Human Spongiform Encephalopathies Research Articles

Clinical characteristics and diagnostics of human spongiform encephalopathies: an update

Human spongiform encephalopathies are rare transmissible neurodegenerative diseases of the brain and the nervous system that are caused by misfolding of the physiological prion protein into apathological form and its deposition in the central nervous system (CNS). Prion diseases include Creutzfeldt-Jakob disease (CJD, sporadic or familial), Gerstmann-Straussler-Scheinker syndrome (GSS) and fatal familial insomnia (FFI). Prion diseases can be differentiated into three etiological categories: spontaneous (sporadic CJD), inherited (familial CJD, FFI, and GSS) and acquired (variant CJD and iatrogenic CJD). Most cases occur sporadically. Prion diseases can lead to avariety of neurological symptoms and always have an inevitably fatal course. Cerebrospinal fluid analysis and magnetic resonance imaging (MRI) play acrucial role in the diagnostics of prion diseases and may facilitate an early and reliable clinical diagnosis. Acausal treatment or specific therapeutic agents are not yet available. In general, apalliative therapeutic concept is indicated.

Forma esporádica de enfermedad de Creutzfeldt-Jakob: reporte de dos casos

La enfermedad de Creutzfeldt-Jakob es la encefalopatía espongiforme más común en el ser humano y prototipo de las patologías causadas por priones. Se caracteriza histológicamente por astrogliosis y degeneración de la sustancia gris. Típicamente inicia con síntomas prodrómicos no específicos progresando a demencia con mioclonias y ataxia. Presentamos dos casos de mujeres en edad media con deterioro cognitivo progresivo, dificultades motrices, alteraciones del lenguaje y mioclonias que conducen a la muerte. En electroencefalogramas de ondas trifásicas lentas periódicas así como elevación de proteínas tau y 14-3-3 en LCR por apoyo del The National Prion Disease Pathology Surveillance Center - Cleveland, todos estos hallazgos definen las condiciones para el diagnóstico clínico de enfermedad por priones. El diagnóstico diferencial en el contexto de demencia rápidamente progresiva es amplio, incluyendo infecciones, intoxicaciones, trastornos metabólicos, autoinmunidad, vasculopatías y neoplasias que podrían explicar un posible subregistro en las estadísticas regionales. Existe una posible asociación de riesgo entre enfermedad por priones y médicos patólogos que, aunque discutida, podría limitar el estudio de los especímenes histológicos que son la clave del diagnóstico definitivo. A pesar de la importancia en salud pública de estas condiciones, el actual modelo de salud limita el manejo integral de los pacientes.

Investigating new treatments for Creutzfeldt–Jakob disease

For many years, therapeutic interventions for patients with Creutzfeldt–Jakob disease (CJD) or other forms of human spongiform encephalopathy were beyond clinical consideration. In the 1980s and early 1990s, only individual case reports were available in the literature (figure); clinical trials and systematic clinical observations of patients with CJD did not begin until the mid-1990s. Trials and systematic observations have since examined agents such as flupirtine, quinacrine, doxycycline, and pentosane polysulfate.

Sporadic Creutzfeldt-Jakob Disease among Physicians, Germany, 1993-2018.

We investigated sporadic Creutzfeldt-Jakob disease (sCJD) among physicians in Germany by analyzing occupational information of patients with sCJD recorded by the German CJD Surveillance Unit (1993-2005; 1,250 patients, of whom 4 [0.32%] were physicians) and the National Reference Center for Human Spongiform Encephalopathies (2006-2016; 1,491 patients, of whom 13 [0.87%] were physicians). Among the physicians, we did not identify any neurologists, neurosurgeons, psychiatrists, or pathologists. A cumulative sum test showed an increase in reported physicians over time. Data for 2017-2018 indicated an increased rate of physicians among all notified sCJD cases (5/239 [2.1%]) when we used the total population of Germany as control group. Our data suggest the possibility of an increased risk for sCJD among physicians in Germany. However, we can only speculate about the reasons, and larger multinational studies are needed to replicate the finding and to clarify whether this finding is a general or a country-specific phenomenon.

