Prion diseases

Review of the Brain's Behaviour after Injury and Disease for Its Application in an Agent-Based Model (ABM)

The brain is the most complex organ in the human body and, as such, its study entails great challenges (methodological, theoretical, etc.). Nonetheless, there is a remarkable amount of studies about the consequences of pathological conditions on its development and functioning. This bibliographic review aims to cover mostly findings related to changes in the physical distribution of neurons and their connections-the connectome-both structural and functional, as well as their modelling approaches. It does not intend to offer an extensive description of all conditions affecting the brain; rather, it presents the most common ones. Thus, here, we highlight the need for accurate brain modelling that can subsequently be used to understand brain function and be applied to diagnose, track, and simulate treatments for the most prevalent pathologies affecting the brain.

An overview on glycation: molecular mechanisms, impact on proteins, pathogenesis, and inhibition

The formation of a heterogeneous set of advanced glycation end products (AGEs) is the final outcome of a non-enzymatic process that occurs in vivo on long-life biomolecules. This process, known as glycation, starts with the reaction between reducing sugars, or their autoxidation products, with the amino groups of proteins, DNA, or lipids, thus gaining relevance under hyperglycemic conditions. Once AGEs are formed, they might affect the biological function of the biomacromolecule and, therefore, induce the development of pathophysiological events. In fact, the accumulation of AGEs has been pointed as a triggering factor of obesity, diabetes-related diseases, coronary artery disease, neurological disorders, or chronic renal failure, among others. Given the deleterious consequences of glycation, evolution has designed endogenous mechanisms to undo glycation or to prevent it. In addition, many exogenous molecules have also emerged as powerful glycation inhibitors. This review aims to provide an overview on what glycation is. It starts by explaining the similarities and differences between glycation and glycosylation. Then, it describes in detail the molecular mechanism underlying glycation reactions, and the bio-molecular targets with higher propensity to be glycated. Next, it discusses the precise effects of glycation on protein structure, function, and aggregation, and how computational chemistry has provided insights on these aspects. Finally, it reports the most prevalent diseases induced by glycation, and the endogenous mechanisms and the current therapeutic interventions against it.

Sensory disturbances in Creutzfeldt-Jakob disease

BACKGROUND

Creutzfeldt-Jakob disease (CJD) is a fatal neurodegenerative disease characterized by rapidly progressive dementia, motor impairments, and psychiatric symptoms. Sensory disturbances were occasionally reported as well. The study aims to describe the sensory symptoms of the disease.

METHODS

The CJD Israeli National Database was screened for patients who presented sensory symptoms throughout the disease course. Symptoms, characteristics, and distribution were reviewed and the demographic and clinical data (sex, etiologies of the disease, age of onset, disease duration, neurological exam finding, tau protein level, EEG and MRI findings) were compared with the demographics and clinical data of CJD without sensory symptoms. Then, the patients with sensory symptoms were divided into patients with symptom distribution consistent with peripheral nervous system (PNS) involvement and central nervous system (CNS) involvement. The demographics and clinical data of the 2 groups were compared.

RESULTS

Eighty-four CJD patients with sensory symptoms and 645 CJD patients without sensory symptoms were included in the study. Sensory symptoms were more common in genetic E200K CJD patients (14.6% vs. 5.6% respectively, p = 0.0005) (chi-squared test). Numbness and neuropathic pain were the most common symptoms and distribution of symptoms of "stocking gloves" with decreased deep tendon reflexes suggesting peripheral neuropathy in 44% of the patients. In these patients, the classical EEG findings of Periodic Sharp Wave Complexes were less often found (58% vs. 22%, p = 0.02) (chi-squared test).

CONCLUSIONS

Sensory symptoms are more common in E200K patients and often follow peripheral neuropathy distribution that suggests PNS involvement.

The epidemiological and clinical characteristics of patients with young-onset genetic Creutzfeldt-Jakob disease

OBJECTIVES

The onset of Creutzfeldt-Jakob disease (CJD) is usually around the age of 60, but younger patients have been described as well. Our study characterizes the demographic and clinical features of young-onset CJD patients.

METHODS

The CJD Israeli National Database was reviewed, and the patients were divided into groups of young (<40-year-old) (Y|) and older disease onset (>40-year-old) (O). Each group was further divided into sporadic (sCJD) and genetic (gCJD) patients. Clinical and demographic parameters were compared between the groups.

RESULTS

The study included 731 patients (Y- 18 patients, O- 713 patients). MRI showed classical features more often in the older population (O-76.9%, Y-36%, p = 0.006). Rapidly progressive dementia as a presenting feature was more common in the older group (O = 58%, Y = 27.7%, p = 0.019) whereas cerebellar onset (gait instability, dysarthria) was more common in the younger group (O = 6.7%, Y = 27.7%, p = 0.036)). Among gCJD patients, rapidly progressive dementia was commonly seen in older patients (O = 54%, Y = 21% p = 0.008) whereas cerebellar symptoms were seen in young patients (O = 7%, Y = 30% p = 0.01) Typical MRI findings were seen in 37% of young people compared to 87% of older patients (p = 0.002). No significant differences were between young and older patients in the sCJD group.

CONCLUSION

Young-onset gCJD patients have unique disease features including less typical brain MRI changes, a lower prevalence of dementia, and a higher prevalence of cerebellar signs at disease onset.

Case report: Creutzfeldt-Jakob disease presenting with anxiety symptoms in a COVID-19 post-infection patient

Creutzfeldt-Jakob Disease (CJD) is a rare, rapidly progressive, and fatal neurodegenerative disorder. We describe a man whose initial manifestations of CJD occurred shortly after contracting Coronavirus disease 2019 (COVID-19). He first developed anxiety and short-term memory loss a few weeks after a mild COVID-19 infection. He subsequently developed parkinsonism, eventually progressed to akinetic mutism, and passed away 5 months after symptom onset. This case highlights a potential temporal relationship between COVID-19 infection and the onset of neurodegenerative symptoms. Microglia and astrocytes in the central nervous system (CNS) and 'S1' spike proteins on SARS-CoV-2 are potential mediators in neuroinflammation and neurodegeneration.

A longitudinal 18F-FDG PET/MRI study in asymptomatic stage of genetic Creutzfeldt-Jakob disease linked to G114V mutation

BACKGROUND

Pathogenic prion protein may start to deposit in some brain regions and cause functional alterations in the asymptomatic stage in Creutzfeldt-Jakob disease. The study aims to determine the trajectory of the brain metabolic changes for prion protein diseases at the preclinical stage.

