Sporadic Creutzfeldt-Jakob disease (sCJD) is characterized by great phenotypic variability regarding clinical course and neuropathology. The most prominent disease modifiers are a polymorphism in Codon 129 of the prion protein gene and conformational variations of the misfolded prion protein. The cellular form of the prion protein restricts replication of viruses and may be involved in viral host defense, and viral infections influence the presentation and neuropathology in prion diseased mice. We investigated the occurrence of reactivated persistent viral infections of the brain in brain tissue samples of 25 sCJD patients. No evidence of reactivated JCV and CMV infections could be detected. This suggests that JCV and CMV infections are not reactivated as consequence of prion disease and do not act as disease modifiers in sCJD.
Prion; Creutzfeldt-Jakob disease; persistent viral infection; JCV; CMV; disease modifier
Immunological responses may contribute to disease progression and clinical heterogeneity in neurodegenerative dementia, for example, Alzheimer’s disease (AD) and Creutzfeldt-Jakob disease (CJD). Recently, a rapidly progressive form of AD (rpAD) has been described. On neuropathological grounds classical AD and rpAD are not distinguishable at present. All those protein aggregopathies show a state of chronic inflammation with microglia activation and production of proinflammatory cytokines. In this context, it is hypothesized that the severity of the surrounding inflammation substantially contributes to disease progression and accelerated disease courses as seen in rpAD.
Using a cytokine multiplex array based on Luminex Technology, we studied 17 pro- and anti-inflammatory cytokines in cerebrospinal fluid (CSF) and serum from patients with classical dementia (AD) or rapidly progressive dementia (Creutzfeldt-Jakob disease (CJD), rpAD). For controls, we chose patients with multiple sclerosis (MS) and non-neurodegenerative diseases. We found a significant and isolated elevation of proinflammatory cytokines (IL-13, TNF-α and G-CSF) in the serum of rpAD patients. In CSF, IL-8 and MCP-1 chemokines were significantly elevated in CJD patients and MCP-1 in AD patients.
In conclusion, we found a characteristic proinflammatory cytokine response in the serum of rpAD patients. It might explain the more rapidly progressive course of the rpAD subform and can be helpful in distinguishing between classical AD and rpAD.
Electronic supplementary material
The online version of this article (doi:10.1186/s12974-014-0170-y) contains supplementary material, which is available to authorized users.
Creutzfeldt-Jakob disease (CJD) is a heterogenic neurodegenerative disorder associated with abnormal post-translational processing of cellular prion protein (PrPc). CJD displays distinctive clinical and pathological features which correlate with the genotype at the codon 129 (methionine or valine: M or V respectively) in the prion protein gene and with size of the protease-resistant core of the abnormal prion protein PrPsc (type 1: 20/21 kDa and type 2: 19 kDa). MM1 and VV2 are the most common sporadic CJD (sCJD) subtypes. PrP mRNA expression levels in the frontal cortex and cerebellum are reduced in sCJD in a form subtype-dependent. Total PrP protein levels and PrPsc levels in the frontal cortex and cerebellum accumulate differentially in sCJD MM1 and sCJD VV2 with no relation between PrPsc deposition and spongiform degeneration and neuron loss, but with microgliosis, and IL6 and TNF-α response. In the CSF, reduced PrPc, the only form present in this compartment, occurs in sCJD MM1 and VV2. PrP mRNA expression is also reduced in the frontal cortex in advanced stages of Alzheimer disease, Lewy body disease, progressive supranuclear palsy, and frontotemporal lobe degeneration, but PrPc levels in brain varies from one disease to another. Reduced PrPc levels in CSF correlate with PrP mRNA expression in brain, which in turn reflects severity of degeneration in sCJD.
