Brain Protein Aging and Dementia Control

Home > Groups and Members > Public Offering Members of Projects Research (2015-2016)

Public Offering Members of Projects Research (2015-2016)

Name Masahiro Ono
Affiliation / Position Graduate School of Pharmaceutical Sciences, Kyoto University
Associate Professor
Research Project Development of SPECT imaging probes targeting β-amyloid and tau
Research Outline As the population is rapidly aging all over the world, the increase of the number of patients with Alzheimer’s disease has become one of the serious social issues. To diagnose AD for a number of people before the onset, it is necessary to apply in vivo molecular imaging technique with routine diagnostic use. Several PET imaging probes targeting β-amyloid plaques (Aβ) and neurofibrillary tangles (tau) in the brain have been tested clinically and demonstrated potential utility. However, PET imaging probes labeled with positron emitters with the short half-life (11C; 20 min, 18F; 110 min) limits their use at PET facilities with on-site cyclotrons. On the other hand, since much more hospitals possess SPECT facilities, Aβ and tau imaging probes labeled with isotopes for SPECT (123I; 13 h, 99mTc; 6 h) will have more widespread clinical applicability. The objective in this study is to develop novel SPECT imaging probes targeting Aβ and tau, which may lead to convenient imaging methods for detecting AD.
Name Takenobu Murakami
Affiliation / Position Neurology/Advanced Clinical Research Center, Faculty of Medicine, Fukushima Medical University
Assistant Professor
Research Project Elucidation of mechanisms on the impairment of cortical plasticity in dementia and application to the new strategy for early diagnosis
Research Outline It is well-known that accumulation of amyloid-beta protein (Aβ) in the brain causes impairment of synaptic plasticity, triggering dementia in Alzheimer’s disease (AD). Additionally, Aβ deposits have already started in the preclinical stage; about 10-15 years before the onset of cognitive decline. Hence, we propose that the unveiling of mechanisms of synaptic breakdown caused by Aβ is crucial for the early detection of AD, and this may lead to the prevention of the onset of dementia. In the present study, we examine whether the cortical plastic changes can be induced in the human primary motor cortex of dementia patients including AD by using transcranial magnetic stimulation (TMS). Furthermore, combining TMS with the standardized cognitive battery, measurements of biomarkers in cerebrospinal fluids, and functional neuroimaging studies; e.g. positron-emission tomography (PET-MRI), we investigate the relevance among each of these tests and TMS study. We hypothesize that changes in the cortical plasticity will be successfully induced by TMS in early stages in AD and mild cognitive impairment patients. However, it can be speculated that poorer induction of cortical plasticity will be related to the progression of dementia. We expect that the investigation of cortical plasticity using TMS may record synaptic dysfunction caused by Aβ deposition which the conventional studies cannot detect.
Name Kotaro Mizuta
Affiliation / Position Kyoto University
Assistant Professor
Research Project Visualization of breakdown processes of neuronal microcircuits in Alzheimer’s disease
Research Outline Neural circuit breakdown caused by accumulation of aged brain proteins leads to decline of cognitive functions in Alzheimer’s disease (AD), and AD patients are known to exhibit dysfunction of spatial memory as an early symptoms. Hippocampus plays an essential role in memory formation for space but it is not well understood how neuronal circuit breakdown progresses in the hippocampus affected by AD mainly because of the technical difficulty to monitor hippocampal neuronal activities for more than many weeks with previously available techniques. In this study, we image hippocampal neuronal activities in mice learning over many months by a combinatorial use of two-photon calcium imaging that simultaneously visualizes more than 1000 cells in a single cell resolution, new AD model mice with hippocampal neurons labeled genetically by the fluorescent calcium sensor protein G-CaMP7 and a virtual reality system for head-fixed mice. We aim to elucidate the entire process of AD pathology that may consist of abnormal neuronal activity, generation and accumulation of aged brain proteins and functional circuit breakdown in hippocampal microcircuits of AD model mice performing virtual recognition tasks.