METHODS

At baseline, we enrolled five asymptomatic PRNP G114V mutation carriers, six affected genetic PRNP E200K CJD patients and 23 normal controls. All participants completed clinical, diffusion-weighted imaging (DWI) and 18F fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) examinations. Longitudinal follow-up was completed in five asymptomatic mutation carriers. We set three-time points to identify the changing trajectory in the asymptomatic carriers group including baseline, 2-year and 4-year follow-up.

RESULTS

At baseline, DWI signals, the cerebral glucose standardized uptake value rate ratio (SUVR) and clinical status in 5 asymptomatic cases were normal. At the follow-up period, mild hypometabolism on PET images was found in asymptomatic carriers without any DWI abnormal signal. Further group quantitatively analysis showed hypometabolic brain regions in the asymptomatic genetic CJD group were in the insula, frontal, parietal, and temporal lobes in 4-year follow-up. The SUVR changing trajectories of all asymptomatic cases were within the range between the normal controls and affected patients. Notably, the SUVR of one asymptomatic individual whose baseline age was older showed a rapid decline at the last follow-up.

CONCLUSIONS

Our study illustrates that the neurodegenerative process associated with genetic CJD may initiate before the clinical presentation of the disease.

Stress and viral insults do not trigger E200K PrP conversion in human cerebral organoids

Prion diseases are a group of rare, transmissible, and invariably fatal neurodegenerative diseases that affect both humans and animals. The cause of these diseases is misfolding of the prion protein into pathological isoforms called prions. Of all human prion diseases, 10-15% of cases are genetic and the E200K mutation, which causes familial Creutzfeldt-Jakob disease (CJD), is the most prevalent. For both sporadic and genetic disease, it remains uncertain as to how initial protein misfolding is triggered. Prior studies have linked protein misfolding with oxidative stress insults, deregulated interactions with cellular cofactors, and viral infections. Our previous work developed a cerebral organoid (CO) model using human induced pluripotent stem cells containing the E200K mutation. COs are three-dimensional human neural tissues that permit the study of host genetics and environmental factors that contribute to disease onset. Isogenically matched COs with and without the E200K mutation were used to investigate the propensity of E200K PrP to misfold following cellular insults associated with oxidative stress. Since viral infections have also been associated with oxidative stress and neurodegenerative diseases, we additionally investigated the influence of Herpes Simplex Type-1 virus (HSV1), a neurotropic virus that establishes life-long latent infection in its host, on E200K PrP misfolding. While COs proved to be highly infectable with HSV1, neither acute nor latent infection, or direct oxidative stress insult, resulted in evidence of E200K prion misfolding. We conclude that misfolding into seeding-active PrP species is not readily induced by oxidative stress or HSV1 in our organoid system.

Genetic Creutzfeldt-Jakob disease in Turkish Jews-demographic and clinical features

BACKGROUND

The largest cluster of genetic Creutzfeldt- Jakob Disease (CJD) exists in Libyan Jews carrying the E200K mutation in the PRNP gene. However, there is another cluster of genetic CJD with E200K mutation in families of Turkish-Jewish origin.

AIMS

In this retrospective study, we aim to describe the demographic and clinical features of this population of patients.

MATERIAL AND METHODS

The Israeli National CJD database was searched for demographic, clinical, imaging, and laboratory data of genetic CJD patients of Libyan and Turkish ancestry with the E200K mutation. The data of Libyan and Turkish patients were compared with notice similar or different demographic or clinical courses.

RESULTS

Four hundred and twenty-three patients with CJD of Libyan (L) ancestry and 27 patients with CJD of Turkish (T) ancestry were identified. There were no significant differences in demographic and clinical data between the two populations (age of onset: T = 62 ± 8.8, L = 60 ± 9.7; age of death: T = 63 ± 8.6, L = 61 ± 9.7; and disease duration: T = 7.8 ± 8.4 months, L = 9.6 ± 13.6 months). Rapidly progressive dementia was the most common presentation in both groups, followed by pure cerebellar onset. The levels of tau protein in CSF did not differ between groups (T = 1290 ± 397.6 pg/ml, L = 1276 ± 594.2 pg/ml). MRI and EEG showed classical CJD features in most patients in both groups.

DISCUSSION

The E200K mutation is the most common mutation among gCJD patients and was reported in different ethnical populations, suggesting several independent haplotypes of the mutation. The Turkish-Jew cluster, first described in this study, shares similar demographic and clinical features with the bigger cluster of Libyan-Jews CJD patients.

CONCLUSION

E200K gCJD patients of Turkish ancestry share similar demographic and clinical features to patients of Libyan descent, suggesting a common origin of both populations.

Thalamic-insomnia phenotype in E200K Creutzfeldt-Jakob disease: A PET/MRI study

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gCJD with PRNP E200K mutations frequently manifested as a thalamic-insomnia phenotype.

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Some features of the E200K phenotype are somewhere in between typical CJD and FFI.

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PET is a sensitive approach to help identify the functional changes in prion disease.

Background

Insomnia and thalamic involvement were frequently reported in patients with genetic Creutzfeldt-Jakob disease (gCJD) with E200K mutations, suggesting E200K might have discrepancy with typical sporadic CJD (sCJD). The study aimed to explore the clinical and neuroimage characteristics of genetic E200K CJD patients by comprehensive neuroimage analysis.

Methods

Six patients with gCJD carried E200K mutation on Prion Protein (PRNP) gene, 13 patients with sporadic CJD, and 22 age- and sex-matched normal controls were enrolled in the study. All participants completed a hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) examination. Signal intensity on diffusion-weighted imaging (DWI) and metabolism on PET were visually rating analyzed, statistical parameter mapping analysis was performed on PET and 3D-T1 images. Clinical and imaging characteristics were compared between the E200K, sCJD, and control groups.

Results

There was no group difference in age or gender among the E200K, sCJD, and control groups. Insomnia was a primary complaint in patients with E200K gCJD (4/2 versus 1/12, p = 0.007). Hyperintensity on DWI and hypometabolism on PET of the thalamus were observed during visual rating analysis of images in patients with E200K gCJD. Gray matter atrophy (uncorrected p < 0.001) and hypometabolism (uncorrected p < 0.001) of the thalamus were more pronounced in patients with E200K gCJD.

Conclusion

The clinical and imaging characteristics of patients with gCJD with PRNP E200K mutations manifested as a thalamic-insomnia phenotype. PET is a sensitive approach to help identify the functional changes in the thalamus in prion disease.

Prognostic Features of Sporadic Creutzfeldt-Jakob Disease: An Analysis of Taiwan's Nationwide Surveillance

OBJECTIVES

To study the prognostic features of Creutzfeldt-Jakob disease (CJD) and shed light on its future therapy.

DESIGN

Retrospective cohort study of a longitudinal national cohort of the Taiwan Centers for Disease Control.

