In Vivo Assessment of Astrocyte Reactivity in Patients with Progressive Supranuclear Palsy

OBJECTIVE

Although astrocytic pathology is a pathological hallmark of progressive supranuclear palsy (PSP), its pathophysiological role remains unclear. This study aimed to assess astrocyte reactivity in vivo in patients with PSP. Furthermore, we investigated alterations in brain lactate levels and their relationship with astrocyte reactivity.

METHODS

We included 30 patients with PSP-Richardson syndrome and 30 healthy controls; in patients, tau deposition was confirmed through 18F-florzolotau positron emission tomography. Myo-inositol, an astroglial marker, and lactate were quantified in the anterior cingulate cortex through magnetic resonance spectroscopy. We measured plasma biomarkers, including glial fibrillary acidic protein as another astrocytic marker. The anterior cingulate cortex was histologically assessed in postmortem samples of another 3 patients with PSP with comparable disease durations.

RESULTS

The levels of myo-inositol and plasma glial fibrillary acidic protein were significantly higher in patients than those in healthy controls (p < 0.05); these increases were significantly associated with PSP rating scale and cognitive function scores (p < 0.05). The lactate level was high in patients, and correlated significantly with high myo-inositol levels. Histological analysis of the anterior cingulate cortex in patients revealed reactive astrocytes, despite mild tau deposition, and no marked synaptic loss.

INTERPRETATION

We discovered high levels of astrocyte biomarkers in patients with PSP, suggesting astrocyte reactivity. The association between myo-inositol and lactate levels suggests a link between reactive astrocytes and brain energy metabolism changes. Our results indicate that astrocyte reactivity in the anterior cingulate cortex precedes pronounced tau pathology and neurodegenerative processes in that region, and affects brain function in PSP. ANN NEUROL 2024.

Pharmacological evaluation of E2730, a novel selective uncompetitive GAT1 inhibitor, on epileptiform activities in resected brain tissues from human focal cortical dysplasia ex vivo

Focal cortical dysplasia (FCD) is an important etiology of focal epilepsy in children and adults. However, only a few preclinical models sufficiently reproduce the characteristic histopathologic features of FCD. To improve the success rate of clinical trials for antiseizure medications (ASMs) in patients with FCD, more human-relevant preclinical models are needed, and epileptic foci resected from patients are a powerful tool for this purpose. Here, we conducted ex vivo studies using epileptic foci resected from patients with FCD type II to evaluate the pharmacologic effects of the ASM candidate E2730, a selective uncompetitive inhibitor of γ-aminobutyric acid transporter 1. We used the same ex vivo assay system to assess carbamazepine (CBZ), an ASM often prescribed for focal epilepsy, as a reference. At the higher dose tested (200 µM), both E2730 and CBZ suppressed spontaneous epileptiform activities almost completely. At the lower dose (100 µM), CBZ reduced the area of brain tissue showing epileptiform activity, whereas E2730 significantly decreased the number of epileptiforms. These findings suggest that E2730-both as a single agent and in combination with CBZ-merits evaluation in clinical trials involving patients with FCD.

Stage-dependent immunity orchestrates AQP4 antibody-guided NMOSD pathology: a role for netting neutrophils with resident memory T cells in situ

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the CNS characterized by the production of disease-specific autoantibodies against aquaporin-4 (AQP4) water channels. Animal model studies suggest that anti-AQP4 antibodies cause a loss of AQP4-expressing astrocytes, primarily via complement-dependent cytotoxicity. Nonetheless, several aspects of the disease remain unclear, including: how anti-AQP4 antibodies cross the blood-brain barrier from the periphery to the CNS; how NMOSD expands into longitudinally extensive transverse myelitis or optic neuritis; how multiphasic courses occur; and how to prevent attacks without depleting circulating anti-AQP4 antibodies, especially when employing B-cell-depleting therapies. To address these knowledge gaps, we conducted a comprehensive 'stage-dependent' investigation of immune cell elements in situ in human NMOSD lesions, based on neuropathological techniques for autopsied/biopsied CNS materials. The present study provided three major findings. First, activated or netting neutrophils and melanoma cell adhesion molecule-positive (MCAM+) helper T (TH) 17/cytotoxic T (TC) 17 cells are prominent, and the numbers of these correlate with the size of NMOSD lesions in the initial or early-active stages. Second, forkhead box P3-positive (FOXP3+) regulatory T (Treg) cells are recruited to NMOSD lesions during the initial, early-active or late-active stages, suggesting rapid suppression of proinflammatory autoimmune events in the active stages of NMOSD. Third, compartmentalized resident memory immune cells, including CD103+ tissue-resident memory T (TRM) cells with long-lasting inflammatory potential, are detected under "standby" conditions in all stages. Furthermore, CD103+ TRM cells express high levels of granzyme B/perforin-1 in the initial or early-active stages of NMOSD in situ. We infer that stage-dependent compartmentalized immune traits orchestrate the pathology of anti-AQP4 antibody-guided NMOSD in situ. Our work further suggests that targeting activated/netting neutrophils, MCAM+ TH17/TC17 cells, and CD103+ TRM cells, as well as promoting the expansion of FOXP3+ Treg cells, may be effective in treating and preventing relapses of NMOSD.

Acute respiratory failure caused by brainstem demyelinating lesions in an older patient with an atypical relapsing autoimmune disorder

An 84-year-old man presented with somnolence, dysphagia, and right hemiplegia, all occurring within a month, approximately one year after initial admission due to subacute, transient cognitive decline suggestive of acute disseminated encephalomyelitis involving the cerebral white matter. Serial magnetic resonance imaging (MRI) studies over that period revealed three high-intensity signal lesions on fluid-attenuated inversion recovery images, appearing in chronological order in the left upper and left lower medulla oblongata and left pontine base. Despite some clinical improvement following methylprednisolone pulse therapy, the patient died of respiratory failure. Autopsy revealed four fresh, well-defined lesions in the brainstem, three of which corresponded to the lesions detected radiologically. The remaining lesion was located in the dorsal medulla oblongata and involved the right solitary nucleus. This might have appeared at a later disease stage, eventually causing respiratory failure. Histologically, all four lesions showed loss of myelin, preservation of axons, and infiltration of lymphocytes, predominantly CD8-positive T cells, consistent with the histological features of autoimmune demyelinating diseases, particularly the confluent demyelination observed in the early and acute phases of multiple sclerosis (MS). In the cerebral white matter, autoimmune demyelination appeared superimposed on ischemic changes, consistent with the cerebrospinal fluid (CSF) and MRI findings on initial admission. No anti-AQP4 or MOG antibodies or those potentially causing autoimmune encephalitis/demyelination were detected in either the serum or CSF. Despite several similarities to MS, such as the relapsing-remitting disease course and lesion histology, the entire clinicopathological picture in the present patient, especially the advanced age at onset and development of brainstem lesions in close proximity within a short time frame, did not fit those of MS or other autoimmune diseases that are currently established. The present results suggest that exceptionally older individuals can be affected by an as yet unknown inflammatory demyelinating disease of the CNS.

Recent advances in liquid biopsy of central nervous system lymphomas: case presentations and review of the literature

Surgical biopsy is the gold standard for diagnosing central nervous system (CNS) lymphomas. However, reliable liquid biopsy methods for diagnosing CNS lymphomas have quickly developed and have been implicated in clinical decision-making. In the current report, we introduce two patients for whom liquid biopsy was essential for diagnosing CNS lymphomas and discuss the rapidly growing applications of this technology.

Availability of individual proteins for quantitative analysis in postmortem brains preserved in two different brain banks

AIM

Postmortem brain research is necessary for elucidating the pathology of schizophrenia; an increasing number of studies require a combination of suitable tissue samples preserved at multiple brain banks. In this study, we examined whether a comparative study of protein expression levels can be conducted using postmortem brain samples preserved in different facilities.

METHODS

We compared the demographic factors of postmortem brain samples preserved in two institutions and measured and compared the expression levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glial fibrillary acidic protein (GFAP) in the prefrontal cortex and superior temporal gyrus. GAPDH is generally used as a loading control for western blotting, and GFAP is considered as an astrocyte marker in the brain.

RESULTS

We found significant differences between the two institutions in postmortem interval, age at death, and preservation time. To reduce the effects of these differences on our measurements, the parameters were set as covariates in our analyses of covariance. Subsequently, no differences in GAPDH and GFAP expression were found between institutions.

