Regulating Factors of PrPres Glycosylation in Creutzfeldt-Jakob Disease - Implications for the Dissemination and the Diagnosis of Human Prion Strains

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

Anticardiolipin antibodies in patients with multiple sclerosis do not represent a subgroup of patients according to clinical, familial, and biological characteristics

Objectives: To determine whether patients with MS who are positive for aCL Ab have specific characteristics. Methods: 285 consecutive patients with MS were tested for aCL Ab positivity. Patients also underwent complete autoimmune screening and were systematically evaluated for clinical characteristics and individual or family history of autoimmune disease. Results: aCL Ab positivity was found in 42 patients (15%). The main isotype was aCL IgM (32 patients, 11%). Demographics and clinical characteristics including sex, age at onset, course of the disease, expanded disability status scale score, and progression index were not different between aCL Ab positive and aCL Ab negative patients. Clinical systems involved at onset or during the course of the disease were not different from what is usually observed in MS. aCL Ab positivity was not associated with an increased frequency of autoimmune disease and was not predictive of a family history of autoimmune disease. Patients positive for aCL IgM were more frequently positive for the presence of non-organ specific antibodies (53% v 39%, respectively, p = 0.02). Conclusions: These results do not support the hypothesis that patients with MS with aCL Ab constitute a subgroup of MS according to demographic clinical and familial characteristics. The greater frequency of other antibodies in aCL Ab positive patients suggests that they only reflect a more general autoimmune activation in MS

SET translocation is associated with increase in caspase cleaved amyloid precursor protein in CA1 of Alzheimer and Down syndrome patients.

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

Prion-like protein Doppel expression is not modified in scrapie-infected cells and in the brains of patients with Creutzfeldt–Jakob disease

AbstractDoppel protein has been discovered in prnp knock-out mouse lines, with overproduction of this protein in the brain causing ataxia and neurodegeneration. We investigated whether Doppel expression (i) affected or was affected by the course of prion propagation in neuroblastoma cells, or (ii) modulated Creutzfeldt–Jakob disease pathogenesis. No change in Doppel production was detected in N2a cells, before or after infection. Transient murine Doppel gene expression had no effect on N2a viability or PrPSc production. A sensitive immunometric assay revealed low levels of Doppel in human brain, reflecting weak transcription of the corresponding gene. No difference in brain Doppel levels was observed between Creutzfeldt–Jakob disease patients and controls, adding further evidence that Doppel is unlikely to be involved in prion disease pathogenesis

Sporadic Creutzfeldt-Jakob disease mimicking nonconvulsive status epilepticus.

International audienceBACKGROUND: Nonconvulsive status epilepticus (NCSE) in patients with confusion may be difficult to distinguish from nonepileptic (metabolic/toxic, postanoxic, and spongiform) encephalopathies. This study aimed to describe the misleading presentation of patients with sporadic Creutzfeldt-Jakob disease (sCJD) who were initially diagnosed with a refractory NCSE (rNCSE). METHODS: We retrospectively reviewed the clinical characteristics, EEG records, brain MRI scans, 14-3-3 protein detection in CSF, genotype of the prion protein gene, and neuropathologic data of patients referred to our neurologic intensive care unit (NICU) with this presentation. RESULTS: Ten patients with a final diagnosis of definite (n = 7) or probable (n = 3) sCJD were referred to our NICU with an initial diagnosis of rNCSE. Reanalysis of the EEG ruled out ictal rhythmic activities, but showed diffuse, periodic, or semiperiodic sharp-wave complexes (PSWC) with short period. PSWC were briefly attenuated by auditory (n = 5) or painful (n = 3) stimuli and by IV injection of antiepileptic drugs (n = 5) but without clinical improvement. In addition, PSWC showed fluctuations according to the vigilance level (n = 5). Brain MRI showed hyperintensities in basal ganglia (n = 9/10) and in cortical areas (n = 7/10). 14-3-3 Protein was detected in CSF (n = 10). Only 2 sCJD subtypes were found (MM1 5/7, MV1 2/7). CONCLUSIONS: This series of patients suggests that sporadic Creutzfeldt-Jakob disease should be considered as a differential diagnosis, rather than as a cause, of apparent refractory nonconvulsive status epilepticus. Criteria for nonconvulsive status epilepticus diagnosis should rely on careful examination of both EEG parameters and clinical state so that aggressive, unnecessary treatments can be avoided

New role of P2X7 receptor in an Alzheimer's disease mouse model

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