Name Masashi Aoki
Affiliation / Position Department of Neurology, Tohoku University School of Medicine
Professor and Chair
Research Project Translational research from basic to clinical with the aim of developing therapies for neurodegenarative disease
Research Outline Implementation of translational research from basic to clinical with the aim of developing therapies for Amyotrophic Lateral Sclerosis (ALS)
Amyotrophic lateral sclerosis (ALS) is an adult onset neurodegenerative disorder characterized by the death of upper and lower motor neurons. We developed rats that express a human SOD1 transgene with two different ALS-associated mutations develop striking motor neuron degeneration and paralysis. Hepatocyte growth factor (HGF) is one of the most potent survival-promoting factors for motor neurons. We administered human recombinant HGF (hrHGF) by continuous intrathecal delivery to the transgenic rats at onset of paralysis. Intrathecal administration of hrHGF attenuates motor neuron degeneration and prolonged the duration of the disease by 63 %. The results should prompt further clinical trials in ALS using continuous intrathecal administration of hrHGF.
Name Motoyuki Itoh
Affiliation / Position Department of Biochemistry, Graduate School of Pharmaceutical Sciences, Chiba University
Research Project Analysis of biochemical changes associated with aging in CADASIL mutated Notch3
Research Outline CADASIL is an inherited cerebrovascular disease leading to subcortical ischemic stroke and dementia.
CADASIL is associated with mutations in Notch3 epidermal growth factor like repeats. Notch signaling plays important roles in a variety of tissues for their development and homeostasis. It has been proposed that Notch3 mutations cause an abnormal accumulation of Notch3 extracellular domain in blood vessel walls, but do not affect Notch signaling activity. However, the precise mechanisms of disease progression remain unclear. In this research project, we will analyze CADASIL Notch3 protein activity, turnover, and in vivo functions by examining 1) ligand mediated- and 2) aging mediated-CADASIL Notch3 protein turnover and 3) the phenotypes of zebrafish CADASIL model.
Name Kaoru Yamada
Affiliation / Position The University of Tokyo, Graduate School of Medicine, Department of Neuropathology
Assistant professor
Research Project Elucidation of molecular mechanisms for tau release that triggers intercellular spreading of tau pathology.
Research Outline Intracellular accumulation of misfolded tau protein as neurofibrillary tangles characterizes a set of neurodegenerative diseases called tauopathies. Despite the recognition that tau contributes to neuronal dysfunction, there is no clear understanding how tau pathology is developed in the diseases. Recent in vivo and cell culture studies have suggested that tau pathology propagates within synaptically connected neuronal network via extracellular space. This transcellular spreading of tau pathology suggests new pathological mechanisms in which pathological tau species in a form of aggregates or fibrils are first released into the extracellular space and then taken up by neighboring neurons and induce further aggregation. This concept leads to the idea that interfering the processes involved in tau spreading could be a potential therapeutic strategy against tauopathies. In this study, we investigate molecular mechanisms that regulate the release of pathological tau species into the extracellular space and aim to elucidate how this release process contributes to intracellular propagation of tau pathology.
Name Yuri Shibata
Affiliation / Position The Institute of Medical Science, The University of Tokyo
Assistant professor
Research Project The functional analysis of p47 in neurodegenerative diseases
Research Outline Many neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), are characterized by the ubiquitin-positive protein aggregates. Mutations in the valosin-containing protein (VCP) have recently been identified in familial ALS and Inclusion Body Myopathy, Paget’s disease and Frontotemporal Dementia (IBMPFD), and VCP mutations lead to defects in autophagy-mediated protein degradation. Although pathogenic mutations span the N-domain of VCP, the binding domain for its cofactors, the involvement of VCP cofactors in neurodegenerative diseases remains unclear. Furthermore, the linkage types of polyubiquitin chain of protein aggregates are less well elucidated. In this study, we aim to: (1) elucidate the role of VCP cofactor p47 in neurodegenerative diseases; (2) identify the linkage type of ubiquitin-positive aggregates; and (3) determine the inhibitory effect of linkage-specific deubiquitinase on the accumulation of ubiquitinated proteins.
