Publications by authors named "Akiyoshi Kakita"

332 Publications

Current medico-psycho-social conditions of patients with West syndrome in Japan.

Epileptic Disord 2021 Jul 13. Epub 2021 Jul 13.

Department of Pediatrics, School of Medicine, Shinshu University, Matsumoto, Japan.

Objective: To unveil current medical and psychosocial conditions of patients with West syndrome in Japan.

Methods: A cross-sectional analysis was performed in patients with West syndrome registered in the Rare Epilepsy Syndrome Registry (RES-R) of Japan. Furthermore, new-onset patients registered in the RES-R were observed prospectively and their outcomes after one and two years of follow-up were compared with data at onset.

Results: For the cross-sectional study, 303 patients with West syndrome were included. Seizures (such as spasms, tonic seizures and focal seizures) occurred daily in 69.3% of the patients at registration. Seizure frequency of less than one per year was observed in cases of unknown etiology (22.6%), genetic etiology (23.8%) and malformation of cortical development (MCD; 19.1%). Neurological findings were absent in 37.0%, but a high rate of abnormality was seen in patients with Aicardi syndrome, hypoxic-ischemic encephalopathy (HIE), genetic etiology and MCD other than focal cortical dysplasia, accompanied by a >50% rate of bedridden patients. Abnormal EEG was found in 96.7%, and CT/MRI was abnormal in 62.7%. Treatments included antiepileptic drug therapy (94.3%), hormonal therapy (72.6%), diet therapy (8.3%) and surgery (15.8%). Intellectual/developmental delay was present in 88.4%, and was more severe in patients with Aicardi syndrome, genetic etiology and HIE. Autism spectrum disorder was found in 13.5%. For the longitudinal study, 27 new-onset West syndrome patients were included. The follow-up study revealed improved seizure status after two years in 66.7%, but worsened developmental status in 55.6%, with overall improvement in 51.9%.

Significance: The study reveals the challenging neurological, physical and developmental aspects, as well as intractable seizures, in patients with West syndrome. More than a half of the children showed developmental delay after onset, even though seizures were reduced during the course of the disease.
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http://dx.doi.org/10.1684/epd.2021.1301DOI Listing
July 2021

Predicting BRAF V600E mutation in glioblastoma: utility of radiographic features.

Brain Tumor Pathol 2021 Jul 3. Epub 2021 Jul 3.

Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Detection of BRAF V600E mutation in glioblastomas (GBMs) is important because of potential therapeutic implications. Still, the relative paucity of these mutations makes molecular detection in all GBMs controversial. In the present study, we analyzed clinical, radiographic and pathologic features of 12 BRAF V600E-mutant GBMs and 12 matched controls from 2 institutions. We found that a majority of BRAF V600E-mutant GBMs displayed a combination of well-circumscribed lesions, large cystic components with thin walls and solid cortical component on MRI, but with some overlap with matched BRAF wildtype controls (p = 0.069). BRAF V600E-mutant GBMs were also apt to gross total resection (83% vs 17%, p = 0.016) and morphologically displayed epithelioid features (83% vs 0%, p < 0.0001). Identification of these clinical, radiographic, and pathologic characteristics should prompt testing for BRAF V600E in IDH-wildtype GBM.
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http://dx.doi.org/10.1007/s10014-021-00407-0DOI Listing
July 2021

Role of VAPB and vesicular profiles in α-synuclein aggregates in multiple system atrophy.

Brain Pathol 2021 Jul 1:e13001. Epub 2021 Jul 1.

Department of Neuropathology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.

The pathological hallmark of multiple system atrophy (MSA) is fibrillary aggregates of α-synuclein (α-Syn) in the cytoplasm and nucleus of both oligodendrocytes and neurons. In neurons, α-Syn localizes to the cytosolic and membrane compartments, including the synaptic vesicles, mitochondria, and endoplasmic reticulum (ER). α-Syn binds to vesicle-associated membrane protein-binding protein B (VAPB) in the ER membrane. Overexpression of wild-type and familial Parkinson's disease mutant α-Syn perturbs the association between the ER and mitochondria, leading to ER stress and ultimately neurodegeneration. We examined brains from MSA patients (n = 7) and control subjects (n = 5) using immunohistochemistry and immunoelectron microscopy with antibodies against VAPB and phosphorylated α-Syn. In controls, the cytoplasm of neurons and glial cells was positive for VAPB, whereas in MSA lesions VAPB immunoreactivity was decreased. The proportion of VAPB-negative neurons in the pontine nucleus was significantly higher in MSA (13.6%) than in controls (0.6%). The incidence of cytoplasmic inclusions in VAPB-negative neurons was significantly higher (42.2%) than that in VAPB-positive neurons (3.6%); 67.2% of inclusion-bearing oligodendrocytes and 51.1% of inclusion-containing neurons were negative for VAPB. Immunoelectron microscopy revealed that α-Syn and VAPB were localized to granulofilamentous structures in the cytoplasm of oligodendrocytes and neurons. Many vesicular structures labeled with anti-α-Syn were also observed within the granulofilamentous structures in the cytoplasm and nucleus of both oligodendrocytes and neurons. These findings suggest that, in MSA, reduction of VAPB is involved in the disease process and that vesicular structures are associated with inclusion formation.
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http://dx.doi.org/10.1111/bpa.13001DOI Listing
July 2021

Long Spinal Cord Lesions Caused by Venous Congestive Myelopathy Associated with Intravascular Large B-cell Lymphoma.

