Prion diseases are fatal transmissible neurodegenerative disorders that affect animals and humans. Prions are proteinaceous infectious particles consisting of a misfolded isoform of the cellular prion protein PrP, termed...Prion diseases are fatal transmissible neurodegenerative disorders that affect animals and humans. Prions are proteinaceous infectious particles consisting of a misfolded isoform of the cellular prion protein PrP, termed PrP. PrP accumulates in infected neurons due to partial resistance to proteolytic digestion. Using compounds that interfere with the production of PrP or enhance its degradation cure prion infection , but most drugs failed when used to treat prion-infected rodents. In order to synergize the effect of anti-prion drugs, we combined drugs interfering with the generation of PrP with compounds inducing PrP degradation. Here, we tested autophagy stimulators (rapamycin or AR12) and cellulose ether compounds (TC-5RW or 60SH-50) either as single or combination treatment of mice infected with RML prions. Single drug treatments significantly extended the survival compared to the untreated group. As anticipated, also all the combination therapy groups showed extended survival compared to the untreated group, but no combination treatment showed superior effects to 60SH-50 or TC-5RW treatment alone. Unexpectedly, we later found that combining autophagy stimulator and cellulose ether treatment in cultured neuronal cells mitigated the pro-autophagic activity of AR12 and rapamycin, which can in part explain the results. Overall, we show that it is critical to exclude antagonizing drug effects when attempting combination therapy. In addition, we identified AR-12 as a pro-autophagic drug that significantly extends survival of prion-infected mice, has no adverse side effects on the animals used in this study, and can be useful in future studies.
After the discovery of two atypical bovine spongiform encephalopathy (BSE) forms in France and Italy designated H- and L-BSE, the question arose whether these new forms differed from classical BSE (C-BSE) in their pathog...After the discovery of two atypical bovine spongiform encephalopathy (BSE) forms in France and Italy designated H- and L-BSE, the question arose whether these new forms differed from classical BSE (C-BSE) in their pathogenesis. Samples collected from cattle in the clinical stage of BSE during an intracranial challenge study with L- and H-BSE were analysed using biochemical and histological methods as well as in a transgenic mouse bioassay. Our results generally confirmed what had been described for C-BSE to be true also for both atypical BSE forms, namely the restriction of the pathological prion protein (PrP) and BSE infectivity to the nervous system. However, analysis of samples collected under identical conditions from both atypical H- and L-BSE forms allowed us a more precise assessment of the grade of involvement of different tissues during the clinical end stage of disease as compared to C-BSE. One important feature is the involvement of the peripheral nervous and musculoskeletal tissues in both L-BSE and H-BSE affected cattle. We were, however, able to show that in H-BSE cases, the PrP depositions in the central and peripheral nervous system are dominated by a glial pattern, whereas a neuronal deposition pattern dominates in L-BSE cases, indicating differences in the cellular and topical tropism of both atypical BSE forms. As a consequence of this cell tropism, H-BSE seems to spread more rapidly from the CNS into the periphery via the glial cell system such as Schwann cells, as opposed to L-BSE which is mostly propagated via neuronal cells.
We describe a case of probable sporadic Creutzfeldt-Jakob disease in the setting of well-controlled HIV and discuss whether exist, in fact, HIV-related factors that may predispose to the development of prion disease. To...We describe a case of probable sporadic Creutzfeldt-Jakob disease in the setting of well-controlled HIV and discuss whether exist, in fact, HIV-related factors that may predispose to the development of prion disease. To the best of our knowledge, this is the third report of this association.
