Regulation of immune-modulatory genes in left superior temporal cortex of schizophrenia patients: a genome-wide microarray study

OBJECTIVES

The role of neuroinflammation in schizophrenia has been an issue for long time. There are reports supporting the hypothesis of ongoing inflammation and others denying it. This may be partly ascribed to the origin of the materials (CSF, blood, brain tissue) or to the genes selected for the respective studies. Moreover, in some locations, inflammatory genes may be up-regulated, others may be down-regulated.

METHODS

Genome-wide microarrays have been used for expression profiling in post-mortem brains of schizophrenia patients. Array data have been analyzed by gene set enrichment analysis (GSEA) and further confirmed with selected genes by real-time PCR.

RESULTS

In Brodman Area 22 of left superior temporal cortex, at least 70 genes (19%) out of 369 down-regulated genes (P < 0.05) belonged to the immune system. 23 from those 70 genes were randomly selected for real-time PCR. Six reached significance level at P < 0.05.

CONCLUSIONS

The present data support a brain-specific view of the role immune-modulatory genes may play in the left superior temporal cortex in schizophrenia, because immune functions in the patients are not disturbed. In keeping with comparable, previous studies supporting the notion that schizophrenia is a disease of the synapse, we hypothesize that dysregulation of immune-related genes modifies synaptic functions and stability in this region.

Phenotypic variability of sporadic human prion disease and its molecular basis: past, present, and future

Human prion diseases are rare neurodegenerative disorders related to prion protein misfolding that can occur as sporadic, familial or acquired forms. In comparison to other more common neurodegenerative disorders, prion diseases show a wider range of phenotypic variation and largely transmit to experimental animals, a feature that led to the isolation and characterization of different strains of the transmissible agent or prion with distinct biological properties. Biochemically distinct PrP(Sc) types have been demonstrated which differ in their size after proteinase cleavage, glycosylation pattern, and possibly other features related to their conformation. These PrP(Sc) types, possibly enciphering the prion strains, together with the naturally occurring polymorphism at codon 129 in the prion protein gene have a major influence on the disease phenotype. In the sporadic form, the most common but perhaps least understood form of human prion disease, there are at least six major combinations of codon 129 genotype and prion protein isotype, which are significantly related to distinctive clinical-pathological subgroups of the disease. In this review, we provide an update on the current knowledge and classification of the disease subtypes of the sporadic human prion diseases as defined by molecular features and pathological changes. Furthermore, we discuss the molecular basis of phenotypic variability taking into account the results of recent transmission studies that shed light on the extent of prion strain variation in humans.

Genetic Creutzfeldt-Jakob disease and fatal familial insomnia: insights into phenotypic variability and disease pathogenesis

Human prion diseases are a group of rare neurodegenerative disorders characterized by the conversion of the constitutively expressed prion protein, PrP(C), into an abnormally aggregated isoform, called PrP(Sc). While most people who develop a prion disease have no identifiable cause and a few acquire the disease through an identified source of infection, about 10-15% of patients are affected by a genetic form and carry either a point mutation or an insertion of octapeptide repeats in the prion protein gene. Prion diseases show the highest extent of phenotypic heterogeneity among neurodegenerative disorders and comprise three major disease entities with variable though overlapping phenotypic features: Creutzfeldt-Jakob disease (CJD), fatal insomnia and the Gerstmann-Sträussler-Scheinker syndrome. Both CJD and fatal insomnia are fully transmissible diseases, a feature that led to the isolation and characterization of different strains of the agent or prion showing distinctive clinical and neuropathological features after transmission to syngenic animals. Here, we review the current knowledge of the effects of the pathogenic mutations linked to genetic CJD and fatal familial insomnia on the prion protein metabolism and physicochemical properties, the disease phenotype and the strain characteristics. The data derived from studies in vitro and from those using cell and animal models are compared with those obtained from the analyses of the naturally occurring disease. The extent of phenotypic variation in genetic prion disease is analyzed in comparison to that of the sporadic disease, which has recently been the topic of a systematic and detailed characterization.

Clinical features of rapidly progressive Alzheimer's disease

OBJECTIVE

To characterize clinical features, CSF biomarkers and genetic polymorphisms of patients suffering from a rapidly progressing subtype of Alzheimer's dementia (rpAD).

METHODS

Retrospective analyses of 32 neuropathologically confirmed cases differentially diagnosed as AD out of a group with rapidly progressive dementia. CSF biomarkers (14-3-3, tau, beta-amyloid 1-42) and genetic markers (PRNP codon 129, apolipoprotein E, ApoE, polymorphism) were determined.

RESULTS

Median survival was 26 months, age at onset 73 years. Biomarkers: mean beta-amyloid 1-42: 266 pg/ml, median tau: 491 pg/ml, 14-3-3 positive: 31%. Genetic polymorphisms showed a predominance of methionine homozygosity at PRNP codon 129 and a low frequency of ApoE4 (38%, no homozygous patients). Thirty-five symptoms were studied. Frequent symptoms were myoclonus (75%), disturbed gait (66%) and rigidity (50%).

DISCUSSION

rpAD is associated with a diversity of neurological signs even able to mimic Creutzfeldt-Jakob disease. Biomarkers and genetic profile differ from those seen in classical AD. The findings on biomarkers, symptomatology and genetics may aid the differential diagnostic process.