SETTING AND PARTICIPANTS

All patients with suspected CJD are reported to the CJD surveillance unit of the Taiwan Centers for Disease Control. An expert committee discussed the reported cases and designated a consensus-based diagnosis. From 1996 to 2020, a total of 809 cases were referred to the CJD surveillance unit for confirmation; of these, 441 cases (women, n = 230) were determined to be sporadic CJD.

METHODS

We investigated the clinical manifestations and laboratory findings for 400 patients diagnosed with definite or probable sporadic CJD. We used Kaplan-Meier analyses and Cox proportional hazards model to identify prognostic factors.

RESULTS

The mean age of onset was 67 ± 9.9 years. The mean survival duration was 13.3 ± 14.2 (median 10) months. The leading clinical symptoms were myoclonus (73%) and akinetic mutism (54%). For PRNP polymorphism, 99% of patients (195/197) showed a methionine homozygous genotype at codon 129 (M129M). The sensitivity of periodic sharp wave complexes (PSWCs) on electroencephalograms (EEGs) was 59.7%. The sensitivity of cerebrospinal fluid 14-3-3 protein and total tau protein (>1200 pg/mL) were 69.7% and 75.6%, respectively. Younger patients lived longer than those aged ≥65 years [hazard ratio (HR) 0.466, P < .001]. Women had a better survival probability in the first 3 years than their male counterparts (HR 0.712, P = .005). PSWCs had a persistent negative effect on survival (HR 0.788, P < .05). Although uncommon, epileptic seizures were the only clinical prognostic factor for survival time (HR 0.768, P < .05). PSWCs can be used as an EEG biomarker for prognosis. Epileptic seizures, though not common, are the only clinical prognostic factor for a short survival.

CONCLUSIONS AND IMPLICATIONS

We found that a lower age of onset and female gender favor the survival of patients with sCJD. PSWCs are EEG biomarkers unfavorable for survival, and so are epileptic seizures.

Sporadic Creutzfeldt-Jakob disease: A case report

Being considered among the most fatal neurological conditions, Creutzfeldt-Jakob disease is a transmissible spongiform encephalopathy characterized by its unknown etiology and rapidly progressive neurodegenerative symptoms that often lead to a mean survival of 6 to 12 months. The accumulation of the prionic protein causes brain matter degeneration, which leads to a set of clinical findings that include rapidly progressive dementia, myoclonus, tremors, cerebellar ataxia, and extrapyramidal signs. This clinical presentation is non-specific, which makes CJD a very difficult condition to diagnose, due to the low level of clinical suspicion. However, combining this clinical presentation with neuroimaging, a lumbar puncture and an encephalogram will help us make the correct diagnosis. We present the case of a 57-year-old male presenting to the Emergency department with complaint of personality change and intermittent memory loss. The patient's physical exam was significant for resting pill roll tremor, bilateral cogwheel rigidity, dysmetria, and shuffling gait. Magnetic resonance imaging of his brain showed symmetric bilateral diffusion signal abnormality involving the cortex, bilateral caudate heads and putamina. Continuous electroencephalogram revealed multiple bifrontal delta discharges with triphasic morphology. Lumbar puncture was significant for presence of 14-3-3 protein in cerebrospinal fluid. The multiple examinations performed in conjunction with the previous findings supported the diagnosis of acute encephalopathy secondary to sporadic CJD.

Spatial distribution of abnormal EEG activity in Creutzfeldt-Jakob disease

OBJECTIVES

Electroencephalogram (EEG) pattern in Creutzfeldt-Jakob disease (CJD) is characterized by diffuse abnormal activity, although lateralization to one hemisphere has been described in the first stages of the disease. This study aimed to determine whether abnormal EEG activity predominantly occurs in anterior versus posterior brain regions.

METHODS

As part of a prospective study, the demographics, clinical features and MRI findings of genetic E200K CJD patients were collected. EEG was performed and the recordings reviewed for the typical periodic sharp wave complex (PSWC) and non-specific slow activity. Data were analyzed using the qEEG tool, and the activity in anterior and posterior regions of the brain compared.

RESULTS

Eleven genetic E200K CJD patients were included in the study (67% women). The average age was 59.1 ± 8.4 SD years and the average disease duration was 2.4 ± 2.1 months. EEG showed the classic PSWC pattern in 5/11 (45%) of the patients, and slow activity was seen in 9/11 (82%). EEG was normal in 2 patients. PSWC activity was diffuse in 2/5 patients and unilateral in 3/5 patients; slow activity was diffuse in 9 patients. Quantitative analysis of PSWC and slow activity showed no significant difference between anterior and posterior distribution.

CONCLUSION

The abnormal EEG activity in CJD is diffuse with no clear spatial predominance in anterior or posterior brain regions.

Comparative analysis of heparin affecting the biochemical properties of chicken and murine prion proteins

The conversion of cellular prion protein (PrP^C) to disease-provoking conformer (PrP^Sc) is crucial in the pathogenesis of prion diseases. Heparin has been shown to enhance mammalian prion protein misfolding. As spontaneous prion disease has not been reported in non-mammalian species, such as chicken, it is interesting to explore the influence of heparin on the conversion of chicken prion protein (ChPrP). Herein, we investigated the influences of heparin on biochemical properties of full-length recombinant ChPrP, with murine prion protein (MoPrP) as control. The results showed that at low heparin concentration (10 μg/mL), a great loss of solubility was observed for both MoPrP and ChPrP using solubility assays. In contrast, when the concentration of heparin was high (30 μg/mL), the solubility of MoPrP and ChPrP both decreased slightly. Using circular dichroism, PK digestion and transmission electron microscopy, significantly increased β-sheet content, PK resistance and size of aggregates were observed for MoPrP interacted with 30 μg/mL heparin, whereas 30 μg/mL heparin-treated ChPrP showed less PK resistance and slight increase of β-sheet structure. Therefore, heparin can induce conformational changes in both MoPrP and ChPrP and the biochemical properties of the aggregates induced by heparin could be modified by heparin concentration. These results highlight the importance of concentration of cofactors affecting PrP misfolding.

Familial Creutzfeldt-Jakob disease homozygous to the E200K mutation: clinical characteristics and disease course

OBJECTIVE

To characterize the demographic, clinical features and disease course of familial Creutzfeldt-Jakob disease (fCJD) patients homozygous to the E200K mutation.

METHODS

The Israeli National CJD Database was screened for patients homozygous to the E200K mutation. Patients' demographic data, clinical presentation and neurological findings, tau protein levels in the cerebrospinal fluid (CSF) and EEG, were assessed.