Although there have been no reports of facial mimicry in patients with Creutzfeldt-Jakob disease (CJD), we encountered a patient with genetic CJD with prion protein gene codon 180 mutation (V180I gCJD) who apparently sho...Although there have been no reports of facial mimicry in patients with Creutzfeldt-Jakob disease (CJD), we encountered a patient with genetic CJD with prion protein gene codon 180 mutation (V180I gCJD) who apparently showed this interesting clinical finding. The patient was an 87-year-old Japanese woman, and the first observed CJD symptom was poor spontaneity. She gradually showed cognitive dysfunction and subsequently gait disturbance. A prion protein gene analysis revealed a V180I mutation with methionine homozygosity at codon 129. Facial mimicry was observed 7 months after disease onset and continued for approximately 9 months. Pathological laughing and startle reaction were also observed during approximately the same period, whereas myoclonus was observed at a later stage, 12 months after disease onset, and was very mild in degree. Electroencephalography studies showed a diffuse slow basic pattern without periodic sharp wave complexes. Diffusion-weighted magnetic resonance imaging showed extensive hyperintensity in the cerebral cortex, and there was also hyperintensity with edematous swelling in the same regions on T2-weighted and fluid-attenuated inversion recovery images. On the basis of the magnetic resonance imaging findings and the findings of previous case reports of V180I gCJD, we speculate that the characteristic extensive cerebrocortical involvement observed in V180I gCJD was implicated in the pathogenesis of the facial mimicry observed in this case.
The diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) can only be confirmed by abnormal protease-resistant prion protein accumulation in post-mortem brain tissue. The relationships between sCJD and cerebrospinal flu...The diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) can only be confirmed by abnormal protease-resistant prion protein accumulation in post-mortem brain tissue. The relationships between sCJD and cerebrospinal fluid (CSF) proteins such as 14-3-3, tau, and α-synuclein (a-syn) have been investigated for their potential value in pre-mortem diagnosis. Recently, deep-learning (DL) methods have attracted attention in neurodegenerative disease research. We established DL-aided pre-mortem diagnostic methods for CJD using multiple CSF biomarkers to improve their discriminatory sensitivity and specificity. Enzyme-linked immunosorbent assays were performed on phospho-tau (p-tau), total-tau (t-tau), a-syn, and β-amyloid (1-42), and western blot analysis was performed for 14-3-3 protein from CSF samples of 49 sCJD and 256 non-CJD Korean patients, respectively. The deep neural network structure comprised one input, five hidden, and one output layers, with 20, 40, 30, 20 and 12 hidden unit numbers per hidden layer, respectively. The best performing DL model demonstrated 90.38% accuracy, 83.33% sensitivity, and 92.5% specificity for the three-protein combination of t-tau, p-tau, and a-syn, and all other patients in a separate CSF set (n = 15) with other neuronal diseases were correctly predicted to not have CJD. Thus, DL-aided pre-mortem diagnosis may provide a suitable tool for discriminating CJD patients from non-CJD patients.
Chronic wasting disease (CWD) agents are shed into biological samples, facilitating their horizontal transmission between cervid species. Once prions enter the environment, binding of PrP by soil particles may maintain t...Chronic wasting disease (CWD) agents are shed into biological samples, facilitating their horizontal transmission between cervid species. Once prions enter the environment, binding of PrP by soil particles may maintain them near the soil surface, posing a challenge for decontamination. A 2 N sodium hydroxide (NaOH) or 2% sodium hypochlorite (NaClO) solution is traditionally recommended for prion decontamination of equipment and surfaces. Using protein misfolding cyclic amplification with beads and a bioassay with TgElk mice, we compared the effects of these disinfectants in CWD-contaminated soil for 1 or 16 h to those of controls of known infectious titres. Our results suggest that 2 N NaOH in a 1/5 farm soil volume provides a large decrease (>10-fold) in prion infectivity.
Genetic Creutzfeldt-Jakob disease (gCJD) accounts for approximately 10-15% of human prion diseases. It is an autosomal dominant disease caused by missense or insertion mutations of the gene that encodes prion protein (PR...Genetic Creutzfeldt-Jakob disease (gCJD) accounts for approximately 10-15% of human prion diseases. It is an autosomal dominant disease caused by missense or insertion mutations of the gene that encodes prion protein (PRNP). In general, the manifestations and neuropathological changes of gCJD are similar to those of sporadic CJD (sCJD), and the diagnostic sensitivities of cerebrospinal fluid (CSF) markers, electroencephalography (EEG), and magnetic resonance imaging (MRI) are generally lower in gCJD than sCJD. Here we report on a 56-year-old Chinese woman who was diagnosed with gCJD and suspected to have thyroid cancer. The patient carried the glutamate to alanine substitution at codon 196 (E196A) of PRNP, which is quite a rare mutation and has only been reported in China. To our knowledge, this is the fourth case of E196A gCJD in the world. Here, we compared the manifestations and assistant examinations of the current patient with those of three previously reported Chinese patients with E196A gCJD in order to illustrate the common features of E196A gCJD.