prion protein; Creutzfeldt-Jakob disease; cerebrospinal fluid; brain; mRNA; neurodegenerative diseases
Despite existing criteria, differential diagnosis of Vascular Dementia (VD) and Alzheimer's disease (AD) remains difficult. The aim of this study is to figure out cognitive and biomarker profiles that may help to distinguish between VD, AD and AD + Cerebral Small Vessel Disease (CSVD). We examined a cohort of patients with CSVD (n = 92). After stratification of cognitive impaired patients (n = 59) using the standard CSF beta-amyloid 42/40 ratio cut-off point of 0.975, we obtained two groups which differed with respect to several features: 32 patients with normal beta-amyloid 42/40 ratio (>0.975) showed markedly impaired blood-brain-barrier function as indicated by an elevated albumin ratio (median 8.35). They also differed in cognitive profiles when compared to 27 patients with AD typical beta-amyloid ratio and normal albumin ratio. We also enrolled an additional group of patients with AD (no significant CSVD on MRI, n = 27) which showed no impairment of the blood-brain-barrier. We showed a negative correlation between the albumin ratio and executive cognitive function (p = 0.016) and a negative correlation between memory function and typical AD markers like Tau (p = 0.004) and p181-Tau (p = 0.023) in our cohort. We suppose that the group of patients with normal beta-amyloid ratio represents VD while patients in the other groups represent AD+CSVD and pure AD. Our results support the idea that a dysfunction of the blood-brain-barrier might be contributing factor in the development of cognitive decline in CSVD as it seems to be of more importance than the severity of white matter lesions.
The development of in vitro amplification systems allows detecting femtomolar amounts of prion protein scrapie (PrPSc) in human cerebrospinal fluid (CSF). We performed a CSF study to determine the effects of prion disease type, codon 129 genotype, PrPSc type, and other disease-related factors on the real-time quaking-induced conversion (RT-QuIC) response. We analyzed times to 10,000 relative fluorescence units, areas under the curve and the signal maximum of RT-QuIC response as seeding parameters of interest. Interestingly, type of prion disease (sporadic vs. genetic) and the PRNP mutation (E200K vs. V210I and FFI), codon 129 genotype, and PrPSc type affected RT-QuIC response. In genetic forms, type of mutation showed the strongest effect on the observed outcome variables. In sporadic CJD, MM1 patients displayed a higher RT-QuIC signal maximum compared to MV1 and VV1. Age and gender were not associated with RT-QuIC signal, but patients with a short disease course showed a higher seeding efficiency of the RT-QuIC response. This study demonstrated that PrPSc characteristics in the CSF of human prion disease patients are associated with disease subtypes and rate of decline as defined by disease duration.
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The online version of this article (doi:10.1007/s12035-014-8709-6) contains supplementary material, which is available to authorized users.
Cerebrospinal fluid; Creutzfeldt-Jakob disease; Premortem test; Prion protein; Real-time quaking-induced conversion assay
Background/Objective: PrPc has been suggested to play a role in AD pathophysiology. CSF concentrations of PrPc have been shown to be reduced in AD compared with healthy controls. Furthermore, serum levels of PrPc have recently been reported to be associated with the cognitive status of healthy elderly subjects. Therefore, we hypothesized that CSF levels of PrPc could be associated with cognitive function of AD patients at the time of diagnosis.
Methods: AD patients (n = 114) included into an observational study underwent CERAD testing and lumbar puncture at time of diagnosis / study inclusion. CSF PrPc was determined. Generalized linear models were fitted to assess the associations of PrPc plus a variety of possible confounding factors and CERAD subscale measures.
Results: No association of CSF PrPc and cognitive status could be established, while other factors (i.e., use of antipsychotic drugs, use of anti-dementia drugs, female sex, pre-progression time) were related to worse cognitive function in some domains.
Conclusion: CSF PrPc appears not to be a useful biochemical surrogate of cognitive status in AD at the time of diagnosis. Follow-up analyses will examine possible associations with the speed of cognitive decline.
Alzheimer; prion protein; cognition; CSF; biomarker
We report the presence of infectivity in erythrocytes, leukocytes, and plasma of 1 person with variant Creutzfeldt-Jakob disease and in the plasma of 2 in 4 persons whose tests were positive for sporadic Creutzfeldt-Jakob disease. The measured infectivity levels were comparable to those reported in various animals with transmissible spongiform encephalopathies.