Loss of STI1-mediated neuronal survival and differentiation in disease-associated mutations of prion protein.

Cellular prion protein (PrPC ) is widely expressed and displays a variety of well-described functions in the central nervous system (CNS). Mutations of the PRNP gene are known to promote genetic human spongiform encephalopathies, but the components of gain- or loss-of-function mutations to PrPC remain a matter for debate. Among the proteins described to interact with PrPC is Stress-inducible protein 1 (STI1), a co-chaperonin that is secreted from astrocytes and triggers neuroprotection and neuritogenesis through its interaction with PrPC . In this work, we evaluated the impact of different PrPC pathogenic point mutations on signaling pathways induced by the STI1-PrPC interaction. We found that some of the pathogenic mutations evaluated herein induce partial or total disruption of neuritogenesis and neuroprotection mediated by mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinases 1 and 2 (ERK1/2) and protein kinase A (PKA) signaling triggered by STI1-PrPC engagement. A pathogenic mutant PrPC that lacked both neuroprotection and neuritogenesis activities fail to promote negative dominance upon wild-type PrPC . Also, a STI1-α7-nicotinic acetylcholine receptor-dependent cellular signaling was present in a PrPC mutant that maintained both neuroprotection and neuritogenesis activities similar to what has been previously observed by wild-type PrPC . These results point to a loss-of-function mechanism underlying the pathogenicity of PrPC mutations.

Prion Deposition in the Retina of Sporadic Cruetzfeldt‐Jakob Disease

IntroductionHuman spongiform encephalopathies, also known as prion diseases, are a rare group of infectious, heritable, and acquired diseases leading to rapid cognitive decline. Prion diseases are considered a serious public health threat due to the high level of infectivity and delayed presentation. Up to 50% of patients with prion disease develop visual symptoms during their clinical course, possibly secondary to abnormal prion protein (PrPSc) accumulation within the eye or within the visual pathway in the brain. Few studies, however, have investigated the presence and deposition pattern of PrPSc within the eye of patients with sporadic Creutzfeldt‐Jakob disease (sCJD). Knowing the presence or levels of PrPSc in the eye is important to assess the potential risk of transmission from common ophthalmic surgical procedures (cornea transplantations and cataract extractions). Additionally, the current gold standard of diagnosis for prion disease remains brain autopsy. If PrPSc expression is present consistently in the eye, ocular imaging modalities with PrPSc‐binding compounds may potentially enable earlier diagnosis. Here, we investigate the expression of PrPSc within retinas of confirmed prion disease cases collected from post‐mortem enucleations.MethodsFrom December 2015 to May 2017, 28 eyes were collected from 14 autopsies of clinically suspected prion disease and 6 of non‐prion disease at a single institution. sCJD was confirmed in all cases by brain autopsy and genetic analysis of the PRNP gene. Immunohistochemistry was performed with antibodies against PrP and PrP deposition within the retina was evaluated and compared with normal controls. Subjects included both male and female patients with ages ranging from 51–80 years old. The clinical disease course ranged from 2–24 months.ResultsIn twelve of the fourteen prion disease cases, PrPSc deposits were observed in the retina by immunohistochemistry. PrPScwas limited to the outer and inner plexiform layers of the retina and was most prominent in the outer plexiform layer, with the majority of cases exhibiting a coarse, 5–10 um well‐aligned ovoid deposits. Controls showed no PrPSc staining in any retinal layers. In the sclera, cornea, lens, and optic nerve, no deposits were observed.ConclusionPrPSc deposits were present in a majority of retinas of patients with confirmed prion disease, primarily within the outer plexiform layer, and these deposits can be detected immunohistochemically. Our findings confirm previous isolated reports of retinal PrPSc deposition in the largest series of documented prion cases to date. We suggest that the retina potentially serves as a diagnostic target in clinically suspected prion disease. Additionally, retinal involvement may contribute to visual symptoms commonly associated with prion disease.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Prions, prionoid complexes and amyloids: the bad, the good and something in between.