Here, we report an autopsy-verified patient with MM2-coritical-type sporadic Creutzfeldt-Jakob disease (MM2C-type sCJD) presenting cortical blindness during a course of glaucoma and age-related macular degeneration, and...Here, we report an autopsy-verified patient with MM2-coritical-type sporadic Creutzfeldt-Jakob disease (MM2C-type sCJD) presenting cortical blindness during a course of glaucoma and age-related macular degeneration, and focus on the difficulties involved in early clinical diagnosis. An 83-year-old man was admitted to our hospital 15 months after the onset of cortical blindness, and 9 months after the onset of progressive dementia. Neurological examination revealed dementia, frontal signs, visual disturbance, dysphagia, myoclonus and exaggerated tendon reflexes in the four extremities. Diffusion-weighted MRI (DW-MRI) showed cortical hyperintensities predominantly in the bilateral occipital lobes. gene analysis showed no mutations with methionine homozygosity at codon 129. Cerebrospinal fluid (CSF) examination revealed elevation of 14-3-3 and total tau protein. The symptoms progressed gradually, and the patient died of aspiration pneumonia, 30 months after the onset. Neuropathological examination revealed extensive large confluent vacuole-type spongiform changes in the cerebral cortices. Prion protein (PrP) immunostaining showed perivascular and plaque-type PrP deposits. We diagnosed our patient as MM2C-type sCJD. There are two difficulties in the early clinical diagnosis of MM2C-type sCJD with ocular disease in the elderly; delayed utilization of DW-MRI, and accompaniment of ocular disease. For early diagnosis of MM2C-type sCJD, we conclude that clinician should perform DW-MRI for patients with isolated dementia or cortical visual disturbance.
: Fatal familial insomnia (FFI) is a rare autosomal-dominant inherited prion disease characterized clinically by severe sleep disorder, motor signs, dysautonomia and abnormal behaviour. FFI is caused by a missense mutati...: Fatal familial insomnia (FFI) is a rare autosomal-dominant inherited prion disease characterized clinically by severe sleep disorder, motor signs, dysautonomia and abnormal behaviour. FFI is caused by a missense mutation at codon 178 of the prion protein gene (PRNP). Our study is aimed to explore typical clinical and genetic features of two Chinese pedigrees with FFI and review the related literatures. : Two FFI cases with family histories were recruited in our study. The main clinical features, genetic features and possible pathophysiologic mechanisms of these two FFI cases were analysed. : The foremost symptoms seemed to be sleep disturbances and psychosis. Progressive sympathetic symptoms, movement disturbances and memory loss were frequently observed as well. Electroencephalography (EEG) showed a minor slowing without periodic triphasic waves. Polysomnography (PSG) showed reduction in total sleep time and disturbance of sleep-related respiratory. Brain magnetic resonance imaging (MRI) did not reveal obvious abnormality. Genetic analysis disclosed the prion protein gene mutation at codon 178 (D178N), with methionine (Met) homozygosity at the polymorphic position 129 (Met129Met). : The major clinical features of Chinese FFI are sleep dysfunction, psychiatric symptoms and sympathetic symptoms. Our patients have similar clinical characteristics as that of the typical FFI cases.