Creutzfeldt-Jakob disease; CJD; vCJD; sCJD; prions; blood; infectivity; transmissible spongiform encephalopathy; TSE
The present study identifies deregulated cytokines and mediators of the immune response in the frontal cortex and cerebellum of sporadic Creutzfeldt–Jakob disease (sCJD) MM1 and VV2 subtypes compared to age-matched controls. Deregulated genes include pro- and anti-inflammatory cytokines, toll-like receptors, colony stimulating factors, cathepsins, members of the complement system, and members of the integrin and CTL/CTLD family with particular regional and sCJD subtype patterns. Analysis of cytokines and mediators at protein level shows expression of selected molecules and receptors in neurons, in astrocytes, and/or in microglia, thus suggesting interactions between neurons and glial cells, mainly microglia, in the neuroinflammatory response in sCJD. Similar inflammatory responses have been shown in the tg340 sCJD MM1 mice, revealing a progressive deregulation of inflammatory mediators with disease progression. Yet, inflammatory molecules involved are subjected to species differences in humans and mice. Moreover, inflammatory-related cell signaling pathways NFκB/IKK and JAK/STAT are activated in sCJD and sCJD MM1 mice. Together, the present observations show a self-sustained complex inflammatory and inflammatory-related responses occurring already at early clinical stages in animal model and dramatically progressing at advanced stages of sCJD. Considering this scenario, measures tailored to modulate (activate or inhibit) specific molecules could be therapeutic options in CJD.
Creutzfeldt–Jakob disease; neuroinflammation; prion protein; cytokines; microglia
Since more than a decade ApoE is known to be a strong risk factor for Alzheimer's disease (AD); however, molecular pathways mediating this risk are still unclear. In recent years it has been hypothesized that ApoE might play a role in the disintegration of blood-brain barrier (BBB). In the present study we addressed the question if ApoE genotypes might be associated with BBB function measured by albumin ratio (QAlb) in a large cohort of patients with different types of dementia.
Five hundred twenty (520) patients with Creutzfeldt-Jakob disease (CJD, n = 350), Alzheimer's disease (n = 71) and cerebral small vessel disease (n = 99) were assessed for their ApoE genotype. BBB function was measured in all patients using QAlb and was compared between ApoE genotypes. Dominant and additive genetic models were assumed in order to investigate the potential effect of ApoE on BBB function.
We observed no systematic differences in QAlb between ApoE genotypes within the present study. Increased QAlb levels were shown for those without E3 allele in the subgroup of CJD patients when assuming a dominant genetic model (p = 0.035). This could not be confirmed for patients with other forms of dementia (p = 0.234).
Although there was some evidence for a protective effect of E3 alleles in CJD patients, this study does not support the hypothesis of a systematic role of ApoE genotypes in BBB function in individuals with a diagnosis of dementia. Thus, changes in BBB function do not seem to contribute to the increased risk of cognitive decline associated with certain ApoE genotypes. The interpretation of the results of this study must take into account that BBB function was only assessed by measuring QAlb which has been shown to be a good marker for overall BBB integrity but might not reflect all qualities of the barrier.
Results from recent experiments with rodents imply that Alzheimer disease might be inducible by seeding Aβ peptides into recipient animals. In respect to this new experimental data, public health aspects as well as epidemiological data have to be reevaluated. In this article, the available experimental and epidemiological data are reviewed.
Alzheimer; transmissibility; prion; dementia; epidemiology
Vascular factors are thought to contribute to the development of disease pathology in neurodegenerative dementia such as Alzheimer’s disease (AD). Another entity, called vascular dementia (VaD), comprises a less defined group of dementia patients having various vascular diseases that especially emerge in the elderly population and require valid options for examination and differential diagnosis. In the context of a retrospective study, we analyzed the cerebrospinal fluid (CSF) biomarkers t-tau, p-tau and Aß42 of a total of 131 patients with AD (n = 47), mild cognitive impairment (MCI) (n = 22), VaD (n = 44) and stroke (n = 18). We found a remarkable alteration in CSF biomarker profile in AD, VaD and in acute ischemic events. CSF profile in AD patients was altered in a very similar way as in stroke patients, without statistical differences. In stroke, increase depend largely on size and duration after the initial event. Total tau levels were useful to differ between VaD and stroke. Aß42 decreased in a similar way in AD, VaD and stroke and had a trend to lower levels in MCI but not in controls.