Prions are infectious agents causing transmissible spongiform encephalopathies in humans and animals. These protein-based particles template conformational changes in a host-encoded prion protein to an insoluble self-like conformation. Prions are also present in yeast, where they support protein-based epigenetic inheritance. There is emerging evidence that prion-like (prionoid) particles can support a variety of pathological and beneficial functions. The recent data on the prionoid spread of other pathological amyloids are discussed in light of differences between prions and prion-like aggregates. On the other hand, prion-like action has also been found to support important functions such as memory, and amyloids were shown to have a variety of physiological roles from storage to scaffolding in simple organisms and in humans. Higher-order protein complexes play important roles in signalling. Many death-fold domains can polymerise upon nucleation to enhance sensitivity and induce a robust response. Although these polymers are structurally different from amyloids, some of them are characterised by prionoid activities, such as intercellular spread. The initial activation of these complexes is vital for organismal health, whereas prolonged activation leading to unresolved inflammation underlies autoinflammatory and other diseases. Prionoid complexes play important roles far beyond prion diseases and neurodegeneration.

Absence of Evidence for a Causal Link between Bovine Spongiform Encephalopathy Strain Variant L-BSE and Known Forms of Sporadic Creutzfeldt-Jakob Disease in Human PrP Transgenic Mice.

Since the quasi-extinction of classical BSE, atypical BSE forms are the sole BSE variants circulating in cattle worldwide. They are observed in rare cases of old cattle, making them difficult to detect. Extrapolation of our results suggests that L-BSE may propagate in humans as an unrecognized form of CJD, and we urge both the continued utilization of precautionary measures to eliminate these agents from the human food chain and active surveillance for CJD phenotypes in the general population.

Prion-Specific Antibodies Produced in Wild-Type Mice.

Peptide-specific antibodies produced against synthetic peptides are of high value in probing protein structure and function, especially when working with challenging proteins, including not readily available, non-immunogenic, toxic, and/or pathogenic proteins. Here, we present a straightforward method for production of mouse monoclonal antibodies (MAbs) against peptides representing two sites of interest in the bovine prion protein (boPrP), the causative agent of bovine spongiform encephalopathy ("mad cow disease") and new variant Creutzfeldt-Jakob's disease (CJD) in humans, as well as a thorough characterization of their reactivity with a range of normal and pathogenic (misfolded) prion proteins. It is demonstrated that immunization of wild-type mice with ovalbumin-conjugated peptides formulated with Freund's adjuvant induces a good immune response, including high levels of specific anti-peptide antibodies, even against peptides very homologous to murine protein sequences. In general, using the strategies described here for selecting, synthesizing, and conjugating peptides and immunizing 4-5 mice with 2-3 different peptides, high-titered antibodies reacting with the target protein are routinely obtained with at least one of the peptides after three to four immunizations with incomplete Freund's adjuvant.

Glycosylphosphatidylinositol Anchoring Directs the Assembly of Sup35NM Protein into Non-fibrillar, Membrane-bound Aggregates

In prion-infected hosts, PrPSc usually accumulates as non-fibrillar, membrane-bound aggregates. Glycosylphosphatidylinositol (GPI) anchor-directed membrane association appears to be an important factor controlling the biophysical properties of PrPSc aggregates. To determine whether GPI anchoring can similarly modulate the assembly of other amyloid-forming proteins, neuronal cell lines were generated that expressed a GPI-anchored form of a model amyloidogenic protein, the NM domain of the yeast prion protein Sup35 (Sup35(GPI)). We recently reported that GPI anchoring facilitated the induction of Sup35(GPI) prions in this system. Here, we report the ultrastructural characterization of self-propagating Sup35(GPI) aggregates of either spontaneous or induced origin. Like membrane-bound PrPSc, Sup35(GPI) aggregates resisted release from cells treated with phosphatidylinositol-specific phospholipase C. Sup35(GPI) aggregates of spontaneous origin were detergent-insoluble, protease-resistant, and self-propagating, in a manner similar to that reported for recombinant Sup35NM amyloid fibrils and induced Sup35(GPI) aggregates. However, GPI-anchored Sup35 aggregates were not stained with amyloid-binding dyes, such as Thioflavin T. This was consistent with ultrastructural analyses, which showed that the aggregates corresponded to dense cell surface accumulations of membrane vesicle-like structures and were not fibrillar. Together, these results showed that GPI anchoring directs the assembly of Sup35NM into non-fibrillar, membrane-bound aggregates that resemble PrPSc, raising the possibility that GPI anchor-dependent modulation of protein aggregation might occur with other amyloidogenic proteins. This may contribute to differences in pathogenesis and pathology between prion diseases, which uniquely involve aggregation of a GPI-anchored protein, versus other protein misfolding diseases.