CONCLUSIONS

When studies are conducted using brain samples preserved in different brain banks, differences in demographic factors should be carefully considered and taken into account by statistical methods to minimize their impact as much as possible. Since there was no significant difference in the protein expression levels of GAPDH and GFAP in either region between the two institutions that preserved the postmortem brains, we concluded that it is possible to perform protein quantitative analysis assuming that there is no effect of difference between two institutions.

Successful Multimodal Treatment of Intracranial Growing Teratoma Syndrome with Malignant Features

Molecular analysis of the growing teratoma syndrome has not been extensively studied. Here, we report a 14-year-old boy with a growing mass during treatment for a mixed germ cell tumor of the pineal region. Tumor markers were negative; thus, growing teratoma syndrome was suspected. A radical resection via the occipital transtentorial approach was performed, and histopathological examination revealed a teratoma with malignant features. Methylation classifier analysis confirmed the diagnosis of teratoma, and DMRT1 loss and 12p gain were identified by copy number variation analysis, potentially elucidating the cause of growth and malignant transformation of the teratoma. The patient remains in remission after intense chemoradiation treatment as a high-risk germ cell tumor.

A novel PET probe to selectively image heat shock protein 90α/β isoforms in the brain

BACKGROUND

Heat shock proteins (HSPs) are present throughout the brain. They function as molecular chaperones, meaning they help with the folding and unfolding of large protein complexes. These chaperones are vital in the development of neuropathological conditions such as Alzheimer's disease and Lewy body disease, with HSP90, a specific subtype of HSP, playing a key role. Many studies have shown that drugs that inhibit HSP90 activity have beneficial effects in the neurodegenerative diseases. Therefore, HSP90 PET imaging ligand can be used effectively to study HSP90 in neurodegenerative diseases. Among four HSP90 isoforms, two cytosolic isoforms (HSP90α and HSP90β) thought to be involved in the structural homeostasis of the proteins related to the neurodegenerative diseases. Currently, no useful PET imaging ligands selectively targeting the two cytosolic isoforms of HSP90 have been available yet.

RESULTS

In this study, we developed a novel positron emission tomography (PET) imaging ligand, [11C]BIIB021, by 11C-radiolabeling (a positron emitter with a half-life of 20.4 min) 6-Chloro-9-[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]-9H-purin-2-amine (BIIB021), an inhibitor with a high affinity for and selectivity to HSP90α and HSP90β. [11C]BIIB021 was synthesized with a high yield, molar activity and radiochemical purity. [11C]BIIB021 showed a high binding affinity for rat brain homogenate as well as human recombinant HSP90α and HSP90β proteins. Radioactivity was well detected in the rat brain (SUV 1.4). It showed clear specific binding in PET imaging of healthy rats and autoradiography of healthy rat and human brain sections. Radiometabolite was detected in the brain, however, total distribution volume was well quantified using dual-input graphical model. Inhibition of p-glycoprotein increased brain radioactivity concentrations. However, total distribution volume values with and without p-glycoprotein inhibition were nearly the same.

CONCLUSIONS

We have developed a new PET imaging agent, [11C]BIIB021, specifically targeting HSP90α/β. We have been successful in synthesizing [11C]BIIB021 and in vitro and in vivo imaging HSP90α/β. However, the quantification of HSP90α/β is complicated by the presence of radiometabolites in the brain and the potential to be a substrate for p-glycoprotein. Further efforts are needed to develop radioligand suitable for imaging of HSP90α/β.

Marked alteration of phosphoinositide signaling-associated molecules in postmortem prefrontal cortex with bipolar disorder

AIM

The etiology of bipolar disorder (BD) remains unknown; however, lipid abnormalities in BD have received increasing attention in recent years. In this study, we examined the expression levels of enzyme proteins associated with the metabolic pathway of phosphoinositides (PIs) and their downstream effectors, protein kinase B (Akt1) and glycogen synthase kinase 3β (GSK3β), which have been assumed to be the targets of mood stabilizers such as lithium, in the postmortem brains of patients with BD.

METHODS

The protein expression levels of phosphatidylinositol 4-phosphate 5-kinase type-1 gamma (PIP5K1C), phosphatidylinositol 4-kinase alpha (PIK4CA), phosphatase and tensin homolog deleted from chromosome 10 (PTEN), Akt1, and GSK3β were measured using enzyme-linked immunosorbent assays and multiplex fluorescent bead-based immunoassays in the prefrontal cortex (PFC). Specifically, PTEN, Akt1, GSK3β, and PIP5K1C were measured in seven BD patients and 48 controls. Additionally, PIK4CA was analyzed in 10 cases and 34 controls.

RESULTS

PTEN expression levels were markedly decreased in the PFCs of patients with BD, whereas those of Akt and GSK3β were prominently elevated. Moreover, patients medicated with lithium exhibited higher Akt1 expression levels and lower PTEN expression levels in comparison with the untreated group.

CONCLUSION

Our results suggest that the expression levels of Akt1/GSK3β and its upstream regulator PTEN are considerably altered.

Polygenic effects on the risk of Alzheimer's disease in the Japanese population

BACKGROUND

Polygenic effects have been proposed to account for some disease phenotypes; these effects are calculated as a polygenic risk score (PRS). This score is correlated with Alzheimer's disease (AD)-related phenotypes, such as biomarker abnormalities and brain atrophy, and is associated with conversion from mild cognitive impairment (MCI) to AD. However, the AD PRS has been examined mainly in Europeans, and owing to differences in genetic structure and lifestyle, it is unclear whether the same relationships between the PRS and AD-related phenotypes exist in non-European populations. In this study, we calculated and evaluated the AD PRS in Japanese individuals using genome-wide association study (GWAS) statistics from Europeans.

METHODS

In this study, we calculated the AD PRS in 504 Japanese participants (145 cognitively unimpaired (CU) participants, 220 participants with late mild cognitive impairment (MCI), and 139 patients with mild AD dementia) enrolled in the Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI) project. In order to evaluate the clinical value of this score, we (1) determined the polygenic effects on AD in the J-ADNI and validated it using two independent cohorts (a Japanese neuropathology (NP) cohort (n = 565) and the North American ADNI (NA-ADNI) cohort (n = 617)), (2) examined the AD-related phenotypes associated with the PRS, and (3) tested whether the PRS helps predict the conversion of MCI to AD.

RESULTS

The PRS using 131 SNPs had an effect independent of APOE. The PRS differentiated between CU participants and AD patients with an area under the curve (AUC) of 0.755 when combined with the APOE variants. Similar AUC was obtained when PRS calculated by the NP and NA-ADNI cohorts was applied. In MCI patients, the PRS was associated with cerebrospinal fluid phosphorylated-tau levels (β estimate = 0.235, p value = 0.026). MCI with a high PRS showed a significantly increased conversion to AD in APOE ε4 noncarriers with a hazard rate of 2.22. In addition, we also developed a PRS model adjusted for LD and observed similar results.

CONCLUSIONS

We showed that the AD PRS is useful in the Japanese population, whose genetic structure is different from that of the European population. These findings suggest that the polygenicity of AD is partially common across ethnic differences.

Identification of region-specific gene isoforms in the human brain using long-read transcriptome sequencing

In neurological and neuropsychiatric diseases, different brain regions are affected, and differences in gene expression patterns could potentially explain this mechanism. However, limited studies have precisely explored gene expression in different regions of the human brain. In this study, we performed long-read RNA sequencing on three different brain regions of the same individuals: the cerebellum, hypothalamus, and temporal cortex. Despite stringent filtering criteria excluding isoforms predicted to be artifacts, over half of the isoforms expressed in multiple samples across multiple regions were found to be unregistered in the GENCODE reference. We then especially focused on genes with different major isoforms in each brain region, even with similar overall expression levels, and identified that many of such genes including GAS7 might have distinct roles in dendritic spine and neuronal formation in each region. We also found that DNA methylation might, in part, drive different isoform expressions in different regions. These findings highlight the significance of analyzing isoforms expressed in disease-relevant sites.

