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An abstract of the article "Identification of crystals in kidneys of AIDS patients treated with foscarnet," by L. Maurice-Estepa, M. Daudon, C. Katlama, C. Jouanneau, V. Sazdovitch, B. Lacour and H. Beaufils is presented.

Langerhans cell Histiocytosis (LCH) and Erdheim-Chester disease (ECD) are clonal myeloid disorders, associated with MAP-Kinase activating mutations and an increased risk of neurodegeneration. Surprisingly, we found pervasive PU.1 + microglia mutant clones across the brain of LCH and ECD patients with and without neurological symptoms, associated with microgliosis, reactive astrocytosis, and neuronal loss. The disease predominated in the grey nuclei of the rhombencephalon, a topography attributable to a local proliferative advantage of mutant microglia. Presence of clinical symptoms was associated with a longer evolution of the disease and a larger size of PU.1 + clones (p= 0.0003). Genetic lineage tracing of PU.1 + clones suggest a resident macrophage lineage or a bone marrow precursor origin depending on patients. Finally, a CSF1R-inhibitor depleted mutant microglia and limited neuronal loss in mice suggesting an alternative to MAPK inhibitors. These studies characterize a progressive neurodegenerative disease, caused by clonal proliferation of inflammatory microglia (CPIM), with a decade(s)-long preclinical stage of incipient disease that represent a therapeutic window for prevention of neuronal death., Competing Interests: Conflict of Interest. FG has performed consulting for Third Rock venture in the past. Targeted Sequencing was funded in part by a grant from Third Rock venture. FG and RV are inventors in MSKCC’s United States application or PCT international application number PCT/US2018/047964 filed on 8/24/2018 (KINASE MUTATION-ASSOCIATED NEURODEGENERATIVE DISORDERS)

Alteration of brain aerobic glycolysis is often observed early in the course of Alzheimer's disease (AD). Whether and how such metabolic dysregulation contributes to both synaptic plasticity and behavioral deficits in AD is not known. Here, we show that the astrocytic l-serine biosynthesis pathway, which branches from glycolysis, is impaired in young AD mice and in AD patients. l-serine is the precursor of d-serine, a co-agonist of synaptic NMDA receptors (NMDARs) required for synaptic plasticity. Accordingly, AD mice display a lower occupancy of the NMDAR co-agonist site as well as synaptic and behavioral deficits. Similar deficits are observed following inactivation of the l-serine synthetic pathway in hippocampal astrocytes, supporting the key role of astrocytic l-serine. Supplementation with l-serine in the diet prevents both synaptic and behavioral deficits in AD mice. Our findings reveal that astrocytic glycolysis controls cognitive functions and suggest oral l-serine as a ready-to-use therapy for AD., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Extracellular aggregates of amyloid β (Aβ) peptides, which are characteristic of Alzheimer's disease (AD), act as an essential trigger for glial cell activation and the release of ATP, leading to the stimulation of purinergic receptors, especially the P2X7 receptor (P2X7R). However, the involvement of P2X7R in the development of AD is still ill-defined regarding the dual properties of this receptor. Particularly, P2X7R activates the NLRP3 inflammasome leading to the release of the pro-inflammatory cytokine, IL-1β; however, P2X7R also induces cleavage of the amyloid precursor protein generating Aβ peptides or the neuroprotective fragment sAPPα. We thus explored in detail the functions of P2X7R in AD transgenic mice. Here, we show that P2X7R deficiency reduced Aβ lesions, rescued cognitive deficits and improved synaptic plasticity in AD mice. However, the lack of P2X7R did not significantly affect the release of IL-1β or the levels of non-amyloidogenic fragment, sAPPα, in AD mice. Instead, our results show that P2X7R plays a critical role in Aβ peptide-mediated release of chemokines, particularly CCL3, which is associated with pathogenic CD8 + T cell recruitment. In conclusion, our study highlights a novel detrimental function of P2X7R in chemokine release and supports the notion that P2X7R may be a promising therapeutic target for AD.

Abeta deposits and tau pathology were investigated in 24 French patients that died from iatrogenic Creutzfeldt-Jakob disease after exposure to cadaver-derived human growth hormone (c-hGH) in the 1980s. Abeta deposits were found only in one case that had experienced one of the longest incubation periods. Three cases had also intracellular tau accumulation. The analysis of 24 batches of c-hGH, produced between 1974 and 1988, demonstrated for the first time the presence of Abeta and tau contaminants in c-hGH (in 17 and 6 batches, respectively). The incubation of prion disease was shorter in the French patients than the incubation times reported in two previously published British series. We interpreted the low incidence of Abeta in this French series as a consequence of the shorter incubation period observed in France, as compared to that observed in the United Kingdom. This concept suggested that a mean incubation period for the development of detectable Abeta deposits would be longer than 18 years after the first exposure. Moreover, we hypothesized that tau pathology might also be transmissible in humans.