Intern Med 2021 Jun 19. Epub 2021 Jun 19.

Department of Neurology, Tsubame Rosai Hospital, Japan.

Intravascular large B-cell lymphoma (IVLBCL) is a subtype of B-cell lymphoma, characterized by lymphoma cell proliferation within small blood vessels. We herein describe a rare case with long spinal cord lesions caused by venous congestive myelopathy associated with IVLBCL. An 81-year-old man presented with paraplegia of the lower limbs and sensory disturbances. Magnetic resonance imaging revealed intramedullary longitudinal T2-hyperintensity lesions in the thoracic cords. The patient died three months after disease onset, and a neuropathological analysis revealed predominantly atypical B-lymphocytes located sparsely in the veins of the spinal cord. IVLBCL should be considered in the differential diagnoses of long spinal cord lesions.
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http://dx.doi.org/10.2169/internalmedicine.6717-20DOI Listing
June 2021

Cytosolic dsDNA of mitochondrial origin induces cytotoxicity and neurodegeneration in cellular and zebrafish models of Parkinson's disease.

Nat Commun 2021 05 25;12(1):3101. Epub 2021 May 25.

Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan.

Mitochondrial dysfunction and lysosomal dysfunction have been implicated in Parkinson's disease (PD), but the links between these dysfunctions in PD pathogenesis are still largely unknown. Here we report that cytosolic dsDNA of mitochondrial origin escaping from lysosomal degradation was shown to induce cytotoxicity in cultured cells and PD phenotypes in vivo. The depletion of PINK1, GBA and/or ATP13A2 causes increases in cytosolic dsDNA of mitochondrial origin and induces type I interferon (IFN) responses and cell death in cultured cell lines. These phenotypes are rescued by the overexpression of DNase II, a lysosomal DNase that degrades discarded mitochondrial DNA, or the depletion of IFI16, which acts as a sensor for cytosolic dsDNA of mitochondrial origin. Reducing the abundance of cytosolic dsDNA by overexpressing human DNase II ameliorates movement disorders and dopaminergic cell loss in gba mutant PD model zebrafish. Furthermore, IFI16 and cytosolic dsDNA puncta of mitochondrial origin accumulate in the brain of patients with PD. These results support a common causative role for the cytosolic leakage of mitochondrial DNA in PD pathogenesis.
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http://dx.doi.org/10.1038/s41467-021-23452-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8149644PMC
May 2021

Low Detection Rate of H3K27M Mutations in Cerebrospinal Fluid Obtained from Lumbar Puncture in Newly Diagnosed Diffuse Midline Gliomas.

Diagnostics (Basel) 2021 Apr 9;11(4). Epub 2021 Apr 9.

Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata 951-8585, Japan.

Recent studies have suggested the feasibility of detecting H3K27M mutations in the cerebrospinal fluid of diffuse midline glioma (DMG) patients. However, cerebrospinal fluid from patients in these studies were collected mainly during biopsy, ventriculo-peritoneal shunt procedures or postmortem. We assessed circulating tumor DNA (ctDNA) extracted from cerebrospinal fluid (CSF) and plasma in a series of 12 radiographically suspected and/or pathologically confirmed diffuse midline glioma patients and assessed for K27M mutation using digital droplet PCR. In 10 patients, CSF was obtained by lumbar puncture at presentation. A definitive detection of K27M mutation was achieved in only one case (10%); K27M mutation was suspected in three other cases (30%). K27M mutation was detected in two patients in CSF obtained by ventricular tap during a ventriculo-peritoneal shunt for obstructive hydrocephalus. Cases in which a definitive assessment was possible (definite K27M or definite wildtype) tended to be younger (median 7.5 years vs. 40.5 years; = 0.07) and have a higher concentration of CSF protein (median 123 mg/dL vs. 27.5 mg/dL; = 0.21) compared to nondefinite cases. Low proliferation and apoptotic rates seemed to be characteristics of DMG unfavorable for liquid biopsy. More advanced lesions with necrosis and evidence of dissemination were unlikely to be candidates for lumbar puncture due to the fear of exacerbating obstructive hydrocephalus. Methods to safely sample CSF and a more sensitive detection of ctDNA are necessary for reliable liquid biopsy of DMG at presentation.
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http://dx.doi.org/10.3390/diagnostics11040681DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070169PMC
April 2021

Hemiplegic-type ALS: clinicopathological features of two autopsied patients.

J Neurol Neurosurg Psychiatry 2021 Apr 21. Epub 2021 Apr 21.

Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan.

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http://dx.doi.org/10.1136/jnnp-2021-326257DOI Listing
April 2021

Betaine ameliorates schizophrenic traits by functionally compensating for KIF3-based CRMP2 transport.