Missense mutation of NRAS is associated with malignant progression in neurocutaneous melanosis

Neurocutaneous melanosis (NCM) is a rare congenital neurocutaneous syndrome characterized by congenital melanocytic nevus of skin and abnormal proliferation of leptomeningeal melanocytes. Early acquisition of post-zygotic somatic mutations has been postulated to underlie the pathogenesis of NCM. The pathogenesis of NCM remains to be fully elucidated, and treatment options have not been established. Here, we report for the first time, multiregional genomic analyses in a 3-year-old autopsied girl with leptomeningeal melanomatosis associated with NCM, in which a ventriculo-peritoneal (VP) shunt was inserted for the treatment of hydrocephalus. The patient expired six months after the onset due to respiratory failure caused by abdominal dissemination via VP shunt. We performed multiregional exome sequencing to identify genomic differences among brain and abdominal tumors, nevus, and normal tissues. A total of 87 somatic mutations were found in 71 genes, with a significantly large number of gene mutations found in the tumor site. The genetic alterations detected in the nevus were only few and not shared with other sites. Three mutations, namely GNAQ R183Q, S1PR3 G89S and NRAS G12V, considered pathogenic, were found, although S1PR3 mutations have not been previously reported in melanocytic tumors. GNAQ and S1PR3 mutations were shared in both tumor and normal sites. Moreover, the mutant allele frequencies of the two mutations were markedly higher in tumor sites than in normal sites, with copy-neutral loss-of-heterozygosity (CN-LOH) occurring in tumor. NRAS mutation was found only in the abdominal tumor and was thought to be responsible for malignant progression in the present case. Multiregional comprehensive genetic analysis may lead to discovering novel driver mutations associated with tumorigenesis and targeted therapy.

Elevation of inositol pyrophosphate IP7 in the mammalian spinal cord of amyotrophic lateral sclerosis

Background

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder associated with progressive impairment of spinal motor neurons. Continuous research endeavor is underway to fully understand the molecular mechanisms associating with this disorder. Although several studies have implied the involvement of inositol pyrophosphate IP7 in ALS, there is no direct experimental evidence proving this notion. In this study, we analyzed inositol pyrophosphate IP7 and its precursor IP6 in the mouse and human ALS biological samples to directly assess whether IP7 level and/or its metabolism are altered in ALS disease state.

Methods

We used a liquid chromatography-mass spectrometry (LC-MS) protocol originally-designed for mammalian IP6 and IP7 analysis. We measured the abundance of these molecules in the central nervous system (CNS) of ALS mouse model SOD1(G93A) transgenic (TG) mice as well as postmortem spinal cord of ALS patients. Cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMCs) from ALS patients were also analyzed to assess if IP7 status in these biofluids is associated with ALS disease state.

Results

SOD1(G93A) TG mice showed significant increase of IP7 level in the spinal cord compared with control mice at the late stage of disease progression, while its level in cerebrum and cerebellum remains constant. We also observed significantly elevated IP7 level and its product-to-precursor ratio (IP7/IP6) in the postmortem spinal cord of ALS patients, suggesting enhanced enzymatic activity of IP7-synthesizing kinases in the human ALS spinal cord. In contrast, human CSF did not contain detectable level of IP6 and IP7, and neither the IP7 level nor the IP7/IP6 ratio in human PBMCs differentiated ALS patients from age-matched healthy individuals.

Conclusion

By directly analyzing IP7 in the CNS of ALS mice and humans, the findings of this study provide direct evidence that IP7 level and/or the enzymatic activity of IP7-generating kinases IP6Ks are elevated in ALS spinal cord. On the other hand, this study also showed that IP7 is not suitable for biofluid-based ALS diagnosis. Further investigation is required to elucidate a role of IP7 in ALS pathology and utilize IP7 metabolism on the diagnostic application of ALS.

Multi-omics analyses of choroid plexus carcinoma cell lines reveal potential targetable pathways and alterations

PURPOSE

Choroid plexus carcinomas (CPCs) are extremely rare brain tumors and carry a dismal prognosis. Treatment options are limited and there is an urgent need to develop models to further research. In the present study, we established two CPC cell lines and performed multi-omics analyses. These cell lines serve as valuable models to propose new treatments in these rare but deadly brain tumors.

METHODS

Multi-omic profiling including, (i) methylation array (EPIC 850 K), (ii) whole genome sequencing (WGS), (iii) CANCERPLEX cancer genome panel testing, (iv) RNA sequencing (RNA-seq), and (v) proteomics analyses were performed in CCHE-45 and NGT131 cell lines.

RESULTS

Both cell lines were classified as methylation class B. Both harbored pathogenic TP53 point mutations; CCHE-45 additionally displayed TP53 loss. Furthermore, alterations of the NOTCH and WNT pathways were also detected in both cell lines. Two protein-coding gene fusions, BZW2-URGCP, and CTTNBP2-ERBB4, mutations of two oncodrivers, GBP-4 and KRTAP-12-2, and several copy number alterations were observed in CCHE-45, but not NGT131. Transcriptome and proteome analysis identified shared and unique signatures, suggesting that variability in choroid plexus carcinoma tumors may exist. The discovered difference's importance and implications highlight the possible diversity of choroid plexus carcinoma and call for additional research to fully understand disease pathogenesis.

CONCLUSION

Multi-omics analyses revealed that the two choroid plexus carcinoma cell lines shared TP53 mutations and other common pathway alterations and activation of NOTCH and WNT pathways. Noticeable differences were also observed. These cell lines can serve as valuable models to propose new treatments in these rare but deadly brain tumors.

Reliable detection of genetic alterations in cyst fluid DNA for the diagnosis of brain tumors

PURPOSE

Liquid biopsy of cyst fluid in brain tumors has not been extensively studied to date. The present study was performed to see whether diagnostic genetic alterations found in brain tumor tissue DNA could also be detected in cell-free DNA (cfDNA) of cyst fluid in cystic brain tumors.

METHODS

Cyst fluid was obtained from 22 patients undergoing surgery for a cystic brain tumor with confirmed genetic alterations in tumor DNA. Pathological diagnoses based on WHO 2021 classification and diagnostic alterations in the tumor DNA, such as IDH1 R132H and TERT promoter mutation for oligodendrogliomas, were detected by Sanger sequencing. The same alterations were analyzed by both droplet digital PCR (ddPCR) and Sanger sequencing in cyst fluid cfDNA. Additionally, multiplex ligation-dependent probe amplification (MLPA) assays were performed to assess 1p/19q status, presence of CDKN2A loss, PTEN loss and EGFR amplification, to assess whether differentiating between astrocytomas and oligodendrogliomas and grading is possible from cyst fluid cfDNA.

RESULTS

Twenty-five genetic alterations were found in 22 tumor samples. All (100%) alterations were detected in cyst fluid cfDNA by ddPCR. Twenty of the 25 (80%) alterations were also detected by Sanger sequencing of cyst fluid cfDNA. Variant allele frequency (VAF) in cyst fluid cfDNA was comparable to that of tumor DNA (R = 0.62, Pearson's correlation). MLPA was feasible in 11 out of 17 (65%) diffuse gliomas, with close correlation of results between tumor DNA and cyst fluid cfDNA.

CONCLUSION

Cell-free DNA obtained from cyst fluid in cystic brain tumors is a reliable alternative to tumor DNA when diagnosing brain tumors.

Tau filaments from amyotrophic lateral sclerosis/parkinsonism-dementia complex adopt the CTE fold

The amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) of the island of Guam and the Kii peninsula of Japan is a fatal neurodegenerative disease of unknown cause that is characterized by the presence of abundant filamentous tau inclusions in brains and spinal cords. Here, we used electron cryo-microscopy to determine the structures of tau filaments from the cerebral cortex of three cases of ALS/PDC from Guam and eight cases from Kii, as well as from the spinal cord of two of the Guam cases. Tau filaments had the chronic traumatic encephalopathy (CTE) fold, with variable amounts of Type I and Type II filaments. Paired helical tau filaments were also found in three Kii cases and tau filaments with the corticobasal degeneration fold in one Kii case. We identified a new Type III CTE tau filament, where protofilaments pack against each other in an antiparallel fashion. ALS/PDC is the third known tauopathy with CTE-type filaments and abundant tau inclusions in cortical layers II/III, the others being CTE and subacute sclerosing panencephalitis. Because these tauopathies are believed to have environmental causes, our findings support the hypothesis that ALS/PDC is caused by exogenous factors.