Name Hiromitsu Tanaka
Affiliation / Position Kyoto University, Graduate School of Science, Department of Biophysics
Assistant Professor
Research Project Visualization of pathological effects of Aβ oligomers in synapse
Research Outline We have succeeded in formation of postsynaptic-like membrane (PSLM) directly on the glass surface in hippocampal neuronal culture by coating the glass with a kind of presynaptic adhesion molecule Neurexin, and performed live-cell imaging of glutamate receptor tagged by fluorescent protein with total internal reflection fluorescence microscopy. This method has enabled us to record the location and movement of glutamate receptors around PSLM with a high signal to noise ratio. Using this new method, we aim to elucidate pathological effects of amyloid beta (Aβ) oligomers on synaptic proteins such as AMAPA-type ionotropic glutamate receptors during synaptic plasticity. This study would contribute the understanding of pathogenic mechanism of Alzheimer’s disease and molecular mechanism of learning and memory.
Name Mikiko Ohno
Affiliation / Position Department of the Cardiovascular Medicine, Kyoto University
Assistant Professor
Research Project Investigation of the role of M16 family proteases
trough regulating the brain protein aging in Alzheimer’s disease
Research Outline Amyloid-beta (A-beta) peptide, one of the component of senile plaques of patients with Alzheimer’s disease (AD), is derived from proteolytic cleavage of amyloid precursor protein (APP) by beta- and gamma-secretases. Alpha-cleavage of APP by alpha-secretase has a potential to preclude the generation of A-beta, because it occurs within the A-beta domain. We previously reported that a metalloendopeptidase, nardilysin (N-arginine dibasic convertase; NRDc) enhances alpha-cleavage of APP which results in decreased generation of A-beta in vitro. To clarify the in vivo role of NRDc in AD, we intercrossed transgenic mice expressing NRDc in a forebrain with AD model mice. We demonstrate that neuron-specific overexpression of NRDc prevents A-beta deposition in AD mouse model. The activity of alpha-secretase in the mouse brain was enhanced by the overexpression of NRDc, and was reduced by the deletion of NRDc. Our data indicate that NRDc controls A-beta formation through the regulation of alpha-secretase.
IDE (insulin degrading enzyme) is also a member of the M16 family, which has a homology at the enzymatic domain with NRDc. IDE is known to degrade A-beta plaque by the enzymatic activity in vitro and in vivo. However, little is known about the significance of enzymatic activity of NRDc itself.
In this study, we focus on the pathophysiological significance of the M16 family metalloprotease (NRDc, IDE). Our purpose is to explore 1) the significance of NRDc as a biomarker for detecting the MCI and AD, 2) the significance of alpha-secretase activity as anti-amyloidogenic effect, 3) the significance of the enzymatic activity of NRDc itself against A-beta or other brain-aging proteins.
Name Suehiro Sakaguchi
Affiliation / Position Division of Molecular Neurobiology, Institute for Enzyme Research, Tokushima University
Research Project Identification of a molecule important for the cell toxicity and intracelluar trafficking of prions
Research Outline We recently reported that abnormal prion protein accumulates in endosomal compartments, particularly in the recycling endosome compartment, and thereby disturbs post-Golgi trafficking of membrane proteins, eventually causing functional deficiency of the membrane proteins. These results suggest that the accumulation of abnormal prion protein in the recycling endosome might be prerequisite for the abnormal prion protein to exert its cell toxicity. However, the mechanism underlying the trafficking of abnormal prion protein to the recycling endosome remains unknown.
We recently identified sortilin, a cargo receptor molecule, as an abnormal prion protein-binding protein, and found that prion infection reduced sortilin. We speculate that sortilin might be involved in the trafficking of abnormal prion protein to the recycling endosome. In this study, we elucidate the role of sortilin in the trafficking of abnormal prion protein.
Name Gen Matsumoto
Affiliation / Position Nagasaki University School of Medicine
Research Project Neuronal senescence and neurodegenerative diseases with long-term cultured primary neurons
Research Outline In humans, neuron can live for more than a hundred years that is beyond the lifetime of individuals. Neuronal senescence is one of the most prominent risk factors in a number of neurodegenerative diseases, but how the neuronal senescence links to neurodegenerative diseases is unclear. We aim to elucidate the molecular mechanism behind the neuronal aging to understand what is happen in neurons when they get aged and ask the question why the protein degradation system in aged neurons is impaired. To investigate the neuronal senescence, we are developing a long-term cultured mouse primary neuron system that may enable to approach the neuron aging with cell biologically. Using cultured aged neurons, we are studying the reason why the protein degradation systems, especially selective autophagy system, are restricted in aged neurons.