RESULTS

Ten homozygous E200K patients were identified (80% males). Average age of onset was 47.5 ± 6.1 years (range 40-56) and the average age of death was 49.3 ± 7. 7 years (range 42-63) with average disease duration of 27.7 ± 9.7 months (range 2-97). Initial clinical presentation included behavioral change in 4/10 patients, cognitive decline in 3/10 patients and focal neurological deficits in 2/10 patients. Throughout the disease course, the clinical signs in descending order of prevalence included cerebellar (70%), brainstem (60%), extrapyramidal (50%), pyramidal (50%), frontal lobe signs (30%), and disturbances of ocular motility (30%) Compared to the 228 heterozygous E200K fCJD patients, the 10 homozygous patients were significantly younger at disease onset (47.5 vs 59.7 years, p < 0.001), had a longer disease duration (27.7 vs 8.5 months, p < 0.001) and presented more frequently with behavioral changes as initial manifestation (4/10 vs. 34/228, p = 0.05).

CONCLUSIONS

Homozygous E200K fCJD patients are characterized by a relatively younger age of onset and longer disease duration. Behavioral changes as a presenting symptom were more common in homozygous patients and cerebellar dysfunction was the most common neurological manifestation throughout the disease course.

Pseudo-anticipation in Creutzfeldt-Jakob disease is due to a rhomboid-shaped artifact

BACKGROUND AND PURPOSE

Previous studies have reported conflicting results regarding possible anticipation in familial E200K Creutzfeldt-Jakob disease (fCJD). Our objective was to use a large database to assess the age of disease onset (AODO) in CJD.

METHODS

The study population included 477 CJD patients [266 with fCJD, 145 with sporadic CJD (sCJD) and 66 patients of Libyan origin but negative family history] from the Israeli registry of CJD conducted since 1954. In all patients, AODO in relatives and family trees was documented. Comparison of AODO was done using a paired t test and regression using Pearson correlation for birth and year of onset.

RESULTS

The initial analysis in 52/73 families in which more than one generation was affected revealed an AODO of 63.30 ± 9.44 in the first generation compared to 56.96 ± 8.99 in the second generation (P < 0.001). However, inspection of individual AODO values plotted by year of birth showed a clear rhomboid methodological artifact generated by missing data of many young onset CJD patients who died before the database began to function in 1954 and of many late onset CJD patients missing at the present time since they will only develop the disease in the future. The 'generation' effect completely disappears if analysis is performed by year of disease onset or for the periods in which complete data are available.

CONCLUSIONS

In this very large dataset, true anticipation in fCJD patients was not detected. It is plausible that previous reports supporting the presence of anticipation are biased by a rhomboid-shaped data availability artifact.

The association of quantitative EEG and MRI in Creutzfeldt-Jakob Disease

INTRODUCTION

Previous studies showed concordance between the typical Periodic Sharp Wave Complex (PSWC) activity in EEG of Creutzfeldt-Jakob Disease (CJD) patients and the MRI findings, while the concordance with slow activity in EEG is less established. The aim of this study was to better characterize the association between MRI findings and EEG changes using quantitative EEG (qEEG) analysis.

METHODS

The demographics, clinical features, and the MRI findings of 12 familial E200K patients with CJD were gathered. EEG test was done and reviewed for the typical PSWC and for the non-specific slow activity. A possible association between the MRI findings and the EEG activity was examined. Then, EEG was analyzed using qEEG tool, and the association between the qEEG finding and the MRI was examined.

RESULTS

Twelve patients were included in the study (67% women). Cortical MRI lesions finding were seen in 6/12 (50%) of the patients, and deep gray mater lesions were seen in 8/12 patients (67%). EEG showed the classic PSWC in 6/12 (50%) of the patients where slow activity was seen in 10/12 (83%). Slow activity and cortical MRI findings were associated in only 2/6 (33%) where deep gray matter findings and the slow activity had concordance of 4/8 (50%). qEEG analysis improved this concordance between slow activity and cortical findings to 3/6 (50%) and with the deep gray matter findings to 5/8 (63%).

CONCLUSIONS

Quantitative EEG analysis modesty but not significantly, improves the association of EEG slow activity in familial E200K CJD patients with MRI findings.

Analysis of 22 Years of Surveillance for Prion Diseases in Slovenia, 1996 to 2017

Introduction

The objective was to present the results of surveillance of prion diseases in Slovenia that was established in 1996 and then to assess the interdisciplinary approach according to the algorithm of case management and reporting data to the National Register at the National Institute of Public Health.

Methods

A descriptive study of Creutzfeldt-Jakob disease (CJD) recorded in the period from 1996 to 2017 was carried out.

Results

A total of 123 cases of prion disease were notified between 1996 and 2017. Out of these, 68 were recorded and confirmed by autopsy as sporadic CJD with an average incidence rate of 1,5 cases per million population per year. In one case a gene analysis showed mutation E200K in prion protein gene, PRNP. Two cases of the Gerstman-Sträussler Scheinker syndrome and one clinical case of fatal insomnia with new PRNP mutation, N181S, were notified. Diagnostic value of protein 14-3-3 analysis in the liquor reached 82% sensitivity and 71% specificity. 25 cases of notified clinically possible/probable CJD were disproved after autopsy. In eleven notified possible CJD cases the autopsy had not been performed. Variant CJD has not yet been proven in Slovenia.

Conclusion

Incidence rates were comparable with other European countries. Completeness of reporting and proper management of CJD cases according to the algorithm of reporting, management and case confirmation would need some improvement. A well-functioning surveillance system, including timely notifications, would enable an appropriate epidemiological investigation and an effective response to public health risks, thus the awareness of prion diseases should not decline.

Different effects of lipid on conformational conversion of chicken and murine prion proteins

Prion diseases are characterized by the conformational conversion of the cellular prion protein (PrP^C) to the pathogenic isoform (PrP^Sc). Lipids have been found to interact with PrP^C and contribute to the efficient formation of PrP^Sc. Non-mammalian PrPs are not readily to undergo the conversion process into an infectious isoform, yet the effect of lipid on the conformational conversion of non-mammalian PrP^C remains to be explored. Herein, the effects of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) on full-length recombinant chicken PrP (ChPrP) 24-249 and murine PrP (MoPrP) 23-230 were investigated. Firstly, it was found that in the presence of chemical denaturant, POPG remarkably inhibited MoPrP amyloid fibril growth, while had slight effect on that of ChPrP as estimated by amyloid fibril growth and transmissible electronic microscope assays. Secondly, under physiological condition, POPG induced conformation changes in both MoPrP and ChPrP using Thioflavin T (ThT) fluorescence, circular dichroism, proteinase K digestion and transmission electron microscopy assays. With a POPG:PrP molar ratio of 30:1, the ThT fluorescence of MoPrP was found to be lower than that of ChPrP, however, the POPG-induced MoPrP had higher β-sheet content and was more proteinase K-resistant than POPG-induced ChPrP. In summary, the present results suggested that the effects of POPG on conformational conversion of MoPrP and ChPrP were different under both denaturation and physiological conditions.