Cell Rep 2021 Apr;35(2):108971

Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Tokyo 113-0033, Japan. Electronic address:

In schizophrenia (SCZ), neurons in the brain tend to undergo gross morphological changes, but the related molecular mechanism remains largely elusive. Using Kif3b mice as a model with SCZ-like behaviors, we found that a high-betaine diet can significantly alleviate schizophrenic traits related to neuronal morphogenesis and behaviors. According to a deficiency in the transport of collapsin response mediator protein 2 (CRMP2) by the KIF3 motor, we identified a significant reduction in lamellipodial dynamics in developing Kif3b neurons as a cause of neurite hyperbranching. Betaine administration significantly decreases CRMP2 carbonylation, which enhances the F-actin bundling needed for proper lamellipodial dynamics and microtubule exclusion and may thus functionally compensate for KIF3 deficiency. Because the KIF3 expression levels tend to be downregulated in the human prefrontal cortex of the postmortem brains of SCZ patients, this mechanism may partly participate in human SCZ pathogenesis, which we hypothesize could be alleviated by betaine administration.
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http://dx.doi.org/10.1016/j.celrep.2021.108971DOI Listing
April 2021

Detailed Postmortem Profiling of Inflammatory Mediators Expression Revealed Post-inflammatory Alternation in the Superior Temporal Gyrus of Schizophrenia.

Front Psychiatry 2021 18;12:653821. Epub 2021 Mar 18.

Department of Neuropsychiatry, School of Medicine, Fukushima Medical University, Fukushima, Japan.

Recent studies have lent support to the possibility that inflammation is associated with the pathology of schizophrenia. In the study of measurement of inflammatory mediators, which are markers of inflammation, elevated inflammatory cytokine levels in the brain and blood have been reported in patients with schizophrenia. Several postmortem brain studies have also reported changes in the expression of inflammatory cytokines. However, it is not clear how these elevated inflammatory cytokines interact with other inflammatory mediators, and their association with the pathology of schizophrenia. We comprehensively investigated the expression of 30 inflammatory mediators in the superior temporal gyrus (STG) of 24 patients with schizophrenia and 26 controls using a multiplex method. Overall, inflammatory mediator expression in the STG was mostly unchanged. However, the expression of interleukin (IL)1-α and interferon-gamma-inducible protein (IP)-10 was decreased [IL-1α, median (IQR), 0.51 (0.37-0.70) vs. 0.87 (0.47-1.23), = 0.01; IP-10, 13.99 (8.00-36.64) vs. 30.29 (10.23-134.73), = 0.05], whereas that of IFN-α was increased [2.34 (1.84-4.48) vs. 1.94 (1.39-2.36), = 0.04] in schizophrenia, although these alterations did not remain significant after multiple testing. Clustering based on inflammatory mediator expression pattern and analysis of upstream transcription factors using pathway analysis revealed that the suppression of IL-1α and IP-10 protein expression may be induced by regulation of a common upstream pathway. Neuroinflammation is important in understanding the biology of schizophrenia. While neuroimaging has been previously used, direct observation to determine the expression of inflammatory mediators is necessary. In this study, we identified protein changes, previously unreported, using comprehensive protein analysis in STG. These results provide insight into post-inflammatory alternation in chronic schizophrenia.
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http://dx.doi.org/10.3389/fpsyt.2021.653821DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8012534PMC
March 2021

Topoisomerase IIβ immunoreactivity (IR) co-localizes with neuronal marker-IR but not glial fibrillary acidic protein-IR in GLI3-positive medulloblastomas: an immunohistochemical analysis of 124 medulloblastomas from the Japan Children's Cancer Group.

Brain Tumor Pathol 2021 Apr 11;38(2):109-121. Epub 2021 Mar 11.

Department of Neuropathology, Aichi Medical University, Institute for Medical Science of Aging, Aichi, Japan.

We previously reported observing GLI3 in medulloblastomas expressing neuronal markers (NM) and/or glial fibrillary acidic protein (GFAP). Furthermore, patients with medulloblastomas expressing NM or GFAP tended to show favorable or poor prognosis, respectively. In the present study, we focused on the role of topoisomerase IIβ (TOP2β) as a possible regulator for neuronal differentiation in medulloblastomas and examined the pathological roles of GLI3, NM, GFAP, and TOP2β expressions in a larger population. We divided 124 medulloblastomas into three groups (NM-/GFAP-, NM +/GFAP-, and GFAP +) based on their immunoreactivity (IR) against NM and GFAP. The relationship among GLI3, NM, GFAP, and TOP2β was evaluated using fluorescent immunostaining and a publicly available single-cell RNA sequencing dataset. In total, 87, 30, and 7 medulloblastomas were classified as NM-/GFAP-, NM + /GFAP-, and GFAP +, and showed intermediate, good, and poor prognoses, respectively. GLI3-IR was frequently observed in NM +/GFAP-  and GFAP + , and TOP2β-IR was frequently observed only in NM +/GFAP-  medulloblastomas. In fluorescent immunostaining, TOP2β-IR was mostly co-localized with NeuN-IR but not with GFAP-IR. In single-cell RNA sequencing, TOP2β expression was elevated in CMAS/DCX-positive, but not in GFAP-positive, cells. NM-IR and GFAP-IR are important for estimating the prognosis of patients with medulloblastoma; hence they should be assessed in clinical practice.
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http://dx.doi.org/10.1007/s10014-021-00396-0DOI Listing
April 2021

Genetic Variations and Neuropathologic Features of Patients with PRKN Mutations.

Mov Disord 2021 Jul 11;36(7):1634-1643. Epub 2021 Feb 11.

Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan.

Background: Mutations in PRKN are the most common cause of autosomal recessive juvenile parkinsonism. The objective of this study was to investigate the association between genotype and pathology in patients with PRKN mutations.