V180I genetic Creutzfeldt-Jakob disease: Severe degeneration of the inferior olivary nucleus in an autopsied patient with identification of the M2T prion strain

Genetic Creutzfeldt-Jakob disease (gCJD) with a V180I mutation (V180I gCJD) is the most common type of gCJD in Japan, characterized by an older age at onset, slower progression, and moderate to severe cortical degeneration with spongiform changes and sparing of the brainstem and cerebellum. Degeneration of the inferior olivary nucleus (IO) is rarely observed in patients with CJD but is known to occur in fatal familial insomnia (FFI) and MM2-thalamic-type sporadic CJD (sCJD-MM2T) involving type 2 prion protein (M2T prion). Here we report on an 81-year-old Japanese woman who initially developed depressive symptoms followed by progressive cognitive impairment, myoclonus, and hallucinations and died after a clinical course of 23 months. Insomnia was not evident. Genetic analysis of the prion protein (PrP) identified a V180I mutation with methionine/valine heterozygosity at codon 129. Pathologic analysis demonstrated extensive spongiform degeneration, neuronal loss in the cortices, and weak synaptic-type PrP deposition. Except for IO degeneration, the clinicopathologic features and Western blotting PrP band pattern were compatible with those of previously reported V180I gCJD cases. Quantitative analysis revealed that the neuronal density of the IO, especially in the dorsal area, was considerably reduced to the same extent as that of a patient with sCJD-MM2T but preserved in other patients with V180I gCJD and sCJD-MM1 (this patient, 2.3 ± 0.53/mm2 ; a patient with sCJD-MM2T, 4.2 ± 2; a patient with V180I gCJD, 60.5 ± 9.3; and a patient with sCJD-MM1, 84.5 ± 17.9). Use of the protein misfolding cyclic amplification (PMCA) method confirmed the presence of the M2T prion strain, suggesting that the latter might be associated with IO degeneration in V180I gCJD. Autopsy studies are necessary to better understand the nature of CJD, since even if patients present with the common clinical picture, pathologic analysis might provide new insights, as was the case here.

[Case of hereditary Y69H (p.Y89H) transthyretin variant leptomeningeal amyloidosis presenting with drop attacks and recurrent transient language disorder]

We report a 73-year-old woman who started developing recurrent transient aphasia at the age of 66 years. During the attacks, she was aware she could not understand what was being said and both her spoken and written speech were meaningless. The attacks usually lasted for a few days, following which she could explain what had happened. Anti-epileptics did not improve her symptoms. She also noticed tremor of her right hand and gait disturbance at the age of 71 years. The recurrent transient aphasia was followed by drop attacks. At the time of her admission to our hospital, she showed paraplegia, phonological paraphasia, and difficulty in understanding complex sentences. Her language disturbance resembled a logopenic variant of primary progressive aphasia. However, the symptoms fluctuated for a few days and subsequently improved. Electroencephalography showed no abnormalities. Gadolinium-enhanced brain and spinal MRI showed diffuse leptomeningeal enhancement over the surface of the spinal cord, brain stem, and cerebrum on T1-weighed imaging. Surgical biopsy of a varicose vein in the subarachnoid space at the level of the Th11 spinal cord was performed. Pathological evaluation of the biopsied specimens revealed TTR-immunolabeled amyloid deposits in the subarachnoid vessel walls and on the arachnoid membrane. Gene analysis revealed c.265T>C, p.Y89H (Y69H) TTR mutation, which is known as one of the causative mutations of familial leptomeningeal amyloidosis. Leptomeningeal forms of transthyretin amyloidosis might present transient focal neurological episodes.

Clinical, imaging, and molecular features of radiation-induced glioblastomas developing more than 20 years after radiation therapy for intracranial germinomatous germ cell tumor: illustrative cases

BACKGROUND

Germinomatous germ cell tumor is highly sensitive to chemoradiotherapy; patients are expected to survive for decades. Many radiation-induced malignant gliomas (RIMGs) occur >10 years after radiotherapy. Standard therapy for RIMGs has not been established because of the lesion's rarity, the patient's shorter survival period, and the risk of radiation necrosis by repeat radiation.

OBSERVATIONS

Two patients, a 32-year-old man and a 50-year-old man, developed glioblastomas more than 20 years after radiation monotherapy for germinoma with or without mature teratoma. The first patient showed a tumor in the left frontotemporal region with disseminated lesions and died 2 months after partial resection of the tumor without responding to the chemotherapy with temozolomide and bevacizumab. Methylation classifier analysis classified the pathology as closest to diffuse pediatric-type high-grade glioma, Rtk1 subtype. The second patient showed a tumor mass in the brainstem and left cerebellar peduncle, which worsened progressively during chemotherapy with temozolomide and bevacizumab. The tumor transiently responded to stereotactic radiotherapy with the CyberKnife. However, the patient died of RIMG recurrence-related aspiration pneumonia 11 months after the biopsy. Methylation classifier analysis classified the pathology as closest to infratentorial pilocytic astrocytoma.

LESSONS

Chemoradiotherapy may improve the survival of patients with RIMGs. Furthermore, molecular features may influence the clinical, locoregional, and pathological features of RIMG.

Progressive conus medullaris lesions are suggestive of intravascular large B-cell lymphoma

BACKGROUND AND PURPOSE

Spinal cord lesions are observed in 40% of all central nervous system lesions in intravascular large B-cell lymphoma (IVLBCL). However, because IVLBCL is a very rare disease, its clinical features are not well defined, which may delay appropriate diagnosis and treatment, whilst the acute to subacute course of brain lesions in patients with IVLBCL is well established. Therefore, this study aimed to clarify the clinical features of spinal cord lesions in patients with IVLBCL.

METHODS

The medical records of patients with IVLBCL admitted to our hospital between 2010 and 2020 were searched. The inclusion criteria were preceding neurological symptoms without non-neurological symptoms and pathologically confirmed IVLBCL in various organs. Clinical features of spinal cord involvement in patients with IVLBCL were assessed and distinguished from those of brain involvement.

RESULTS

Sixteen consecutive patients with IVLBCL were divided into two groups: six patients with spinal involvement (spinal cord type) and 10 patients with brain involvement (brain type). In the spinal cord type, four patients had chronic progression and two had subacute progression. Acute progression (0% vs. 80.0%) and sudden onset (0% vs. 50.0%) occurred significantly less frequently in the spinal cord than in the brain. All spinal cord lesions involved the conus medullaris.

CONCLUSIONS

Spinal cord involvement in IVLBCL has a predominantly chronic progressive course that is exclusive to brain involvement. Conus medullaris lesions are suggestive of IVLBCL and are useful for early and accurate diagnosis and treatment.

Ethnicity-dependent effect of rs1799971 polymorphism on OPRM1 expression in the postmortem brain and responsiveness to antipsychotics

Schizophrenia is associated with aberration of inhibitory neurons. Although the mu-opioid receptor (MOR) is an essential modulator of inhibitory neurons, the effect of rs1799971 polymorphism in the MOR gene on risk of schizophrenia is controversial. Moreover, the disturbance of opioids systems in patients with schizophrenia has not been fully examined. We firstly conducted preliminary meta-analyses integrating Asian and European populations separately over 12,000 subjects to assess the effect of rs1799971 on risk of schizophrenia. Based on the above result, we also investigated the effect on the expression levels of MOR mRNA in the prefrontal cortex (PFC) and caudate nucleus of 41 postmortem brains. In addition, we determined whether these levels were related to antemortem schizophrenia symptoms and pharmacotherapeutic effects. The rs1799971 G-allele reduced the risk of schizophrenia in Asian populations (OR: 0.56, 95%CI: 0.32-0.98, p = 0.042) but increased it in European populations (OR: 1.66, 95%CI: 1.08-2.56, p = 0.022). It decreased MOR mRNA levels in PFC in the Japanese population (p = 0.031). Increased MOR mRNA level in PFC correlated with higher total score of antemortem schizophrenia symptoms (p = 0.017). Furthermore, the pharmacotherapeutic effect of first-generation antipsychotics was higher for genotype AA than AG/GG of rs1799971 (p = 0.036). The rs1799971 affects risk of schizophrenia and MOR mRNA expression and the effect varies according to ethnicity. Overexpression of MOR might induce severe schizophrenia symptoms. Therefore, MOR modulation may be the key clue for treating antipsychotics-resistant schizophrenia, and genotyping rs1799971 may provide a better pharmacotherapeutic strategy.