A Quick Method to Evaluate the Effect of the Amino Acid Sequence in the Misfolding Proneness of the Prion Protein

Prion diseases or transmissible spongiform encephalopathies (TSEs) are a group of neurodegenerative diseases where the misfolding of the prion protein (PrP) is a crucial event. Based on studies in TSE-affected humans and the generation of transgenic mouse models overexpressing different mutated versions of the PrP, we conclude that both wild-type and mutated PrPs exhibit differential propensity to misfold in vivo. Here, we describe a new method in vitro to assess and quantify the PrP misfolding phenomenon in order to better understand the molecular mechanisms involved in this process.

Activation of the unfolded protein response and granulovacuolar degeneration are not common features of human prion pathology

Human prion diseases are fatal neurodegenerative disorders with a genetic, sporadic or infectiously acquired aetiology. Neuropathologically, human prion diseases are characterized by deposition of misfolded prion protein and neuronal loss. In post-mortem brain tissue from patients with other neurodegenerative diseases characterized by protein misfolding, including Alzheimer’s disease (AD) and frontotemporal lobar degeneration with tau pathology (FTLD-tau), increased activation of the unfolded protein response (UPR) has been observed. The UPR is a cellular stress response that copes with the presence of misfolded proteins. Recent studies have indicated that UPR activation is also involved in experimental models of prion disease and have suggested intervention in the UPR as a therapeutic strategy. On the other hand, it was previously shown that the active form of the UPR stress sensor dsRNA-activated protein kinase-like ER kinase (PERK) is not increased in post-mortem brain tissue samples from human prion disease cases. In the present study, we assessed the active form of another UPR stress sensor, inositol-requiring enzyme 1α (IRE1α), in human post-mortem frontal cortex of a large cohort of sporadic, inherited and acquired prion disease patients (n = 47) and non-neurological controls. Immunoreactivity for phosphorylated IRE1α was not increased in prion disease cases compared with non-neurological controls. In addition, immunoreactivity for phosphorylated PERK was unaltered in human prion disease cases included in the current cohort. Moreover, no difference in the extent of granulovacuolar degeneration, a pathological feature associated with the presence of UPR activation markers, was detected. Our data indicate that, in contrast to AD and primary tauopathies, activation of the UPR is not a common feature of human prion pathology.

Patient with rapidly evolving neurological disease with neuropathological lesions of Creutzfeldt-Jakob disease, Lewy body dementia, chronic subcortical vascular encephalopathy and meningothelial meningioma

We report a case of rapidly evolving neurological disease in a patient with neuropathological lesions of Creutzfeldt-Jakob disease (CJD), Lewy body dementia (LBD), chronic subcortical vascular encephalopathy and meningothelial meningioma. The coexistence of severe multiple pathologies in a single patient strengthens the need to perform accurate clinical differential diagnoses in rapidly progressive dementias.

Epidemiological characteristics of human prion diseases

Human prion diseases are a group of transmissible, progressive, and invariably fatal neurodegenerative disorders, which include Kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome, and fatal familial insomnia. Human prion diseases affect approximately 1–2 persons per million worldwide annually, occurring in sporadic, inherited, and acquired forms. These diseases have attracted both scientific and public attention not only because of their mysterious pathogen, but also due to their considerable threat to public health since the emergence of the variant CJD.

There are still no specific therapeutic and prophylactic interventions available for prion diseases, thus active surveillance of human prion diseases is critical for disease control and prevention. Since 1993, CJD surveillance systems have been established in many countries and regions, and several long-term multinational cooperative projects have been conducted.

In this paper, the epidemiological characteristics of various human prion diseases and the active surveillance systems pertaining to them in different countries and regions are summarized and reviewed.

Reduced Hyperpolarization-Activated Current Contributes to Enhanced Intrinsic Excitability in Cultured Hippocampal Neurons from PrP(-/-) Mice

Genetic ablation of cellular prion protein (PrP^C) has been linked to increased neuronal excitability and synaptic activity in the hippocampus. We have previously shown that synaptic activity in hippocampi of PrP-null mice is increased due to enhanced N-methyl-D-aspartate receptor (NMDAR) function. Here, we focused on the effect of PRNP gene knock-out (KO) on intrinsic neuronal excitability, and in particular, the underlying ionic mechanism in hippocampal neurons cultured from P0 mouse pups. We found that the absence of PrP^C profoundly affected the firing properties of cultured hippocampal neurons in the presence of synaptic blockers. The membrane impedance was greater in PrP-null neurons, and this difference was abolished by the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker ZD7288 (100 μM). HCN channel activity appeared to be functionally regulated by PrP^C. The amplitude of voltage sag, a characteristic of activating HCN channel current (I_h), was decreased in null mice. Moreover, I_h peak current was reduced, along with a hyperpolarizing shift in activation gating and slower kinetics. However, neither HCN1 nor HCN2 formed a biochemical complex with PrP^C. These results suggest that the absence of PrP downregulates the activity of HCN channels through activation of a cell signaling pathway rather than through direct interactions. This in turn contributes to an increase in membrane impedance to potentiate neuronal excitability.

Unusual presentations in patients with E200K familial Creutzfeldt-Jakob disease

BACKGROUND AND PROPOSE

Familial Creutzfeldt-Jakob disease (fCJD) in Jews of Libyan ancestry is caused by an E200K mutation in the PRNP gene. The typical presenting symptoms include cognitive decline, behavioral changes and gait disturbances; however, some patients may have an unusual presentation such as a stroke-like presentation, alien hand syndrome or visual disturbances. The aim of this paper is to describe uncommon presentations in our series of consecutive patients with E200K fCJD.

METHODS

The study group included consecutive fCJD patients followed up as part of a longitudinal prospective study ongoing since 2003 or hospitalized since 2005. The clinical diagnosis of probable CJD was based on accepted diagnostic criteria and supported by typical magnetic resonance imaging, electroencephalographic findings, elevated cerebrospinal fluid tau protein levels and by genetic testing for the E200K mutation. Disease symptoms and signs were retrieved from the medical files.

RESULTS

The study population included 77 patients (42 men) with a mean age of disease onset of 60.6 ± 7.2 years. The most prevalent presenting symptoms were cognitive decline followed by gait impairment and behavioral changes. However, six patients had an unusual presentation including auditory agnosia, monoparesis, stroke-like presentation, facial nerve palsy, pseudobulbar syndrome and alien hand syndrome.

