The SARS-CoV-2 envelope PDZ binding motif acts as a virulence factor disrupting host's epithelial cell-cell junctions.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for coronavirus disease 2019 (COVID-19), disrupts the alveolar epithelial barrier and exacerbates airway inflammation, leading to acute respiratory failure. The Envelope (E) protein is key to virulence, notably through its PDZ-binding motif (PBM), which interacts with host PDZ proteins, affecting signaling pathways and pathogenicity. This study investigates the PBM's role in virulence by generating PBM-deficient mutant viruses and assessing their impact in vitro and in vivo.

Analysis of short tandem repeats linked to polyglutamine diseases from whole-genome sequencing reveals intermediate alleles of associated with an early disease onset in carriers.

Carriers of the GGGGCC pathogenic expansion in can develop symptoms of frontotemporal dementia and/or amyotrophic lateral sclerosis, with variable and unpredictable ages at onset. Previous studies aiming to decipher the genetic bases of the clinical variability in this rare disease included bi-allelic polymorphisms, excluding short tandem repeats. Whole-genome sequencing data of 195 patients were used to consider all short tandem repeats linked to polyglutamine disorders as potential genetic modifiers given the existing links between and polyglutamine diseases.

Intronic FGF14 GAA repeat expansions impact progression and survival in multiple system atrophy.

Partial phenotypic overlap has been suggested between multiple system atrophy and spinocerebellar ataxia 27B, the autosomal dominant ataxia caused by an intronic GAA•TTC repeat expansion in FGF14. In this study, we investigated the frequency of FGF14 GAA•TTC repeat expansion in clinically diagnosed and pathologically confirmed multiple system atrophy cases. We screened 657 multiple system atrophy cases (193 clinically diagnosed and 464 pathologically confirmed) and 1003 controls.

Monocytic meningitis complicating histiocytosis and response to MEK-inhibitor: a case series.

Central nervous system (CNS) involvement is common in histiocytosis, yet cerebrospinal fluid (CSF) analysis often yields normal results. We present three cases of monocytic meningitis associated with histiocytosis. The first patient was diagnosed with Erdheim-Chester disease (ECD) and exhibited evidence of a MAP2K1 mutation, concomitant with chronic myelomonocytic leukemia.

MAPT mutations in amyotrophic lateral sclerosis: clinical, neuropathological and functional insights.

Background: Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are part of a well-established disease continuum, underpinned by TDP43-pathology. In contrast, the clinical manifestations of Tau-linked disorders are typically limited to cognitive phenotypes or atypical parkinsonism, although few reports describe motor neuron involvement associated with MAPT (microtubule-associated protein Tau) mutations. This study aimed to investigate the contribution of MAPT to the ALS phenotype.

Role of clonal inflammatory microglia in histiocytosis-associated neurodegeneration.

Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD) are clonal myeloid disorders associated with mitogen-activated protein (MAP)-kinase-activating mutations and an increased risk of neurodegeneration. We found microglial mutant clones in LCH and ECD patients, whether or not they presented with clinical symptoms of neurodegeneration, associated with microgliosis, astrocytosis, and neuronal loss, predominantly in the rhombencephalon gray nuclei. Neurological symptoms were associated with PU.

Demyelinating neuropathy as the initial presentation of familial E200K Creutzfeldt-Jakob disease in two patients.

Objective: To describe peripheral neuropathy associated with familial Creutzfeldt-Jakob disease.

Methods: We report two unrelated patients with genetic Creutzfeldt-Jakob disease with demyelinating peripheral neuropathy as initial presentation, with a comprehensive clinical, electrophysiological and neuropathological description.

Results: Both patients exhibited gait disturbance and paresthesia.

Prospective 25-year surveillance of prion diseases in France, 1992 to 2016: a slow waning of epidemics and an increase in observed sporadic forms.

BackgroundPrion diseases are rare, fatal disorders that have repeatedly raised public health concerns since the early 1990s. An active prion disease surveillance network providing national level data was implemented in France in 1992.AimWe aimed to describe the epidemiology of sporadic, genetic and infectious forms of prion diseases in France since surveillance implementation.

Performance of clinical metagenomics in France: a prospective observational study.

Background: Metagenomic next-generation sequencing (mNGS) allows untargeted identification of a broad range of pathogens, including rare or novel microorganisms. Despite the recognition of mNGS as a valuable diagnostic tool for infections, the most relevant indications for this innovative strategy remain poorly defined. We aimed to assess the determinants of positivity and clinical utility of mNGS.

Pathogenesis and outcome of VA1 astrovirus infection in the human brain are defined by disruption of neural functions and imbalanced host immune responses.