The presence of pathology related to the deposition of amyloid-β (Aβ) has been recently reported in iatrogenic Creutzfeldt-Jakob disease (iCJD) acquired from inoculation of growth hormone (GH) extracted from human cadaveric pituitary gland or use of cadaveric dura mater (DM) grafts.To investigate this phenomenon further, a cohort of 27 iCJD cases - 21 with adequate number of histopathological sections - originating from Australia, France, Italy, and the Unites States, were examined by immunohistochemistry, amyloid staining, and Western blot analysis of the scrapie prion protein (PrP Sc ), and compared with age-group matched cases of sporadic CJD (sCJD), Alzheimer disease (AD) or free of neurodegenerative diseases (non-ND).Cases of iCJD and sCJD shared similar profiles of proteinase K-resistant PrP Sc with the exception of iCJD harboring the "MMi" phenotype. Cerebral amyloid angiopathy (CAA), either associated with, or free of, Thioflavin S-positive amyloid core plaques (CP), was observed in 52% of 21 cases of iCJD, which comprised 37.5% and 61.5% of the cases of GH- and DM-iCJD, respectively. If only cases younger than 54 years were considered, Aβ pathology affected 41%, 2% and 0% of iCJD, sCJD and non-ND, respectively. Despite the patients' younger age CAA was more severe in iCJD than sCJD, while Aβ diffuse plaques, in absence of Aβ CP, populated one third of sCJD. Aβ pathology was by far most severe in AD. Tau pathology was scanty in iCJD and sCJD.In conclusion, (i) despite the divergences in the use of cadaveric GH and DM products, our cases combined with previous studies showed remarkably similar iCJD and Aβ phenotypes indicating that the occurrence of Aβ pathology in iCJD is a widespread phenomenon, (ii) CAA emerges as the hallmark of the Aβ phenotype in iCJD since it is observed in nearly 90% of all iCJD with Aβ pathology reported to date including ours, and it is shared by GH- and DM-iCJD, (iii) although the contributions to Aβ pathology of other factors, including GH deficiency, cannot be discounted, our findings increase the mounting evidence that this pathology is acquired by a mechanism resembling that of prion diseases.

Diagnostic criteria of Creutzfeldt-Jakob disease (CJD), a rare and fatal transmissible nervous system disease with public health implications, are determined by clinical data, electroencephalogram (EEG), detection of 14-3-3 protein in cerebrospinal fluid (CSF), brain magnetic resonance imaging and prion protein gene examination. The specificity of protein 14-3-3 has been questioned. We reviewed data from 1,572 autopsied patients collected over an 18-year period (1992-2009) and assessed whether and how 14-3-3 detection impacted the diagnosis of sporadic CJD in France, and whether this led to the misdiagnosis of treatable disorders. 14-3-3 detection was introduced into diagnostic criteria for CJD in 1998. Diagnostic accuracy decreased from 92% for the 1992-1997 period to 85% for the 1998-2009 period. This was associated with positive detections of 14-3-3 in cases with negative EEG and alternative diagnosis at autopsy. Potentially treatable diseases were found in 163 patients (10.5%). This study confirms the usefulness of the recent modification of diagnosis criteria by the addition of the results of CSF real-time quaking-induced conversion, a method based on prion seed-induced misfolding and aggregation of recombinant prion protein substrate that has proven to be a highly specific test for diagnosis of sporadic CJD.

TDP-43-positive inclusions are present in the amygdala in frontotemporal lobar degeneration (FTLD) and motor neuron disease (MND) including amyotrophic lateral sclerosis. Behavioral abnormalities, one of the chief symptoms of FTLD, could be, at least partly, related to amygdala pathology. We examined TDP-43 inclusions in the amygdala of patients with sporadic FTLD/MND (sFTLD/MND), FTLD/MND with mutation of the C9ORF72 (FTLD/MND-C9) and FTLD with mutation of the progranulin (FTLD-GRN). TDP-43 inclusions were common in each one of these subtypes, which can otherwise be distinguished on topographical and genetic grounds. Conventional and immunological stainings were performed and we quantified the numerical density of inclusions on a regional basis. TDP-43 inclusions in amygdala could be seen in 10 out of 26 sFTLD/MND cases, 5 out of 9 FTLD/MND-C9 cases, and all 4 FTLD-GRN cases. Their numerical density was lower in FTLD/MND-C9 than in sFTLD/MND and FTLD-GRN. TDP-43 inclusions were more numerous in the ventral region of the basolateral nucleus group in all subtypes. This contrast was apparent in sporadic and C9-mutated FTLD/MND, while it was less evident in FTLD-GRN. Such differences in subregional involvement of amygdala may be related to the region-specific neuronal connections that are differentially affected in FTLD/MND and FTLD-GRN., (© 2017 American Association of Neuropathologists, Inc. All rights reserved.)

The transmission of classical bovine spongiform encephalopathy (C-BSE) through contaminated meat product consumption is responsible for variant Creutzfeldt-Jakob disease (vCJD) in humans. More recent and atypical forms of BSE (L-BSE and H-BSE) have been identified in cattle since the C-BSE epidemic. Their low incidence and advanced age of onset are compatible with a sporadic origin, as are most cases of Creutzfeldt-Jakob disease (CJD) in humans. Transmissions studies in primates and transgenic mice expressing a human prion protein (PrP) indicated that atypical forms of BSE may be associated with a higher zoonotic potential than classical BSE, and require particular attention for public health. Recently, methods designed to amplify misfolded forms of PrP have emerged as promising tools to detect prion strains and to study their diversity. Here, we validated real-time quaking-induced conversion assay for the discrimination of atypical and classical BSE strains using a large series of bovine samples encompassing all the atypical BSE cases detected by the French Centre of Reference during 10 years of exhaustive active surveillance. We obtained a 100% sensitivity and specificity for atypical BSE detection. In addition, the assay was able to discriminate atypical and classical BSE in non-human primates, and also sporadic CJD and vCJD in humans. The RT-QuIC assay appears as a practical means for a reliable detection of atypical BSE strains in a homologous or heterologous PrP context.

Alzheimer's disease is characterized by the combined presence of amyloid plaques and tau pathology, the latter being correlated with the progression of clinical symptoms. Neuroinflammatory changes are thought to be major contributors to Alzheimer's disease pathophysiology, even if their precise role still remains largely debated. Notably, to what extent immune responses contribute to cognitive impairments promoted by tau pathology remains poorly understood. To address this question, we took advantage of the THY-Tau22 mouse model that progressively develops hippocampal tau pathology paralleling cognitive deficits and reappraised the interrelationship between tau pathology and brain immune responses. In addition to conventional astroglial and microglial responses, we identified a CD8-positive T cell infiltration in the hippocampus of tau transgenic mice associated with an early chemokine response, notably involving CCL3. Interestingly, CD8-positive lymphocyte infiltration was also observed in the cortex of patients exhibiting frontemporal dementia with P301L tau mutation. To gain insights into the functional involvement of T cell infiltration in the pathophysiological development of tauopathy in THY-Tau22 mice, we chronically depleted T cells using anti-CD3 antibody. Such anti-CD3 treatment prevented hippocampal T cell infiltration in tau transgenic animals and reverted spatial memory deficits, in absence of tau pathology modulation. Altogether, these data support an instrumental role of hippocampal T cell infiltration in tau-driven pathophysiology and cognitive impairments in Alzheimer's disease and other tauopathies., (© The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain.)

