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13
result(s) for
"Shirafuji, Norimichi"
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Autophagy and Tau Protein
by
Enomoto, Soichi
,
Nakamoto, Yasunari
,
Hamano, Tadanori
in
Alzheimer's disease
,
Autophagy
,
Homeostasis
2021
Neurofibrillary tangles, which consist of highly phosphorylated tau protein, and senile plaques (SPs) are pathological hallmarks of Alzheimer’s disease (AD). In swollen axons, many autophagic vacuoles are observed around SP in the AD brain. This suggests that autophagy function is disturbed in AD. We used a neuronal cellular model of tauopathy (M1C cells), which harbors wild type tau (4R0N), to assess the effects of the lysosomotrophic agent NH4Cl, and autophagy inhibitors chloroquine and 3 methyladenine (3MA). It was found that chloroquine, NH4Cl and 3MA markedly increased tau accumulation. Thus, autophagy lysosomal system disturbances disturbed the degradation mechanisms of tau protein. Other studies also revealed that tau protein, including aggregated tau, is degraded via the autophagy lysosome system. Phosphorylated and C terminal truncated tau were also reported to disturb autophagy function. As a therapeutic strategy, autophagy upregulation was suggested. Thus far, as autophagy modulators, rapamycin, mTOCR1 inhibitor and its analogues, lithium, metformin, clonidine, curcumin, nicotinamide, bexaroten, and torehalose have been proposed. As a therapeutic strategy, autophagic modulation may be the next target of AD therapeutics.
Journal Article
Homocysteine Increases Tau Phosphorylation, Truncation and Oligomerization
2018
Increased plasma homocysteinemia is considered a risk factor of dementia, including Alzheimer’s disease (AD) and vascular dementia. However, the reason elevated plasma homocysteinemia increases the risk of dementia remains unknown. A pathological hallmark of AD is neurofibrillary tangles (NFTs) that consist of pathologically phosphorylated tau proteins. The effect of homocysteine (Hcy) on tau aggregation was explored using human neuroblastoma M1C cells that constitutively express human wild-type tau (4R0N) under the control of a tetracycline off system, primary mouse cultured neurons, and by inducing hyperhomocysteinemia in a mouse model of tauopathy (HHCy mice). A wide range of Hcy concentrations (10–1000 µM) increased total tau and phosphorylated tau protein levels. Hcy activated glycogen synthase kinase 3, and cyclin dependent kinase 5, major tau phosphokinases, and inactivated protein phosphatase 2A, a main tau phosphatase. Hcy exhibited cytotoxic effects associated with enhanced activation of caspase. Truncation of tau in the C-terminus, the cleavage site of caspase 3 (i.e., D421, detected by the TauC3 antibody) was also increased. Total tau, phosphorylated tau, as well as C-terminal cleaved tau were increased in the sarkosyl insoluble tau fraction. Hcy also increased the level of tau oligomers, as indicated by the tau oligomer complex 1 (TOC1) antibody that specifically identifies oligomeric tau species, in the tris insoluble, sarkosyl soluble fraction. The levels of TOC1-positive oligomeric tau were increased in brain lysates from HHCy mice, and treating HHCy mice with S-adenosylmethionine, an intermediate of Hcy, reduced the levels of oligomeric tau to control levels. These observations suggest that Hcy increases the levels of phosphorylated tau as well as truncated tau species via caspase 3 activation, and enhanced tau oligomerization and aggregation.
Journal Article
Intravascular Large B-Cell Lymphoma Diagnosed After Recurrent Stroke: Case Report and Literature Review
2025
Background/Objectives: We describe a case of intravascular large B-cell lymphoma (IVLBCL) presenting with recurrent cerebral infarctions and review similar reported cases. Our aim is to explore potential early diagnostic markers and discuss their prognostic implications. Methods/Results: A 79-year-old man with a history of hypertension, hyperuricemia, and postoperative bladder cancer presented with five to six cerebral infarctions over an 11-month period, despite successive changes in antiplatelet and anticoagulant medications. Neurological examination revealed decreased pain sensation, bilateral hearing loss, and right thenar atrophy. Laboratory studies showed elevated inflammatory markers and soluble IL-2 receptor. CSF analysis revealed elevated protein, β2-microglobulin, IL-6, and IL-10 levels. A skin biopsy was performed to investigate suspected IVLBCL. Histopathological examination of the skin biopsy revealed large pleomorphic CD20-positive cells within the vasculature, confirming a diagnosis of IVLBCL. The patient was treated with chemotherapy, including dose-adjusted R-CHOP and high-dose methotrexate, and achieved complete remission. No recurrence of cerebral infarction was observed during a two-year follow-up period. Conclusions: This case highlights the importance of considering IVLBCL in patients with recurrent strokes of unknown etiology, especially when laboratory or imaging findings suggest systemic involvement. Early recognition and appropriate tissue diagnosis, such as skin biopsy, are essential for timely treatment and favorable prognosis.