Methods: We performed a sequence and copy number variation analysis of PRKN, mRNA transcripts, Parkin protein expression, and neuropathology in 8 autopsied patients.

Results: All the patients harbored biallelic PRKN mutations. Two patients were homozygous and heterozygous, respectively, for the missense mutation p.C431F. Seven patients had exon rearrangements, including 2 patients from a single family who harbored a homozygous deletion of exon 4, and 3 patients who carried a homozygous duplication of exons 6-7, a homozygous duplication of exons 10-11, and a heterozygous duplication of exons 2-4. In the other 2 patients, we found a compound heterozygous duplication of exon 2, deletion of exon 3, and a heterozygous duplication of exon 2. However, sequencing of cDNA prepared from mRNA revealed 2 different transcripts derived from triplication of exon 2 and deletion of exons 2-3 and from duplication of exons 2-4 and deletion of exons 3-4. Western blotting and immunohistochemistry revealed faint or no expression of Parkin in their brains. In the substantia nigra pars compacta, a subfield-specific pattern of neuronal loss and mild gliosis were evident. Lewy bodies were found in 3 patients. Peripheral sensory neuronopathy was a feature.

Conclusions: Genomic and mRNA analysis is needed to identify the PRKN mutations. Variable mutations may result in no or little production of mature Parkin and the histopathologic features may be similar. © 2021 International Parkinson and Movement Disorder Society.
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http://dx.doi.org/10.1002/mds.28521DOI Listing
July 2021

Novel tankyrase inhibitors suppress TDP-43 aggregate formation.

Biochem Biophys Res Commun 2021 01 30;537:85-92. Epub 2020 Dec 30.

Department of Neuropathology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.

Transactive response DNA-binding protein of 43 kDa (TDP-43) abnormally forms aggregates in certain subtypes of frontotemporal lobar degeneration (FTLD) and in amyotrophic lateral sclerosis (ALS). The pathological forms of TDP-43 have reported to be associated with poly(ADP-ribose) (PAR), which regulates the properties of these aggregates. A recent study has indicated that tankyrase, a member of the PAR polymerase (PARP) family, regulates pathological TDP-43 formation under conditions of stress, and tankyrase inhibitors suppress TDP-43 aggregate formation and cytotoxicity. Since we reported the development of tankyrase inhibitors that are more specific than conventional inhibitors, in this study, we examined their effects on the formation of TDP-43 aggregates in cultured cells. Time-lapse imaging showed that TDP-43 aggregates appeared in the nucleus within 30 min of treatment with sodium arsenite. Several tankyrase inhibitors suppressed the formation of aggregates and decreased the levels of the tankyrase protein. Immunohistochemical studies demonstrated that tankyrase was localized to neuronal cytoplasmic inclusions in the spinal cords of patients with ALS. Moreover, the tankyrase protein levels were significantly higher in the brains of patients with FTLD than in the brains of control subjects. These findings suggest that the inhibition of tankyrase activity protects against TDP-43 toxicity. Tankyrase inhibitors may be a potential treatment to suppress the progression of TDP-43 proteinopathies.
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http://dx.doi.org/10.1016/j.bbrc.2020.12.037DOI Listing
January 2021

Serotonin/5-HT1A Signaling in the Neurovascular Unit Regulates Endothelial CLDN5 Expression.

Int J Mol Sci 2020 Dec 29;22(1). Epub 2020 Dec 29.

Department of Basic Pathology, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan.

We previously reported that site-selective claudin-5 (CLDN5) breakdown and protein kinase A (PKA) activation are observed in brain microvessels of schizophrenia, but the underlying molecular basis remains unknown. The 5-HT1 receptors decline the intracellular cAMP levels and inactivate the major downstream PKA, and the 5-HT1A receptor is a promising target for schizophrenia. Therefore, we elucidated the involvement of serotonin/5-HT1A signaling in the endothelial CLDN5 expression. We demonstrate, by immunohistochemistry using post-mortem human brain tissue, that the 5-HT1A receptor is expressed in brain microvascular endothelial cells (BMVECs) and mural cells of the normal prefrontal cortex (PFC) gray matter. We also show that PKA is aberrantly activated not only in BMVECs but also in mural cells of the schizophrenic PFC. We subsequently revealed that the endothelial cell-pericyte tube-like structure was formed in a novel two-dimensional co-culture of human primary BMVECs and a human brain-derived pericyte cell line, in both of which the 5-HT1A receptor was expressed. Furthermore, we disclose that the serotonin/5-HT1A signaling enhances endothelial CLDN5 expression in BMVECs under two-dimensional co-culture conditions. Our findings provide novel insights into the physiological and pathological significance of serotonin/5-HT1A signaling in the region-specific regulation of the blood-brain barrier.
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http://dx.doi.org/10.3390/ijms22010254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7795278PMC
December 2020

Astrocytes release glutamate via cystine/glutamate antiporter upregulated in response to increased oxidative stress related to sporadic amyotrophic lateral sclerosis.

Neuropathology 2020 Dec 10;40(6):587-598. Epub 2020 Dec 10.

Faculty of Medicine, Tokyo Women's Medical University, Tokyo, Japan.