Pathologic modifications of the Tau protein leading to neurofibrillary tangle (NFT) formation are a common feature of a wide range of neurodegenerative diseases known as tauopathies, which include Alzheimer's disease (AD). We previously showed that the immunophilin FKBP52 physically and functionally interacts with Tau, and we recently reported that FKBP52 levels are abnormally low in AD patients' brains. To decipher the mechanism of FKBP52 decrease in AD brains, we performed multiple labeling immunohistofluorescence and lysosomal purification using postmortem brain samples of healthy controls (n = 8) and AD (n = 20) patients. Confocal analysis revealed that FKBP52 localizes to the endolysosomal system. We also report FKBP52 colocalization with the truncated Tau-D(421) in the autophagy-endolysosomal system in some AD neurons and that the decrease of FKBP52 correlates with NFT formation. Additional experiments of autophagy inhibition in Tau-inducible SH-SY5Y cells allowed demonstrating FKBP52 release in the extracellular milieu. Our findings point out the possibility that FKBP52 could be abnormally released from NFTs negative neurons in AD brains in correlation with the early pathologic Tau-D(421) neuronal accumulation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Single nucleotide polymorphisms in PICALM, a key component of clathrin-mediated endocytosis machinery, have been identified as genetic susceptibility loci for late onset Alzheimer's disease (LOAD). We previously reported that PICALM protein levels were decreased in AD brains and that PICALM was co-localised with neurofibrillary tangles in LOAD, familial AD with PSEN1 mutations and Down syndrome. In the present study, we analysed PICALM expression, cell localisation and association with pathological cellular inclusions in other tauopathies and in non-tau related neurodegenerative diseases. We observed that PICALM was associated with neuronal tau pathology in Pick disease and in progressive supranuclear palsy (PSP) and co-localised with both 3R and 4R tau positive inclusions unlike in corticobasal degeneration (CBD) or in frontotemporal lobar degeneration (FTLD)-MAPT P301L. PICALM immunoreactivities were not detected in tau-positive tufted astrocytes in PSP, astrocytic plaques in CBD, Lewy bodies in Lewy body disease, diffuse type (LBD) and in TDP-43-positive inclusions in FTLD. In the frontal cortex in tauopathies, the ratio of insoluble to soluble PICALM was increased while the level of soluble PICALM was decreased and was inversely correlated with the level of phosphotau. PICALM decrease was also significantly correlated with increased LC3-II and decreased Beclin-1 levels in tauopathies and in non-tau related neurodegenerative diseases. These results suggest that there is a close relationship between abnormal PICALM processing, tau pathology and impairment of autophagy in human neurodegenerative diseases., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Chordoid glioma of the third ventricle (CG3V) is a rare tumor developing in a stereotyped localization. It has been related to the circumventricular organ of the lamina terminalis, in the anterior part of the third ventricle, but its oncogenesis is poorly understood. TTF-1 transcription factor is involved in the development and adult physiology of the ventral forebrain. We studied the histopathologic and immunohistochemical features of a multicentric series of 17 cases of CG3V. We described additional histologic patterns (solid, fibrosing, and fusiform) to the typical chordoid pattern. TTF-1 was constantly expressed in CG3V, as in developing and adult lamina terminalis. The anti-TTF-1 SPT24 clone was more sensitive than the 8G7G3/1 clone. No mutation of IDH1 R132, IDH2 R172, or BRAF V600 codons was found. We showed TTF-1 as a useful marker for the diagnosis of CG3V and the understanding of its oncogenesis.

Specific extracellular deposits, glial or neuronal inclusions help defining an ever increasing number of neurodegenerative diseases. Deposits or inclusions are aggregates of proteins: Aβ peptide and tau proteins in Alzheimer disease, a-synuclein in Parkinson disease, for instance. The protein that specifically accumulates in a given disease may be modified by a mutation that can increase its aggregability. Most often the sequence of the protein is normal. Misfolding, despite the protein normal sequence, is then considered the cause of the aggregation. The ubiquitin-proteasome system detects and eliminates misfolded proteins from the cell. Almost all the inclusions are indeed labeled by anti-ubiquitin antibodies, but, in neurodegenerative diseases, the system is unable to get rid of them. The large protein aggregates constituting the inclusions are poorly reactive. Their formation has been consi- dered a defense mechanism, protecting the cell against the toxic action of soluble oligomers that are, in that hypothesis, the real toxic agent, neutralized through aggregation. Soluble oligomers of Aβ peptide, tau or a-synuclein,for instance, have indeed been isolated and were shown to be toxic. In the prion hypothesis, the misfolded configuration may be passed from the misfolded to the normal protein by simple contact. There are indeed experimental evidences suggesting that this prion-like mechanism does occur in transgenic rodent models of Aβ, tau or a-synuclein pathology. This might be the explanation of thepropagation of the pathology through connections, observed in many neurodegenerative diseases. There is currently no epidemiological data suggesting a transmission of neurodegenerative diseases, comparable to the transmission of Creutzfeldt-Jakob or other prion diseases. The prion-like mechanisms of protein aggregation observed in the experimental animals or suspected through human neuropathology make that possibility not as remote as previously thought.

