The innate immune system in the central nervous system (CNS) is mainly represented by specialized tissue‐resident macrophages, called microglia. In the past years, various species‐, host‐ and tissue‐specific as well as environmental factors were recognized that essentially affect microglial properties and functions in the healthy and diseased brain. Host microbiota are mostly residing in the gut and

Microglia are known as the tissue‐resident macrophages of the central nervous system (CNS). Yet their unique ontogeny and distinguishing features endowed by the privileged nature of their environment have set them apart from other myeloid cells in the body. Microglia spectrum of activity enables their participation in the maintenance of homeostasis and disease processes via their interaction with CNS

Microglia, the resident innate immune cells of the central nervous system (CNS), play an important role in brain development and homeostasis, as well as in neuroinflammatory, neurodegenerative and psychiatric diseases. Studies in animal models have been used to determine the origin and development of microglia, and how these cells alter their transcriptional and phenotypic signatures during CNS pathology

Stroke, in association with its complications, is one of the leading causes of mortality and morbidity worldwide. Cerebral ischemia triggers an inflammatory response in the brain that is controlled by the activation of resident microglia as well as the infiltration of peripheral myeloid and lymphoid cells into the brain parenchyma. This inflammation has been shown to have both beneficial and detrimental

Multiple sclerosis (MS) is a disabling neuroinflammatory disease, which is little understood and lacks a sufficient therapeutic regimen. Myeloid cells have repeatedly shown to play a pivotal role in the disease progression. During homeostasis, only the CNS‐resident microglia and CNS‐associated macrophages are present in the CNS. Neuroinflammation causes peripheral immune cells to infiltrate the CNS

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS) in which inflammation plays a key pathological role. Recent evidences showed that systemic inflammation induces increasing cell infiltration within meninges and perivascular spaces in the brain parenchyma, triggering resident microglial ad astrocytic activation. The anti‐inflammatory enzyme A20, also named

Spinocerebellar ataxia type 23 (SCA23) is a late‐onset neurodegenerative disorder characterized by slowly progressive gait and limb ataxia, for which there is no therapy available. It is caused by pathogenic variants in PDYN, which encodes prodynorphin (PDYN). PDYN is processed into the opioid peptides α‐neoendorphin, and dynorphins (Dyn) A and B; inhibitory neurotransmitters that function in pain

Pediatric low‐grade gliomas were shown to be characterized by an array of distinct molecular aberrations. The recent cIMPACT‐4 consensus proposed pediatric low‐grade gliomas of the diffuse type to be characterized by distinct molecular changes rather than distinct histological features (2). Very recently, Fukuoka et al. described a small series of pediatric oligodendroglioma‐like tumors with BRAF V600E

Genetic variants in TMEM106B are a major risk factor for several neurodegenerative diseases including frontotemporal degeneration, limbic‐predominant age‐related TDP‐43 encephalopathy, Parkinson`s disease, late‐onset‐Alzheimer`s disease and constitute a genetic determinant of differential aging. TMEM106B encodes an integral lysosomal membrane protein but its precise physiological function in the central

The neurofibrillary tangles (NFT) and amyloid‐ß plaques (AP) that comprise Alzheimer’s disease (AD) neuropathology are associated with neurodegeneration and microglial activation. Activated microglia exist on a dynamic spectrum of morphologic subtypes that include resting, surveillant microglia capable of converting to activated, hypertrophic microglia closely linked to neuroinflammatory processes

The coronavirus disease 2019 (COVID‐19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). COVID‐19 symptoms are not limited to the respiratory tract, but complications have been described involving other organs including brain.

The group of CNS mesenchymal (non‐meningothelial) and primary glial/neuronal tumors in association with EWSR1 – non‐ETS rearrangements comprises a growing spectrum of entities, mostly reported in isolation with incomplete molecular profiling. Archival files from three pediatric institutions were queried for unusual cases of pediatric (≤21 years) CNS EWSR1‐rearranged tumors confirmed by at least one

Pericytes are vascular mural cells that surround capillaries of the central nervous system (CNS). They are crucial for brain development and contribute to CNS homeostasis by regulating blood–brain barrier function and cerebral blood flow. It has been suggested that pericytes are lost in Alzheimer's disease (AD), implicating this cell type in disease pathology. Here, we have employed state‐of‐the‐art

A repeat expansion in the C9orf72 gene is the most prevalent genetic cause of frontotemporal dementia (C9‐FTD). Several studies have indicated the involvement of the unfolded protein response (UPR) in C9‐FTD. In human neuropathology, UPR markers are strongly associated with granulovacuolar degeneration (GVD). In this study, we aim to assess the presence of UPR markers together with the presence of