Gerstmann‐Sträussler‐Scheinker Syndrome with Variable Phenotype in a New Kindred with PRNP‐P102L Mutation

Gerstmann-Sträussler-Scheinker syndrome (GSS) is a dominantly inherited disorder belonging to the group of transmissible human spongiform encephalopathies or prion diseases. Several families affected by GSS with patients carrying mutations in the prion protein gene have been described worldwide. We report clinical, genealogical, neuropathology and molecular study results from two members of the first Argentine kindred affected by GSS. Both family members presented a frontotemporal-like syndrome, one with and the other without ataxia, with different lesions on neuropathology. A Pro to Leu point mutation at codon 102 (P102L) of the prion protein gene was detected in one of the subjects studied. The pathogenic basis of phenotypic variability observed in this family remains unclear, but resembles that observed in other P102L GSS patients from the same family.

Seeded Fibrillation as Molecular Basis of the Species Barrier in Human Prion Diseases

Prion diseases are transmissible spongiform encephalopathies in humans and animals, including scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease (CWD) in deer, and Creutzfeldt-Jakob disease (CJD) in humans. The hallmark of prion diseases is the conversion of the host-encoded prion protein (PrPC) to its pathological isoform PrPSc, which is accompanied by PrP fibrillation. Transmission is not restricted within one species, but can also occur between species. In some cases a species barrier can be observed that results in limited or unsuccessful transmission. The mechanism behind interspecies transmissibility or species barriers is not completely understood. To analyse this process at a molecular level, we previously established an in vitro fibrillation assay, in which recombinant PrP (recPrP) as substrate can be specifically seeded by PrPSc as seed. Seeding with purified components, with no additional cellular components, is a direct consequence of the “prion-protein-only” hypothesis. We therefore hypothesise, that the species barrier is based on the interaction of PrPC and PrPSc. Whereas in our earlier studies, the interspecies transmission in animal systems was analysed, the focus of this study lies on the transmission from animals to humans. We therefore combined seeds from species cattle, sheep and deer (BSE, scrapie, CWD) with human recPrP. Homologous seeding served as a control. Our results are consistent with epidemiology, other in vitro aggregation studies, and bioassays investigating the transmission between humans, cattle, sheep, and deer. In contrast to CJD and BSE seeds, which show a seeding activity we can demonstrate a species barrier for seeds from scrapie and CWD in vitro. We could show that the seeding activity and therewith the molecular interaction of PrP as substrate and PrPSc as seed is sufficient to explain the phenomenon of species barriers. Therefore our data supports the hypothesis that CWD is not transmissible to humans.