A vast body of evidence implicates increased oxidative stress and extracellular glutamate accumulation in the pathomechanism of sporadic amyotrophic lateral sclerosis (ALS). Cystine/glutamate antiporter (xCT) carries extracellular cystine uptake and intracellular glutamate release (cystine/glutamate exchange) in the presence of oxidative stress. The aim of the present study was to determine the involvement of xCT in ALS. Immunohistochemical observations in the spinal cord sections demonstrated that xCT was mainly expressed in astrocytes, with staining more intense in 12 sporadic ALS patients as compared to 12 age-matched control individuals. Western blot and densitometric analyses of the spinal cord samples revealed that the relative value of xCT/β-actin optical density ratio was significantly higher in the ALS group as compared to the control group. Next, we conducted cell culture experiments using a human astrocytoma-derived cell line (1321N1) and a mouse motor neuron/neuroblastoma hybrid cell line (NSC34). In 1321N1 cells, the normalized xCT expression levels in cell lysates were significantly increased by H O treatment. Glutamate concentrations in 1321 N1 cell culture-conditioned media were significantly elevated by H O treatment, and the H O -driven elevations were completely canceled by the xCT inhibitor erastin pretreatment. In motor neuron-differentiated NSC34 cells (NSC34d cells), both the normalized xCT expression levels in the cell lysates and glutamate concentrations in the cell-conditioned media were constant with or without H O treatment. The present results provide in vivo and in vitro evidence that astrocytes upregulate xCT expression to release glutamate in response to increased oxidative stress associated with ALS, contributing to extracellular glutamate accumulation.
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http://dx.doi.org/10.1111/neup.12716DOI Listing
December 2020

Longitudinal GluCEST MRI Changes and Cerebral Blood Flow in 5xFAD Mice.

Contrast Media Mol Imaging 2020 25;2020:8831936. Epub 2020 Nov 25.

Neurology, University of California, Davis, USA.

Many of the focal neurological symptoms associated with Alzheimer's disease (AD) are due to synaptic loss. Glutamate chemical exchange saturation transfer (GluCEST) magnetic resonance imaging (MRI) is a candidate method to assess synaptic dysfunction. We assessed chronological changes in GluCEST in a 5xFAD mouse model of AD, comparing Glucest effects and regional cerebral blood flow (CBF). GluCEST effects and CBF in 5xFAD mice aged 1-15 months and their littermates (WT) were measured. Neurite orientation dispersion and density imaging (NODDI) MRI reflecting dendritic/axonal density was also measured and compared with GluCEST in 7-month-old mice. While regional CBF's decrease began at 7 months, GluCEST-reduction effects preceded hypoperfusion of the temporal cortex and hippocampus. While longitudinal 5xFAD mouse measurements revealed a correlation between the regional GluCEST effects and CBF, a generalized linear mixed model revealed statistically different correlations in cortical and basal brain regions. Further, NODDI-derived neurite density correlated with GluCEST effects in the parietal cortex, but not in the hippocampus, thereby revealing regional differences in pathophysiological mechanisms. Finally, GluCEST's effects correlated with regional synaptophysin. These results demonstrate that GluCEST can reflect subtle synaptic changes and may be a potential imaging method for AD diagnosis as well as serve as a biomarker of AD progression.
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http://dx.doi.org/10.1155/2020/8831936DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7714610PMC
November 2020

Comparison of Common and Disease-Specific Post-translational Modifications of Pathological Tau Associated With a Wide Range of Tauopathies.

Front Neurosci 2020 4;14:581936. Epub 2020 Nov 4.

Department of Brain and Neuroscience, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.

Tauopathies are the most common type of neurodegenerative proteinopathy, being characterized by cytoplasmic aggregates of hyperphosphorylated tau protein. The formation and morphologies of these tau inclusions, the distribution of the lesions and related metabolic changes in cytoplasm differ among different tauopathies. The aim of this study was to examine whether there are differences in the post-translational modifications (PTMs) in the pathological tau proteins. We analyzed sarkosyl-insoluble pathological tau proteins prepared from brains of patients with Alzheimer's disease, Pick's disease, progressive supranuclear palsy, corticobasal degeneration, globular glial tauopathy, and frontotemporal dementia and parkinsonisms linked to chromosome 17 with tau inclusions using liquid chromatography mass spectrometry. In pathological tau proteins associated with a wide range of tauopathies, 170 PTMs in total were identified including new PTMs. Among them, common PTMs were localized in the N- and C-terminal flanking regions of the microtubule binding repeats and PTMs, which were considered to be disease-specific, were found in microtubule binding repeats forming filament core. These suggested that the differences in PTMs reflected the differences in tau filament core structures in each disease.
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http://dx.doi.org/10.3389/fnins.2020.581936DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7672045PMC
November 2020

GLI3 Is Associated With Neuronal Differentiation in SHH-Activated and WNT-Activated Medulloblastoma.

J Neuropathol Exp Neurol 2021 01;80(2):129-136

Department of Pathology, Brain Research Institute, Niigata University.