Alzheimer’s disease (AD) is a growing global healthcare epidemic. Owing to advances in technology, genome‐scale studies of various layers of molecular information have been undertaken in recent years and robust variation in key loci have now been published and reproduced by others. This mini‐symposium highlights four key areas of current research in the field of molecular biology in AD, including articles

Alzheimer's disease (AD) is the most common neurodegenerative disease and, owing to its increasing prevalence, represents one of the leading public health problems in aging populations. The molecular causes underlying the onset and progression of AD are manifold and hitherto still incompletely understood. Research over nearly four decades has clearly delineated genetics to play a crucial role in AD

Alzheimer’s disease (AD) represents a devastating progressive neurodegenerative disease with a complex pathophysiology, affecting millions of people worldwide. Recent epigenome‐wide association studies suggest a key role for epigenetic mechanisms in its development and course. Despite the fact that current evidence on the role of epigenetic dysregulation in aging and AD is convincing, the pioneering

The past decade has seen the maturation of multiple different forms of high‐dimensional molecular profiling to the point that these methods could be deployed in initially hundreds and more recently thousands of human samples. In the field of Alzheimer's disease (AD), these profiles have been applied to the target organ: the aging brain. In a growing number of cases, the same samples were profiled with

Recent studies have highlighted a potential role of genetic and epigenetic variation in the development of Alzheimer’s disease. Application of the CRISPR‐Cas genome‐editing platform has enabled investigation of the functional impact that Alzheimer’s disease‐associated gene mutations have on gene expression. Moreover, recent advances in the technology have led to the generation of CRISPR‐Cas–based tools

Published descriptions of the neuropathological features of COVID‐19 patients have been controversial, ranging from only modest or no pathology to severe hypoxic and hemorrhagic phenotypes, thrombotic complications, acute disseminated encephalomyelitis‐like changes, and encephalitis and meningitis. Here, we describe the neuropathological findings of four COVID‐19‐positive patients autopsied at the

Loss of function mutations within the vesicular trafficking protein Ras analogy in brain 39B (RAB39B) are associated with rare X‐linked Parkinson’s disease (PD). Physiologically, RAB39B is localized to Golgi vesicles and recycling endosomes and is required for glutamatergic receptor maturation but also for alpha‐Synuclein (aSyn) homeostasis and the inhibition of its aggregation. Despite evidence linking

White matter (WM) disease is associated with disruption of the gliovascular unit, which involves breach of the blood–brain barrier (BBB). We quantified pericytes as components of the gliovascular unit and assessed their status in vascular and other common dementias. Immunohistochemical and immunofluorescent methods were developed to assess the distribution and quantification of pericytes connected

Deposition of extensively hyperphosphorylated tau in specific brain cells is a clear pathological hallmark in Alzheimer's disease and a number of other neurodegenerative disorders, collectively termed the tauopathies. Furthermore, hyperphosphorylation of tau prevents it from fulfilling its physiological role as a microtubule‐stabilizing protein and leaves it increasingly vulnerable to self‐assembly

Meningiomas are common in adults (~35% of brain tumors) but rare in children, where they exhibit unique clinical, pathological and molecular features compared to adult counterparts. Thus, data generated from adult cohorts may be imperfectly suited to guiding diagnostic, prognostic and treatment decisions for children. We studied 50 meningioma patients ≤18 years with available clinical and pathological

Epithelioid glioblastoma (E‐GBM) was recently designated as a subtype of glioblastoma (GBM) by the World Health Organization (2016). E‐GBM is an aggressive and rare variant of GBM that primarily occurs in children and young adults. Although most characterized cases of E‐GBM harbor a mutation of the BRAF gene in which valine (V) is substituted by glutamic acid (E) at amino acid 600 (BRAF‐V600E), in

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting both the upper and lower motor neurons. Although ALS typically leads to death within 3 to 5 years after initial symptom onset, approximately 10% of patients with ALS live more than 10 years after symptom onset. We set out to determine similarities and differences in clinical presentation and neuropathology in

Congenital brain tumors are rare accounting for 0.5%–1.9% of all pediatric brain tumors. While different criteria have been used to classify a tumor as congenital, those diagnosed prior to 6 months of age are considered to be “probably” congenital in origin. We performed an institutional review of all central nervous system (CNS) tumors (surgical and autopsy specimens from 1990 to 2019) in patients

