Publications by authors named "Satoru Morimoto"

This study introduces a novel method for rapidly and efficiently inducing human spinal lower motor neurons (LMNs) from induced pluripotent stem cells (iPSCs) to eventually elucidate the pathomechanisms of amyotrophic lateral sclerosis (ALS) and facilitate drug screening. Previous methods were limited by low induction efficiency, poor LMN purity, or labor-intensive induction and evaluation processes. Our protocol overcomes these challenges, achieving around 80% induction efficiency within just two weeks by combining a small molecule-based approach with transcription factor transduction.

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Purpose: Although neuropathological comorbidities, including Alzheimer's disease neuropathological change (AD-NC) and limbic-predominant age-related TAR DNA-binding protein 43encephalopathy neuropathological change (LATE-NC), are associated with medial temporal atrophy in patients with Lewy body disease (LBD), the diagnostic performance of magnetic resonance imaging (MRI)-derived indices remains unclear. This study aimed to investigate the diagnostic performance of MRI-derived indices representing medial temporal atrophy in differentiating between LBD with AD-NC and/or LATE-NC (mixed LBD [mLBD]) and without these comorbidities (pure LBD [pLBD]).

Methods: This study included 24 and 16 patients with pathologically confirmed mLBD and pLBD, respectively.

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Article Synopsis
  • Advanced genetic studies have identified mutations in the FUS/TLS gene, important for DNA repair and RNA processing, as a cause of familial ALS.
  • A CRISPR-Cas9 technique was used to create mouse models with the FUS-ALS mutation, which exhibited progressive motor impairment and neuron damage, similar to symptoms seen in ALS patients.
  • The findings support the idea that disruptions in nuclear structure are significant in ALS, highlighting the potential of these models for future research and therapy development.
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Amyotrophic lateral sclerosis (ALS) is a major neurodegenerative disease for which there is currently no curative treatment. The blood-brain barrier (BBB), multiple physiological functions formed by mainly specialized brain microvascular endothelial cells (BMECs), serves as a gatekeeper to protect the central nervous system (CNS) from harmful molecules in the blood and aberrant immune cell infiltration. The accumulation of evidence indicating that alterations in the peripheral milieu can contribute to neurodegeneration within the CNS suggests that the BBB may be a previously overlooked factor in the pathogenesis of ALS.

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Background: Extracellular vesicles (EVs) hold the potential for elucidating the pathogenesis of amyotrophic lateral sclerosis (ALS) and serve as biomarkers. Notably, the comparative and longitudinal alterations in the protein profiles of EVs in serum (sEVs) and cerebrospinal fluid (CSF; cEVs) of sporadic ALS (SALS) patients remain uncharted. Ropinirole hydrochloride (ROPI; dopamine D2 receptor [D2R] agonist), a new anti-ALS drug candidate identified through induced pluripotent stem cell (iPSC)-based drug discovery, has been suggested to inhibit ALS disease progression in the Ropinirole Hydrochloride Remedy for Amyotrophic Lateral Sclerosis (ROPALS) trial, but its mechanism of action is not well understood.

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Amyotrophic Lateral Sclerosis/Parkinsonism-Dementia Complex (ALS/PDC), a rare and complex neurological disorder, is predominantly observed in the Western Pacific islands, including regions of Japan, Guam, and Papua. This enigmatic condition continues to capture medical attention due to affected patients displaying symptoms that parallel those seen in either classical amyotrophic lateral sclerosis (ALS) or Parkinson's disease (PD). Distinctly, postmortem examinations of the brains of affected individuals have shown the presence of α-synuclein aggregates and TDP-43, which are hallmarks of PD and classical ALS, respectively.

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Recent studies suggest that increased cerebrospinal fluid (CSF) phospho-tau is associated with brain amyloid pathology rather than the tau pathology. However, confirmation using gold standard neuropathological assessments remains limited. This study aimed to determine background pathologies associated with aberrant CSF p-tau181 and amyloid-beta 1-42 (Aβ42) in Alzheimer's disease (AD) and other neurodegenerative diseases.