Glioma-associated oncogene homolog 3 (GLI3), whose main function is to inhibit GLI1, has been associated with neuronal differentiation in medulloblastoma. However, it is not clear what molecular subtype(s) show increased GLI3 expression. GLI3 levels were assessed by immunohistochemistry in 2 independent cohorts, including a total of 88 cases, and found to be high in both WNT- and SHH-activated medulloblastoma. Analysis of bulk mRNA expression data and single cell RNA sequencing studies confirmed that GLI1 and GLI3 are highly expressed in SHH-activated medulloblastoma, whereas GLI3 but not GLI1 is highly expressed in WNT-activated medulloblastoma. Immunohistochemical analysis has shown that GLI3 is expressed inside the neuronal differentiated nodules of SHH-activated medulloblastoma, whereas GLI1/2 are expressed in desmoplastic areas. In contrast, GLI3 is diffusely expressed in WNT-activated medulloblastoma, whereas GLI1 is suppressed. Our data suggest that GLI3 may be a master regulator of neuronal differentiation and morphology in these subgroups.
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http://dx.doi.org/10.1093/jnen/nlaa141DOI Listing
January 2021

Progressive supranuclear palsy: Neuropathology of patients with a short disease duration due to unexpected death.

Neuropathology 2021 Jun 17;41(3):174-182. Epub 2020 Nov 17.

Departments of Pathology, Brain Research Institute, Niigata University, Niigata, Japan.

Progressive supranuclear palsy (PSP) presents with a wide variety of signs/symptoms, making early initial diagnosis difficult. We investigated the clinical and neuropathological features of five patients with autopsy-proven PSP of short duration, ranging from 11 to 41 months (average, 26.2 months) due to unexpected death, focusing particularly on the distribution and severity of neuronal loss as well as neuronal and glial tau pathology in the affected brain. Clinical features were studied retrospectively through careful review of the medical records, and neuropathological examinations were carried out, along with tau immunohistochemistry using a monoclonal antibody AT8. These patients were diagnosed as having probable PSP (n = 4) and suggestive PSP (n = 1), respectively. In all cases, neuronal loss was evident in the substantia nigra, subthalamic nucleus, globus pallidus, and locus ceruleus. AT8-identified tau lesions, that is, pretangles/neurofibrillary tangles (PTs/NFTs), tufted astrocytes (TAs), and coiled bodies/neuropil threads (CBs/NTs), were distributed widely in the brain regions, especially in patients with longer disease duration. All cases showed variation in the regional tau burden among PTs/NFTs, TAs, and CBs/NTs. There was also a tendency for tau deposition to be more predominant in neuronal cells in the brainstem and cerebellum and in glial cells in the cerebral cortex and subcortical gray matter. These findings suggest that in PSP, the initial signs/symptoms are associated with degeneration and subsequent death of neurons with pathological tau deposition, and that the tau deposition in neuronal cells is independent of that in glial cells.
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http://dx.doi.org/10.1111/neup.12707DOI Listing
June 2021

Proteomic profile differentiating between mesial temporal lobe epilepsy with and without hippocampal sclerosis.

Epilepsy Res 2020 12 6;168:106502. Epub 2020 Nov 6.

Department of Pathology, Aichi Developmental Disability Center, Japan; Pathology Research Team, Faculty of Health Sciences, Kyorin University, Japan. Electronic address:

Hippocampal sclerosis (HS) is the most common neuropathological condition in adults with drug-resistant epilepsy and represents a critical feature in mesial temporal lobe epilepsy (MTLE) syndrome. Although epileptogenic brain tissue is associated with glutamate excitotoxicity leading to oxidative stress, the proteins that are targets of oxidative damage remain to be determined. In the present study we designed comprehensive analyses of changes in protein expression level and protein oxidation status in the hippocampus or neocortex to highlight proteins associated with excitotoxicity by comparing MTLE patients with relatively mild excitotoxicity (MTLE patients without HS, MTLE-non-HS) and those with severe excitotoxicity (MTLE patients with HS, MTLE-HS). We performed 2-dimensional fluorescence difference gel electrophoresis, 2D-oxyblot analysis, and mass spectrometric amino acid sequencing. We identified 16 proteins at 18 spots in which the protein expression levels differed between sclerotic and non-sclerotic hippocampi. In the sclerotic hippocampus, the expression levels of several synaptic proteins were decreased, and those of some glia-associated proteins increased. We confirmed histologically that all MTLE-HS cases examined exhibited severe neuronal cell loss and remarkable astrocytic gliosis in the hippocampi. In all MTLE-non-HS cases examined, neurons were spared and gliosis was unremarkable. Therefore, we consider that decreased synaptic proteins are a manifestation of loss of neuronal cell bodies and dendrites, whereas increased glia-associated proteins are a manifestation of proliferation and hypertrophy of astrocytes. These are considered to be the result of hippocampal sclerosis. In contrast, the expression level of d-3-phosphoglycerate dehydrogenase (PHGDH), an l-serine synthetic enzyme expressed exclusively by astrocytes, was decreased, and that of stathmin 1, a neurite extension-related protein expressed by neurons, was increased in the sclerotic hippocampus. These findings cannot be explained solely as the result of hippocampal sclerosis. Rather, these changes can be involved in the continuation of seizure disorders in MTLE-HS. In addition, the protein carbonylation detection, an indicator of protein oxidation caused by excitotoxicity of multiple seizures and/or status epilepticus, revealed that the carbonyl level of collapsin response mediator protein 2 (CRMP2) increased significantly in the sclerotic hippocampus. In conclusion, protein identification following profiling of protein expression levels and detection of oxidative proteins indicated potential pathognomonic protein changes. The decreased expression of PHGDH, increased expression of stathmin 1, and carbonylation of CRMP2 differentiate between MTLE with and without HS. Therefore, further investigations of PHGDH, stathmin 1 and CRMP2 are promising to study more detailed effects of excitotoxicity on epileptogenic hippocampal tissue.
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http://dx.doi.org/10.1016/j.eplepsyres.2020.106502DOI Listing
December 2020

Toward allele-specific targeting therapy and pharmacodynamic marker for spinocerebellar ataxia type 3.