Agent strain variation in human prion disease: insights from a molecular and pathological review of the National Institutes of Health series of experimentally transmitted disease

Six clinico-pathological phenotypes of sporadic Creutzfeldt-Jakob disease have been characterized which correlate at the molecular level with the type (1 or 2) of the abnormal prion protein, PrP(TSE), present in the brain and with the genotype of polymorphic (methionine or valine) codon 129 of the prion protein gene. However, to what extent these phenotypes with their corresponding molecular combinations (i.e. MM1, MM2, VV1 etc.) encipher distinct prion strains upon transmission remains uncertain. We studied the PrP(TSE) type and the prion protein gene in archival brain tissues from the National Institutes of Health series of transmitted Creutzfeldt-Jakob disease and kuru cases, and characterized the molecular and pathological phenotype in the affected non-human primates, including squirrel, spider, capuchin and African green monkeys. We found that the transmission properties of prions from the common sporadic Creutzfeldt-Jakob disease MM1 phenotype are homogeneous and significantly differ from those of sporadic Creutzfeldt-Jakob disease VV2 or MV2 prions. Animals injected with iatrogenic Creutzfeldt-Jakob disease MM1 and genetic Creutzfeldt-Jakob disease MM1 linked to the E200K mutation showed the same phenotypic features as those infected with sporadic Creutzfeldt-Jakob disease MM1 prions, whereas kuru most closely resembled the sporadic Creutzfeldt-Jakob disease VV2 or MV2 prion signature and neuropathology. The findings indicate that two distinct prion strains are linked to the three most common Creutzfeldt-Jakob disease clinico-pathological and molecular subtypes and kuru, and suggest that kuru may have originated from cannibalistic transmission of a sporadic Creutzfeldt-Jakob disease of the VV2 or MV2 subtype.

Intravascular large B-cell lymphoma presenting as dementia and hemolytic anemia

BACKGROUND

Intravascular lymphoma (IVL) is an uncommon disease characterized by atypical lymphoid cells growing inside the lumina of small vessels. The diversity of clinical presentation due to possible involvement of multiple organs often complicates its diagnosis.

CASE REPORT

Here, we report on a case of IVL with rapidly progressive dementia and Coombs-negative hemolytic anemia. Interestingly, the erythrocytes exhibited a decreased osmotic resistance. Bone marrow histopathology revealed increased erythropoiesis and, finally, a small monoclonal B lymphocyte population. Cerebral magnetic resonance imaging (MRI) demonstrated few micro-bleedings. Computed tomography (CT) showed bilateral ground-glass opacity of the lungs. Within a few days, the patient developed respiratory failure and died. On post-mortem examination, intravascular large B-cell lymphoma with almost complete infiltration of the brain and lungs was diagnosed.

CONCLUSION

IVL should be considered early in situations of unexplained neuropsychiatric disease along with markedly elevated levels of lactic dehydrogenase, anemia, and hemolysis.

Converse modulation of toxic alpha-synuclein oligomers in living cells by N'-benzylidene-benzohydrazide derivates and ferric iron

Intracellular alpha-synuclein (alpha-syn) aggregates are the pathological hallmark in several neurodegenerative diseases including Parkinson's disease, dementia with Lewy bodies and multiple system atrophy. Recent evidence suggests that small oligomeric aggregates rather than large amyloid fibrils represent the main toxic particle species in these diseases. We recently characterized iron-dependent toxic alpha-syn oligomer species by confocal single molecule fluorescence techniques and used this aggregation model to identify several N'-benzylidene-benzohydrazide (NBB) derivatives inhibiting oligomer formation in vitro. In our current work, we used the bioluminescent protein-fragment complementation assay (BPCA) to directly analyze the formation of toxic alpha-syn oligomers in cell culture and to investigate the effect of iron and potential drug-like compounds in living cells. Similar to our previous findings in vitro, we found a converse modulation of toxic alpha-syn oligomers by NBB derivates and ferric iron, which was characterized by an increase in aggregate formation by iron and an inhibitory effect of certain NBB compounds. Inhibition of alpha-syn oligomer formation by the NBB compound 293G02 was paralleled by a reduction in cytotoxicity indicating that toxic alpha-syn oligomers are present in the BPCA cell culture model and that pharmacological inhibition of oligomer formation can reduce toxicity. Thus, this approach provides a suitable model system for the development of new disease-modifying drugs targeting toxic oligomer species. Moreover, NBB compounds such as 293G02 may provide useful tool compounds to dissect the functional role of toxic oligomer species in cell culture models and in vivo.

Imaging glioma cell invasion in vivo reveals mechanisms of dissemination and peritumoral angiogenesis

Infiltration of cancer cells into normal tissue is a hallmark of malignant gliomas and compromises treatment options. A lack of appropriate models limits the study of this invasion in vivo, which makes it difficult to fully understand its anatomy and the role of dynamic interactions with structures of the normal brain. We developed a novel methodology by utilizing multiphoton laser scanning microscopy (MPLSM) to image the movement of glioma cells deep within the normal brain of live mice in real time. This allowed us to track the invasion of individual RFP-expressing GL261 cells in relation to perfused vasculature or GFP-labeled endothelial cells repetitively over days, up to a depth of 0.5 mm. Glioma cells moved faster and more efficiently when the abluminal site of a blood vessel was utilized for invasion. Cells that invaded perivascularly were frequently found next to (a) multiple capillary structures where microvessels run parallel to each other, (b) capillary loops or glomeruloid-like bodies, and (c) dilated capillaries. Dynamic MPLSM for more than 48 h revealed that single invasive glioma cells induced intussusceptive microvascular growth and capillary loop formation, specifically at the microvascular site with which they had contact. As the main tumor grew by cooption of existing brain vessels, these peritumoral vascular changes may create a beneficial environment for glioma growth. In conclusion, our study revealed new mechanisms of peritumoral angiogenesis and invasion in gliomas, providing an explanation for their interdependence.