OBJECTIVE: To evaluate whether EPC-MVs could promote bone regeneration by directly regulating osteoblast through miR-126. The underlying mechanisms were also explored. METHODS: EPCs were isolated from bone marrow mononuc...OBJECTIVE: To evaluate whether EPC-MVs could promote bone regeneration by directly regulating osteoblast through miR-126. The underlying mechanisms were also explored. METHODS: EPCs were isolated from bone marrow mononuclear cells. EPC-MVs were collected from EPCs cultured medium. The lentivirus was used to induce miR-126 over-expression in EPCs and EPC-MVs. miR-126 expression was detected by qRT-PCR. The proliferation, migration, apoptosis and differentiation abilities of osteoblast cells MC3T3-E1 were analysed in the presence or absence of EPC-MVs or miR-126 overexpressed EPC-MVs (EPC-MVs-miR126). The proteins of Erk1/2 and Bcl-2 were analysed by western blot. Erk1/2 inhibitor was used for pathway exploration. RESULTS: EPC-MVs reduced apoptosis and promoted proliferation and migration of MC3T3-E1 cells, which could be enhanced by miR-126 enrichment (p< 0.05). Neither EPC-MVs nor EPC-MVs-miR126 had an effect on MC3T3-E1 cell osteogenic differentiation (p> 0.05). EPC-MVs-miR126 had better effects than EPC-MVs on upregulating the expressions of p-Erk1/2 and Bcl-2, which were abolished by Erk1/2 inhibitor. ERK1/2-Bcl-2 activity plays a crucial role in the regulation of EPC-MVs/EPC-MVs-miR126 on the effect of MC3T3-E1 cells. CONCLUSION: EPC-MVs promote proliferation and migration of MC3T3-E1 cell while reduced apoptosis via the miR-126/Erk1/2-Bcl-2 pathway. A combination of EPC-MVs and miR-126 might provide novel therapeutic targets for bone regeneration and fracture healing through regulating osteoblast.
Chronic wasting disease (CWD) is a naturally occurring infectious, fatal, transmissible spongiform encephalopathy of cervids. Currently, disease confirmation relies on post-mortem detection of infectious prions in the me...Chronic wasting disease (CWD) is a naturally occurring infectious, fatal, transmissible spongiform encephalopathy of cervids. Currently, disease confirmation relies on post-mortem detection of infectious prions in the medial retropharyngeal lymph nodes or obex in the brain via immunohistochemistry (IHC). Detection of CWD in living animals using this method is impractical, and IHC and other experimental assays are not reliable in detecting low concentrations of prion present in biofluids or faeces. Here, we evaluate the capability of faecal volatile organic compound analysis to discriminate between CWD-positive and -exposed white-tailed deer located at two positive cervid farms, and two groups of CWD-negative deer from two separate disease-free farms.
The major neurological feature of prion diseases is a neuronal loss accomplished through either apoptosis or autophagy. In this review, I compared axonal alterations in prion diseases to those described 40 years earlier...The major neurological feature of prion diseases is a neuronal loss accomplished through either apoptosis or autophagy. In this review, I compared axonal alterations in prion diseases to those described 40 years earlier as a result of nerve ligation. I also demonstrated that autophagic vacuoles and autophagosomes are a major part of dystrophic neurites. Furthermore, I summarized the current status of the autophagy in prion diseases and hypothesize, that spongiform change may originate from the autophagic vacuoles. This conclusion should be supported by other methods, in particular laser confocal microscopy. We observed neuronal autophagic vacuoles in different stages of formation, and our interpretation of the 'maturity' of their formation may or may not equate to actual developmental stages. Initially, a part of the neuronal cytoplasm was sequestrated within double or multiple membranes (phagophores) and often exhibited increased electron-density. The intracytoplasmic membranes formed labyrinth-like structures that suggest a multiplication of those membranes. The autophagic vacuoles then expand and eventually, a vast area of the cytoplasm was transformed into a merging mass of autophagic vacuoles. Margaret R. Matthews published a long treatise in the Philosophical Transactions of the Royal Society of London in which she had described in great detail the ultrastructure of postganglionic branches of the superior cervical ganglion in the rat following ligation of them. The earliest changes observed by Matthews between 6 h to 2 days in the proximal stump were distensions of proximal axons. Analogously, in our models, an increased number of 'regular' (round) and 'irregular' MVB and some autophagic vacuoles were observed collectively, both processes were similar.
