Publications by authors named "Hirofumi Aoyagi"

Background And Objectives: Anti-IgLON5 disease is an autoimmune neurodegenerative disorder characterized by various phenotypes, notably sleep and movement disorders and tau pathology. Although the disease is known to be associated with the neuronal cell adhesion protein IgLON5, the physiologic function of IgLON5 remains elusive. There are conflicting views on whether autoantibodies cause loss of function, activation of IgLON5, or inflammation-associated neuronal damage, ultimately leading to the disease.

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Brain aging causes a progressive decline in functional capacity and is a strong risk factor for dementias such as Alzheimer's disease. To characterize age-related proteomic changes in the brain, we used quantitative proteomics to examine brain tissues, cortex and hippocampus, of mice at three age points (3, 15, and 24 months old), and quantified more than 7000 proteins in total with high reproducibility. We found that many of the proteins upregulated with age were extracellular proteins, such as extracellular matrix proteins and secreted proteins, associated with glial cells.

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It is known that the human cellular models of Alzheimer's disease (AD) and tauopathy can only recapitulate the very early stage of the disease. To overcome these limitations, we developed a technology to make forebrain organoids (FBOs) from feeder-free induced pluripotent stem cells (iPSC)s by regulating a FGF2 concentration and applied this method to generate FBOs from patients with familial AD (fAD FBOs). The obtained fAD FBOs recapitulated the amyloid-β pathology and increased tau phosphorylation but not tau aggregates.

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Abnormally accumulated tau protein aggregates are one of the hallmarks of neurodegenerative diseases, including Alzheimer's disease (AD). In order to investigate proteomic alteration driven by tau aggregates, we implemented quantitative proteomics to analyze disease model mice expressing human transgene (hTau-Tg) and quantified more than 9,000 proteins in total. We applied the weighted gene co-expression analysis (WGCNA) algorithm to the datasets and explored protein co-expression modules that were associated with the accumulation of tau aggregates and were preserved in proteomes of AD brains.

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Tau deposition in the brain is a pathological hallmark of many neurodegenerative disorders, including Alzheimer's disease (AD). During the course of these tauopathies, tau spreads throughout the brain via synaptically-connected pathways. Such propagation of pathology is thought to be mediated by tau species ("seeds") containing the microtubule binding region (MTBR) composed of either three repeat (3R) or four repeat (4R) isoforms.

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Frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), an autosomal, dominantly inherited neurodegenerative disorder caused by tau gene mutations, is neuropathologically characterized by intraneuronal filamentous inclusions of hyperphosphorylated tau protein. Biochemical and immunocytochemical analyses have shown that only mutant tau is deposited in patients harboring P301L missense mutation, whereas both wild-type and mutant tau are deposited in patients harboring R406W mutation (Miyasaka, T., Morishima-Kawashima, M.

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