Incidence and spectrum of sporadic Creutzfeldt-Jakob disease variants with mixed phenotype and co-occurrence of PrPSc types: an updated classification

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, PrP(Sc), and the methionine (M)/valine (V) polymorphic codon 129 of the prion protein. The existence of affected subjects showing mixed phenotypic features and concurrent PrP(Sc) 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. PrP(Sc) 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. PrP(Sc) 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 PrP(Sc) type 2. In contrast, molecular typing best detected the concurrent PrP(Sc) 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.

Influence of ADAM10 on prion protein processing and scrapie infectiosity in vivo

Both the cellular prion protein (PrP(c)) and the amyloid precursor protein (APP) are physiologically subjected to complex proteolytic processing events. While for APP the proteinases involved--alpha-, beta- and gamma-secretase--have been identified in vitro and in vivo, the cleavage of PrP(c) by now has been linked only to the shedding activity of the metalloproteinase ADAM10 and/or ADAM17 in cell culture. Here we show that neuronal overexpression of the alpha-secretase ADAM10 in mice reduces all PrP(c) species detected in the brain instead of leading to enhanced amounts of specific cleavage products of PrP(c). Additionally, the incubation time of mice after scrapie infection is significantly increased in mice moderately overexpressing ADAM10. This indicates that overexpression of ADAM10 rather influences the amount of the cellular prion protein than its processing in vivo.

Tauopathies with parkinsonism: clinical spectrum, neuropathologic basis, biological markers, and treatment options

Tauopathies with parkinsonism represent a spectrum of disease entities unified by the pathologic accumulation of hyperphosphorylated tau protein fragments within the central nervous system. These pathologic characteristics suggest shared pathogenetic pathways and possible molecular targets for disease-modifying therapeutic interventions. Natural history studies, for instance, in progressive supranuclear palsy, frontotemporal dementia with parkinsonism linked to chromosome 17, corticobasal degeneration, and Niemann-Pick disease type C as well as in amyotrophic lateral sclerosis/Parkinson-dementia complex permit clinical characterization of the disease phenotypes and are crucial to the development and validation of biological markers for differential diagnostics and disease monitoring, for example, by use of neuroimaging or proteomic approaches. The wide pathologic and clinical spectrum of the tauopathies with parkinsonism is reviewed in this article, and perspectives on future advances in the understanding of the pathogenesis are given, together with potential therapeutic strategies.

Staging/typing of Lewy body related alpha-synuclein pathology: a study of the BrainNet Europe Consortium

When 22 members of the BrainNet Europe (BNE) consortium assessed 31 cases with alpha-synuclein (alphaS) immunoreactive (IR) pathology applying the consensus protocol described by McKeith and colleagues in 2005, the inter-observer agreement was 80%, being lowest in the limbic category (73%). When applying the staging protocol described by Braak and colleagues in 2003, agreement was only 65%, and in some cases as low as 36%. When modifications of these strategies, i.e., McKeith's protocol by Leverenz and colleagues from 2009, Braak's staging by Müller and colleagues from 2005 were applied then the agreement increased to 78 and 82%, respectively. In both of these modifications, a reduced number of anatomical regions/blocks are assessed and still in a substantial number of cases, the inter-observer agreement differed significantly. Over 80% agreement in both typing and staging of alphaS pathology could be achieved when applying a new protocol, jointly designed by the BNE consortium. The BNE-protocol assessing alphaS-IR lesions in nine blocks offered advantages over the previous modified protocols because the agreement between the 22 observers was over 80% in most cases. Furthermore, in the BNE-protocol, the alphaS pathology is assessed as being present or absent and thus the quality of staining and the assessment of the severity of alphaS-IR pathology do not alter the inter-observer agreement, contrary to other assessment strategies. To reach these high agreement rates an entity of amygdala-predominant category was incorporated. In conclusion, here we report a protocol for assessing alphaS pathology that can achieve a high inter-observer agreement for both the assignment to brainstem, limbic, neocortical and amygdala-predominant categories of synucleinopathy and the Braak stages.

Tauopathies with parkinsonism: clinical spectrum, neuropathologic basis, biological markers, and treatment options

Tauopathies with parkinsonism represent a spectrum of disease entities unified by the pathologic accumulation of hyperphosphorylated tau protein fragments within the central nervous system. These pathologic characteristics suggest shared pathogenetic pathways and possible molecular targets for disease-modifying therapeutic interventions. Natural history studies, for instance, in progressive supranuclear palsy, frontotemporal dementia with parkinsonism linked to chromosome 17, corticobasal degeneration, and Niemann-Pick disease type C as well as in amyotrophic lateral sclerosis/Parkinson-dementia complex permit clinical characterization of the disease phenotypes and are crucial to the development and validation of biological markers for differential diagnostics and disease monitoring, for example, by use of neuroimaging or proteomic approaches. The wide pathologic and clinical spectrum of the tauopathies with parkinsonism is reviewed in this article, and perspectives on future advances in the understanding of the pathogenesis are given, together with potential therapeutic strategies.