Journal Article
Clioquinol Decreases Levels of Phosphorylated, Truncated, and Oligomerized Tau Protein
by
Sasaki, Hirohito
,
Endo, Yoshinori
,
Ueno, Asako
in
Alzheimer Disease - drug therapy
,
Alzheimer Disease - metabolism
,
Alzheimer Disease - pathology
2021
The neuropathological hallmarks of Alzheimer’s disease (AD) are senile plaques (SPs), which are composed of amyloid β protein (Aβ), and neurofibrillary tangles (NFTs), which consist of highly phosphorylated tau protein. As bio-metal imbalance may be involved in the formation of NFT and SPs, metal regulation may be a direction for AD treatment. Clioquinol (CQ) is a metal-protein attenuating compound with mild chelating effects for Zn2+ and Cu2+, and CQ can not only detach metals from SPs, but also decrease amyloid aggregation in the brain. Previous studies suggested that Cu2+ induces the hyperphosphorylation of tau. However, the effects of CQ on tau were not fully explored. To examine the effects of CQ on tau metabolism, we used a human neuroblastoma cell line, M1C cells, which express wild-type tau protein (4R0N) via tetracycline-off (TetOff) induction. In a morphological study and ATP assay, up to 10 μM CQ had no effect on cell viability; however, 100 μM CQ had cytotoxic effects. CQ decreased accumulation of Cu+ in the M1C cells (39.4% of the control), and both total and phosphorylated tau protein. It also decreased the activity of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) (37.3% and 60.7% levels of the control, respectively), which are tau kinases. Of note, activation of protein phosphatase 2A (PP2A), which is a tau phosphatase, was also observed after CQ treatment. Fractionation experiments demonstrated a reduction of oligomeric tau in the tris insoluble, sarkosyl soluble fraction by CQ treatment. CQ also decreased caspase-cleaved tau, which accelerated the aggregation of tau protein. CQ activated autophagy and proteasome pathways, which are considered important for the degradation of tau protein. Although further studies are needed to elucidate the mechanisms responsible for the effects of CQ on tau, CQ may shed light on possible AD therapeutics.
Journal Article
Effectiveness of a self-reporting yes/no survey for dementia screening—trial in Fukui, Japan
by
Fujita, Youshi
,
Endo, Yoshinori
,
Ueno, Asako
in
Aging Neuroscience
,
dementia screening
,
epidemiology
2023
Background: Early intervention for dementia patients is extremely important for the prevention of dementia. However, so far, it is not clear as to what kind of screening will be useful for the early detection of dementia. Objective: We aimed to investigate the relationship between the results of a short self-reporting yes/no survey selected in Kihon Checklist, developed by the Japanese Ministry of Health, Labor and Welfare to identify older adults who are at risk of requiring support/care, and other original items developed by Dementia Prevention Team, Fukui, Japan, and Mini-Mental State Examination (MMSE) scores, and determine the diagnostic efficacy of the self-reporting yes/no survey. Methods: Self-reporting yes/no surveys were conducted for 87,687 individuals aged ≥65 years, living in Fukui, Japan, and did not have Long-Term Care Insurance, Japan. According to the survey results, selected individuals were advised to visit a local hospital to be assessed with MMSE. Results: Individuals who could not make a call by looking up phone numbers and manage their own deposits and savings at the bank or automatic teller machine (ATM) had an increased risk of low MMSE score (≤23; odds ratio: 2.74 [1.89–3.97]; 95% confidence interval: 2.12 [1.46–3.07]). Conclusions: Self-reporting yes/no survey could effectively screen for dementia. Not being able to make a call by looking up phone numbers and not being able to manage their own deposits and savings at the bank or ATM are signs of dementia.