Aims: Although demyelination is an important cause of neurological deficits in multiple sclerosis (MS), recently axonal pathology and concomitant involvement of sodium channels (Nav) became a focus of major interest. Studies in experimental autoimmune encephalomyelitis (EAE) and MS have shown diffuse expression of Nav1.6 and Nav1.2 along demyelinated axons. However, the relation between this expression by the axon and its environment is not yet known. The aim of this exploratory study was to identify the neuropathological characteristics of the plaque associated with the changes of sodium channel axonal expression., Methods: We analysed by immunohistochemistry the expression of Nav1.6 and Nav1.2 along demyelinated axons in 64 plaques from 12 MS cases. To characterize the plaques, we used Luxol fast blue staining and immunohistochemistry for myelin basic protein, microglia/macrophages, T and B cells, reactive astrocytes and axonal lesions performed on sections of formalin-fixed, paraffin-embedded tissue., Results: The presence of diffuse axonal expression of Nav1.6 was equally distributed between active demyelinating and inactive not demyelinating plaques based on presence or absence of myelin laden macrophages respectively. However, presence of diffuse axonal expression of Nav1.6 was more frequent within plaques with T cells infiltrate and microglial hyperplasia. On the other hand, Nav1.2 diffuse axonal expression seemed to be independent of the neuropathological environment of the plaque., Conclusions: The cellular environment of the axon influences the differential expression of Nav channels. A better understanding of the influence of the inflammation on sodium channels mediated axonal degeneration could offer therapeutic perspectives., (© 2013 British Neuropathological Society.)

Caspase cleaved amyloid precursor protein (APPcc) and SET are increased and mislocalized in the neuronal cytoplasm in Alzheimer Disease (AD) brains. Translocated SET to the cytoplasm can induce tau hyperphosphorylation. To elucidate the putative relationships between mislocalized APPcc and SET, we studied their level and distribution in the hippocampus of 5 controls, 3 Down syndrome and 10 Alzheimer patients. In Down syndrome and Alzheimer patients, APPcc and SET levels were increased in CA1 and the frequency of both localizations in the neuronal cytoplasm was high in CA1, and low in CA4. As the increase of APPcc is already present at early stages of AD, we overexpressed APPcc in CA1 and the dentate gyrus neurons of adult mice with a lentiviral construct. APPcc overexpression in CA1 and not in the dentate gyrus induced endogenous SET translocation and tau hyperphosphorylation. These data suggest that increase in APPcc in CA1 neurons could be an early event leading to the translocation of SET and the progression of AD through tau hyperphosphorylation., (Copyright © 2014 Elsevier Inc. All rights reserved.)

PICALM, a clathrin adaptor protein, plays important roles in clathrin-mediated endocytosis in all cell types. Recently, genome-wide association studies identified single nucleotide polymorphisms in PICALM gene as genetic risk factors for late-onset Alzheimer disease (LOAD). We analysed by western blotting with several anti-PICALM antibodies the pattern of expression of PICALM in human brain extracts. We found that PICALM was abnormally cleaved in AD samples and that the level of the uncleaved 65-75 kDa full-length PICALM species was significantly decreased in AD brains. Cleavage of human PICALM after activation of endogenous calpain or caspase was demonstrated in vitro. Immunohistochemistry revealed that PICALM was associated in situ with neurofibrillary tangles, co-localising with conformationally abnormal and hyperphosphorylated tau in LOAD, familial AD and Down syndrome cases. PHF-tau proteins co-immunoprecipitated with PICALM. PICALM was highly expressed in microglia in LOAD. These observations suggest that PICALM is associated with the development of AD tau pathology. PICALM cleavage could contribute to endocytic dysfunction in AD.

Mutations in SQSTM1 encoding the sequestosome 1/p62 protein have recently been identified in familial and sporadic cases of amyotrophic lateral sclerosis (ALS). p62 is a component of the ubiquitin inclusions detected in degenerating neurons in ALS patients. We sequenced SQSTM1 in 90 French patients with familial ALS (FALS) and 74 autopsied ALS cases with sporadic ALS (SALS). We identified, at the heterozygote state, one missense c.1175C>T, p.Pro392Leu (exon 8) in one of our FALS and one substitution in intron 7 (the c.1165+1G>A, previously called IVS7+1 G-A, A390X) affecting the exon 7 splicing site in one SALS. These mutations that are located in the ubiquitin-associated domain (UBA domain) of the p62 protein have already been described in Paget's disease and ALS patients carrying these mutations had both concomitant Paget's disease. However, we also identified two novel missense mutations in two SALS: the c.259A>G, p.Met87Val in exon 2 and the c.304A>G, p.Lys102Glu in exon 3. These mutations that were not detected in 360 control subjects are possibly pathogenic. Neuropathology analysis of three patients carrying SQSTM1 variants revealed the presence of large round p62 inclusions in motor neurons, and immunoblot analysis showed an increased p62 and TDP-43 protein levels in the spinal cord. Our results confirm that SQSTM1 gene mutations could be the cause or genetic susceptibility factor of ALS in some patients.

Human neurodegenerative diseases characterized by abnormal intraneuronal inclusions of the tau protein, or "tauopathies", include Alzheimer's disease (AD), Pick's disease, progressive supranuclear palsy, corticobasal degeneration as well as fronto-temporal dementia and Parkinsonism linked to chromosome 17 (FTDP-17). Several abnormalities of tau may contribute to the pathological processes, yet the mechanisms involved in tau cellular toxicity remain unclear. Previously, we demonstrated an interaction between various isoforms of tau and the immunophilin FKBP52 (FK506-Binding Protein), suggesting a direct involvement of FKBP52 in tau function. Here we analyze the expression of FKBP52 in human brains of patients with different tauopathies, including AD. Immunohistofluorescence studies carried out on cerebral cortex in different tauopathies reveal that FKBP52 is not sequestered by filamentous tau inclusions while FKBP52 is colocalized with tau in the control case brains. We found that FKBP52 expression level is abnormally low in frontal cortex of AD and FTDP-17 brains, as compared to controls, despite no alteration in the FKBP52 mRNA expression level. The possible involvement of FKBP52 in pathological tau expression/function is discussed.