Mixed brain pathologies in dementia: the BrainNet Europe consortium experience

BACKGROUND

Dementia results from heterogeneous diseases of the brain. Mixed disease forms are increasingly recognized.

METHODS

We performed a survey within brain banks of BrainNet Europe to estimate the proportion of mixed disease forms underlying dementia and age- and gender-specific influences.

RESULTS

Data collected in 9 centres from 3,303 individuals were analysed. The proportion of patients with mixed diagnoses among all cases with Alzheimer disease (AD), vascular pathology (VP), argyrophilic grain dementia (AGD), and synucleinopathies, such as Lewy body dementia (LBD), Parkinson disease (PD) and synuclein pathology only in the amygdala, was 53.3%. Mixed pathology was more frequently reported with LBD, PD, AGD, and VP than with AD. The percentage of mixed diagnoses for AGD and VP significantly differed between centres. In patients younger than 75 years, synucleinopathies, and pure forms of AD, VP, and AGD were more frequent in men. Above 75 years of age, more women had pure AD and pure AGD.

CONCLUSIONS

The most obvious neuropathological alteration should not terminate the diagnostic procedure since copathology is likely to be found. Neuropathological interpretation of AGD and VP has not been sufficiently established in a consensus. Pure forms of synucleinopathies are unlikely sole substrates for dementia.

Increased alpha-synuclein aggregation following limited cleavage by certain matrix metalloproteinases

Recent evidence indicates that protein aggregation and in particular the formation of toxic protein oligomers is a key mechanism in synucleinopathies such as Parkinson's disease (PD). Post mortem brain tissue studies as well as animal studies furthermore suggest that matrix metalloproteinases (MMPs) are also involved in the pathogenesis of PD. We used confocal single molecule spectroscopy to characterize the influence of MMPs and other proteases on the aggregation of alpha-synuclein. These studies were complemented by the characterization of alpha-synuclein fragment patterns generated by these proteases using gel electrophoresis and mass spectrometry. Limited digestion by MMP-1 and MMP-3, but not by MMP-9, increased the tendency of alpha-synuclein to aggregate. Proteinase K and Trypsin did not increase the level of de novo aggregation of alpha-synuclein. SDS-PAGE as well as MALDI-ToF analysis of limitedly digested alpha-synuclein demonstrate that all proteases generate different fragments of alpha-synuclein. We provide mass spectrometry data of proteolytic alpha-synuclein fragments and propose specific cleavage sites for MMP-1 and MMP-9 in alpha-synuclein. We furthermore found four additional cleavage sites of MMP-3 that had not been described previously. In order to increase aggregation of alpha-synuclein, specific cleavage between the highly charged C-terminal domain and the aggregation-prone NAC domain of alpha-synuclein seems to be crucial. Our findings obtained in vitro in a well-characterized model of pathological alpha-synuclein aggregation indicate that MMP-1 and MMP-3 may also influence pathogenesis of PD in vivo by generation of specific aggregation-enhancing alpha-synuclein fragments resulting from limited proteolysis.

Management of a twenty-first century brain bank: experience in the BrainNet Europe consortium

Collections of human postmortem brains gathered in brain banks have underpinned many significant developments in the understanding of central nervous system (CNS) disorders and continue to support current research. Unfortunately, the worldwide decline in postmortem examinations has had an adverse effect on research tissue procurement, particularly from control cases (non-diseased brains). Recruitment to brain donor programmes partially addresses this problem and has been successful for dementing and neurodegenerative conditions. However, the collection of brains from control subjects, particularly from younger individuals, and from CNS disorders of sudden onset, remains a problem. Brain banks need to adopt additional strategies to circumvent such shortages. The establishment of brain bank networks allows data on, and access to, control cases and unusual CNS disorders to be shared, providing a larger resource for potential users. For the brain banks themselves, inclusion in a network fosters the sharing of protocols and development of best practice and quality control. One aspect of this collective experience concerns brain bank management, excellence in which is a prerequisite not only for gaining the trust of potential donors and of society in general, but also for ensuring equitable distribution to researchers of high quality tissue samples. This review addresses the legal, ethical and governance issues, tissue quality, and health and safety aspects of brain bank management and data management in a network, as well as the needs of users, brain bank staffing, donor programs, funding issues and public relations. Recent developments in research methodology present new opportunities for researchers who use brain tissue samples, but will require brain banks to adopt more complex protocols for tissue collection, preparation and storage, with inevitable cost implications for the future.

The novel sorting nexin SNX33 interferes with cellular PrP formation by modulation of PrP shedding

The cellular prion protein (PrP(c)) is a glycosyl-phosphatidylinositol (GPI)-anchored protein trafficking in the secretory and endocytic pathway and localized mainly at the plasma membrane. Conversion of PrP(c) into its pathogenic isoform PrP(Sc) is associated with pathogenesis and transmission of prion diseases. Intramolecular cleavage in the middle, the extreme C-terminal part or within the GPI anchor and shedding of PrP(c) modulate this conversion process by reducing the substrate for prion formation. These phenomena provide similarities with the processing of amyloid precursor protein in Alzheimer's disease. Sorting nexins are a family of proteins with important functions in protein trafficking. In this study, we investigated the role of the newly described sorting nexin 33 (SNX33) in trafficking and processing of PrP(c). We found that overexpression of SNX33 in neuronal and non-neuronal cell lines resulted in increased shedding of full-length PrP(c) from the plasma membrane and modulated the rate of PrP(c) endocytosis. This was paralleled by reduction of PrP(Sc) formation in persistently and newly infected cells. Using deletion mutants, we demonstrate that production of PrP fragment N1 is not influenced by SNX33. Our data provide new insights into the cellular mechanisms of PrP(c) shedding and show how this can affect cellular PrP(Sc) conversion.