[An autopsied patient with palatal tremor and fatal bilateral vocal cord abduction paralysis associated with bilateral cerebellar dentate nucleus infarction]

A 74-year-old male patient developed multiple infarcts of the brainstem and cerebellum, followed 14 months later by palatal tremor and bilateral vocal cord abduction paralysis, resulting in death due to type 2 respiratory failure. Pathologic analysis revealed old infarcts extending from the bilateral cerebellar cortices to the dentate nucleus, being more extensive on the right side, accompanied by Wallerian degeneration involving the left red nucleus, right central tegmentum tract, and inferior cerebellar peduncle, followed by pseudohypertrophy of the bilateral inferior olivary nuclei. These lesions, involving the Guillain-Mollaret triangle, may have been responsible for the palatal tremor. On the other hand, there were no evident causative lesions for the vocal cord abduction, including any in the nucleus ambiguus or posterior cricoarytenoid muscles. In this case it is possible that the dysfunction responsible for the palatal tremor may have affected the pathway from the central tegmentum tract, which is part of the Guillain-Mollaret triangle, to the vagus nerve arising from the nucleus ambiguus, which plays a role in vocal cord abduction, thus affecting the vocal cords and resulting in abduction paralysis.

Usefulness and limitations of intraoperative pathological diagnosis using frozen sections for spinal cord tumors

BACKGROUND

Intraoperative pathological diagnosis has a major influence on the intra- and postoperative management of spinal cord tumors. Thus, the aim of this study was to assess the reliability of intraoperative pathological diagnosis for spinal cord lesions by comparing it with the final pathological diagnosis and to determine its usefulness and limitations.

METHOD

Three-hundred and three consecutive patients (mean age, 53.9 years) with neoplastic spinal cord lesions who underwent initial surgery between 2000 and 2021 were included. The anatomical locations of the spinal cord tumors and the implementation rate of intraoperative pathological diagnosis in each tumor type were evaluated. As the primary outcome, we determined the concordance rates between the intraoperative pathological diagnosis and the final diagnosis. When the intraoperative pathological diagnosis and final diagnosis were the same, the diagnosis was defined as a "match." Otherwise, the diagnosis was defined as a "mismatch."

RESULTS

The overall implementation rate of intraoperative pathological diagnosis was 53%, with implementation rates of 71%, 45%, 47%, and 50% for intramedullary, intradural extramedullary, extradural, and dumbbell tumors, respectively. The overall concordance rate was 87.6%, with concordance rates of 80%, 95%, 75%, and 90% for intramedullary, intradural extramedullary, extradural, and dumbbell tumors, respectively (p < 0.05). The diagnoses of ependymomas, low-grade astrocytomas, and high-grade astrocytomas was occasionally difficult among intramedullary tumors. Among intradural extramedullary tumors, differentiation between grade 1 meningioma and high-grade meningioma was difficult using intraoperative pathological diagnosis.

CONCLUSIONS

Surgeons must recognize the lower accuracy of intraoperative pathological diagnosis for intramedullary and extradural lesions and make a final decision by considering the intraoperative gross findings, preoperative clinical course, and imaging.

Evidence for increased DNA damage repair in the postmortem brain of the high stress-response group of schizophrenia

Background

Schizophrenia (SZ) is a disorder diagnosed by specific symptoms and duration and is highly heterogeneous, clinically and pathologically. Although there are an increasing number of studies on the association between genetic and environmental factors in the development of SZ, the actual distribution of the population with different levels of influence of these factors has not yet been fully elucidated. In this study, we focused on stress as an environmental factor and stratified SZ based on the expression levels of stress-responsive molecules in the postmortem prefrontal cortex.

Methods

We selected the following stress-responsive molecules: interleukin (IL) -1β, IL-6, IL-10, tumor necrosis factor-α, interferon-γ, glucocorticoid receptor, brain-derived neurotrophic factor, synaptophysin, S100 calcium-binding protein B, superoxide dismutase, postsynaptic density protein 95, synuclein, apolipoprotein A1 (ApoA1), ApoA2, and solute carrier family 6 member 4. We performed RNA sequencing in the prefrontal gray matter of 25 SZ cases and 21 healthy controls and conducted a hierarchical cluster analysis of SZ based on the gene expression levels of stress-responsive molecules, which yielded two clusters. After assessing the validity of the clusters, they were designated as the high stress-response SZ group and the low stress-response SZ group, respectively. Ingenuity Pathway Analysis of differentially expressed genes (DEGs) between clusters was performed, and Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining was conducted on four cases each in the high and low stress-response SZ groups to validate DNA damage.

Results

We found higher prevalence of family history of SZ in the low stress-response SZ group (0/3 vs. 5/4, p = 0.04). Pathway analysis of DEGs between clusters showed the highest enrichment for DNA double-strand break repair. TUNEL staining showed a trend toward a lower percentage of TUNEL-positive cells in the high stress-response SZ group.

Conclusion

Our results suggest that there are subgroups of SZ with different degrees of stress impact. Furthermore, the pathophysiology of these subgroups may be associated with DNA damage repair. These results provide new insights into the interactions and heterogeneity between genetic and environmental factors.

Phosphorylation of α-synuclein at T64 results in distinct oligomers and exerts toxicity in models of Parkinson's disease

α-Synuclein accumulates in Lewy bodies, and this accumulation is a pathological hallmark of Parkinson's disease (PD). Previous studies have indicated a causal role of α-synuclein in the pathogenesis of PD. However, the molecular and cellular mechanisms of α-synuclein toxicity remain elusive. Here, we describe a novel phosphorylation site of α-synuclein at T64 and the detailed characteristics of this post-translational modification. T64 phosphorylation was enhanced in both PD models and human PD brains. T64D phosphomimetic mutation led to distinct oligomer formation, and the structure of the oligomer was similar to that of α-synuclein oligomer with A53T mutation. Such phosphomimetic mutation induced mitochondrial dysfunction, lysosomal disorder, and cell death in cells and neurodegeneration in vivo, indicating a pathogenic role of α-synuclein phosphorylation at T64 in PD.

Epigenetic upregulation of Schlafen11 renders WNT- and SHH-activated medulloblastomas sensitive to cisplatin

BACKGROUND

Intensive chemotherapeutic regimens with craniospinal irradiation have greatly improved survival in medulloblastoma patients. However, survival markedly differs among molecular subgroups and their biomarkers are unknown. Through unbiased screening, we found Schlafen family member 11 (SLFN11), which is known to improve response to DNA damaging agents in various cancers, to be one of the top prognostic markers in medulloblastomas. Hence, we explored the expression and functions of SLFN11 in medulloblastoma.

METHODS

SLFN11 expression for each subgroup was assessed by immunohistochemistry in 98 medulloblastoma patient samples and by analyzing transcriptomic databases. We genetically or epigenetically modulated SLFN11 expression in medulloblastoma cell lines and determined cytotoxic response to the DNA damaging agents cisplatin and topoisomerase I inhibitor SN-38 in vitro and in vivo.

RESULTS

High SLFN11 expressing cases exhibited significantly longer survival than low expressing cases. SLFN11 was highly expressed in the WNT-activated subgroup and in a proportion of the SHH-activated subgroup. While WNT activation was not a direct cause of the high expression of SLFN11, a specific hypomethylation locus on the SLFN11 promoter was significantly correlated with high SLFN11 expression. Overexpression or deletion of SLFN11 made medulloblastoma cells sensitive and resistant to cisplatin and SN-38, respectively. Pharmacological upregulation of SLFN11 by the brain-penetrant histone deacetylase-inhibitor RG2833 markedly increased sensitivity to cisplatin and SN-38 in SLFN11-negative medulloblastoma cells. Intracranial xenograft studies also showed marked sensitivity to cisplatin by SLFN11-overexpression in medulloblastoma cells.

CONCLUSIONS

High SLFN11 expression is one factor which renders favorable outcomes in WNT-activated and a subset of SHH-activated medulloblastoma possibly through enhancing response to cisplatin.

Identification of schizophrenia symptom-related gene modules by postmortem brain transcriptome analysis

Schizophrenia is a multifactorial disorder, the genetic architecture of which remains unclear. Although many studies have examined the etiology of schizophrenia, the gene sets that contribute to its symptoms have not been fully investigated. In this study, we aimed to identify each gene set associated with corresponding symptoms of schizophrenia using the postmortem brains of 26 patients with schizophrenia and 51 controls. We classified genes expressed in the prefrontal cortex (analyzed by RNA-seq) into several modules by weighted gene co-expression network analysis (WGCNA) and examined the correlation between module expression and clinical characteristics. In addition, we calculated the polygenic risk score (PRS) for schizophrenia from Japanese genome-wide association studies, and investigated the association between the identified gene modules and PRS to evaluate whether genetic background affected gene expression. Finally, we conducted pathway analysis and upstream analysis using Ingenuity Pathway Analysis to clarify the functions and upstream regulators of symptom-related gene modules. As a result, three gene modules generated by WGCNA were significantly correlated with clinical characteristics, and one of these showed a significant association with PRS. Genes belonging to the transcriptional module associated with PRS significantly overlapped with signaling pathways of multiple sclerosis, neuroinflammation, and opioid use, suggesting that these pathways may also be profoundly implicated in schizophrenia. Upstream analysis indicated that genes in the detected module were profoundly regulated by lipopolysaccharides and CREB. This study identified schizophrenia symptom-related gene sets and their upstream regulators, revealing aspects of the pathophysiology of schizophrenia and identifying potential therapeutic targets.