Sci Transl Med 2020 10;12(566)

Department of Pathology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan.

Spinocerebellar ataxia type 3 (SCA3), caused by a CAG repeat expansion in the ataxin-3 gene (), is characterized by neuronal polyglutamine (polyQ) ATXN3 protein aggregates. Although there is no cure for SCA3, gene-silencing approaches to reduce toxic polyQ ATXN3 showed promise in preclinical models. However, a major limitation in translating putative treatments for this rare disease to the clinic is the lack of pharmacodynamic markers for use in clinical trials. Here, we developed an immunoassay that readily detects polyQ ATXN3 proteins in human biological fluids and discriminates patients with SCA3 from healthy controls and individuals with other ataxias. We show that polyQ ATXN3 serves as a marker of target engagement in human fibroblasts, which may bode well for its use in clinical trials. Last, we identified a single-nucleotide polymorphism that strongly associates with the expanded allele, thus providing an exciting drug target to abrogate detrimental events initiated by mutant ATXN3. Gene-silencing strategies for several repeat diseases are well under way, and our results are expected to improve clinical trial preparedness for SCA3 therapies.
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http://dx.doi.org/10.1126/scitranslmed.abb7086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7927160PMC
October 2020

Fatal Progressive Meningoencephalitis Diagnosed in Two Members of a Family With X-Linked Agammaglobulinemia.

Front Pediatr 2020 18;8:579. Epub 2020 Sep 18.

Department of Pediatrics, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.

Chronic enteroviral meningoencephalitis is a well-known complication in patients with X-linked agammaglobulinemia (XLA). However, progressive neurodegenerative disorders or chronic neuroinflammatory diseases with no causative microorganisms have been recognized as rare central nervous system (CNS) complications in XLA. We herein report a family in which two of three members with XLA had developed progressive meningoencephalitis with an unknown etiology. A 15-month-old male infant presented with left-sided ptosis. Initially, the family denied any family history of inherited diseases, but later disclosed a family history of agammaglobulinemia previously diagnosed in two family members. In the early 1980s, one of the elder brothers of the index patient's mother who had been treated with intramuscular immunoglobulin [or later intravenous immunoglobulin (IVIG)] for agammaglobulinemia deceased at 10 years of age after showing progressive neurological deterioration during the last several years of his life. The index patient was diagnosed with XLA caused by Bruton tyrosine kinase deficiency (654delG; Val219Leufs9), and chronic meningoencephalitis with an unknown infectious etiology. Magnetic resonance imaging of the brain demonstrated inflammatory changes in the basal ganglia, hypothalamus, midbrain, and pons, with multiple nodular lesions with ring enhancement, which showed impressive amelioration after the initiation of IVIG replacement therapy. Pleocytosis, which was characterized by an increase in CD4-positive and CD8-positive T cells expressing an activation marker and an elevation in inflammatory cytokines in the cerebrospinal fluid, was identified. No microorganism was identified as a cause of CNS complications. He thereafter developed brain infarction at 19 months of age and fatal status epilepticus at 5 years of age, despite regular IVIG with high trough levels and regular intraventricular immunoglobulin administration. The etiology of this rare CNS complication in XLA is currently unknown. Previous studies have suggested a possible association of IVIG, which was clearly denied in our index case because of the demonstration of his neurological disorder at presentation. In the future, extensive and unbiased molecular methods to detect causative microorganisms, as well as to investigate the possible role of autoimmunity are needed to clarify the etiology of CNS complications.
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http://dx.doi.org/10.3389/fped.2020.00579DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7530192PMC
September 2020

Exploring the factors underlying remyelination arrest by studying the post-transcriptional regulatory mechanisms of cystatin F gene.

J Neurochem 2021 Jun 1;157(6):2070-2090. Epub 2020 Oct 1.

Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan.

Remyelination plays an important role in determining the fate of demyelinating disorders. However, it is arrested during chronic disease states. Cystatin F, a papain-like lysosomal cysteine proteinase inhibitor, is a crucial regulator of demyelination and remyelination. Using hemizygous proteolipid protein transgenic 4e (PLP ) mice, an animal model of chronic demyelination, we found that cystatin F mRNA expression was induced at 2.5 months of age and up-regulated in the early phase of demyelination, but significantly decreased in the chronic phase. We next investigated cystatin F regulatory factors as potential mechanisms of remyelination arrest in chronic demyelinating disorders. We used the CysF-STOP-tetO::Iba-mtTA mouse model, in which cystatin F gene expression is driven by the tetracycline operator. Interestingly, we found that forced cystatin F mRNA over-expression was eventually decreased. Our findings show that cystatin F expression is modulated post-transcriptionally. We next identified embryonic lethal, abnormal vision, drosophila like RNA-binding protein 1 (ELAVL-1), and miR29a as cystatin F mRNA stabilizing and destabilizing factors, respectively. These roles were confirmed in vitro in NIH3T3 cells. Using postmortem plaque samples from human multiple sclerosis patients, we also confirmed that ELAVL-1 expression was highly correlated with the previously reported expression pattern of cystatin F. These data indicate the important roles of ELAVL-1 and miR29a in regulating cystatin F expression. Furthermore, they provide new insights into potential therapeutic targets for demyelinating disorders.
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http://dx.doi.org/10.1111/jnc.15190DOI Listing
June 2021

Novel CHP1 mutation in autosomal-recessive cerebellar ataxia: autopsy features of two siblings.