Staging of neurofibrillary pathology in Alzheimer's disease: a study of the BrainNet Europe Consortium

It has been recognized that molecular classifications will form the basis for neuropathological diagnostic work in the future. Consequently, in order to reach a diagnosis of Alzheimer's disease (AD), the presence of hyperphosphorylated tau (HP‐tau) and β‐amyloid protein in brain tissue must be unequivocal. In addition, the stepwise progression of pathology needs to be assessed. This paper deals exclusively with the regional assessment of AD‐related HP‐tau pathology. The objective was to provide straightforward instructions to aid in the assessment of AD‐related immunohistochemically (IHC) detected HP‐tau pathology and to test the concordance of assessments made by 25 independent evaluators. The assessment of progression in 7‐µm‐thick sections was based on assessment of IHC labeled HP‐tau immunoreactive neuropil threads (NTs). Our results indicate that good agreement can be reached when the lesions are substantial, i.e., the lesions have reached isocortical structures (stage V–VI absolute agreement 91%), whereas when only mild subtle lesions were present the agreement was poorer (I–II absolute agreement 50%). Thus, in a research setting when the extent of lesions is mild, it is strongly recommended that the assessment of lesions should be carried out by at least two independent observers.

Differential effects of prion particle size on infectivity in vivo and in vitro

The conversion of cellular prion protein to the disease-associated isoform (PrP(Sc)) has been suggested to follow a mechanism of seeded aggregation. Here, we show that fragmentation of PrP(Sc) aggregates by sonication increases converting activity in cell culture in a way similar to in vitro conversion assays. In contrast, under the same conditions the infectious titer of sonicated samples in vivo was reduced. We modified the size distribution of PrP(Sc) by adsorption to nitrocellulose, which resulted in a reduction of the infectious titer in non-sonicated samples and an increase in sonicated samples. Our results indicate that NC-adsorption can (i) block some active sites of PrP(Sc) aggregates and (ii) reduce the rate of clearance from the brain. For large particles with low clearance the effect of NC-particles on the number of available active sites may dominate, whereas for smaller particles (i.e. sonicated samples) the effect of NC-adsorption on clearance dominates resulting in increased infectivity.

Repeated peripheral administrations of CpG oligodeoxynucleotides lead to sustained CNS immune activation

Bacterial DNA containing CpG motifs activates cells of the innate immune system. In this study, we examined the effects of multiple peripheral bacterial DNA-mediated CNS innate immune stimulation. To study this issue, we repeatedly peripherally administered synthetic CpG-oligodeoxynucleotides (CpG-ODN) and assayed effects on CNS-associated TNF-alpha (TNFalpha) and C1q mRNA levels. We for the first time accounted for frequency of CpG-ODN administration and time kinetics of mRNA expression. We were able show that multiple intraperitoneal CpG-ODN administrations have a sustainable effect on immune effectors of the brain and stimulate TNFalpha mRNA secretion even up to 7 days after the last CpG-ODN application. This could on the one hand indicate a depot effect after multiple peripheral CpG-ODN administrations, however, it could also indicate that the cell producing TNFalpha mRNA remains activated for the indicated time period. Furthermore, elevated mRNA levels of C1q were observed, possibly indicating microglial activation after multiple peripheral bacterial DNA administrations. In this study, we have correlated frequency of CpG-ODN administrations with CNS-associated TNFalpha mRNA levels and show that multiple peripheral administrations of CpG-ODN lead to a sustained level of a Th1-associated cytokine in the brain. These findings indicate that the repeated peripherial administration of CpG oligodeoxynucleotides offer a therapeutical possibility for CNS-associated infections and tumors.

Single particle characterization of iron-induced pore-forming alpha-synuclein oligomers

Aggregation of alpha-synuclein is a key event in several neurodegenerative diseases, including Parkinson disease. Recent findings suggest that oligomers represent the principal toxic aggregate species. Using confocal single-molecule fluorescence techniques, such as scanning for intensely fluorescent targets (SIFT) and atomic force microscopy, we monitored alpha-synuclein oligomer formation at the single particle level. Organic solvents were used to trigger aggregation, which resulted in small oligomers ("intermediate I"). Under these conditions, Fe(3+) at low micromolar concentrations dramatically increased aggregation and induced formation of larger oligomers ("intermediate II"). Both oligomer species were on-pathway to amyloid fibrils and could seed amyloid formation. Notably, only Fe(3+)-induced oligomers were SDS-resistant and could form ion-permeable pores in a planar lipid bilayer, which were inhibited by the oligomer-specific A11 antibody. Moreover, baicalein and N'-benzylidene-benzohydrazide derivatives inhibited oligomer formation. Baicalein also inhibited alpha-synuclein-dependent toxicity in neuronal cells. Our results may provide a potential disease mechanism regarding the role of ferric iron and of toxic oligomer species in Parkinson diseases. Moreover, scanning for intensely fluorescent targets allows high throughput screening for aggregation inhibitors and may provide new approaches for drug development and therapy.