CSF; Biomarkers; Aß; Tau; Alzheimer’s disease; Vascular dementia; Stroke
In prion disease, a profound microglial activation that precedes neurodegeneration has been observed in the CNS. It is still not fully elucidated whether microglial activation has beneficial effects in terms of prion clearance or whether microglial cells have a mainly detrimental function through the release of pro-inflammatory cytokines. To date, no disease-modifying therapy exists. Several immunization attempts have been performed as one therapeutic approach. Recently, naturally occurring autoantibodies against the prion protein (nAbs-PrP) have been detected. These autoantibodies are able to break down fibrils of the most commonly used mutant prion variant PrP106-126 A117V and prevent PrP106-126 A117V-induced toxicity in primary neurons. In this study, we examined the phagocytosis of the prion peptide PrP106-126 A117V by primary microglial cells and the effect of nAbs-PrP on microglia. nAbs-PrP considerably enhanced the uptake of PrP106-126 A117V without inducing an inflammatory response in microglial cells. PrP106-126 A117V uptake was at least partially mediated through scavenger receptors. Phagocytosis of PrP106-126 A117V with nAbs-PrP was inhibited by wortmannin, a potent phosphatidylinositol 3-kinase inhibitor, indicating a separate uptake mechanism for nAbs-PrP mediated phagocytosis. These data suggest the possible mechanisms of action of nAbs-PrP in prion disease.
Although primarily a neurological complaint, systemic inflammation is present in Alzheimer's Disease, with higher than normal levels of proinflammatory cytokines and chemokines in the periphery as well as the brain. A gradient of these factors may enhance recruitment of activated immune cells into the brain via chemotaxis. Here, we investigated the phenotypes of circulating immune cells in AD patients with multi-colour flow cytometry to determine whether their expression of chemokine receptors is consistent with this hypothesis. In this study, we confirmed our previously reported data on the shift of early- to late-differentiated CD4+ T-cells in AD patients. The percentage of cells expressing CD25, a marker of acute T-cell activation, was higher in patients than in age-matched controls, and percentages of CCR6+ cells were elevated. This chemokine receptor is primarily expressed on pro-inflammatory memory cells and Th17 cells. The proportion of cells expressing CCR4 (expressed on Th2 cells) and CCR5 (Th1 cells and dendritic cells) was also greater in patients, and was more pronounced on CD4+ than CD8+ T-cells. These findings allow a more detailed insight into the systemic immune status of patients with Alzheimer's disease and suggest possible novel targets for immune therapy.
Prion diseases are fatal neurodegenerative diseases of humans and animals caused by the misfolding and aggregation of prion protein (PrP). Mammalian prion diseases are under strong genetic control but few risk factors are known aside from the PrP gene locus (PRNP). No genome-wide association study (GWAS) has been done aside from a small sample of variant Creutzfeldt–Jakob disease (CJD). We conducted GWAS of sporadic CJD (sCJD), variant CJD (vCJD), iatrogenic CJD, inherited prion disease, kuru and resistance to kuru despite attendance at mortuary feasts. After quality control, we analysed 2000 samples and 6015 control individuals (provided by the Wellcome Trust Case Control Consortium and KORA-gen) for 491032-511862 SNPs in the European study. Association studies were done in each geographical and aetiological group followed by several combined analyses. The PRNP locus was highly associated with risk in all geographical and aetiological groups. This association was driven by the known coding variation at rs1799990 (PRNP codon 129). No non-PRNP loci achieved genome-wide significance in the meta-analysis of all human prion disease. SNPs at the ZBTB38–RASA2 locus were associated with CJD in the UK (rs295301, P = 3.13 × 10−8; OR, 0.70) but these SNPs showed no replication evidence of association in German sCJD or in Papua New Guinea-based tests. A SNP in the CHN2 gene was associated with vCJD [P = 1.5 × 10−7; odds ratio (OR), 2.36], but not in UK sCJD (P = 0.049; OR, 1.24), in German sCJD or in PNG groups. In the overall meta-analysis of CJD, 14 SNPs were associated (P < 10−5; two at PRNP, three at ZBTB38–RASA2, nine at nine other independent non-PRNP loci), more than would be expected by chance. None of the loci recently identified as genome-wide significant in studies of other neurodegenerative diseases showed any clear evidence of association in prion diseases. Concerning common genetic variation, it is likely that the PRNP locus contains the only strong risk factors that act universally across human prion diseases. Our data are most consistent with several other risk loci of modest overall effects which will require further genetic association studies to provide definitive evidence.
The definitive diagnosis of genetic prion diseases (gPrD) requires pathological confirmation. To date, diagnosis has relied upon the finding of the biomarkers 14-3-3 protein and total tau (t-tau) protein in the cerebrospinal fluid (CSF), but many researchers have reported that these markers are not sufficiently elevated in gPrD, especially in Gerstmann-Sträussler-Scheinker syndrome (GSS). We recently developed a new in vitro amplification technology, designated “real-time quaking-induced conversion (RT-QUIC)”, to detect the abnormal form of prion protein in CSF from sporadic Creutzfeldt-Jakob disease (sCJD) patients. In the present study, we aimed to investigate the presence of biomarkers and evaluate RT-QUIC assay in patients with gPrD, as the utility of RT-QUIC as a diagnostic tool in gPrD has yet to be determined.