1650 – Probable creutzfeld-jakob disease: a neuropsychiatric presentation

Creutzfeld-Jakob disease (CJD) is the commonest form of transmissible human subacute spongiform encephalopathy, with a worldwide distribution of 0.5 to 1.0 per million population. A retrospective review in 1998 from Singapore General Hospital revealed 5 possible cases over 2 years, in an island with a population of 4 million. We present a 76 year-old Chinese man, with a premorbid personality of an independent person who was neat and meticulous, admitted for a 3 month-history of progressive behavioural change, associated with memory impairment and unsteady gait. He had long-standing hypertension which was well-controlled. The abnormal behaviour included frequent complaints of people coming to his house to have meetings, frequent misplacing of his belongings, as well as decreased self-hygiene. This has affected his daily functioning. There were no other symptoms of dementia. Initial MMSE was 16/30, with impairment in 2-point orientation (place/person), the serial sevens, and delayed recall. There was marked inattention. There was no evidence of mood disorder. No perceptual disorder was elicited. The brain MRI revealed cortical hyperintensities (“cortical ribboning”) in right frontal, parietal, temporal, and caudate nucleus. Physical examination on the 5th day of admission revealed mild bradykinesia, mild hypertonia of all 4 limbs, mildly impaired proprioception, mildly unsteady gait, as well as occasional myoclonic jerks of the head. Electroencephalogram showed generalised fronto-central fairly rhythmical periodic complexes with triphasic morphology.Cerebrospinal fluid protein 14-3-3 were negative. Over the next 12 days, his Abbreviated Mental Test (AMT) decreased from 8/10 to 5/10. The clinical picture was highly suggestive of sporadic CJD.

Protein Misfolding Cyclic Amplification of Prions

Prions are infectious agents that cause the inevitably fatal transmissible spongiform encephalopathy (TSE) in animals and humans(9,18). The prion protein has two distinct isoforms, the non-infectious host-encoded protein (PrP(C)) and the infectious protein (PrP(Sc)), an abnormally-folded isoform of PrP(C 8). One of the challenges of working with prion agents is the long incubation period prior to the development of clinical signs following host inoculation(13). This traditionally mandated long and expensive animal bioassay studies. Furthermore, the biochemical and biophysical properties of PrP(Sc) are poorly characterized due to their unusual conformation and aggregation states. PrP(Sc) can seed the conversion of PrP(C) to PrP(Sc) in vitro(14). PMCA is an in vitro technique that takes advantage of this ability using sonication and incubation cycles to produce large amounts of PrP(Sc), at an accelerated rate, from a system containing excess amounts of PrP(C) and minute amounts of the PrP(Sc) seed(19). This technique has proven to effectively recapitulate the species and strain specificity of PrP(Sc) conversion from PrP(C), to emulate prion strain interference, and to amplify very low levels of PrP(Sc) from infected tissues, fluids, and environmental samples(6,7,16,23) . This paper details the PMCA protocol, including recommendations for minimizing contamination, generating consistent results, and quantifying those results. We also discuss several PMCA applications, including generation and characterization of infectious prion strains, prion strain interference, and the detection of prions in the environment.

New Variant Creutzfeldt-Jacob Disease Presenting With Catatonia: A Rare Presentation

New Variant Creutzfeldt-Jacob Disease Presenting With Catatonia: A Rare Presentation

Gerstmann–Sträussler–Scheinker syndrome masquerading multiple sclerosis

Gerstmann–Sträussler–Scheinker syndrome (GSS) is a rare degenerative disorder of the central nervous system that belongs to the family of human spongiform encephalopathies, or prion diseases. GSS is almost always inherited and mostly carried in an autosomal dominant pattern. Nevertheless, GSS is genetically and phenotypically heterogeneous; among the different prion diseases GSS has the longest clinical course thereby has the potential to mimic the clinical course of different neurological disorders. Here, we report of a patient with a progressive ataxic syndrome, with MRI and CSF findings suggestive of a demyelinating-inflammatory process as multiple sclerosis and the cues that prompted to a final diagnosis of GSS.

Biological Effects and Use of PrP Sc - and PrP-Specific Antibodies Generated by Immunization with Purified Full-Length Native Mouse Prions