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Background: The influence of limbic-predominant age-related TAR DNA-binding protein of 43 kDa encephalopathy neuropathological change (LATE-NC) on structural alterations in argyrophilic grain disease (AGD) have not been documented. This study aimed to investigate the morphological impact of LATE-NC on AGD through voxel-based morphometry (VBM) technique.

Materials And Methods: Fifteen individuals with pathologically verified AGD, comprising 6 with LATE-NC (comorbid AGD [cAGD]) and 9 without LATE-NC (pure AGD [pAGD]), along with 10 healthy controls (HC) were enrolled.

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Article Synopsis
  • - The ALS/PDC is a serious, fatal neurodegenerative disease found in Guam and Japan, marked by the presence of tau protein accumulations in the brain and spinal cord.
  • - Researchers used advanced electron cryo-microscopy techniques to analyze tau filaments from multiple ALS/PDC cases, discovering a range of filament structures, including a newly identified Type III CTE tau filament.
  • - The findings suggest that ALS/PDC, along with other related conditions, may be triggered by environmental factors, supporting the idea of exogenous causes behind these tauopathies.
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Human neural cell models derived from induced pluripotent stem cells (iPSCs) have been widely accepted to model various neurodegenerative diseases such as Alzheimer's disease (AD) . Although the most common sources of iPSCs are fibroblasts and peripheral blood mononuclear cells, the collection of these cells is invasive. To reduce the donor's burden, we propose the use of urine-derived cells (UDCs), which can be obtained non-invasively from a urine sample.

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It has been more than 10 years since the hopes for disease modeling and drug discovery using induced pluripotent stem cell (iPSC) technology boomed. Recently, clinical trials have been conducted with drugs identified using this technology, and some promising results have been reported. For amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease, several groups have identified candidate drugs, ezogabine (retigabine), bosutinib, and ropinirole, using iPSCs-based drug discovery, and clinical trials using these drugs have been conducted, yielding interesting results.

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Background: Due to confusing clinicoradiological features such as amnestic symptoms and hippocampal atrophy in frontotemporal lobar degeneration (FTLD), antemortem differentiation between FTLD and Alzheimer's disease (AD) can be challenging. Although asymmetric atrophy of the cerebral peduncle is regarded as a representative imaging finding in some disorders of the FTLD spectrum, the utility of this finding has not been sufficiently evaluated for differentiating between FTLD and AD.

Objective: This study aimed to explore the diagnostic performance of asymmetric cerebral peduncle atrophy on axial magnetic resonance imaging as a simple radiological discriminator between FTLD and AD.

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Non-human primates (NHPs) are the closest animal model to humans; thus, gene engineering technology in these species holds great promise for the elucidation of higher brain functions and human disease models. Knockin (KI) gene targeting is a versatile approach to modify gene(s) of interest; however, it generally suffers from the low efficiency of homology-directed repair (HDR) in mammalian cells, especially in non-expressed gene loci. In the current study, we generated a tyrosine hydroxylase (TH)-2A-Cre KI model of the common marmoset monkey (marmoset; Callithrix jacchus) using an HDR-biased CRISPR-Cas9 genome editing approach using Cas9-DN1S and RAD51.

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Article Synopsis
  • The APOE4 genotype is identified as the strongest risk factor for sporadic Alzheimer's disease, but its specific molecular effects on synapses are still unclear.
  • Researchers created a model using human stem cells to compare the effects of APOE3 and APOE4 genotypes on astrocytes and their interaction with neurons.
  • The study found that APOE4 astrocytes lead to reduced dendritic spine dynamics and increased levels of a protein called EDIL3, which may contribute to synaptic impairments in Alzheimer's disease.
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Background: Amyotrophic lateral sclerosis/Parkinsonism-dementia complex in Kii peninsula, Japan (Kii ALS/PDC), is an endemic neurodegenerative disease whose causes and pathogenesis remain unknown. However, astrocytes in autopsied cases of Kii ALS/PDC show characteristic lesions. In addition, relationships between extracellular vesicles (EVs) and neurodegenerative diseases are increasingly apparent.