56 CSF samples were obtained from gPrD patients, including 20 cases of GSS with P102L mutation, 12 cases of fatal familial insomnia (FFI; D178N), and 24 cases of genetic CJD (gCJD), comprising 22 cases with E200K mutation and 2 with V203I mutation. We subjected all CSF samples to RT-QUIC assay, analyzed 14-3-3 protein by Western blotting, and measured t-tau protein using an ELISA kit. The detection sensitivities of RT-QUIC were as follows: GSS (78%), FFI (100%), gCJD E200K (87%), and gCJD V203I (100%). On the other hand the detection sensitivities of biomarkers were considerably lower: GSS (11%), FFI (0%), gCJD E200K (73%), and gCJD V203I (67%). Thus, RT-QUIC had a much higher detection sensitivity compared with testing for biomarkers, especially in patients with GSS and FFI.
RT-QUIC assay is more sensitive than testing for biomarkers in gPrD patients. RT-QUIC method would thus be useful as a diagnostic tool when the patient or the patient's family does not agree to genetic testing, or to confirm the diagnosis in the presence of a positive result for genetic testing.
To date, cerebrospinal fluid analysis, particularly protein 14-3-3 testing, presents an important approach in the identification of Creutzfeldt–Jakob disease cases. However, one special point of criticism of 14-3-3 testing is the specificity in the differential diagnosis of rapid dementia. The constant observation of increased cerebrospinal fluid referrals in the national surveillance centres over the last years raises the concern of declining specificity due to higher number of cerebrospinal fluid tests performed in various neurological conditions. Within the framework of a European Community supported longitudinal multicentre study (‘cerebrospinal fluid markers’) we analysed the spectrum of rapid progressive dementia diagnoses, their potential influence on 14-3-3 specificity as well as results of other dementia markers (tau, phosphorylated tau and amyloid-β1–42) and evaluated the specificity of 14-3-3 in Creutzfeldt–Jakob disease diagnosis for the years 1998–2008. A total of 29 022 cerebrospinal fluid samples were analysed for 14-3-3 protein and other cerebrospinal fluid dementia markers in patients with rapid dementia and suspected Creutzfeldt–Jakob disease in the participating centres. In 10 731 patients a definite diagnosis could be obtained. Protein 14-3-3 specificity was analysed for Creutzfeldt–Jakob disease with respect to increasing cerebrospinal fluid tests per year and spectrum of differential diagnosis. Ring trials were performed to ensure the comparability between centres during the reported time period. Protein 14-3-3 test specificity remained high and stable in the diagnosis of Creutzfeldt–Jakob disease during the observed time period across centres (total specificity 92%; when compared with patients with definite diagnoses only: specificity 90%). However, test specificity varied with respect to differential diagnosis. A high 14-3-3 specificity was obtained in differentiation to other neurodegenerative diseases (95–97%) and non-neurological conditions (91–97%). We observed lower specificity in the differential diagnoses of acute neurological diseases (82–87%). A marked and constant increase in cerebrospinal fluid test referrals per year in all centres did not influence 14-3-3 test specificity and no change in spectrum of differential diagnosis was observed. Cerebrospinal fluid protein 14-3-3 detection remains an important test in the diagnosis of Creutzfeldt–Jakob disease. Due to a loss in specificity in acute neurological events, the interpretation of positive 14-3-3 results needs to be performed in the clinical context. The spectrum of differential diagnosis of rapid progressive dementia varied from neurodegenerative dementias to dementia due to acute neurological conditions such as inflammatory diseases and non-neurological origin.