CONCLUSIONS

Our case series illustrates the wide phenotypic variability of the clinical presentation of patients with fCJD and widens the clinical spectrum of the disease. A high level of clinical suspicion may prove useful in obtaining early diagnosis and therefore avoiding costly and inefficient diagnostic and therapeutic strategies.

Creutzfeldt-Jakob disease: updated diagnostic criteria, treatment algorithm, and the utility of brain biopsy

Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative condition with a rapid disease course and a mortality rate of 100%. Several forms of the disease have been described, and the most common is the sporadic type. The most challenging aspect of this disease is its diagnosis—the gold standard for definitive diagnosis is considered to be histopatho-logical confirmation—but newer tests are providing means for an antemortem diagnosis in ways less invasive than brain biopsy. Imaging studies, electroencephalography, and biomarkers are used in conjunction with the clinical picture to try to make the diagnosis of CJD without brain tissue samples, and all of these are reviewed in this article. The current diagnostic criteria are limited; test sensitivity and specificity varies with the genetics of the disease as well as the clinical stage. Physicians may be unsure of all diagnostic testing available, and may order outdated tests or prematurely request a brain biopsy when the diagnostic workup is incomplete. The authors review CJD, discuss the role of brain biopsy in this patient population, provide a diagnostic pathway for the patient presenting with rapidly progressive dementia, and propose newer diagnostic criteria.

A Learner-led, Discussion-based Elective on Emerging Infectious Disease

Objective. To implement a learner-led, discussion-based course aimed at exposing second-year pharmacy learners to the study of emerging infectious diseases from a global health perspective and to assess the role and importance of pharmacists in the management of disease outbreaks. Design. Learners examined literature pertinent to an emerging infectious disease in a 3-credit, discussion-based course and participated in peer discussion led by a designated learner. Instructional materials included journal articles, audio-visual presentations, documentaries, book chapters, movies, newspaper/magazine articles, and other materials. Learning outcomes were measured based on the ability of learners to perform critical thinking and analysis, communicate with their peers, and participate in class discussions. Assessment. The course was offered to 2 consecutive cohorts consisting of 14 and 16 learners, respectively. Overall, every learner in the first cohort achieved a final grade of A for the course. In the second cohort, the overall grade distribution consisted of grades of A, B, and C for the course. Learner evaluations indicated that the active-learning, discussion-based environment significantly enhanced interest in the topic and overall performance in the course. Conclusion. The elective course on emerging infectious diseases provided in-depth exposure to disease topics normally not encountered in the pharmacy curriculum. Learners found the material and format valuable, and the course enhanced their appreciation of infectious diseases, research methodology, critical thinking and analysis, and their roles as pharmacists.

Creutzfeldt-Jakob Disease Subtype-Specific Regional and Temporal Regulation of ADP Ribosylation Factor-1-Dependent Rho/MLC Pathway at Pre-Clinical Stage

Small GTPases of the Arf family mainly activate the formation of coated carrier vesicles. We showed that class-I Arf1 interacts specifically with full length GPI-anchored cellular prion protein (PrP(C)). Several recent reports have also demonstrated a missing link between the endoplasmic reticulum and the Golgi-complex role for proper folding, but the exact molecular mechanism is not yet fully understood. In the present study, we identified and characterized the interactive role of Arf1 during PrP(C) intracellular distribution under pathophysiological conditions. PrP(C) interaction with Arf1 was investigated in cortical primary neuronal cultures of PrP(C) wild type and knockout mice (PrP(-/-)). Arf1 and PrP(C) co-binding affinity was confirmed using reverse co-immunoprecipitation, co-localization affinity using confocal laser-scanning microscopy. Treatment with brefeldin-A modulated Arf1 expression and resulted in down-regulation and redistribution of PrP(C) into cytosolic region. In the pre-symptomatic stage of the disease, Arf1 expression was significantly downregulated in the frontal cortex in tg340 mice expressing about fourfold of human PrP-M129 with PrP null background that had been inoculated with human sCJD MM1 brain tissue homogenates (sCJD MM1 mice). In addition, the frontal cortex of CJD human brain demonstrated significant binding capacity of Arf1 protein using co-immunoprecipitation analysis. We also examined Arf1 expression in the brain of CJD patients with the subtypes MM1 and VV2 and found that it was regulated in a region-specific manner. In the frontal cortex, Arf1 expression was not significantly changed in either MM1 or VV2 subtype. Interestingly, Arf1 expression was significantly reduced in the cerebellum in both subtypes as compared to controls. Furthermore, we observed altered RhoA activity, which in turn affects myosin light-chain (MLC) phosphorylation and Arf1-dependent PI3K pathway. Together, our findings underscore a key early symptomatic role of Arf1 in neurodegeneration. Targeting the Arf/Rho/MLC signaling axis might be a promising strategy to uncover the missing link which probably influences disease progression and internal homeostasis of misfolded proteins.

Seizures in E200K familial and sporadic Creutzfeldt-Jakob disease

BACKGROUND

Although seizures (other than myoclonus) are frequently reported in Creutzfeldt-Jakob disease (CJD), their frequency, clinical manifestations, and effect on the disease course is unknown.

OBJECTIVES

To characterize the frequency of seizures in E200K familial and sporadic CJD, to describe its semiology, EEG and MRI findings.

METHODS

In this retrospective study, we reviewed all patients with CJD who were seen in the Sheba Medical Center between the years 2003-2012 and underwent clinical evaluation, genetic testing, EEG and MRI studies. The diagnosis of seizures was carried out based on documentation of episodes consistent with seizures or episode of unresponsiveness correlated with ictal activity in EEG.

RESULTS

Sixty-four probable patients with CJD were included in the study, 57 (89%) with E200K familial (fCJD) and 7 (11%) with sporadic (sCJD). Seizures occurred in 8 patients: 3 of 7 (43%) in patients with sCJD compared to 5/57 (9%) in patients with E200K fCJD (P = 0.04, chi-square test). Two of E200K fCJD patients with seizures had other non-prion etiologies for seizures (brain metastasis, known history of temporal lobe epilepsy which started 44 years before the diagnosis of CJD). Seizures occurred late in the course of the disease with an average of 12 days between the onset of seizures and death.

CONCLUSION

Seizures in E200K fCJD were infrequent and occurred late in the disease course. This difference suggests that E200K fCJD represents a separate subtype of the disease with distinct clinical characteristics.