The aim of the presented study was to reveal the frequency of insomnia spells in E200K genetic Creutzfeldt-Jakob disease (gCJD) patients. Clinical records of 22 subjects diagnosed with E200K gCJD were retrospectively rev...The aim of the presented study was to reveal the frequency of insomnia spells in E200K genetic Creutzfeldt-Jakob disease (gCJD) patients. Clinical records of 22 subjects diagnosed with E200K gCJD were retrospectively reviewed. The patients w/wo insomnia (n = 4, 18%/n = 18, 82%) did not differ in age, sex and the duration of the symptomatic phase. Analysis of the clinical features in the groups yielded differences in the clinical signs in the early phase of the disorder, proportion of homozygotes (Met/Met) at codon 129, MRI changes in the thalamus and the typical EEG abnormality. The study suggests that apart from traditional clinical features, the insomnia is not a rare early symptom in phenotype of E200K gCJD based on early thalamic involvement.
Genetic variability in the prion protein (Prnp) gene influences host susceptibility to many pathogenic prion diseases. Understanding the distribution of susceptible Prnp variants and determining factors influencing spati...Genetic variability in the prion protein (Prnp) gene influences host susceptibility to many pathogenic prion diseases. Understanding the distribution of susceptible Prnp variants and determining factors influencing spatial genetic patterns are important components of many chronic wasting disease mitigation strategies. Here, we describe Prnp variability in white-tailed deer (Odocoileus virginianus) from the Mid-Atlantic region of the United States of America, an area with a recent history of infection and low disease incidence. This population is characterized by lower rates of polymorphism and significantly higher frequencies of the more susceptible 96GG genotype compared to previously surveyed populations. The prevalence of the most susceptible genotypes at disease-associated loci did vary among subregions, indicating that populations have innate differences in genotype-dictated susceptibility.
A number of fungal proteins are capable of adopting multiple alternative, self-perpetuating prion conformations. These prion variants are associated with functional alterations of the prion-forming protein and thus the g...A number of fungal proteins are capable of adopting multiple alternative, self-perpetuating prion conformations. These prion variants are associated with functional alterations of the prion-forming protein and thus the generation of new, heritable traits that can be detrimental or beneficial. Here we sought to determine the extent to which the previously-reported ZnCl-sensitivity trait of yeast harboring the [PSI] prion is modulated by genetic background and prion variant, and whether this trait is accompanied by prion-dependent proteomic changes that could illuminate its physiological basis. We also examined the degree to which prion variant and genetic background influence other prion-dependent phenotypes. We found that ZnCl exposure not only reduces colony growth but also limits chronological lifespan of [PSI] relative to [psi] cells. This reduction in viability was observed for multiple prion variants in both the S288C and W303 genetic backgrounds. Quantitative proteomic analysis revealed that under exposure to ZnCl the expression of stress response proteins was elevated and the expression of proteins involved in energy metabolism was reduced in [PSI] relative to [psi] cells. These results suggest that cellular stress and slowed growth underlie the phenotypes we observed. More broadly, we found that prion variant and genetic background modulate prion-dependent changes in protein abundance and can profoundly impact viability in diverse environments. Thus, access to a constellation of prion variants combined with the accumulation of genetic variation together have the potential to substantially increase phenotypic diversity within a yeast population, and therefore to enhance its adaptation potential in changing environmental conditions.
The description of prions as causal agents of Transmissible Spongiform Encephalopathies (TSE), is nowadays accepted as an important breakthrough in biology as revealed the existence of a completely new group of pathogens...The description of prions as causal agents of Transmissible Spongiform Encephalopathies (TSE), is nowadays accepted as an important breakthrough in biology as revealed the existence of a completely new group of pathogens and a new way of transmission for biological information. A common feature of many neurodegenerative disorders is the presence of protein aggregates in the nervous system and as evidences highlighting the similarities of these proteins with TSE-causing prions increase, the line separating the infectious prions from other protein aggregates becomes thinner than previously thought. However, instead of encompassing all these amyloidogenic proteins under the umbrella term "prion", new terminology has raised including the terms prion-like, prionoid, quasi-prion or propagon. The International Prion Conference held in Santiago de Compostela in 2018, offered the perfect forum to discuss this topic and maybe set the basis for an agreed terminology. For that, a round table was organized with several experts on the field to discuss whether Aβ, tau, α-synuclein and others are prions, prion-like proteins, or should be named otherwise. This commentary intends to summarize the topics discussed at the round table and shed some light on this controverted topic, drawing together the opinions of many experts participating at the session.