Genome-wide association study identifies a new susceptibility locus in PLA2G4C for Multiple System Atrophy

To elucidate the molecular basis of multiple system atrophy (MSA), a neurodegenerative disease, we conducted a genome-wide association study (GWAS) in a Japanese MSA case/control series followed by replication studies in Japanese, Korean, Chinese, European and North American samples. In the GWAS stage rs2303744 on chromosome 19 showed a suggestive association ( P = 6.5 × 10 ^-7 ) that was replicated in additional Japanese samples ( P = 2.9 × 10 ^-6 . OR = 1.58; 95% confidence interval, 1.30 to 1.91), and then confirmed as highly significant in a meta-analysis of East Asian population data ( P = 5.0 × 10 ^-15 . Odds ratio= 1.49; 95% CI 1.35 to 1.72). The association of rs2303744 with MSA remained significant in combined European/North American samples ( P =0.023. Odds ratio=1.14; 95% CI 1.02 to 1.28) despite allele frequencies being quite different between these populations. rs2303744 leads to an amino acid substitution in PLA2G4C that encodes the cPLA2γ lysophospholipase/transacylase. The cPLA2γ-Ile143 isoform encoded by the MSA risk allele has significantly decreased transacylase activity compared with the alternate cPLA2γ-Val143 isoform that may perturb membrane phospholipids and α-synuclein biology.

Tau Filaments from Amyotrophic Lateral Sclerosis/Parkinsonism-Dementia Complex (ALS/PDC) adopt the CTE Fold

The amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) of the island of Guam and the Kii peninsula of Japan is a fatal neurodegenerative disease of unknown cause that is characterised by the presence of abundant filamentous tau inclusions in brains and spinal cords. Here we used electron cryo-microscopy (cryo-EM) to determine the structures of tau filaments from the cerebral cortex of three cases of ALS/PDC from Guam and eight cases from Kii, as well as from the spinal cord of two of the Guam cases. Tau filaments had the chronic traumatic encephalopathy (CTE) fold, with variable amounts of Type I and Type II filaments. Paired helical tau filaments were also found in two Kii cases. We also identified a novel Type III CTE tau filament, where protofilaments pack against each other in an anti-parallel fashion. ALS/PDC is the third known tauopathy with CTE-type filaments and abundant tau inclusions in cortical layers II/III, the others being CTE and subacute sclerosing panencephalitis. Because these tauopathies are believed to have environmental causes, our findings support the hypothesis that ALS/PDC is caused by exogenous factors.

Brain-specific glycosylation of protein tyrosine phosphatase receptor type Z (PTPRZ) marks a demyelination-associated astrocyte subtype

Astrocytes are the most abundant glial cell type in the brain, where they participate in various homeostatic functions. Transcriptomically diverse astrocyte subpopulations play distinct roles during development and disease progression. However, the biochemical identification of astrocyte subtypes, especially by membrane surface protein glycosylation, remains poorly investigated. Protein tyrosine phosphatase receptor type zeta (PTPRZ) is a highly expressed membrane protein in CNS glia cells that can be modified with diverse glycosylation, including the unique HNK-1 capped O-mannosyl (O-Man) core M2 glycan mediated by brain-specific branching enzyme GnT-IX. Although PTPRZ modified with HNK-1 capped O-Man glycans (HNK-1-O-Man⁺ PTPRZ) is increased in reactive astrocytes of demyelination model mice, whether such astrocytes emerge in a broad range of disease-associated conditions or are limited to conditions associated with demyelination remains unclear. Here, we show that HNK-1-O-Man⁺ PTPRZ localizes in hypertrophic astrocytes of damaged brain areas in patients with multiple sclerosis. Furthermore, we show that astrocytes expressing HNK-1-O-Man⁺ PTPRZ are present in two demyelination mouse models (cuprizone-fed mice and a vanishing white matter disease model), while traumatic brain injury does not induce glycosylation. Administration of cuprizone to Aldh1l1-eGFP and Olig2^KICreER/+ ;Rosa26^eGFP mice revealed that cells expressing HNK-1-O-Man⁺ PTPRZ are derived from cells in the astrocyte lineage. Notably, GnT-IX but not PTPRZ mRNA was upregulated in astrocytes isolated from the corpus callosum of cuprizone-model mice. These results suggest that the unique PTPRZ glycosylation plays a key role in the patterning of demyelination-associated astrocytes.

[Surgical Pathological Features of Epileptogenic Brain Lesions: Cortical Dysplasia and Tumors]

Cortical dysplasia and tumors are representative brain lesions associated with intractable epilepsy. Focal cortical dysplasia type II is characterized by cortical cytoarchitectural abnormalities, dysmorphic neurons, and balloon cells, and is associated with somatic mutations of mTOR pathway molecules. Glioneuronal and neuronal tumors, including dysembryoplastic neuroepithelial tumor and ganglioglioma, are the major tumor types for the clinical phenotype. Recently, various subtypes and characterizing molecular profiles have been recognized.

An integrated genetic analysis of epileptogenic brain malformed lesions

Focal cortical dysplasia is the most common malformation during cortical development, sometimes excised by epilepsy surgery and often caused by somatic variants of the mTOR pathway genes. In this study, we performed a genetic analysis of epileptogenic brain malformed lesions from 64 patients with focal cortical dysplasia, hemimegalencephy, brain tumors, or hippocampal sclerosis. Targeted sequencing, whole-exome sequencing, and single nucleotide polymorphism microarray detected four germline and 35 somatic variants, comprising three copy number variants and 36 single nucleotide variants and indels in 37 patients. One of the somatic variants in focal cortical dysplasia type IIB was an in-frame deletion in MTOR, in which only gain-of-function missense variants have been reported. In focal cortical dysplasia type I, somatic variants of MAP2K1 and PTPN11 involved in the RAS/MAPK pathway were detected. The in-frame deletions of MTOR and MAP2K1 in this study resulted in the activation of the mTOR pathway in transiently transfected cells. In addition, the PTPN11 missense variant tended to elongate activation of the mTOR or RAS/MAPK pathway, depending on culture conditions. We demonstrate that epileptogenic brain malformed lesions except for focal cortical dysplasia type II arose from somatic variants of diverse genes but were eventually linked to the mTOR pathway.

Periodic cycles of seizure clustering and suppression in children with epilepsy strongly suggest focal cortical dysplasia

AIM

We investigated characteristic seizure patterns in epilepsy caused by focal cortical dysplasia (FCD), which differ from epilepsy by other aetiologies in surgical cases with lesions on magnetic resonance imaging (MRI), then examined if these features were applicable to patients with epilepsy without any lesions on MRI.

METHOD

We retrospectively studied clinicopathological features in 291 (143 females) children with epilepsy who had undergone resective surgery after comprehensive evaluation, including 277 cases with lesions on MRI (136 females, age at resection 0-17 years [mean 6 years 10 months, SD 5 years 7 months]) and 14 cases without any lesions on MRI (seven females, age 0-16 years [mean 7 years 8 months, SD 4 years 8 months]).

RESULTS

Among 277 patients with lesions on MRI, 87 cases exhibited recurrent periodic cycles of seizure clustering (≥5 seizures/day for ≥1 week) and suppression (no seizures for ≥1 week); of these, 80 cases (92%) were pathologically diagnosed with FCD. Other pathologies included glial scar, hippocampal sclerosis, hemimegalencephaly, and cortical tuber in three, two, one, and one case respectively. All 14 patients without any lesions on MRI had significant recurrent periodic seizure cycles and FCD histopathologically.

INTERPRETATION

Periodic seizure cycles characterized by clustering and suppression in patients with epilepsy strongly suggest the presence of FCD regardless of MRI findings, and comprehensive evaluations for epilepsy surgery should be proceeded.