Different species of alpha-synuclein oligomers induce calcium influx and seeding

Aggregation of alpha-synuclein (alpha-syn) has been linked to the pathogenesis of Parkinson's disease (PD) and other neurodegenerative diseases. Increasing evidence suggests that prefibrillar oligomers and protofibrils, rather than mature fibrils of alpha-syn, are the pathogenic species in PD. Despite extensive effort on studying oligomerization of alpha-syn, no studies have compared different oligomer species directly on a single-particle level and investigated their biological effects on cells. In this study, we applied a novel highly sensitive single molecule detection system that allowed a direct comparison of different oligomer types. Furthermore, we studied biological effects of different oligomer types on cells. For this purpose, we developed new oligomerization protocols, that enabled the use of these different oligomers in cell culture. We found that all of our three aggregation protocols resulted in heterogeneous populations of oligomers. Some types of oligomers induced cell death via disruption of cellular ion homeostasis by a presumably pore-forming mechanism. Other oligomer types could directly enter the cell resulting in increased alpha-syn aggregation. Based on our results, we propose that under various physiological conditions, heterogeneous populations of oligomeric forms will coexist in an equilibrium. These different oligomer types lead directly or indirectly to cell damage. Our data indicate that inhibition of early alpha-syn aggregation events would consequently prevent all alpha-syn oligomer related toxicities. This has important implications for the development of disease-modifying drugs for the treatment of PD and other synucleinopathies.

Dendritic pathology in prion disease starts at the synaptic spine

Spine loss represents a common hallmark of neurodegenerative diseases. However, little is known about the underlying mechanisms, especially the relationship between spine elimination and neuritic destruction. We imaged cortical dendrites throughout a neurodegenerative disease using scrapie in mice as a model. Two-photon in vivo imaging over 2 months revealed a linear decrease of spine density. Interestingly, only persistent spines (lifetime > or = 8 d) disappeared, whereas the density of transient spines (lifetime < or = 4 d) was unaffected. Before spine loss, dendritic varicosities emerged preferentially at sites where spines protrude from the dendrite. These results implicate that the location where the spine protrudes from the dendrite may be particularly vulnerable and that dendritic varicosities may actually cause spine loss.

Effects of formalin fixation, paraffin embedding, and time of storage on DNA preservation in brain tissue: a BrainNet Europe study

There is a large amount of tissue stored in brain collections and brain banks, but little is known about whether formalin-fixed tissues and paraffin blocks stored for years in brain banks are suitable for the retrospective genetic studies. The study was carried out in order to: (i) compare DNA preservation in frozen, formalin-fixed and paraffin-embedded tissues stored for different periods; (ii) study point mutations and triplet expansions in frozen, formalin-fixed and paraffin-embedded material stored for variable periods, and using different fixative solutions; (iii) compare different methods to optimize DNA extraction and DNA amplification from suboptimally preserved brain tissue. DNA preservation is suitable for genetic studies in samples stored at -80 degrees C for several years. Formalin-fixed, paraffin-embedded tissue was inferior to frozen tissue, but did yield adequate results in many cases depending on the type of fixative solution and time of fixation before embedding. Prolonged fixation in formalin rarely yielded useful DNA. Similar results were obtained in samples from prion diseases. The best results were obtained by using the Qiagen kits (QIAmp DNA Micro) in frozen material, paraffin blocks and formalin-fixed tissue. Genomiphi and TaKaRa Ex Taq methods were also assayed in paraffin blocks and in formalin-fixed samples with limited success.

Impact of vCJD on blood supply

Variant Creutzfeldt-Jakob disease (vCJD) is an at present inevitably lethal neurodegenerative disease which can only be diagnosed definitely post mortem. The majority of the approximately 200 victims to date have resided in the UK where most contaminated beef materials entered the food chain. Three cases in the UK demonstrated that vCJD can be transmitted by blood transfusion. Since BSE and vCJD have spread to several countries outside the UK, it appears advisable that specific risk assessments be carried out in different countries and geographic areas. This review explains the approach adopted by Germany in assessing the risk and considering precautionary measures. A fundamental premise is that the feeding chain of cattle and the food chain have been successfully and permanently cleared from contaminated material. This raises the question of whether transmissions via blood transfusions could have the potential to perpetuate vCJD in mankind. A model calculation based on actual population data showed, however, that this would not be the case. Moreover, an exclusion of transfusion recipients from blood donation would add very little to the safety of blood transfusions, but would have a considerable impact on blood supply. Therefore, an exclusion of transfusion recipients was not recommended in Germany.

Role of the CD8+ dendritic cell subset in transmission of prions

Controversial results have been observed in mouse models regarding the role of lymphoid tissues in prion pathogenesis. To investigate the role of dendritic cells (DC), we used a transgenic mouse model. In this model (CD11c-N17Rac1), a significant reduction of CD8+ CD11c(hi) DC has been described, and the remaining CD8+ DC demonstrate a reduced capacity for the uptake of apoptotic cells. After intraperitoneal prion infection, significantly longer incubation times were observed in CD11c-N17Rac1 mice than in controls, indicating that a defect in CD8+ CD11c(hi) DC significantly impedes neuroinvasion after intraperitoneal infection. In contrast, no distinct differences were observed between CD11c-N17Rac1 mice and controls after oral infection. This provides evidence that oral and intraperitoneal prion infections differ in lymphoreticular requirements.