Journal Article
An exploratory, open-label, randomized, multicenter trial of hachimijiogan for mild Alzheimer’s disease
by
Iritani, Osamu
,
Hieda, Sotaro
,
Kawakatsu, Shinobu
in
Acetylcholinesterase
,
ADAS‐Jcog
,
Alzheimer's disease
2022
Background: Alzheimer’s disease (AD) is a progressive neurodegeneration and is the most prevalent form of dementia. Intervention at an early stage is imperative. Although three acetylcholinesterase inhibitors (AChEIs) are currently approved for the treatment of mild AD, they are not sufficiently effective. Novel treatments for mild AD are of utmost importance. Objective: To assess the effectiveness of hachimijiogan (HJG), a traditional Japanese herbal medicine (Kampo), in the treatment of mild AD. Methods: This exploratory, open-label, randomized, multicenter trial enrolled patients with mild AD whose score on the Mini Mental State Examination (MMSE) was over 21points. All participants had been taking the same dosage of AChEI for more than 3 months. The participants were randomly assigned to an HJG group taking HJG extract 7.5 g/day in addition to AChEI or to a control group treated only with AChEI. The primary outcome was the change from baseline to 6 months post treatment initiation on the Alzheimer’s Disease Assessment Scale-cognitive component- Japanese version(ADAS-Jcog). The secondary outcomes were change from baseline of the Instrumental Activity of Daily Life (IADL), Apathy scale, and Neuropsychiatric Inventory (NPI) -Q score. Results: Among the 77 enrollees, the data of 69(34 HJG and 35 control)were available for analysis. The difference in the change of ADAS-Jcog from baseline to 6 months of the HJG and control groups was 1.29 (90% Confidence interval (CI), −0.74 to 3.32 p = 0.293). In the subgroup analysis, the differences in the change from baseline to 3 and 6 months for women were 3.70 (90% CI ,0.50 to 6.91, p = 0.059) and 2.90 (90% CI,0.09 to 5.71, p = 0.090), respectively. For patients over 65 years, the difference at 3 months was 2.35 (90%CI, 0.01 to 4.68 p = 0.099). No significant differences were found between the HJG and control groups in IADL score, Apathy scale, or NPI-Q score. Conclusion: Although not conclusive, our data indicate that HJG has an adjuvant effect for acetylcholinesterase inhibitors and that it delays the deterioration of the cognitive dysfunction of mild Altzheimer’s disease patients. Clinical Trial Registration: http://clinicaltrials.gov Japan Registry of clinical trials, identifier jRCTs 071190018
Journal Article
Metabolic changes in the plasma of mild Alzheimer’s disease patients treated with Hachimijiogan
by
Iritani, Osamu
,
Hieda, Sotaro
,
Kawakatsu, Shinobu
in
Alzheimer's disease
,
Aspartic acid
,
Biomarkers
2023
Background: Alzheimer’s disease (AD), the most prevalent form of dementia, is a debilitating, progressive neurodegeneration. Amino acids play a wide variety of physiological and pathophysiological roles in the nervous system, and their levels and disorders related to their synthesis have been related to cognitive impairment, the core feature of AD. Our previous multicenter trial showed that hachimijiogan (HJG), a traditional Japanese herbal medicine (Kampo), has an adjuvant effect for Acetylcholine estelase inhibitors (AChEIs) and that it delays the deterioration of the cognitive dysfunction of female patients with mild AD. However, there are aspects of the molecular mechanism(s) by which HJG improves cognitive dysfunction that remain unclear. Objectives: To elucidate through metabolomic analysis the mechanism(s) of HJG for mild AD based on changes in plasma metabolites. Methods: Sixty-seven patients with mild AD were randomly assigned to either an HJG group taking HJG extract 7.5 g/day in addition to AChEI or to a control group treated only with AChEI (HJG:33, Control:34). Blood samples were collected before, 3 months, and 6 months after the first drug administration. Comprehensive metabolomic analyses of plasma samples were done by optimized LC-MS/MS and GC-MS/MS methods. The web-based software MetaboAnalyst 5.0 was used for partial least square-discriminant analysis (PLS-DA) to visualize and compare the dynamics of changes in the concentrations of the identified metabolites. Results: The VIP (Variable Importance in Projection) score of the PLS-DA analysis of female participants revealed a significantly higher increase in plasma metabolite levels after HJG administration for 6 months than was seen in the control group. In univariate analysis, the aspartic acid level of female participants showed a significantly higher increase from baseline after HJG administration for 6 months when compared with the control group. Conclusion: Aspartic acid was a major contributor to the difference between the female HJG and control group participants of this study. Several metabolites were shown to be related to the mechanism of HJG effectiveness for mild AD.