Congenital central hypoventilation syndrome (CCHS) represents a rare genetic disorder usually caused by mutations in the homeodomain transcription factor PHOX2B . Some CCHS patients suffer mainly from deficiencies in CO2 and/or O2 respiratory chemoreflex, whereas other patients present with full apnea shortly after birth. Our goal was to identify the neuropathological mechanisms of apneic presentations

Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytoma predominantly affecting children and young adults. We performed comprehensive genomic characterization on a cohort of 67 patients with histologically defined PXA (n = 53, 79%) or anaplastic PXA (A‐PXA, n = 14, 21%), including copy number analysis (ThermoFisher Oncoscan, n = 67), methylation profiling (Illumina EPIC array, n = 43) and targeted

Olfactory dysfunction is one of the early symptoms seen in Parkinson’s disease (PD). However, the mechanisms underlying olfactory pathology that impacts PD disease progression and post‐mortem appearance of alpha‐synuclein (α‐Syn) inclusions in and beyond olfactory bulb in PD remain unclear. It has been suggested that environmental toxins inhaled through the nose can induce inflammation in the olfactory

The molecular biology of ependymomas is not well understood and this is particularly true for ependymoma relapses. We aimed at finding out if and to which extent, relapses differ from their corresponding primary tumors on the morphological, chromosomal and epigenetic level. We investigated 24 matched ependymoma primary and relapsed tumor samples and, as a first step, compared cell density, necrosis

Zika virus (ZIKV) is a flavivirus that can cause neuropathogenesis in adults and fetal neurologic malformation following the infection of pregnant women. We used a nonhuman primate model, the Indian‐origin Rhesus macaque (IRM), to gain insight into virus‐associated hallmarks of ZIKV‐induced adult neuropathology. We find that the virus causes prevalent acute and chronic neuroinflammation and chronic

SAFB1 is a DNA and RNA binding protein that is highly expressed in the cerebellum and hippocampus and is involved in the processing of coding and non‐coding RNAs, splicing and dendritic function. We analyzed SAFB1 expression in the post‐mortem brain tissue of spinocerebellar ataxia (SCA), Huntington’s disease (HD), Multiple sclerosis (MS), Parkinson’s disease patients and controls. In SCA cases, the

Tuberous sclerosis complex (TSC) is a rare hereditary disease, which results from the mutation of either TSC1 or TSC2 , and its clinical features include benign tumors and dysfunctions in numerous organs, including the brain. Many individuals with TSC manifest neuropsychiatric symptoms, such as learning impairments, cognitive deficits and anxiety. Current pharmacological treatment for TSC is the use

Aggregation of the protein α‐synuclein (α‐syn) into insoluble intracellular assemblies termed Lewy bodies (LBs) is thought to be a critical pathogenic event in LB diseases such as Parkinson’s disease and dementia with LBs. In LB diseases, the majority of α‐syn is phosphorylated at serine 129 (pS129), suggesting that this is an important disease‐related post‐translational modification (PTM). However

cIMPACT‐NOW (the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy) was established to evaluate and make practical recommendations on recent advances in the field of CNS tumor classification, particularly in light of the rapid progress in molecular insights into these neoplasms. For Round 2 of its deliberations, cIMPACT‐NOW Working Committee 3 was reconstituted and convened

Biotin is an essential cofactor for carboxylases that regulates the energy metabolism. Recently, high‐dose pharmaceutical‐grade biotin (MD1003) was shown to improve clinical parameters in a subset of patients with chronic progressive multiple sclerosis. To gain insight into the mechanisms of action, we investigated the efficacy of high‐dose biotin in a genetic model of chronic axonopathy caused by

Advances in our understanding of the biological basis and molecular characteristics of ependymal tumors since the latest iteration of the World Health Organization (WHO) classification of CNS tumors (2016) have prompted the cIMPACT‐NOW group to recommend a new classification. Separation of ependymal tumors by anatomic site is an important principle of the new classification and was prompted by methylome

Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy characterized by accumulation of hyperphosphorylated tau (p‐tau) in perivascular aggregates in neurons and glia at the depths of neocortical sulci and progresses to diffuse neocortical, allocortical and brainstem structures. The strongest risk factor is exposure to repetitive head impacts acquired most commonly through contact

Emerging evidence from multiple studies indicates that Parkinson’s disease (PD) patients suffer from a spectrum of autonomic and respiratory motor deficiencies in addition to the classical motor symptoms attributed to substantia nigra degeneration of dopaminergic neurons. Animal models of PD show a decrease in the resting respiratory rate as well as a decrease in the number of Phox2b‐expressing retrotrapezoid