Familial Creutzfeldt-Jakob disease with the E200K mutation: longitudinal neuroimaging from asymptomatic to symptomatic CJD

Familial Creutzfeldt-Jakob disease (fCJD) in Jews of Libyan ancestry is caused by an E200K mutation in the PRNP gene. While carriers are born with this mutation, they usually remain asymptomatic until middle age. Early detection of conversion is crucial for understanding and eventually for the treatment of the disease. The aim of this study was to report longitudinal MRI data in E200K individuals who eventually converted from healthy mutation carriers to clinically symptomatic CJD. As a part of a prospective study, asymptomatic E200K mutation carriers were scanned annually until their conversion to symptomatic disease. Standardized diffusion and anatomical MR sequences were performed before and after clinical conversion in the subjects and those were compared to 15 non-carrier siblings ("healthy controls"). Blinded radiological readings and region of interest analyses were performed. Radiological readings of individual cases failed to detect characteristic changes in the scans taken before the conversion. Region of interest analysis of diffusion changes in pre-symptomatic stage was inconclusive; however, ADC reduction was found in early and late stages of the disease. Computerized volumetric analysis revealed monotonic volume reductions in thalamus, putamen and caudate following conversion, and the lateral ventricles showed dilatation of up to 62 % after clinical conversion. Although the clinical manifestations at disease onset are variable, the diffusion abnormalities and/or volume changes in the thalamus and basal ganglia during conversion may indicate early involvement of the thalamostriatal neuronal circuit.

Characterization of sleep disorders in patients with E200K familial Creutzfeldt-Jakob disease

The largest cluster of E200K familial Creutzfeldt-Jakob disease (fCJD) which occurs is in Jews of Libyan origin in Israel. Insomnia is a very common early complaint in those patients and may even be the presenting symptom. The aim of this study was to assess and characterize sleep pathology in E200K fCJD patients. To do so, sleep studies of 10 consecutive fCJD patients were compared with those of 39 age and gender-matched controls. All patients presented pathological sleep characterized by fragmentation of sleep, loss of sleep spindles and reduced REM sleep amount. Respiration was characterized by irregular rhythm, periodic breathing, apneas and hypopneas, either central or obstructive. EMG recordings revealed repeated movements in sleep, with loss of REM atonia. Comparing to controls, a significant decrease of total sleep time, sleep efficacy and slow-wave sleep as well as a significant increase in the number of awakenings, apnea-hypopnea index and mixed and central apneas were evident in CJD patients. Comparison of two sequential sleep studies in one patient revealed a 40 % reduction of the total sleep time, a 40 % reduction in sleep efficacy and a 40-fold increase of the number of arousals in the second study. A significant correlation was found between the disease severity, as reflected by the CJD Neurological Scale and Periodic leg movement index. These definite and characteristic sleep pathologies in patients with fCJD associated with the E200K mutation may serve as a new diagnostic tool in the disease.

The role of advanced glycation end products in various types of neurodegenerative disease: a therapeutic approach

Protein glycation is initiated by a nucleophilic addition reaction between the free amino group from a protein, lipid or nucleic acid and the carbonyl group of a reducing sugar. This reaction forms a reversible Schiff base, which rearranges over a period of days to produce ketoamine or Amadori products. The Amadori products undergo dehydration and rearrangements and develop a cross-link between adjacent proteins, giving rise to protein aggregation or advanced glycation end products (AGEs). A number of studies have shown that glycation induces the formation of the β-sheet structure in β-amyloid protein, α-synuclein, transthyretin (TTR), copper-zinc superoxide dismutase 1 (Cu, Zn-SOD-1), and prion protein. Aggregation of the β-sheet structure in each case creates fibrillar structures, respectively causing Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, familial amyloid polyneuropathy, and prion disease. It has been suggested that oligomeric species of glycated α-synuclein and prion are more toxic than fibrils. This review focuses on the pathway of AGE formation, the synthesis of different types of AGE, and the molecular mechanisms by which glycation causes various types of neurodegenerative disease. It discusses several new therapeutic approaches that have been applied to treat these devastating disorders, including the use of various synthetic and naturally occurring inhibitors. Modulation of the AGE-RAGE axis is now considered promising in the prevention of neurodegenerative diseases. Additionally, the review covers several defense enzymes and proteins in the human body that are important anti-glycating systems acting to prevent the development of neurodegenerative diseases.

Review: Laboratory diagnosis and surveillance of Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is a representative human transmissible spongiform encephalopathy associated with central nervous system degeneration. Prions, the causative agents of CJD, are composed of misfolded prion proteins and are able to self-replicate. While CJD is a rare disease affecting only 1-1.5 people per million worldwide annually, it has attracted both scientific and public attention as a threatening disease since an epidemic of variant CJD (vCJD) cases appeared in the mid-1990s. Due to its unconventional transmission and invariable fatality, CJD poses a serious risk to public health. The hundreds of sporadic, genetic, and iatrogenic CJD cases as well as potential zoonotic transmission suggest that CJD is an ongoing concern for the field of medicine. Nevertheless, treatment aimed at clinical prevention and treatment that reverses the course of disease does not exist currently. Active surveillance and effective laboratory diagnosis of CJD are, therefore, critical. In this report, the surveillance systems and laboratory tests used currently to diagnose CJD in different countries are reviewed. The current efforts to improve surveillance and diagnosis for CJD using molecular and biochemical findings are also described.

Glycated proteome: from reaction to intervention

Glycation, a nonenzymatic reaction between reducing sugars and proteins, is a proteome wide phenomenon, predominantly observed in diabetes due to hyperglycemia. Glycated proteome of plasma, kidney, lens, and brain are implicated in the pathogenesis of various diseases, including diabetic complications, neurodegenerative diseases, cancer, and aging. This review discusses the strategies to characterize protein glycation, its functional implications in different diseases, and intervention strategies to protect the deleterious effects of protein glycation.

Synaptic dysfunction in prion diseases: a trafficking problem?

Synaptic dysfunction is an important cause of neurological symptoms in prion diseases, a class of clinically heterogeneous neurodegenerative disorders caused by misfolding of the cellular prion protein (PrP^C). Experimental data suggest that accumulation of misfolded PrP^C in the endoplasmic reticulum (ER) may be crucial in synaptic failure, possibly because of the activation of the translational repression pathway of the unfolded protein response. Here, we report that this pathway is not operative in mouse models of genetic prion disease, consistent with our previous observation that ER stress is not involved. Building on our recent finding that ER retention of mutant PrP^C impairs the secretory trafficking of calcium channels essential for synaptic function, we propose a model of pathogenicity in which intracellular retention of misfolded PrP^C results in loss of function or gain of toxicity of PrP^C-interacting proteins. This neurotoxic modality may also explain the phenotypic heterogeneity of prion diseases.