Name Shingo Ito
Affiliation / Position Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University
Assistant Professor
Research Project Contribution of insulin receptor to the regulation of carrier-mediated transport systems at the human blood–brain barrier as supporting and protecting interface for the brain
Research Outline The blood–brain barrier (BBB) is a dynamic and functional neurovascular unit comprised of the brain capillary endothelial cells. The BBB segregates brain parenchyma from circulating blood and also expresses various transport systems, which supply nutrients to the brain and removes toxic metabolites and proteins from the brain, to maintain brain homeostasis. Since the BBB directly contacts with circulating blood, we have hypothesized that major diseases in lifestyle relate to diseases such as dementia, and are connected by BBB dysfunction caused by the impairment of insulin signaling, such as insulin resistance, which could be a new therapeutic target for neurodegenerative diseases. The purpose of the present study is to investigate the contribution of insulin receptor to the regulation of carrier-mediated transport systems at the human blood–brain barrier under hyperinsulinemia and insulin resistance using a human BBB model cells and quantitative targeted absolute proteomics.
Name Kanae Ando
Affiliation / Position Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University
Associate professor
Research Project Targeting the initial steps in the cascade leading to accumulation of pathological tau species
Research Outline Tau is a microtubule-binding protein localized to the neuronal axons, where it regulates microtubule stability. However, under pathological conditions including Alzheimer’s disease (AD), tau is hyper-phosphorylated and accumulated in the cytosol in the brain neurons. Accumulation of abnormal tau is thought to cause cell loss, however, it is not clear what changes in tau triggers a pathological cascade leading to accumulation of abnormal tau. Tau phosphorylation at Ser262 has been suggested to occur in the early stages in AD pathogenesis and to play critical roles in tau toxicity. Our recent studies suggest that tau phosphorylation at Ser262 and Ser356 initiates accumulation of toxic tau species. In this project, we will systematically screen genes that affect generation and metabolism of tau phosphorylated at Ser262 and Ser356 by using a Drosophila model. Identification of such genes may lead to development of a novel therapeutic strategy to effectively block the pathological cascade leading to neuron loss.
Name Etsuro Ohta
Affiliation / Position Kitasato University School of Allied Health Sciences
Research Project Elucidation of the neurodegenerative mechanism by Tau using iPS cells
Research Outline Patients with Leucine-Rich-Repeat-Kinase 2 (LRRK2) mutation that is causal molecules of autosomal dominant hereditary form Parkinson’s disease (PD), exhibit clinical features indistinguishable from those of patients with sporadic PD. In addition, it has been reported that PD patient who has LRRK2 mutations cause dementia frequently. So, it is thought that LRRK2 has some kind of influences on the onset of dementia. In our preliminary data using established induced pluripotent stem cells (iPSC) from PD patients with LRRK2 mutation, we found possibility of the augmented Tau phosphorylation. In this study, to elucidate the mechanism of neurodegeneration caused by Tau, we analyze phosphorylation levels of Tau in patient iPSC-derived neurons and the postmortem brain of the patient from whom the iPSC had been established. Furthermore, to elucidate the mechanism of PD and dementia caused by aging, we analyze cellular levels of mRNA and protein in short term or long-term cultured iPSC-derived neurons.
Name Yoshiaki Furukawa
Affiliation / Position Deptartment of Chemistry, Keio University
Associate Professor
Research Project A seeding mechanism on transmissibility of neurodegenerative diseases using C.elegans model
Research Outline Fibrillation of proteins in neurons is a pathological hallmark of many neurodegenerative diseases. Protein fibrillar aggregates can function as a structural template to convert native soluble conformations to abnormal fibrillar aggregates, and this is called as a seeding reaction. Given that protein aggregation proceeds explosively through this seeding reaction, many researchers suppose that seeded aggregation of proteins may control progression or even transmissibility of neurodegenerative diseases. Despite this, the pathological significance of seeded aggregation remains to be clarified. In this research project, a new experimental model using C. elegans will be constructed to test possible roles of seeding reactions in neurodegenerative diseases.