Changes in the substantia nigra of patients with Parkinson's disease were suspected by Brissaud in the late 19th century. They were subsequently confirmed by Tretiakoff but neglected by Lewy, who described the inclusion bodies that bear his name. The experimental Parkinsonian syndrome caused by reserpine led Carlsson to discover the neuromediatory role of dopamine, a finding at the origin of L-DOPA therapy. Identification of a mutation of the alpha-synuclein gene in cases of familial Parkinson's disease with autosomal dominant transmission was followed by the detection of the protein product in Lewy bodies and neurites. Alpha-synuclein is now recognized as being the main constituent of Lewy bodies. Alpha-synuclein immunohistochemistry has revealed that lesions can extend from the autonomous nervous system to the cortex (in Lewy body dementia). The Lewy body itself does not appear to be the direct cause of symptoms, which correlate better with neuronal death. Neuronal death could be due to metabolic disturbances related to alpha-synuclein accumulation, ubiquitin-proteasome system dysfunction, or oxidative stress. Non-autonomous cell death, caused by neuro-inflammation or gliosis, has also been incriminated.

Whether aggregates of prion protein (PrP) reflect neurotoxicity or are neuroprotective in prion diseases is unclear. To address this question, we performed a clinicopathologic study of cerebellar granular neurons in 100 patients affected with sporadic Creutzfeldt-Jakob disease (CJD). There was significant loss of these neurons in the subset of cases with Val/Val genotype at PRNP Codon 129 and Molecular Isotype 2 of abnormal PrP (sporadic CJD-VV2) (n=32) compared with both the other CJD subtypes and to controls. Pathological PrP deposits of the punctate-type (synaptic-type) in this subgroup correlated with neuronal loss and proliferation of astrocytes and microglia. By contrast, the numbers of large deposits (5- to 50-microm-diameter) and numbers of amyloid plaques did not correlate with neuronal loss. These findings are consistent with the view that large aggregates may protect neurons by sequestering neurotoxic PrP oligomers, whereas punctate deposits may indicate the location of neuronal death processes in CJD.

Cytochrome P450 (P450) enzymes and ATP-binding cassette (ABC) transporters modulate the transport and metabolism of both endogenous and exogenous substrates and could play crucial roles in the human brain. In this study, we report the transcript expression profile of seven ABC transporters (ABCB1, ABCC1-C5, and ABCG2), 24 P450s (CYP1, CYP2, and CYP3 families and CYP46A1), and 14 related transcription factors [aryl hydrocarbon receptor, nuclear receptor (NR)1I2/pregnane X receptor, NR1I3/constitutive androstane receptor and NR1C/peroxisome proliferator-activated receptor, NR1H/liver X receptor, NR2B/retinoid X receptor, and NR3A/estrogen receptor subfamilies] in the whole brain, the dura mater, and 17 different encephalic areas. In addition, Western blotting and immunohistochemistry analysis were used to characterize the distribution of the P450s at the cellular and subcellular levels in some brain regions. Our results show the presence of a large variety of xenobiotic transporters and metabolizing enzymes in human brain and show for the first time their apparent selective distribution in different cerebral regions. The most abundant transporters were ABCC5 and ABCG2, which, interestingly, had a higher mRNA expression in the brain compared with that found in the liver. CYP46A1, CYP2J2, CYP2U1, CYP1B1, CYP2E1, and CYP2D6 represented more than 90% of the total P450 and showed selective distribution in different brain regions. Their presence in both microsomal and mitochondrial fractions was shown both in neuronal and glial cells in several brain areas. Thus, our study shows key enzymes of cholesterol and fatty acid metabolism to be present in the human brain and provides novel information of importance for elucidation of enzymes responsible for normal and pathological processes in the human brain.

Dopaminergic cell death in the substantia nigra (SN) is central to Parkinson's disease (PD), but the neurodegenerative mechanisms have not been completely elucidated. Iron accumulation in dopaminergic and glial cells in the SN of PD patients may contribute to the generation of oxidative stress, protein aggregation, and neuronal death. The mechanisms involved in iron accumulation also remain unclear. Here, we describe an increase in the expression of an isoform of the divalent metal transporter 1 (DMT1/Nramp2/Slc11a2) in the SN of PD patients. Using the PD animal model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication in mice, we showed that DMT1 expression increases in the ventral mesencephalon of intoxicated animals, concomitant with iron accumulation, oxidative stress, and dopaminergic cell loss. In addition, we report that a mutation in DMT1 that impairs iron transport protects rodents against parkinsonism-inducing neurotoxins MPTP and 6-hydroxydopamine. This study supports a critical role for DMT1 in iron-mediated neurodegeneration in PD.

Objective: The glycoprofile of pathological prion protein (PrP(res)) is widely used as a diagnosis marker in Creutzfeldt-Jakob disease (CJD) and is thought to vary in a strain-specific manner. However, that the same glycoprofile of PrP(res) always accumulates in the whole brain of one individual has been questioned. We aimed to determine whether and how PrP(res) glycosylation is regulated in the brain of patients with sporadic and variant Creutzfeldt-Jakob disease., Methods: PrP(res) glycoprofiles in four brain regions from 134 patients with sporadic or variant CJD were analyzed as a function of the genotype at codon 129 of PRNP and the Western blot type of PrP(res)., Results: The regional distribution of PrP(res) glycoforms within one individual was heterogeneous in sporadic but not in variant CJD. PrP(res) glycoforms ratio significantly correlated with the genotype at codon 129 of the prion protein gene and the Western blot type of PrP(res) in a region-specific manner. In some cases of sCJD, the glycoprofile of thalamic PrP(res) was undistinguishable from that observed in variant CJD., Interpretation: Regulations leading to variations of PrP(res) pattern between brain regions in sCJD patients, involving host genotype and Western blot type of PrP(res) may contribute to the specific brain targeting of prion strains and have direct implications for the diagnosis of the different forms of CJD.