Journal Article
Traditional Japanese Kampo Medicine Yokukansan decreases phosphorylated tau and oligomeric tau
2024
Background One of the pathological hallmarks in Alzheimer’s disease (AD) brain is neurofibrillary tangles (NFTs) composed of highly phosphorylated tau protein. Clinical benefit of traditional Japanese Kampo Yokukansan for dementia patients, including AD was suggested. In this study, we investigated whether yokukansan participates in the degradation of phosphorylated tau and toxic oligomeric species of tau by using cell culture model of tauopathy, M1C cells. Method Neuronal cellular model of tauopathy, M1C cells which expresses wild type tau protein (4R0N) via tetracycline off induction (TetOff induction) was used in this study. M1C cells were treated with Ten to fifty ug/mL of Yokukansan and analyzed by Western blot analysis. Various phosphorylated tau antibodies (AT 180, AT270, and PS199/202) were used to detect phosphorylated tau. Oligomeric tau was examined by anti‐oligomeric tau specific antibody (TOC‐1) by dot blot analysis. Result Up to 100 µg/mL of Yokukansan has no cytotoxic effects on M1C cells examined by morphological study, and ATP assay. WB analysis disclosed that of 10 to 50 µg/mL of yokukansan decreased phosphorylated tau detected by AT180, AT270, and PS199/202. Oligomeric tau detected by TOC1 also decreased by Yokukansan treatment. Major tau phosphatase GSK3β was inactivated by Yokukansan treatment. Autophagy marker P62 was downregulated by Yokukansan treatment. Conclusion These results suggest that phosphorylated tau and oligomeric tau was reduced by Yokukansan via tau kinase inactivation and autophagy activation. Although the exact mechanisms of yokukansan on tau phosphorylation and oligomerization should be explored, these results shed light on the therapeutics of tauopathy, including AD.
Journal Article
Influences of Vitamin B12 Supplementation on Cognition and Homocysteine in Patients with Vitamin B12 Deficiency and Cognitive Impairment
by
Ueno, Asako
,
Enomoto, Soichi
,
Nakamoto, Yasunari
in
Acids
,
Alzheimer's disease
,
Animal cognition
2022
Vitamin B12 deficiency is associated with cognitive impairment, hyperhomocysteinemia, and hippocampal atrophy. However, the recovery of cognition with vitamin B12 supplementation remains controversial. Of the 1716 patients who visited our outpatient clinic for dementia, 83 had vitamin B12 deficiency. Among these, 39 patients (mean age, 80.1 ± 8.2 years) had undergone Mini-Mental State Examination (MMSE) and laboratory tests for vitamin B12, homocysteine (Hcy), and folic acid levels. The hippocampal volume was estimated using the z-score of the MRI-voxel-based specific regional analysis system for Alzheimer’s disease. This is multi-center, open-label, single-arm study. All the 39 patients were administered vitamin B12 and underwent reassessment to measure the retested for MMSE and Hcy after 21−133 days (median = 56 days, interquartile range (IQR) = 43–79 days). After vitamin B12 supplementation, the mean MMSE score improved significantly from 20.5 ± 6.4 to 22.9 ± 5.5 (p < 0.001). Hcy level decreased significantly from 22.9 ± 16.9 nmol/mL to 11.5 ± 3.9 nmol/mL (p < 0.001). Significant correlation was detected between the extent of change in MMSE scores and baseline Hcy values. The degree of MMSE score was not correlated with hippocampal atrophy assessed by the z-score. While several other factors should be considered, vitamin B12 supplementation resulted in improved cognitive function, at least in the short term, in patients with vitamin B12 deficiency.
Journal Article
Arterial spin labeling imaging for the detection of cerebral blood flow asymmetry in patients with corticobasal syndrome
2022
Purpose
Corticobasal syndrome (CBS) and Parkinson’s disease (PD) both present with asymmetrical extrapyramidal symptoms, often leading to a diagnostic dilemma. Patients with CBS frequently show cerebral blood flow (CBF) asymmetry alongside asymmetrical cortical atrophy. This study aimed to evaluate the clinical utility of arterial spin labeling (ASL) magnetic resonance imaging (MRI) to detect CBF asymmetry in patients with CBS.
Methods
We retrospectively investigated asymmetries of regional CBF and cortical volume, measured using ASL and T1-weighted MRI, in 13 patients with CBS and 22 age-matched patients with PD. Regional CBF and cortical volume values were derived from nine brain regions on each side. CBF and volume asymmetries were calculated as %difference in each region, respectively.
Results
CBF asymmetry showed significantly greater differences in seven of nine regions, such as the perirolandic area (− 8.7% vs. − 1.4%,
p
< 0.001) and parietal cortex (− 9.7% vs. − 1.3%,
p
< 0.001) in patients with CBS compared with patients with PD. In contrast, significant differences in volume asymmetry were observed in three regions included within the seven regions showing CBF asymmetry, which indicated that CBF asymmetry has greater sensitivity than volume asymmetry to detect asymmetricity in CBS.
Conclusion
ASL imaging showed significant CBF asymmetry in a wider range of brain regions in patients with CBS, which suggests that noninvasive MRI with ASL imaging is a promising tool for the diagnosis of CBS, with advantages that include the simultaneous evaluation of asymmetrical hypoperfusion in addition to focal atrophy.
Journal Article