Lentivector-mediated RNAi efficiently suppresses prion protein and prolongs survival of scrapie-infected mice

Prion diseases are fatal neurodegenerative diseases characterized by the accumulation of PrP(Sc), the infectious and protease-resistant form of the cellular prion protein (PrP(C)). We generated lentivectors expressing PrP(C)-specific short hairpin RNAs (shRNAs) that efficiently silenced expression of the prion protein gene (Prnp) in primary neuronal cells. Treatment of scrapie-infected neuronal cells with these lentivectors resulted in an efficient and stable suppression of PrP(Sc) accumulation. After intracranial injection, lentiviral shRNA reduced PrP(C) expression in transgenic mice carrying multiple copies of Prnp. To test the therapeutic potential of lentiviral shRNA, we used what we believe to be a novel approach in which the clinical situation was mimicked. We generated chimeric mice derived from lentivector-transduced embryonic stem cells. Depending on the degree of chimerism, these animals carried the lentiviral shRNAs in a certain percentage of brain cells and expressed reduced levels of PrP(C). Importantly, in highly chimeric mice, survival after scrapie infection was significantly extended. Taken together, these data suggest that lentivector-mediated RNA interference could be an approach for the treatment of prion disease.

Brain Protein Preservation Largely Depends on the Postmortem Storage Temperature

The present study was designed to reveal protein modifications in control cases related with postmortem delay and temperature of storage in 3 paradigms in which the same postmortem tissue sample (frontal cortex) was frozen a short time after death or stored at 1 degrees C, 4 degrees C, or room temperature and then frozen at -80 degrees C at different intervals. No evidence of protein degradation as revealed with monodimensional gel electrophoresis and Western blotting was observed in samples artificially stored at 1 degrees C and then frozen at different intervals up to 50 hours after death. However, the levels of several proteins were modified in samples stored at 4 degrees C and this effect was more marked in samples stored at room temperature. Two-dimensional gel electrophoresis and mass spectrometry further corroborated these observations and permitted the identification of other proteins vulnerable or resistant to postmortem delay. Finally, gel electrophoresis and Western blotting of sarkosyl-insoluble fractions in Alzheimer disease showed reduced intensity of phospho-tau-specific bands with postmortem delay with the effects being more dramatic when the brain samples were stored at room temperature for long periods. These results emphasize the necessity of reducing the body temperature after death to minimize protein degradation.

How a neuropsychiatric brain bank should be run: a consensus paper of Brainnet Europe II

The development of new molecular and neurobiological methods, computer-assisted quantification techniques and neurobiological investigation methods which can be applied to the human brain, all have evoked an increased demand for post-mortem tissue in research. Psychiatric disorders are considered to be of neurobiological origin. Thus far, however, the etiology and pathophysiology of schizophrenia, depression and dementias are not well understood at the cellular and molecular level. The following will outline the consensus of the working group for neuropsychiatric brain banking organized in the Brainnet Europe II, on ethical guidelines for brain banking, clinical diagnostic criteria, the minimal clinical data set of retrospectively analyzed cases as well as neuropathological standard investigations to perform stageing for neurodegenerative disorders in brain tissue. We will list regions of interest for assessments in psychiatric disorder, propose a dissection scheme and describe preservation and storage conditions of tissue. These guidelines may be of value for future implementations of additional neuropsychiatric brain banks world-wide.

Chaperonin TRiC promotes the assembly of polyQ expansion proteins into nontoxic oligomers

Aberrant folding and fibrillar aggregation by polyglutamine (polyQ) expansion proteins are associated with cytotoxicity in Huntington's disease and other neurodegenerative disorders. Hsp70 chaperones have an inhibitory effect on fibril formation and can alleviate polyQ cytotoxicity. Here we show that the cytosolic chaperonin, TRiC, functions synergistically with Hsp70 in this process and is limiting in suppressing polyQ toxicity in a yeast model. In vitro reconstitution experiments revealed that TRiC, in cooperation with the Hsp70 system, promotes the assembly of polyQ-expanded fragments of huntingtin (Htt) into soluble oligomers of approximately 500 kDa. Similar oligomers were observed in yeast cells upon TRiC overexpression and were found to be benign, in contrast to conformationally distinct Htt oligomers of approximately 200 kDa, which accumulated at normal TRiC levels and correlated with inhibition of cell growth. We suggest that TRiC cooperates with the Hsp70 system as a key component in the cellular defense against amyloid-like protein misfolding.

Staging of Alzheimer disease-associated neurofibrillary pathology using paraffin sections and immunocytochemistry

Assessment of Alzheimer's disease (AD)-related neurofibrillary pathology requires a procedure that permits a sufficient differentiation between initial, intermediate, and late stages. The gradual deposition of a hyperphosphorylated tau protein within select neuronal types in specific nuclei or areas is central to the disease process. The staging of AD-related neurofibrillary pathology originally described in 1991 was performed on unconventionally thick sections (100 mum) using a modern silver technique and reflected the progress of the disease process based chiefly on the topographic expansion of the lesions. To better meet the demands of routine laboratories this procedure is revised here by adapting tissue selection and processing to the needs of paraffin-embedded sections (5-15 mum) and by introducing a robust immunoreaction (AT8) for hyperphosphorylated tau protein that can be processed on an automated basis. It is anticipated that this revised methodological protocol will enable a more uniform application of the staging procedure.