Heritability of brain volumes in older adults: the Older Australian Twins Study

The relative contributions of genetic and environmental factors to brain structure change throughout the lifespan. Brain structures have been reported to be highly heritable in middle-aged individuals and younger; however, the influence of genes on brain structure is less studied in older adults. We performed a magnetic resonance imaging study of 236 older twins, with a mean age of 71.4 ± 5.7 years, to examine the heritability of 53 brain global and lobar volumetric measures. Total brain volume (63%) and other volumetric measures were moderately to highly heritable in late life, and these genetic influences tended to decrease with age, suggesting a greater influence of environmental factors as age advanced. Genetic influences were higher in men and on the left hemisphere compared with the right. In multivariate models, common genetic factors were observed for global and lobar total and gray matter volumes. This study examined the genetic contribution to 53 brain global and lobar volumetric measures in older twins for the first time, and the influence of age, sex, and laterality on these genetic contributions, which are useful information for a better understanding of the process of brain aging and helping individuals to have a healthy aging.

Role of proteomics in understanding prion infection

Transmissible spongiform encephalopathies or prion diseases are fatal neurodegenerative pathologies characterized by the autocatalytic misfolding and polymerization of a cellular glycoprotein (cellular prion protein [PrP(C)]) that accumulates in the CNS and leads to neurodegeneration. The detailed mechanics of PrP(C) conversion to its pathological isoform (PrP(TSE)) are unclear but one or more exogenous factors are likely involved in the process of PrP misfolding. In the last 20 years, proteomic investigations have identified several endogenous proteins that interact with PrP(C), PrP(TSE) or both, which are possibly involved in the prion pathogenetic process. However, current approaches have not yet produced convincing conclusions on the biological value of such PrP interactors. Future advancements in the comprehension of the molecular pathogenesis of prion diseases, in experimental techniques and in data analysis procedures, together with a boost in more productive international collaborations, are therefore needed to improve the understanding on the role of PrP interactors. Finally, the advancement of 'omics' techniques in prion diseases will contribute to the development of novel diagnostic tests and effective drugs.

Flotillin-1 mediates PrPc endocytosis in the cultured cells during Cu²⁺ stimulation through molecular interaction

Flotillins are membrane association proteins consisting of two homologous members, flotillin-1 (Flot-1) and flotillin-2 (Flot-2). They define a clathrin-independent endocytic pathway in mammal cells, which are also distinct from some other endocytosis mechanisms. The implicated cargoes of the flotillin-dependent pathway are mainly some GPI-anchored proteins, such as CD59 and Thy-1, which positionally colocalize with flotillins at the plasma membrane microdomains. To see whether flotillins are involved in the endocytosis of PrP(C), the potential molecular interaction between PrP(C) and flotillins in a neuroblastoma cell line SK-N-SH was analyzed. Co-immunoprecipitation assays did not reveal a detectable complex in the cell lysates of a normal feeding situation. After stimulation of Cu(2+), PrP(C) formed a clear complex with Flot-1, but not with Flot-2. Immunofluorescent assays illustrated that PrP(C) colocalized well with Flot-1, and the complexes of PrP(C)-Flot-1 shifted from the cell membrane to the cytoplasm along with the treatment of Cu(2+). Down-regulating the expression of Flot-1 in SK-N-SH cells by Flot-1-specific RNAi obviously abolished the Cu(2+)-stimulated endocytosis process of PrP(C). Moreover, we also found that in the cell line human embryonic kidney 293 (HEK293) without detectable PrP(C) expression, the distribution of cellular Flot-1 maintained almost unchanged during Cu(2+) treatment. Cu(2+)-induced PrP(C)-Flot-1 molecular interaction and endocytosis in HEK293 cells were obtained when expressing wild-type human PrP (PrP(PG5)), but not in the preparation expressing octarepeat-deleted PrP (PrP(PG0)). Our data here provide direct evidences for the molecular interaction and endocytosis of PrP(C) with Flot-1 in the presence of copper ions, and the octarepeat region of PrP(C) is critical for this process, which strongly indicates that the Flot-1-dependent endocytic pathway seems to mediate the endocytosis process of PrP(C) in the special situation.

Gerstmann-Sträussler-Scheinker syndrome with the P102L pathogenic mutation presenting as familial Creutzfeldt-Jakob disease: a case report and review of the literature

Gerstmann-Sträussler-Scheinker syndrome is a rare autosomal dominant disease caused by a mutation in the prion gene, usually manifesting as progressive ataxia with late cognitive decline. A 44-year-old woman with a positive family history developed early personality and behavior changes, followed by paresthesias and ataxia, later associated with memory problems, pyramidal signs, anosognosia and very late myoclonus, spasticity, and severe dysexecutive impairment. Magnetic resonance showed caudate, mesio-frontal, and insular hyper-intensities, electroencephalography revealed generalized triphasic periodic complexes. A pathogenic P102L mutation in the prion gene was detected. Our case differed from classical Gerstmann-Sträussler-Scheinker syndrome by rapid progression, severe dementia, abnormal electroencephalography and magnetic resonance findings, which were highly suggestive of familial Creutzfeldt-Jakob disease.

Mutant PrP suppresses glutamatergic neurotransmission in cerebellar granule neurons by impairing membrane delivery of VGCC α(2)δ-1 Subunit

How mutant prion protein (PrP) leads to neurological dysfunction in genetic prion diseases is unknown. Tg(PG14) mice synthesize a misfolded mutant PrP which is partially retained in the neuronal endoplasmic reticulum (ER). As these mice age, they develop ataxia and massive degeneration of cerebellar granule neurons (CGNs). Here, we report that motor behavioral deficits in Tg(PG14) mice emerge before neurodegeneration and are associated with defective glutamate exocytosis from granule neurons due to impaired calcium dynamics. We found that mutant PrP interacts with the voltage-gated calcium channel α(2)δ-1 subunit, which promotes the anterograde trafficking of the channel. Owing to ER retention of mutant PrP, α(2)δ-1 accumulates intracellularly, impairing delivery of the channel complex to the cell surface. Thus, mutant PrP disrupts cerebellar glutamatergic neurotransmission by reducing the number of functional channels in CGNs. These results link intracellular PrP retention to synaptic dysfunction, indicating new modalities of neurotoxicity and potential therapeutic strategies.

What psychiatrists should know about sporadic Creutzfeldt-Jakob disease

OBJECTIVE

To provide psychiatrists with relevant, up to date information about sporadic Creutzfeldt-Jakob disease.

CONCLUSIONS

A 59-year-old bookkeeper presented with psychiatric symptoms in the context of stressors and past history of depression, for which her GP prescribed sertraline and olanzapine. Following a further deterioration in her mental state she was referred to acute psychiatric services, and there found to have dementia and myoclonus, and investigations supported a diagnosis of probable Creutzfeldt-Jakob disease, sporadic type (sCJD). This paper serves to outline the emerging literature challenging the notion that suggests psychiatric symptoms are uncommon in the presentation of sCJD.