Astroviruses (AstVs) can cause of severe infection of the central nervous system (CNS) in immunocompromised individuals. Here, we identified a human AstV of the VA1 genotype, HAstV-NIH, as the cause of fatal encephalitis in an immunocompromised adult. We investigated the cells targeted by AstV, neurophysiological changes, and host responses by analyzing gene expression, protein expression, and cellular morphology in brain tissue from three cases of AstV neurologic disease (AstV-ND).

The role of environmental factors on sporadic Creutzfeldt-Jakob disease mortality: evidence from an age-period-cohort analysis.

Sporadic Creutzfeldt-Jakob disease (sCJD) is the most common form of prion diseases. The causes of sCJD are still unknown and exogenous factors may play a role. Worldwide, the number of patients with sCJD has progressively increased over time.

Neurofilament accumulations in amyotrophic lateral sclerosis patients' motor neurons impair axonal initial segment integrity.

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron (MN) disease in adults with no curative treatment. Neurofilament (NF) level in patient' fluids have recently emerged as the prime biomarker of ALS disease progression, while NF accumulation in MNs of patients is the oldest and one of the best pathological hallmarks. However, the way NF accumulations could lead to MN degeneration remains unknown.

Ballooned neurons in semi-recent severe traumatic brain injury.

Traumatic brain injury (TBI) is now recognized as an insult triggering a dynamic process of degeneration and regeneration potentially evolving for years with chronic traumatic encephalopathy (CTE) as one major complication. Neurons are at the center of the clinical manifestations, both in the acute and chronic phases. Yet, in the acute phase, conventional neuropathology detects abnormalities predominantly in the axons, if one excludes contusions and hypoxic ischemic changes.

Prevalence, patterns and outcomes of cardiac involvement in Erdheim-Chester disease.

Aims: Cardiac involvement of Erdheim-Chester disease (ECD), a rare L group histiocytosis, has been reported to be associated with poor outcomes, but systematic studies are lacking. The present study aimed to investigate the prevalence, clinical features, imaging features, and prognosis of cardiac involvement in ECD in a large series.

Methods And Results: All patients with ECD who underwent cardiac magnetic resonance (CMR) imaging between 2003 and 2019 at a French tertiary center were retrospectively included.

Imaging Characteristics of Choroid Plexuses in Presymptomatic Multiple Sclerosis: A Retrospective Study.

Background And Objectives: Recent imaging studies have suggested a possible involvement of the choroid plexus (CP) in multiple sclerosis (MS). Here, we investigated whether CP changes are already detectable at the earliest stage of MS, preceding symptom onset.

Methods: This study is a retrospective analysis of 27 patients with presymptomatic MS, 97 patients with clinically definite MS (CDMS), and 53 healthy controls (HCs) who underwent a cross-sectional 3T-MRI acquisition; of which, 22 MS, 19 HCs, and 1 presymptomatic MS (evaluated 8 months before conversion to CDMS) also underwent translocator protein (TSPO) F-DPA-714 PET and were included in the analysis.

Neuropathology of the temporal lobe.

Neuropathological examination of the temporal lobe provides a better understanding and management of a wide spectrum of diseases. We focused on inflammatory diseases, epilepsy, and neurodegenerative diseases, and highlighted how the temporal lobe is particularly involved in those conditions. Although all these diseases are not specific or restricted to the temporal lobe, the temporal lobe is a key structure to understand their pathophysiology.

Assessing and improving the validity of COVID-19 autopsy studies - A multicentre approach to establish essential standards for immunohistochemical and ultrastructural analyses.

Background: Autopsy studies have provided valuable insights into the pathophysiology of COVID-19. Controversies remain about whether the clinical presentation is due to direct organ damage by SARS-CoV-2 or secondary effects, such as overshooting immune response. SARS-CoV-2 detection in tissues by RT-qPCR and immunohistochemistry (IHC) or electron microscopy (EM) can help answer these questions, but a comprehensive evaluation of these applications is missing.

Neurovascular dysfunction in GRN-associated frontotemporal dementia identified by single-nucleus RNA sequencing of human cerebral cortex.

Frontotemporal dementia (FTD) is the second most prevalent form of early-onset dementia, affecting predominantly frontal and temporal cerebral lobes. Heterozygous mutations in the progranulin gene (GRN) cause autosomal-dominant FTD (FTD-GRN), associated with TDP-43 inclusions, neuronal loss, axonal degeneration and gliosis, but FTD-GRN pathogenesis is largely unresolved. Here we report single-nucleus RNA sequencing of microglia, astrocytes and the neurovasculature from frontal, temporal and occipital cortical tissue from control and FTD-GRN brains.