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Article Synopsis
  • Protein misfolding is a significant contributor to neurodegenerative diseases, particularly affecting post-mitotic neurons which can't dilute protein aggregates through cell division.
  • LONRF2 is identified as a protein quality control ubiquitin ligase that helps manage misfolded proteins in post-mitotic cells, primarily neurons.
  • The absence of LONRF2 leads to motor neuron degeneration and functional decline, while adding LONRF2 can protect against deterioration seen in conditions like amyotrophic lateral sclerosis.
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  • iPSC-based drug discovery led to a clinical trial investigating ropinirole for treating sporadic ALS, involving 20 participants over 24 weeks to assess safety and effects.
  • The results showed that while muscle strength and daily activities were stable, the primary functional measure (ALSFRS-R) did not significantly improve compared to the placebo group during the double-blind period.
  • In an open-label extension, the ropinirole group demonstrated a significant slowdown in ALSFRS-R decline and extended disease-progression-free survival, but the study faced challenges like small sample size and participant dropouts, necessitating further research.
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Article Synopsis
  • - The amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) is a serious neurodegenerative disease linked to abnormal tau protein filaments found in the brains and spinal cords of affected individuals from Guam and the Kii peninsula in Japan.
  • - Researchers used electron cryo-microscopy to analyze tau filaments from various ALS/PDC cases and discovered that they had structures similar to those seen in chronic traumatic encephalopathy (CTE), including a novel Type III CTE tau filament.
  • - The study suggests that ALS/PDC may result from environmental factors, as it's classified as a tauopathy along with CTE and another disease, sharing similarities in tau filament characteristics and patterns of inclusions in the brain
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Background: Several genetic factors are associated with the pathogenesis of sporadic amyotrophic lateral sclerosis (ALS) and its phenotypes, such as disease progression. Here, in this study, we aimed to identify the genes that affect the survival of patients with sporadic ALS.

Methods: We enrolled 1076 Japanese patients with sporadic ALS with imputed genotype data of 7 908 526 variants.

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Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is an inherited cerebral small vessel disease (CSVD) caused by biallelic mutations in the high-temperature requirement serine peptidase A1 (HTRA1) gene. Even heterozygous mutations in HTRA1 are recently revealed to cause cardinal clinical features of CSVD. Here, we report the first establishment of a human induced pluripotent stem cell (hiPSC) line from a patient with heterozygous HTRA1-related CSVD.

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Background: Due to clinicoradiological similarities, including amnestic cognitive impairment and limbic atrophy, differentiation of argyrophilic grain disease (AGD) from Alzheimer's disease (AD) is often challenging. Minimally invasive biomarkers, especially magnetic resonance imaging (MRI), are valuable in routine clinical practice. Although it is necessary to explore radiological clues, morphometry analyses using new automated analytical methods, including whole-brain voxel-based morphometry (VBM) and surface-based morphometry (SBM), have not been sufficiently investigated in patients with pathologically confirmed AGD and AD.

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Article Synopsis
  • CSF p-tau181 is a key biomarker for Alzheimer's disease (AD) and the study aimed to see if it changes in patients with Neuronal Intranuclear Inclusion Disease (NIID), a neurodegenerative disorder.
  • The research compared CSF biomarker levels, including p-tau181, across 12 NIID patients, 120 confirmed AD patients, and various other neurocognitive disorder patients.
  • Results showed significantly elevated CSF p-tau181 levels in NIID patients compared to others, indicating that NIID might share some biochemical features with AD despite the differences in other biomarkers like Aβ42.
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