Elevated ratio of C-type lectin-like receptor 2 level and platelet count (C2PAC) aids in the diagnosis of post-operative venous thromboembolism in IDH-wildtype gliomas

INTRODUCTION

Podoplanin (PDPN) is known to induce platelet aggregation via interacting with the C-type lectin-like receptor-2 on platelets and is involved in postoperative venous thromboembolism (VTE) formation. In this study, we investigate the correlation between soluble C-type lectin-like receptor (sCLEC-2) levels and PDPN expression in patients with high grade gliomas and the relationship between sCLEC-2 levels and the occurrence of VTE.

MATERIALS AND METHODS

Forty-four patients harboring high grade gliomas, treated surgically at the Department of Neurosurgery, Niigata University from April 2018 to August 2020, were included. Patients with high grade gliomas were divided into isocitrate dehydrogenase (IDH)- wildtype and mutant groups, and the presence or absence of VTE and the intensity of PDPN by immunohistochemistry were confirmed. Platelet counts, as well as plasma sCLEC-2 and PDPN were measured in these patients. Furthermore, the levels of sCLEC-2 concentration were divided by the platelet count (C2PAC index) for comparison.

RESULTS

IDH-wildtype glioma patients highly expressed PDPN (P < 0.001) compared to IDH-mutant glioma patients. In total, 9 (20.5 %) patients were diagnosed with VTE during the follow-up period, of which 8 patients harbored IDH-wildtype gliomas, and one patient an IDH-mutant glioma. Mean sCLEC-2 levels and C2PAC index in patients with IDH-wildtype gliomas were significantly higher than that of low or no PDPN expression group, which included patients with IDH-mutant gliomas (P = 0.0004, P = 0.0002). In patients with IDH-wildtype gliomas, the C2PAC index in patients with VTE was significantly higher than in patients without VTE (P = 0.0492). The optimal cutoff point of C2PAC for predicting VTE in IDH-wildtype glioma patients was 3.7 with a sensitivity of 87.5 % and specificity of 51.9 %.

CONCLUSION

Platelet activation is strongly involved in the development of VTE in patients with IDH-wildtype high grade gliomas, and C2PAC index is a potential marker to detect VTE formation after surgery.

Human early-onset dementia caused by DAP12 deficiency reveals a unique signature of dysregulated microglia

The TREM2-DAP12 receptor complex sustains microglia functions. Heterozygous hypofunctional TREM2 variants impair microglia, accelerating late-onset Alzheimer's disease. Homozygous inactivating variants of TREM2 or TYROBP-encoding DAP12 cause Nasu-Hakola disease (NHD), an early-onset dementia characterized by cerebral atrophy, myelin loss and gliosis. Mechanisms underpinning NHD are unknown. Here, single-nucleus RNA-sequencing analysis of brain specimens from DAP12-deficient NHD individuals revealed a unique microglia signature indicating heightened RUNX1, STAT3 and transforming growth factor-β signaling pathways that mediate repair responses to injuries. This profile correlated with a wound healing signature in astrocytes and impaired myelination in oligodendrocytes, while pericyte profiles indicated vascular abnormalities. Conversely, single-nuclei signatures in mice lacking DAP12 signaling reflected very mild microglial defects that did not recapitulate NHD. We envision that DAP12 signaling in microglia attenuates wound healing pathways that, if left unchecked, interfere with microglial physiological functions, causing pathology in human. The identification of a dysregulated NHD microglia signature sparks potential therapeutic strategies aimed at resetting microglia signaling pathways.

Cerebrospinal Fluid Biomarkers and Amyloid-β Elimination from the Brain in Cerebral Amyloid Angiopathy-Related Inflammation

BACKGROUND

Cerebrospinal fluid (CSF) biomarkers in patients with cerebral amyloid angiopathy-related inflammation (CAA-ri) have demonstrated inconsistent results.

OBJECTIVE

We investigated the relationship between CSF amyloid-β protein (Aβ) and vascular pathological findings to elucidate the mechanisms of Aβ elimination from the brain in CAA-ri.

METHODS

We examined Aβ40 and Aβ42 levels in CSF samples in 15 patients with CAA-ri and 15 patients with Alzheimer's disease and cerebral amyloid angiopathy (AD-CAA) using ELISA as a cross-sectional study. Furthermore, we pathologically examined Aβ40 and Aβ42 depositions on the leptomeningeal blood vessels (arteries, arterioles, and veins) using brain biopsy samples from six patients with acute CAA-ri and brain tissues of two autopsied patients with CAA-ri.

RESULTS

The median Aβ40 and Aβ42 levels in the CSF showed no significant difference between pre-treatment CAA-ri (Aβ40, 6837 pg/ml; Aβ42, 324 pg/ml) and AD-CAA (Aβ40, 7669 pg/ml, p = 0.345; Aβ42, 355 pg/ml, p = 0.760). Aβ40 and Aβ42 levels in patients with post-treatment CAA-ri (Aβ40, 1770 pg/ml, p = 0.056; Aβ42, 167 pg/ml, p = 0.006) were lower than those in patients with pre-treatment CAA-ri. Regarding Aβ40 and Aβ42 positive arteries, acute CAA-ri cases showed a higher frequency of partially Aβ-deposited blood vessels than postmortem CAA-ri cases (Aβ40, 20.8% versus 3.9%, p = 0.0714; Aβ42, 27.4% versus 2.0%, p = 0.0714, respectively).

CONCLUSION

Lower levels of CSF Aβ40 and Aβ42 could be biomarkers for the cessation of inflammation in CAA-ri reflecting the recovery of the intramural periarterial drainage pathway and vascular function.

Epilepsy surgery without lipoma removal for temporal lobe epilepsy associated with lipoma in the Sylvian fissure

Epileptic seizure is the common symptom associated with lipomas in the Sylvian fissure (Sylvian lipomas). Removal of these lipomas carries risks of hemorrhage and brain damage. We report a surgical strategy of not removing the lipoma in a case of intractable temporal lobe epilepsy associated with Sylvian lipoma. We performed anterior temporal lobectomy with preservation of the pia mater of the Sylvian fissure and achieved seizure freedom. Focal cortical dysplasia type 1 of the epileptic neocortex adjacent to the Sylvian lipoma was pathologically diagnosed. We recommend our surgical procedure in similar cases to avoid complications and achieve adequate seizure control.

Spinocerebellar ataxia type 17-digenic TBP/STUB1 disease: neuropathologic features of an autopsied patient

Spinocerebellar ataxia (SCA) type 17-digenic TBP/STUB1 disease (SCA17-DI) has been recently segregated from SCA17, caused by digenic inheritance of two gene mutations - intermediate polyglutamine-encoding CAG/CAA repeat expansions (polyQ) in TBP (TBP_41 - 49) and STUB1 heterozygosity - the former being associated with SCA17, and the latter with SCA48 and SCAR16 (autosomal recessive). In SCA17, most patients carry intermediate TBP_41 - 49 alleles but show incomplete penetrance, and the missing heritability can be explained by a new entity whereby TBP_41 - 49 requires the STUB1 variant to be symptomatic. The STUB1 gene encodes the chaperone-associated E3 ubiquitin ligase (CHIP) involved in ubiquitin-mediated proteasomal control of protein homeostasis. However, reports of the neuropathology are limited and role of STUB1 mutations in SCA17-DI remain unknown. Here we report the clinicopathologic features of identical twin siblings, one of whom was autopsied and was found to carry an intermediate allele (41 and 38 CAG/CAA repeats) in TBP and a heterozygous missense mutation in STUB1 (p.P243L). These patients developed autosomal recessive Huntington's disease-like symptoms. Brain MRI showed diffuse atrophy of the cerebellum and T2WI revealed hyperintense lesions in the basal ganglia and periventricular deep white matter. The brain histopathology of the patient shared features characteristic of SCA17, such as degeneration of the cerebellar cortex and caudate nucleus, and presence of 1C2-positive neurons. Here we show that mutant CHIP fails to generate the polyubiquitin chain due to disrupted folding of the entire U box domain, thereby affecting the E3 activity of CHIP. When encountering patients with cerebellar ataxia, especially those with Huntington's disease-like symptoms, genetic testing for STUB1 as well as TBP should be conducted for diagnosis of SCA17-DI, even in cases of sporadic or autosomal recessive inheritance.