Demonstration of pathological prion protein accumulation in the central nervous system is required to establish the diagnosis of transmissible subacute encephalopathies. In humans, this is frequently achieved using prion protein immunohistochemistry in paraffin-embedded tissue, a technique that requires multiple epitope retrieval and denaturing pretreatments. In addition to being time-consuming, this procedure induces tissue alterations that preclude accurate morphological examination. The aim of this study was to simplify prion protein immunohistochemistry procedure in human tissue, together with increased sensitivity and specificity. We screened a panel of 50 monoclonal antibodies produced using various immunogens (human and ovine recombinant prion protein, prion protein peptides, denatured scrapie-associated fibrils from 263K-infected Syrian hamsters) and directed against different epitopes along the human prion protein sequence. A panel of different forms of genetic, infectious and sporadic transmissible subacute encephalopathies was assessed. The monoclonal 12F10 antibody provided a high specificity and fast immunodiagnosis with very limited denaturing pretreatments. A standardized and reliable fast immunostaining procedure was established using an automated diagnostic system (Nexes, Ventana Medical Systems) and allowed prion protein detection in the central nervous system and in tonsil biopsies. It was evaluated in a series of 300 patients with a suspected diagnosis of transmissible subacute encephalopathies and showed high sensitivity and specificity.

Sporadic Creutzfeldt-Jakob disease (sCJD) does not always present with typical clinical signs, such as myoclonus in association with periodic sharp-wave complexes. We present a 67-year old female patient with initial falls and vertical gaze palsy, suggesting the diagnosis of Progressive Supranuclear Palsy (PSP). EEG and MRI were not contributory. Typical clinical and paraclinical CJD signs were only seen after 17 months. The diagnosis was confirmed by autopsy. - CJD can be a neurodegenerative chameleon. The present case adds to the scare literature of slowly evolving CJD mimicking Parkinsonism related to tauopathies.

Objective: To report the clinical and neuropathological features in the first patient seen, to our knowledge, with familial Creutzfeldt-Jakob disease and an R208H mutation associated with a Val/Val homozygosity at codon 129 in the prion protein gene (PRNP) and a type 2 protease-resistant prion protein., Patient and Results: A 61-year-old man with a long-standing history of memory loss and emotional disorders had an obvious behavioral change. Then he developed cerebellar ataxia, followed by cognitive decline. He had no myoclonus. Electroencephalography showed slow activity, and 14-3-3 protein detection was negative. Finally, the patient developed akinetic mutism and died 7 months after the onset of ataxia. Neuropathological examination showed severe spongiform changes in the frontal cortex and striatum and gliosis in the striatum and thalamus. Kuru plaques were noted in the cerebellum, notably in the molecular layer. Immunohistochemical findings showed granular, synaptic, perineuronal, and perivacuolar staining with antiprion antibodies. Kuru plaques were also stained., Conclusion: This study strengthens the linkage of the R208H mutation to Creutzfeldt-Jakob disease and points to some particular features such as Kuru plaques and long-standing psychiatric signs.

Human brain cellular prion protein (PrP(c)) is cleaved within its highly conserved domain at amino acid 110/111/112. This cleavage generates a highly stable C-terminal fragment (C1). We examined the relative abundance of holo- and truncated PrP(c) in human cerebral cortex and we found important inter-individual variations in the proportion of C1. Neither age nor postmortem interval explain the large variability observed in C1 amount. Interestingly, our results show that high levels of C1 are associated with the presence of the active ADAM 10 suggesting this zinc metalloprotease as a candidate for the cleavage of PrP(c) in the human brain.

Antigen expression of a human endogenous retrovirus family, HERV-W, in normal human brain and multiple sclerosis lesions was studied by immunohistochemistry by three independent groups. The HERV-W multicopy family was identified in human DNA from the previously characterized multiple sclerosis-associated retroviral element (MSRV). A panel of antibodies against envelope (ENV) and capsid (GAG) antigens was tested. A physiological expression of GAG proteins in neuronal cells was observed in normal brain, whereas there was a striking accumulation of GAG antigen in axonal structures in demyelinated white matter from patients with MS. Prominent HERV-W GAG expression was also detected in endothelial cells of MS lesions from acute or actively demyelinating cases, a pattern not found in any control. A physiological expression of ENV proteins was detected in microglia in normal brain; however,a specific expression in macrophages was apparently restricted to early MS lesions. Thus, converging results from three groups confirm that GAG and ENV proteins encoded by the HERV-W multicopy gene family are expressed in cells of the central nervous system under normal conditions. Similar to HERV-W7q ENV (Syncitin), which is expressed in placenta and has been shown to have a physiological function in syncytio-trophoblast fusion, HERV-W GAG may thus also have a physiological function in human brain. This expression differs in MS lesions, which may either reflect differential regulation of inherited HERV-W copies, or expression of "infectious" MSRV copies. This is compatible with a pathophysiological role in MS, but also illustrates the ambivalence of such HERV antigens, which can be expressed in cell-specific patterns, under physiological or pathological conditions.

Prion epizoonoses spread from animals consumed by humans raise the question of which pathways lead to prion neuroinvasion after oral exposure of humans. Here we show that neurons of sympathetic ganglia of patients with variant Creutzfeldt-Jakob disease (vCJD) accumulate the abnormal isoform of the protein prion. This observation shows the involvement of the sympathetic nervous system in the pathogenesis of vCJD and suggests a role for GUT-associated sympathetic neurons in prion propagation in humans after oral contamination.

We studied whether codon 129 polymorphism of the PrP gene modulates the presence of tau- and Abeta-associated lesions among 188 patients over 70 years of age without evidence of dementia. Val allele carriers, either heterozygotes or homozygotes, were more frequently affected by Abeta-associated lesions than non Val allele carriers, whereas there were no differences for tau-positive neurones. Val allele carriers also had more focal and diffuse Abeta deposits. This association was most significant in the highest Braak's stages for neurofibrillary tangles (>/=III). In this group, cases with at least one Val allele had nearly twice as many Abeta-associated lesions. The most affected areas were the entorhinal cortex, TF-TH and the superior temporal cortex, where odds ratios for focal Abeta deposits ranged from 3.5 to 4.6.