Understanding the structure of PrP is without doubt a sine qua non to understand not only PrP propagation, but also critical features of that process such as the strain phenomenon and transmission barriers. While elucida...Understanding the structure of PrP is without doubt a sine qua non to understand not only PrP propagation, but also critical features of that process such as the strain phenomenon and transmission barriers. While elucidation of the PrP structure has been full of difficulties, we now have a large amount of structural information that allows us to begin to understand it. This commentary article summarizes a round table that took place within the Prion 2018 meeting held in Santiago de Compostela to discuss the state of the art in this matter. Two alternative models of PrP exist: the PIRIBS and the 4-rung β-solenoid models. Both of them have relevant features. The 4-rung β-solenoid model agrees with experimental constraints of brain derived PrP obtained from cryo-EM and X-ray fiber diffraction studies. Furthermore, it allows facile accommodation of the bulky glycans that decorate brain-derived PrP. On the other hand, the infectious PrP23-144 amyloid exhibits a PIRIBS architecture. Perhaps, both types of structure co-exist.
This commentary describes scientific path and accomplishments of our late colleague, Prof. Michael D. Ter-Avanesyan, who made several seminal contributions into prion research.This commentary describes scientific path and accomplishments of our late colleague, Prof. Michael D. Ter-Avanesyan, who made several seminal contributions into prion research.
This commentary is a tribute to the late colleague, Prof. Michael D. Ter-Avanesyan - prominent contributor into knowledge about prion maintenance and function. The commentary describes his early steps in genetics which b...This commentary is a tribute to the late colleague, Prof. Michael D. Ter-Avanesyan - prominent contributor into knowledge about prion maintenance and function. The commentary describes his early steps in genetics which brought him into prion research.
Amyloids are non-branching fibrils that are composed of stacked monomers stabilized by intermolecular β-sheets. Some amyloids are associated with incurable diseases, whereas others, functional amyloids, regulate differen...Amyloids are non-branching fibrils that are composed of stacked monomers stabilized by intermolecular β-sheets. Some amyloids are associated with incurable diseases, whereas others, functional amyloids, regulate different vital processes. The prevalence and significance of functional amyloids in wildlife are still poorly understood. In recent years, by applying new approach of large-scale proteome screening, a number of novel candidate amyloids were identified in the yeast Saccharomyces cerevisiae, many of which are localized in the yeast cell wall. In this work, we showed that one of these proteins, Toh1, possess amyloid properties. The Toh1-YFP hybrid protein forms detergent-resistant aggregates in the yeast cells while being expressed under its own P or inducible P promoter. Using bacterial system for generation of extracellular amyloid aggregates C-DAG, we demonstrated that the N-terminal Toh1 fragment, containing amyloidogenic regions predicted in silico, binds Congo Red dye, manifests 'apple-green' birefringence when examined between crossed polarizers, and forms amyloid-like fibrillar aggregates visualized by TEM. We have established that the Toh1(20-365)-YFP hybrid protein fluorescent aggregates are co-localized with a high frequency with Rnq1C-CFP and Sup35NM-CFP aggregates in the yeast cells containing [PIN] and [PSI] prions, and physical interaction of these aggregated proteins was confirmed by FRET. This is one of a few known cases of physical interaction of non-Q/N-rich amyloid-like protein and Q/N-rich amyloids, suggesting that interaction of different amyloid proteins may be determined not only by similarity of their primary structures but also by similarity of their secondary structures and of conformational folds.