Interlaboratory comparison of assessments of Alzheimer disease-related lesions: a study of the BrainNet Europe Consortium

This interlaboratory study evaluated the reproducibility of the assessments of neuritic plaques and neurofibrillary tangles (NFTs)--the hallmark lesions of Alzheimer disease--and compared the staining between the BrainNet Europe centers. To reduce the topography-related inconsistencies in assessments, we used a 2-mm tissue microarray (TMA) technique. The TMA block included 42 core samples taken from 21 paraffin blocks. The assessments were done on Bielschowsky and Gallyas silver stains using an immunohistochemical (IHC) method with antibodies directed to beta-amyloid (IHC/Abeta) and hyperphosphorylated tau (IHC/HPtau). The staining quality and the assessments differed between the participants, being most diverse with Bielschowsky (good/acceptable stain in 53% of centers) followed by Gallyas (good/acceptable stain in 57%) and IHC/Abeta (good/acceptable stain in 71%). The most uniform staining quality and assessment was obtained with the IHC/HPtau method (good/acceptable stain in 94% of centers). The neuropathologic diagnostic protocol (Consortium to Establish a Registry for Alzheimer Disease, Braak and Braak, and the National Institute of Aging and Reagan [NIA-Reagan] Institute) that was used significantly influenced the agreement, being highest with NIA-Reagan (54%) recommendations. This agreement was improved by visualization of NFTs using the IHC/HPtau method. Therefore, the IHC/HPtau methodology to visualize NFTs and neuropil threads should be considered as a method of choice in a future diagnostic protocol for Alzheimer disease.

HUPO Brain Proteome Project: Summary of the pilot phase and introduction of a comprehensive data reprocessing strategy

The Human Proteome Organisation (HUPO) initiated several projects focusing on the proteome analysis of distinct human organs. The Brain Proteome Project (BPP) is the initiative dedicated to the brain, its development and correlated diseases. Two pilot studies have been performed aiming at the comparison of techniques, laboratories and approaches. With the help of the results gained, objective data submission, storage and reprocessing workflow have been established. The biological relevance of the data will be drawn from the inter-laboratory comparisons as well as from the re-calculation of all data sets submitted by the different groups. In the following, results of the single groups as well as the centralised reprocessing effort will be summarised and compared, showing the added value of this concerted work.

Comparison of extent of tau pathology in patients with frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17), frontotemporal lobar degeneration with Pick bodies and early onset Alzheimer's disease

In order to gain insight into the pathogenesis of frontotemporal lobar degeneration (FTLD), the mean tau load in frontal cortex was compared in 34 patients with frontotemporal dementia linked to chromosome 17 (FTDP-17) with 12 different mutations in the tau gene (MAPT), 11 patients with sporadic FTLD with Pick bodies and 25 patients with early onset Alzheimer's disease (EOAD). Tau load was determined, as percentage of tissue occupied by stained product, by image analysis of immunohistochemically stained sections using the phospho-dependent antibodies AT8, AT100 and AT180. With AT8 and AT180 antibodies, the amount of tau was significantly (P < 0.001 in each instance) less than that in EOAD for both FTDP-17 (8.5% and 10.0% respectively) and sporadic FTLD with Pick bodies (16.1% and 10.0% respectively). With AT100, the amount of tau detected in FTDP-17 was 54% (P < 0.001) of that detected in EOAD, but no tau was detected in sporadic FTLD with Pick bodies using this particular antibody. The amount of insoluble tau deposited within the brain in FTDP-17 did not depend in any systematic way upon where the MAPT mutation was topographically located within the gene, or on the physiological or structural change generated by the mutation, regardless of which anti-tau antibody was used. Not only does the amount of tau deposited in the brain differ between the three disorders, but the pattern of phosphorylation of tau also varies according to disease. These findings raise important questions relating to the role of aggregated tau in neurodegeneration - whether this represents an adaptive response which promotes the survival of neurones, or whether it is a detrimental change that directly, or indirectly, brings about the demize of the affected cell.

Loss of the cellular prion protein affects the Ca2+ homeostasis in hippocampal CA1 neurons

Previous neurophysiological studies on prion protein deficient (Prnp(-/-)) mice have revealed a significant reduction of slow afterhyperpolarization currents (sI(AHP)) in hippocampal CA1 pyramidal cells. Here we aim to determine whether loss of PrP(C.) directly affects the potassium channels underlying sI(AHP) or if sI(AHP) is indirectly disturbed by altered intracellular Ca(2+) fluxes. Patch-clamp measurements and confocal Ca(2+) imaging in acute hippocampal slice preparations of Prnp(-/-) mice compared to littermate control mice revealed a reduced Ca(2+) rise in CA1 neurons lacking PrP(C) following a depolarization protocol known to induce sI(AHP). Moreover, we observed a reduced Ca(2+) influx via l-type voltage gated calcium channels (VGCCs). No differences were observed in the protein expression of the pore forming alpha1 subunit of VGCCs Prnp(-/-) mice. Surprisingly, the beta2 subunit, critically involved in the transport of the alpha1 subunit to the plasma membrane, was found to be up-regulated in knock out hippocampal tissue. On mRNA level however, no differences could be detected for the alpha1C, D and beta2-4 subunits. In conclusion our data support the notion that lack of PrP(C.) does not directly affect the potassium channels underlying sI(AHP), but modulates these channels due to its effect on the intracellular free Ca(2+) concentration via a reduced Ca(2+) influx through l-type VGCCs.