rapid dementia; Creutzfeldt–Jakob disease; cerebrospinal fluid; 14-3-3; specificity; neurodegeneration; differential diagnosis in dementia
Cholesterol is an essential component of eukaryotic plasma membranes and plays an important role in membrane organization and signaling processes. It is the major lipid component of detergent resistant caveolin-1 containing rafts which previously had been reported as a platform for nerve growth factor (NGF) signaling in oligodendrocytes (OL). Surprisingly, a knockdown of caveolin-1 attenuated the process formation of OL (Schmitz et al. J Neurosci Res 88:572–588, 2010), for which a loss of cholesterol could be responsible. In the present report, we could show that a caveolin-1 knockdown resulted in an elevation of cellular cholesterol level; it may indicate an important role of caveolin-1 in cholesterol trafficking to the plasma membrane. Treatment with exogenous PEG cholesterol, which was incorporated to the plasma membrane, supported oligodendroglial process formation, in particular when OL were stimulated by NGF. In this context we have found that OL express NPC1L1 (Niemann–Pick disease type C1-Like 1) which could modulate cholesterol uptake. In contrast, depletion of membrane-bound cholesterol diminished NGF-induced process formation concomitant with a reduced activity of p42/44 mitogen-activated protein kinases.
Caveolin-1; Caveolin containing rafts; Cholesterol; Nerve growth factor; Niemann–Pick disease type C1-Like 1; Oligodendrocytes; TrkA
Since 1987, dura mater graft-associated iatrogenic Creutzfeldt-Jakob disease (dCJD) has been reported in many countries. We report the first case of dCJD in Korea. A 54-yr-old woman, who underwent resection of the meningioma in the left frontal region and received a dura mater graft 23 yr ago presented with dysesthesia followed by psychiatric symptoms and ataxia. Her neurological symptoms rapidly progressed to such an extent that she exhibited myoclonus, dementia, and pyramidal and extrapyramidal signs within 8 weeks. The 14-3-3 protein was detected in her cerebrospinal fluid; however, an electroencephalogram did not reveal characteristic positive sharp wave complexes. Diffusion-weighted magnetic resonance images, obtained serially over 64 days, revealed the rapid progression of areas of high signal intensity in the caudate nucleus and cingulate gyrus to widespread areas of high signal intensity in the cortex and basal ganglia. Pathological examination of brain biopsy specimens confirmed the presence of spongiform changes and deposition of prion protein in the neurons and neuropils.
Creutzfeldt-Jakob Syndrome; Dura Mater Graft; Iatrogenic Disease
Caveolin and caveolin containing rafts are involved in the signaling of growth factors in various cell types. Previous reports of our lab indicated a co-localization of caveolin and the high affinity nerve growth factor (NGF) receptor tyrosine kinase A (TrkA). Mutual effects have been observed among which a caveolin-1 knock-down resulted in an impairment of the NGF signaling cascade rather than in an increase of activity as expected from other growth factor reports. On the other hand, an over-expression of caveolin-1 impaired the NGF stimulated activity of p42/44 mitogen activated protein kinases (MAPK). In this study, we used a caveolin-1 scaffolding domain (CSD) peptide (cavtratin) of which an inhibitory effect on growth factor receptors was reported. Our data showed that cavtratin suppresses the NGF-induced phosphorylation of TrkA as well as the activation of MAPK in porcine oligodendrocytes significantly.
Cavtratin; Caveolin scaffolding domain; Oligodendrocytes; Nerve growth factor; TrkA phosphorylation
Alu DNA elements were long considered to be of no biological significance and thus have been only poorly defined. However, in the past Alu DNA elements with well-defined nucleotide sequences have been suspected to contribute to disease, but the role of Alu DNA element transcripts has rarely been investigated. For the first time, we determined in a real-time approach Alu DNA element transcription in buffy coat cells isolated from the blood of humans suffering from sporadic Creutzfeldt-Jakob disease (sCJD) and other neurodegenerative disorders. The reverse transcribed Alu transcripts were amplified and their cDNA sequences were aligned to genomic regions best fitted to database genomic Alu DNA element sequences deposited in the UCSC and NCBI data bases. Our cloned Alu RNA/cDNA sequences were widely distributed in the human genome and preferably belonged to the “young” Alu Y family. We also observed that some RNA/cDNA clones could be aligned to several chromosomes because of the same degree of identity and score to resident genomic Alu DNA elements. These elements, called paralogues, have purportedly been recently generated by retrotransposition. Along with cases of sCJD we also included cases of dementia and Alzheimer disease (AD). Each group revealed a divergent pattern of transcribed Alu elements. Chromosome 2 was the most preferred site in sCJD cases, besides chromosome 17; in AD cases chromosome 11 was overrepresented whereas chromosomes 2, 3 and 17 were preferred active Alu loci in controls. Chromosomes 2, 12 and 17 gave rise to Alu transcripts in dementia cases. The detection of putative Alu paralogues widely differed depending on the disease. A detailed data search revealed that some cloned Alu transcripts originated from RNA polymerase III transcription since the genomic sites of their Alu elements were found between genes. Other Alu DNA elements could be located close to or within coding regions of genes. In general, our observations suggest that identification and genomic localization of active Alu DNA elements could be further developed as a surrogate marker for differential gene expression in disease. A sufficient number of cases are necessary for statistical significance before Alu DNA elements can be considered useful to differentiate neurodegenerative diseases from controls.