The prion agent is the infectious particle causing spongiform encephalopathies in animals and humans and is thought to consist of an altered conformation (PrP(Sc)) of the normal and ubiquitous prion protein PrP(C). The interaction of the prion agent with the immune system, particularly the humoral immune response, has remained unresolved. Here we investigated the immunogenicity of full-length native and infectious prions, as well as the specific biological effects of the resulting monoclonal antibodies (MAbs) on the binding and clearance of prions in cell culture and in in vivo therapy. Immunization of prion knockout (Prnp(0/0)) mice with phosphotungstic acid-purified mouse prions resulted in PrP-specific monoclonal antibodies with binding specificities selective for PrP(Sc) or for both PrP(C) and PrP(Sc). PrP(Sc)-specific MAb W261, of the IgG1 isotype, reacted with prions from mice, sheep with scrapie, deer with chronic wasting disease (CWD), and humans with sporadic and variant Creutzfeldt-Jakob disease (CJD) in assays including a capture enzyme-linked immunosorbent assay (ELISA) system. This PrP(Sc)-specific antibody was unable to clear prions from mouse neuroblastoma cells (ScN2a) permanently infected with scrapie, whereas the high-affinity MAb W226, recognizing both isoforms, PrP(Sc) and PrP(C), did clear prions from ScN2a cells, as determined by a bioassay. However, an attempt to treat intraperitoneally prion infected mice with full-length W226 or with a recombinant variable-chain fragment (scFv) from W226 could only slightly delay the incubation time. We conclude that (i) native, full-length PrP(Sc) elicits a prion-specific antibody response in PrP knockout mice, (ii) a PrP(Sc)-specific antibody had no prion-clearing effect, and (iii) even a high-affinity MAb that clears prions in vitro (W226) may not necessarily protect against prion infection, contrary to previous reports using different antibodies.

Sporadic Creutzfeldt–Jakob disease presenting as nonconvulsive status epilepticus case report and review of the literature

Creutzfeldt–Jakob disease (CJD) is the most common transmissible human spongiform encephalopathy. Seizures and status epilepticus (SE) are an uncommon finding in CJD. We report a 64-year-old woman with rapid cognitive decline who had electroencephalographic (EEG) changes suggestive of nonconvulsive status epilepticus (NCSE). She was later diagnosed with sporadic CJD (sCJD). We also reviewed the literature for published cases on this topic. MEDLINE was employed to identify all published reports of CJD and SE. We identified 8 references with a total of 12 cases with CJD and NCSE. sCJD should be considered in the differential diagnosis of any patient who presents with rapid cognitive decline and EEG changes consistent with status epilepticus.

TSE risk assessment from carcasses of ovine and caprine animals below 6 months of age from TSE infected flocks intended for human consumption - Scientific Opinion of the Panel on Biological Hazards.

TSE risk assessment from carcasses of ovine and caprine animals below 6 months of age from TSE infected flocks intended for human consumption - Scientific Opinion of the Panel on Biological Hazards.

Fibrillization of recombinant bovine prion protein (rec-PrP) in vitro

112 Conversion of normal prion protein ( PrP c ) from the conformation with predominantly α -helical structure into the conformation rich in β -structures ( PrP sc , β -PrP, and PrP res ) underlies the pathogenesis of prion diseases, a special class of degenerative diseases of the nervous system of humans and animals. Prion diseases, or transmissible spongiform encephalopathies (TSEs) of humans, include the Creutzfeldt–Jakob disease (CJD), the Gerstmann–Straussler–Scheinker syndrome, new variant of CJD, kuru, as well as the fatal familial insomnia. The most well-known transmissible spongiform encephalopathies of animals are scrapie of sheep, chronic wasting disease of deer and moose, and bovine spongiform encephalopathy (mad cow disease) [1]. In the course of development of transmissible spongiform encephalopathies, amyloid fibrils (the so-called scrapie-associated fibrils) are formed in brain tissue of both animals and humans. These fibrils consist of β -PrP and are partially resistant to proteolysis. Transmissible spongiform encephalopathies differ in clinical symptoms, neuropathology, neuroanatomical distribution of PrP sc in tissues, and incubation period. It is believed that this heterogeneity of transmissible spongiform encephalopathies is determined by distinctions in the trimeric structure of pathological isoforms of PrP sc [1]. To understand the molecular mechanisms of conversion, the causes of strain differences of causative agents of transmissible spongiform encephalopathies, and interspecies transmission of prion diseases, transformation of recombinant PrP (rec-PrP) of human and different animal species into amyloid fibrils has been performed in vitro in the past years in several laboratories [3–6]. It was shown that the amino acid sequence of PrP markedly affects the formation and morphology of fibrils.