disease. In this project, global proteomic alterations in the cerebellum of brain from the two most prevalent subtypes (MM1 and VV2) of sCJD were studied. Two-dimensional gel electrophoresis (2DE) coupled mass spectrometric identification revealed 40 proteins in MM1 and 43 proteins in VV2 subtype to be differentially expressed. Of those, 12 proteins showed common differential expression in their expression between two subtypes. Differentially expressed proteins mainly belonged to (i) cell cycle, gene expression and cell death; (ii) cellular stress response/oxidative stress (OS) and (iii) signal transduction and synaptic functions, related molecular functions. We verified 10 differentially expressed proteins at transcriptional and translational level as well. Interestingly, protein deglycase DJ-1 (an antioxidative protein) showed an increase in its messenger RNA (mRNA) expression in both MM1 and VV2 subtypes but protein expression only in VV2 subtype in cerebellum of sCJD patients. Nuclear translocalization of DJ-1 confirmed its expressional alteration due to OS in sCJD. Downstream experiments showed the activation of nuclear factor erythroid-2 related factor 2 (Nrf2)/antioxidative response element (ARE) pathway. DJ-1 protein concentration was significantly increased during the clinical phase in cerebrospinal fluid of sCJD patients and also at presymptomatic and symptomatic stages in cerebellum of humanized PrP transgenic mice inoculated with sCJD (MM1 and VV2) brain. These results suggest the implication of oxidative stress during the pathophysiology of sCJD.
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http://dx.doi.org/10.1007/s12035-016-0294-4DOI Listing
January 2018