transcription of Alu DNA elements; chromosomal patterns of active Alu DNA elements; sporadic CJD; differential gene expression in neurodegeneration
Six subtypes of sporadic Creutzfeldt–Jakob disease with distinctive clinico-pathological features have been identified largely based on two types of the abnormal prion protein, PrPSc, and the methionine (M)/valine (V) polymorphic codon 129 of the prion protein. The existence of affected subjects showing mixed phenotypic features and concurrent PrPSc types has been reported but with inconsistencies among studies in both results and their interpretation. The issue currently complicates diagnosis and classification of cases and also has implications for disease pathogenesis. To explore the issue in depth, we carried out a systematic regional study in a large series of 225 cases. PrPSc types 1 and 2 concurrence was detected in 35% of cases and was higher in MM than in MV or VV subjects. The deposition of either type 1 or 2, when concurrent, was not random and always characterized by the coexistence of phenotypic features previously described in the pure subtypes. PrPSc type 1 accumulation and related pathology predominated in MM and MV cases, while the type 2 phenotype prevailed in VVs. Neuropathological examination best identified the mixed types 1 and 2 features in MMs and most MVs, and also uniquely revealed the co-occurrence of pathological variants sharing PrPSc type 2. In contrast, molecular typing best detected the concurrent PrPSc types in VV subjects and MV cases with kuru plaques. The present data provide an updated disease classification and are of importance for future epidemiologic and transmission studies aimed to identify etiology and extent of strain variation in sporadic Creutzfeldt–Jakob disease.
Prion protein; Brain mapping; Molecular typing; Neurodegeneration; Classification
Recent concern about the possible secondary spread of vCJD through blood transfusion and blood products has highlighted the need for a sensitive test for the identification of PrPTSE/res in clinical specimens collected in a non-invasive way. In addition, a more accurate estimate of the prevalence of pre-clinical vCJD in the population may be possible if there were a test that could be applied to easily available material such as urine. As a step towards this goal, the detection of putative PrPTSE/res in the urine of CJD patients has been improved, based on Proteinase K digestion of samples and western blotting. The modified western blot uses concentrated urine as a starting material. After proteolytic treatment followed by electrophoresis and western blotting, membranes are incubated with an anti-PrP antibody conjugated directly with horseradish peroxidase. This study was conducted on urine samples of CJD and other neurodegenerative disease affected individuals. Proteinase K resistant high molecular weight proteins were detected, which are suggested to be a complex of urinary PrP and immunoglobulin proteins. Whether urine can be used as a diagnostic tool for the detection of PrP could not be answered in this study.
prion; transmissible spongiform encephalopathy; sporadic Creutzfeldt-Jakob disease; variant Creutzfeldt-Jakob disease; urine; PrP; outer membrane protein
The 14-3-3 protein test has been shown to support the clinical diagnosis of sporadic Creutzfeldt-Jakob disease (CJD) when associated with an adequate clinical context, and a high differential potential for the diagnosis of sporadic CJD has been attributed to other cerebrospinal fluid (CSF) proteins such as tau protein, S100b and neuron specific enolase (NSE). So far there has been only limited information available about biochemical markers in genetic transmissible spongiform encephalopathies (gTSE), although they represent 10–15% of human TSEs. In this study, we analyzed CSF of 174 patients with gTSEs for 14-3-3 (n = 166), tau protein (n = 78), S100b (n = 46) and NSE (n = 50). Levels of brain-derived proteins in CSF varied in different forms of gTSE. Biomarkers were found positive in the majority of gCJD (81%) and insert gTSE (69%), while they were negative in most cases of fatal familial insomnia (13%) and Gerstmann-Sträussler-Scheinker syndrome (10%). Disease duration and codon 129 genotype influence the findings in a different way than in sporadic CJD.
Creutzfeldt-Jakob disease; CSF proteins; 14-3-3 protein; Tau