Traumatic brain injury (TBI) is associated with the pathological activation of immune‐competent cells in the brain, such as astrocytes, microglia and infiltrating immune blood cells, resulting in chronic inflammation and gliosis. This may contribute to the secondary injury after TBI, thus understanding of these processes is crucial for the development of effective treatments of post‐traumatic pathologies

Altered autophagy accompanied by abnormal autophagic (rimmed) vacuoles detectable by light and electron microscopy is a common denominator of many familial and sporadic non‐inflammatory muscle diseases. Even in the era of next generation sequencing (NGS), late‐onset vacuolar myopathies remain a diagnostic challenge. We identified 32 adult vacuolar myopathy patients from 30 unrelated families, studied

In this paper (1), the author name You Jing has been corrected to be listed as Jing You. Therefore, the correct author list should be: Wenbo He, Jing You, Qianfen Wan, Ke Xiao, Kening Chen, Yuan Lu, Liang Li, Yajie Tang, Yunte Deng, Zhaohui Yao, Junqiu Yue, Gang Cao.

Medulloblastoma (MB) is the most common CNS embryonal tumor. While the overall cure rate is around 70%, patients with high-risk disease continue to have poor outcome and experience long-term morbidity. MB is among the tumors for which diagnosis, risk stratification, and clinical management has shown the most rapid advancement. These advances are largely due to technological improvements in diagnosis

In this mini‐symposium, four review articles describe recent advances in our understanding of the pathobiology of medulloblastoma. Medulloblastoma is the commonest malignant brain tumor of childhood and has been the subject of intense scientific investigation over several decades.

Aims: Edema of the limbs is uncommon in idiopathic inflammatory myopathies (IIM). The few reported cases have been associated with severe and refractory dermatomyositis (DM), sometimes in association with cancers. We aimed to determine if edematous myositis is a homogeneous subtype based on clinical, serological and pathological features. Methods: This is a retrospective observational study performed

Granular/fuzzy astrocytes (GFAs), a subtype of “aging‐related tau astrogliopathy,” are noted in cases bearing various neurodegenerative diseases. However, the pathogenic significance of GFAs remains unclear. We immunohistochemically examined the frontal cortex, caudate nucleus, putamen and amygdala in 105 cases composed of argyrophilic grain disease cases (AGD, N = 26), and progressive supranuclear

Once people with multiple sclerosis enter the progressive clinical phenotype of their disease, they often develop a syndrome resembling chronic myelopathy dominated by deteriorating spastic paraparesis, bladder, sexual and bowel dysfunction and lower limb sensory loss (10). Nevertheless, MS pathology in the spinal cord is significantly less well studied than in the brain, perhaps in part, due to the

Triggering receptor expressed on myeloid cells 2 TREM2 was identified as a risk factor for late onset Alzheimer’s disease (AD). Here we compared TREM2 cases with a variant (TREM2+) and cases without a TREM2 variant (TREM2− ), considering pathological burden, inflammatory response and altered canonical pathways and biochemical functions between the cohorts. We hypothesised that TREM2+ cases would have

Increased inflammation in the cerebral meninges is associated with extensive subpial cortical grey matter pathology in the forebrain and a more severe disease course in a substantial proportion of secondary progressive multiple sclerosis (SPMS) cases. It is not known whether this relationship extends to spinal cord pathology. We assessed the contribution of meningeal and parenchymal immune infiltrates

Background: Abnormal aggregates of α‐synuclein are pathologic hallmarks of multiple system atrophy (MSA) and Lewy body disease (LBD). LBD sometimes coexists with MSA, but the impact of co‐pathology, particularly diffuse LBD, on presentation of MSA has not been studied. We aimed to determine the frequency and clinicopathologic features of MSA with LBD (MSA+LBD). Methods: Using hematoxylin & eosin and

Microvascular endothelial cell (EC) injury and the subsequent blood‐brain barrier (BBB) breakdown are frequently seen in many neurological disorders, including stroke. We have previously documented that peroxisome proliferator‐activated receptor gamma (PPARγ)‐mediated cerebral protection during ischemic insults needs Krüppel‐like factor 11 (KLF11) as a critical coactivator. However, the role of endothelial

Of the four primary subgroups of medulloblastoma, the most frequent cytogenetic abnormality, i17q, distinguishes Groups 3 and 4 which carry the highest mortality; haploinsufficiency of 17p13.3 is a marker for particularly poor prognosis. At the terminal end of this locus lies miR‐1253, a brain‐enriched microRNA that regulates bone morphogenic proteins during cerebellar development. We hypothesized