Acta Neuropathol Commun 2020 08 12;8(1):134. Epub 2020 Aug 12.

Department of Pathology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8585, Japan.

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http://dx.doi.org/10.1186/s40478-020-01008-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7425070PMC
August 2020

Praja1 RING-finger E3 ubiquitin ligase suppresses neuronal cytoplasmic TDP-43 aggregate formation.

Neuropathology 2020 Dec 19;40(6):570-586. Epub 2020 Jul 19.

Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan.

Transactivation response DNA-binding protein of 43 kDa (TDP-43) is a major constituent of cytoplasmic aggregates in neuronal and glial cells in cases of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). We have previously shown neuronal cytoplasmic aggregate formation induced by recombinant adenoviruses expressing human wild-type and C-terminal fragment (CTF) TDP-43 under the condition of proteasome inhibition in vitro and in vivo. In the present study, we demonstrated that the formation of the adenoviral TDP-43 aggregates was markedly suppressed in rat neural stem cell-derived neuronal cells by co-infection of an adenovirus expressing heat shock transcription factor 1 (HSF1), a master regulator of heat shock response. We performed DNA microarray analysis and searched several candidate molecules, located downstream of HSF1, which counteract TDP-43 aggregate formation. Among these, we identified Praja 1 RING-finger E3 ubiquitin ligase (PJA1) as a suppressor of phosphorylation and aggregate formation of TDP-43. Co-immunoprecipitation assay revealed that PJA1 binds to CTF TDP-43 and the E2-conjugating enzyme UBE2E3. PJA1 also suppressed formation of cytoplasmic phosphorylated TDP-43 aggregates in mouse facial motor neurons in vivo. Furthermore, phosphorylated TDP-43 aggregates were detected in PJA1-immunoreactive human ALS motor neurons. These results indicate that PJA1 is one of the principal E3 ubiquitin ligases for TDP-43 to counteract its aggregation propensity and could be a potential therapeutic target for ALS and FTLD.
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http://dx.doi.org/10.1111/neup.12694DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7818255PMC
December 2020

MicroRNA-5572 Is a Novel MicroRNA-Regulating in Sporadic Amyotrophic Lateral Sclerosis.

Int J Mol Sci 2020 Jun 24;21(12). Epub 2020 Jun 24.

Laboratory of Medical Therapeutics and Molecular Therapeutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi Gifu city, Gifu 501-1196, Japan.

Amyotrophic lateral sclerosis (ALS) is a progressive degenerative disease caused by the loss of motor neurons. Although the pathogenesis of sporadic ALS (sALS) remains unclear, it has recently been suggested that disorders of microRNA (miRNA) may be involved in neurodegenerative conditions. The purpose of this study was to investigate miRNA levels in sALS and the target genes of miRNA. Microarray and real-time RT-PCR analyses revealed significantly-decreased levels of miR-139-5p and significantly increased levels of miR-5572 in the spinal cords of sALS patients compared with those in controls. We then focused on miR-5572, which has not been reported in ALS, and determined its target gene. By using TargetScan, we predicted as the candidate target gene of miR-5572. In a previous study, we found decreased levels in the spinal cords of sALS patients. We revealed that was regulated by miR-5572. Taken together, these results demonstrate that the level of novel miRNA miR-5572 is increased in sALS and that is one of the target genes regulated by miR-5572.
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http://dx.doi.org/10.3390/ijms21124482DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7350020PMC
June 2020

Methylmercury exposure during the vulnerable window of the cerebrum in postnatal developing rats.

Environ Res 2020 09 9;188:109776. Epub 2020 Jun 9.

National Institute for Minamata Disease, Minamata, Japan.

The developing brain is known to be sensitive to the toxic effects of methylmercury (MeHg). The effects of toxic levels of MeHg exposure during the most seemingly vulnerable window of the cerebrum are not well studied. In this study, we aimed to examine the specific effects of toxic levels of MeHg on neurobehavior, neurodegeneration, and selenoenzyme activity in the cerebrum of infant rats. Male Wistar rats (n = 8/group) were orally treated with MeHg at an acute toxic dose (8 mg Hg/kg/day) for 10 consecutive days starting on postnatal day 14 (P14). The MeHg-exposed rats showed a significant reduction in body weight after day 8 and severe neurological symptoms similar to dystonia on day 12 (P25). Motor coordination deficits determined using the rotarod performance test and short-term memory impairment determined using the Y-maze task were observed in the MeHg-exposed rats on day 11 (P24). The MeHg-exposed rats sacrificed on day 12 showed severe cerebral neuronal degeneration, reactive astrocytosis, and TUNEL-positive apoptotic nuclei, with the cerebral Hg concentration of 15.0 ± 1.6 μg/g. Furthermore, the activities of glutathione peroxidase and thioredoxin reductase in the cerebrum in MeHg-exposed rats were lower than those in control. These results indicate that MeHg exposure to infant rats will be useful to predict the effects of MeHg at the cerebral growth spurt in humans.
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http://dx.doi.org/10.1016/j.envres.2020.109776DOI Listing
September 2020