Praja1 RING-finger E3 ubiquitin ligase is a common suppressor of neurodegenerative disease-associated protein aggregation

The formation of misfolded protein aggregates is one of the pathological hallmarks of neurodegenerative diseases. We have previously demonstrated the cytoplasmic aggregate formation of adenovirally expressed transactivation response DNA-binding protein of 43 kDa (TDP-43), the main constituent of neuronal cytoplasmic aggregates in cases of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), in cultured neuronal cells under the condition of proteasome inhibition. The TDP-43 aggregate formation was markedly suppressed by co-infection of adenoviruses expressing heat shock transcription factor 1 (HSF1), a master regulator of heat shock response, and Praja1 RING-finger E3 ubiquitin ligase (PJA1) located downstream of the HSF1 pathway. In the present study, we examined other reportedly known E3 ubiquitin ligases for TDP-43, i.e. Parkin, RNF112 and RNF220, but failed to find their suppressive effects on neuronal cytoplasmic TDP-43 aggregate formation, although they all bind to TDP-43 as verified by co-immunoprecipitation. In contrast, PJA1 also binds to adenovirally expressed wild-type and mutated fused in sarcoma, superoxide dismutase 1, α-synuclein and ataxin-3, and huntingtin polyglutamine proteins in neuronal cultures and suppressed the aggregate formation of these proteins. These results suggest that PJA1 is a common sensing factor for aggregate-prone proteins to counteract their aggregation propensity, and could be a potential therapeutic target for neurodegenerative diseases that include ALS, FTLD, Parkinson's disease and polyglutamine diseases.

Elucidating the multiple genetic alterations involved in the malignant transformation of a KRAS mutant neurenteric cyst. A case report

Neurenteric cyst (NC) shows benign histopathology and rarely demonstrate malignant transformation. We herein describe a case of NC that exhibited malignant transformation. A 65-year-old female presented with gait disturbance due to compression by a cystic mass on the dorsal surface of the medulla oblongata. Partial resection was performed twice, leading to improvement of her symptoms. Two years after the second surgery, gadolinium-perfused T1-weighted magnetic resonance imaging revealed an invasive lesion with contrast enhancement at the trigone of the left lateral ventricle for which partial resection followed by radiotherapy was performed. However, mass regrowth was observed, with the patient eventually succumbing to her disease 11 months after her third surgery. Histopathological analyses of the first and second surgical specimens identified pseudostratified cuboidal epithelial cells, with no nuclear or cellular atypia resembling gastrointestinal mucosa, lining the inner surface of the cystic wall. Based on these findings the lesion was diagnosed as NC. The third surgical specimen exhibited apparent malignant features of the epithelial cells with elongated and hyperchromatic nuclei, several mitotic figures, small necrotic foci, and a patternless or sheet-like arrangement. Based on these findings, the lesion was diagnosed as NC with malignant transformation. Next-generation sequencing revealed KRAS p.G12D mutation in all specimens. Additionally, the third surgical specimen harbored the following 12 de novo gene alterations: ARID1A loss, BAP1 p.F170L, CDKN1B loss, CDKN2A loss, CDKN2B loss, FLCN loss, PTCH1 loss, PTEN loss, PTPRD loss, SUFU loss, TP53 loss, and TSC1 loss. The aforementioned results suggest that KRAS mutation is associated with the development of the NC, and that the additional gene alterations contribute to malignant transformation of the NC.

Pathological substrate of memory impairment in multiple system atrophy

AIMS

Synaptic dysfunction in Parkinson's disease is caused by propagation of pathogenic α-synuclein between neurons. Previously, in multiple system atrophy (MSA), pathologically characterised by ectopic deposition of abnormal α-synuclein predominantly in oligodendrocytes, we demonstrated that the occurrence of memory impairment was associated with the number of α-synuclein-positive neuronal cytoplasmic inclusions (NCIs) in the hippocampus. In the present study, we aimed to investigate how abnormal α-synuclein in the hippocampus can lead to memory impairment.

METHODS

We performed pathological and biochemical analyses using a mouse model of adult-onset MSA and human cases (MSA, N = 25; Parkinson's disease, N = 3; Alzheimer's disease, N = 2; normal controls, N = 11). In addition, the MSA model mice were examined behaviourally and physiologically.

RESULTS

In the MSA model, inducible human α-synuclein was first expressed in oligodendrocytes and subsequently accumulated in the cytoplasm of excitatory hippocampal neurons (NCI-like structures) and their presynaptic nerve terminals with the development of memory impairment. α-Synuclein oligomers increased simultaneously in the hippocampus of the MSA model. Hippocampal dendritic spines also decreased in number, followed by suppression of long-term potentiation. Consistent with these findings obtained in the MSA model, post-mortem analysis of human MSA brain tissues showed that cases of MSA with memory impairment developed more NCIs in excitatory hippocampal neurons along with α-synuclein oligomers than those without.

CONCLUSIONS

Our results provide new insights into the role of α-synuclein oligomers as a possible pathological cause of memory impairment in MSA.

A Machine Learning-Based Approach to Discrimination of Tauopathies Using [18 F]PM-PBB3 PET Images

BACKGROUND

We recently developed a positron emission tomography (PET) probe, [¹⁸ F]PM-PBB3, to detect tau lesions in diverse tauopathies, including mixed three-repeat and four-repeat (3R + 4R) tau fibrils in Alzheimer's disease (AD) and 4R tau aggregates in progressive supranuclear palsy (PSP). For wider availability of this technology for clinical settings, bias-free quantitative evaluation of tau images without a priori disease information is needed.

OBJECTIVE

We aimed to establish tau PET pathology indices to characterize PSP and AD using a machine learning approach and test their validity and tracer capabilities.

METHODS

Data were obtained from 50 healthy control subjects, 46 patients with PSP Richardson syndrome, and 37 patients on the AD continuum. Tau PET data from 114 regions of interest were subjected to Elastic Net cross-validation linear classification analysis with a one-versus-the-rest multiclass strategy to obtain a linear function that discriminates diseases by maximizing the area under the receiver operating characteristic curve. We defined PSP- and AD-tau scores for each participant as values of the functions optimized for differentiating PSP (4R) and AD (3R + 4R), respectively, from others.

RESULTS

The discriminatory ability of PSP- and AD-tau scores assessed as the area under the receiver operating characteristic curve was 0.98 and 1.00, respectively. PSP-tau scores correlated with the PSP rating scale in patients with PSP, and AD-tau scores correlated with Mini-Mental State Examination scores in healthy control-AD continuum patients. The globus pallidus and amygdala were highlighted as regions with high weight coefficients for determining PSP- and AD-tau scores, respectively.

CONCLUSIONS

These findings highlight our technology's unbiased capability to identify topologies of 3R + 4R versus 4R tau deposits. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

SWI by 7T MR Imaging for the Microscopic Imaging Diagnosis of Astrocytic and Oligodendroglial Tumors

BACKGROUND AND PURPOSE

Despite advances in molecular imaging, preoperative diagnosis of astrocytomas and oligodendrogliomas can be challenging. In the present study, we assessed whether 7T SWI can be used to distinguish astrocytomas and oligodendrogliomas and whether malignant grading of gliomas is possible.

MATERIALS AND METHODS

7T SWI was performed on 21 patients with gliomas before surgery with optimization for sharp visualization of the corticomedullary junction. Scoring for cortical thickening and displacement of medullary vessels, characteristic of oligodendroglial tumors, and cortical tapering, characteristic of astrocytic tumors, was performed. Additionally, characteristics of malignancy, including thickening of the medullary veins, the presence of microbleeds, and/or necrosis were scored.

RESULTS

Scoring for oligodendroglial (highest possible score, +3) and astrocytic (lowest score possible, -3) characteristics yielded a significant difference between astrocytomas and oligodendrogliomas (mean, -1.93 versus +1.71, P < .01). Scoring for malignancy was significantly different among the World Health Organization grade II (n = 10), grade III (n = 4), and grade IV (n = 7) tumors (mean, 0.20 versus 1.38 versus 2.79). Cortical thickening was observed significantly more frequently in oligodendrogliomas (P < .02), with a sensitivity of 71.4% and specificity of 85.7%; observation of tapering of the cortex was higher in astrocytomas (P < .01) with a sensitivity of 85.7% and specificity of 100%.

CONCLUSIONS

Visualization of the corticomedullary junction by 7T SWI was useful in distinguishing astrocytomas and oligodendrogliomas. Observation of tapering of the cortex was most sensitive and specific for diagnosing astrocytomas. Reliably predicting malignant grade was also possible by 7T SWI.