The description of dehydroepiandrosterone (DHEA) as a neuroactive neurosteroid has raised the important question of whether the steroid itself and/or its metabolite(s) are active in the brain. Classical transformations of DHEA in brain and peripheral tissues include its conversion to testosterone and estradiol. In the human brain, the metabolism of DHEA to other metabolites is still poorly understood, particularly in aging people and Alzheimer's patients. The present study describes the in vitro transformation of DHEA into 7alpha-hydroxy-DHEA and Delta5-androstene-3beta,17beta-diol, for the first time in the aging brain of patients with Alzheimer's disease in comparison with non-demented controls. Formal identification of DHEA metabolites is provided by gas chromatography-mass spectrometry, thus indicating the presence of NADPH-dependent 7alpha-hydroxylase and 17beta-hydroxysteroid oxidoreductase activities. Under our experimental conditions, the synthesis of 7alpha-hydroxy-DHEA and Delta5-androstene-3beta,17beta-diol occurs in the frontal cortex, hippocampus, amygdala, cerebellum and striatum of both Alzheimer's patients and non-demented controls. In both groups of patients, the pattern of DHEA metabolism is similar, but significant higher synthesis of 7alpha-hydroxy-DHEA in the frontal cortex and Delta5-androstene-3beta,17beta-diol in the cerebellum and striatum were observed compared with those in other brain regions. In addition, a trend toward a significant negative correlation is found between the density of cortical amyloid deposits and the amount of 7alpha-hydroxy-DHEA formed in the frontal cortex and that of Delta5-androstene-3beta,17beta-diol in the hippocampus. Therefore, the biosynthesis of 7alpha-hydroxy-DHEA and/or Delta5-androstene-3beta,17beta-diol is likely to regulate DHEA cerebral concentrations and may contribute to the control of DHEA activity in the aging brain including in Alzheimer's disease.

The prion-like Doppel protein (Dpl) has many biochemical and structural properties in common with the cellular prion protein (PrP(c)), and the physiological role of neither protein is known. Experimental data suggest either direct or indirect interaction between the two proteins. In this study, we investigated the expression pattern and biochemical characteristics of Dpl in human tissues and in Chinese hamster ovary cells transfected with wild-type or variant human Dpl gene constructs. Human Dpl appears to be a glycosylphosphatidylinositol-anchored glycoprotein with N- and O-linked sugars. It was found on Sertoli cells in the testis, on the flagella of epididymal and mature spermatozoa, and in seminal plasma. Dpl coexists only with N-terminally truncated isoforms of PrP(c) on mature spermatozoa. The localization of human Dpl on both Sertoli cells (somatic cells) and spermatozoa (germinal cells) strongly suggests that this protein may play a major role in human male fertility. Finally, our data indicate that spermatozoa are thus an interesting model for studies of the potential interaction between Dpl and PrP(c).

Some neurosteroids have been shown to display beneficial effects on neuroprotection in rodents. To investigate the physiopathological significance of neurosteroids in Alzheimer's disease (AD), we compared the concentrations of pregnenolone, pregnenolone sulfate (PREGS), dehydroepiandrosterone, dehydroepiandrosterone sulfate (DHEAS), progesterone, and allopregnanolone, measured by gas chromatography-mass spectrometry, in individual brain regions of AD patients and aged nondemented controls, including hippocampus, amygdala, frontal cortex, striatum, hypothalamus, and cerebellum. A general trend toward decreased levels of all steroids was observed in all AD patients' brain regions compared with controls: PREGS and DHEAS were significantly lower in the striatum and cerebellum, and DHEAS was also significantly reduced in the hypothalamus. A significant negative correlation was found between the levels of cortical beta-amyloid peptides and those of PREGS in the striatum and cerebellum and between the levels of phosphorylated tau proteins and DHEAS in the hypothalamus. This study provides reference values for steroid concentrations determined by gas chromatography-mass spectrometry in various regions of the aged human brain. High levels of key proteins implicated in the formation of plaques and neurofibrillary tangles were correlated with decreased brain levels of PREGS and DHEAS, suggesting a possible neuroprotective role of these neurosteroids in AD.

Research dealing with tissue is more important to day than ever. Techniques of molecular genetics have indeed permitted the identification of a large number of new proteins that have now to be localised in the tissue and in the cell, in health and disease. This step has to be made in order to elaborate the adequate animal models in which new therapeutics can be tested. In France, however, human tissue samples have become difficult to obtain. Many factors contributed to this situation. Autopsies are now exceptionally performed. Doctors feel confident in their diagnosis and express rarely the need to control it. Families are opposed to post mortem more strongly than before, especially when the reasons for performing it can not be explained before the death of the patient. French law now makes the explicit consent of the patient mandatory before any research. This practically limits all post mortem investigations to those that had been planned before death. The possibility of giving tissue post mortem to allow research has to be publicised, particularly by associations of patients. The organisation that should manage to collect and store the samples at a large scale and over the whole country is lacking. Its structure is still discussed: should it be supported by the state itself, by private funding, possibly by the associations of patients themselves? Patients Associations are ready to play a crucial role: they realised that the present system was inefficient, they are presently trying to organise tissue banks; they will finally have to explain to their members why they should care for research, how they could help and how they will have to accept the absence of immediate spectacular results.

Guidelines for the neuropathological examination of the central nervous system (in adults) are proposed. They include the techniques used for the removal of the brain and spinal cord, the dissection of the skull, the removal of the brain, the fixation of the specimens, the sectioning of the brain, the choice of the blocks for histology, the usual staining methods and the main antibodies to be recommended for immunohistochemistry. Diagrams are given on which the lesions may be drawn and the samples, identified.

The empiric recurrence risk of multiple sclerosis (MS) of relatives of French MS patients is not known. Using a standardized interview, we collected the family histones of 357 consecutive patients followed at our MS clinic; adequate information was obtained on 4784 relatives up to the third degree. Thirty-five patients (9.8%) had a relative with MS. The risk-curve for relatives was the same as in other studies conducted with a similar methodology in Canada. England and Flanders. but the crude overall MS recurrence risk for relatives was lower in France. The genetic burden of MS may be lower in France than in areas of higher MS prevalence.

Tissue banks are of major importance in research on human tissues, in particular as regards the furthering of our knowledge on multiple sclerosis (MS). Individuals who wish to make a 'donation of their brain' for autopsy, or pathologists in possession of biopsy specimens that have not been utilized for diagnosis provide the necessary material for investigation by research teams. In addition to their technical aspects, brain tissue banks provide information and aid in promoting research. Their functioning, usually supported by patient associations, has encountered certain difficulties. At present, it is challenged by a decrease in the number of autopsies.

Three lesions can be seen in the central nervous system: vacuolation ("spongiform state"), hypertrophy and proliferation of astrocytes ("astrogliosis"), and neuronal loss. These are poorly specific changes. In contrast, amyloid plaques and other deposits of PrPres are very specific lesions. The recent widening of the clinico-pathological spectrum of PrPres-induced disorders has shown that none of these lesions was constantly present. The mechanisms of PrPres occurrence and development, neuronal death, involvement of the central nervous system after peripheral inoculation are still hypothetical. B lymphocytes, monocyte-macrophages, peripheral nerves, central synapses are important. New data will be provided by experimental models (transgenic mice, transplantations), and by a full study of all patients affected by prion diseases, which necessarily involves autopsy.

The classification of degenerative dementias with fronto-temporal atrophy has been debated since the description of Pick's disease. The study of a clinico-pathological series of 10 cases using immunohistochemistry lead to the following conclusions: reserving the name of Pick's disease to those cases with argyrophilic inclusions, the most recognisable and characteristic marker at neuropathological examination, allows an easy and reliable diagnosis; keeping on with the splitting of these disorders into various clinico-pathologic entities seems today more useful than grouping them into a single syndrome until new data, based for example on genetic analysis, show that different phenotypes correspond to the same disease.

Distal sensory axonal polyneuropathy (DSP) is the most frequent HIV-associated peripheral neuropathy. DSPs tend to occur in full-blown AIDS and worsen as CD4 cell counts decrease in blood. To assess a possible role for apoptosis in the pathogenesis of the neuropathy, we used in situ end-labelling (ISEL) detecting DNA strand breaks in DRG neurons of 19 HIV-infected patients, of whom nine had axonal polyneuropathy, and 11 controls. Sensory neurons with ISEL-assessed DNA breaks were observed in 9/19 patients with AIDS, 0/3 patients with pre-AIDS, and 1/11 controls. The prevalence of DNA breaks in neurons was higher in AIDS patients than in controls (P < 0.05). Among AIDS patients, DNA breaks in neurons were more abundant in patients with peripheral neuropathy (P < 0.04). It is possible that DNA breaks of DRG neurons induce the axonopathy and consequently play a role in the pathogenesis of DSP. It cannot be excluded, however, that DNA breaks could represent the result rather than the cause of axonopathy. We suggest that ISEL may detect neurons that were primed to apoptosis before death in relation with the HIV infection, and undergo DNA fragmentation at time of death, rather than neurons that underwent premortem both priming and triggering steps of the apoptotic process. This hypothesis could explain why most ISEL-positive neurons lack typical apoptotic morphology and why normal controls do not show ISEL positive cells.

Transmissible non conventional agents are currently called "Prions". This is not a neutral terminology: the attractive Prion hypothesis (the infectious agent being a protein able to replicate in the absence of DNA or RNA) due to Stanley Prusiner is the prevalent one, and has shown to be heuristic, but has not been formally proven and does not easily explain all the data, unless modified and expanded. No simple account has been given for the very unusual physical, chemical, and biological properties of non conventional agents. These infectious agents are associated with degenerative diseases of the nervous system that are either the consequence of a genetic mutation or develop spontaneously in apparently normal individuals, and then can be transmitted to various susceptible hosts, including man. Thus, non conventional agents cannot be considered only as fascinating biological enigmas. They constitute a challenge for public health. The changing characteristics of prion-associated diseases has led to a renewing of their clinical and neuropathological diagnostic criteria. A brief survey of the nosology and neuropathology of prions diseases, with emphasis on new data and on difficulties, is provided. A simple classification based on the familial, sporadic or infectious variety of the disease is suggested. Familial diseases can be named according to the genetic disorder. Sporadic and infectious diseases can be classified following the main clinical symptoms and signs, and the presence or absence of amyloid plaques in the brain, until new tools (analysis of the glycosylation pattern of PrP, strain recognition) allow a more precise nomenclature. The new epidemiology of Prion disorders allowed by these new approaches relies on a full study of Prion diseases affected patients, which necessarily involves their genetic study, and the analysis of brain tissue. This, for practical and ethical reasons, is better achieved by autopsy.

The relationship between dementia and human immunodeficiency virus type 1 (HIV-1) cerebral load is not clearly understood. We used immunohistochemistry and competitive polymerase chain reaction to evaluate the density ofgp 41 immunostained cells and the amount of HIV-1 DNA and RNA in the midfrontal gyrus of 21 HIV-1 infected patients, nine of whom were demented. The amounts of HIV-1 DNA and RNA, and the density of gp 41-positive cells were significantly linked. In this small series of cases, (1) although as a mean, there was a larger viral load in demented patients than in nondemented, this did not reach the significance level (2) discrepancies appeared in the population under study, some demented patients having low viral loads.