Name Nobuyuki Nukina
Affiliation / Position Doshisha University Graduate School of Brain Science、Laboratory of Structural Neuropathology
Research Project The investigation of ubiquitin accumulated pathology in NF-YA conditional knockout mice
Research Outline We have been studying the aggregate interacting proteins(AIPs) in polyglutamine diseases. One of AIPs is a transcriptional factor, NF-YA, which regulates chaperones expression(EMBO J2008). To further elucidate the role of NF-Y in neuronal system, we investigated the conditional knockout mice, which lack NF-YA in cortical neurons and found the new pathology with accumulation of ubiquitin and p62 in the cytoplasm and of ER and nuclear membranes(Nat Commun2014). This pathology might be unnoticed membrane pahology related aging and age-related neurodegeneration. Similar pathology was reported in some type of motor neuron diseases and we will investigate the NF-YA conditional knockouted motor neurons, comparing with cortical neuronal pathology. We will identify the targets of ubiquitin in those mice and also the transmissibility of those accumulated pathological materials.
Name Masaki Fukata
Affiliation / Position National Institute for Physiological Sciences
Research Project Role of LGI1 in aging and dementia
Research Outline To overcome the dementia, it is essential to identify the protein associated with dementia. Although many researchers have been working on Aβ, tau, α-synuclein, and TDP-43, the pathogenic mechanism for dementia remains incompletely understood. So far, we found that epilepsy-related LGI1 functions as a ligand for an ADAM22 transmembrane protein and regulates AMPA receptor-mediated synaptic transmission. Mutation of LGI1 causes defects in its secretion or ADAM22-binding. In addition, we showed a specific role for LGI1 autoantibodies in limbic encephalitis characterized by subacute onset of amnesia and seizures. LGI1 autoantibodies specifically inhibit the ligand-receptor interaction between LGI1 and ADAM22. Here, we will 1) examine the LGI1 expression and distribution in the brain of patients with dementia and the aged brain, 2) develop the treatment targeted at LGI1 and 3) develop the LGI1 imaging in the brain.
Name Kozo Hamada
Affiliation / Position RIKEN/BSI
Research scientist
Research Project Role of endoplasmic reticulum calcium in brain protein aging and its toxic function
Research Outline One of the common symptoms in neurodegenerative diseases is abnormal regulation of conformations, oligomers, and fibrous structures of causative proteins, but its cellular mechanism and gain of toxic function remains elusive. In this study, we focus on the "endoplasmic reticulum calcium" responsible for various cellular processes including synaptic plasticity and endoplasmic reticulum stress, and investigate whether it relates to brain protein aging.
Name Shigeomi Shimizu
Affiliation / Position Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University
Research Project Development of molecularly targeted antiaging agents based on the regulation of alternative autophagy
Research Outline Aging leads to accumulation of damaged or toxic proteins, and which is regulated by the extent of autophagic activity. Autophagy is a catabolic process where cellular contents are digested within lysosomes. It has been thought that ATG5 and ATG7 are essential genes for autophagy, but we recently provided evidence that autophagy can be induced even in ATG5-/- and ATG7-/- cells. This alternative autophagy plays a role to degrade unfavorable proteins. Therefore, in this study, we will elucidate the role of alternative autophagy on a brain disorder, such as alzheimer disease. We also develop therapeutic agents for treatment of brain disorders through induction of alternative autophagy.
Name Hideki Mochizuki
Affiliation / Position Department of Neurology, Osaka University Graduate School of Medicine
Research Project αsyn propagation derived from IPS cells using PD marmoset
Research Outline Parkinson’s disease (PD) is one of the most common chronic neurodegenerative diseases. Lewy bodies, composed of alpha-synuclein (aSyn), are intraneuronal inclusions that characterize PD. aSyn aggregation plays a crucial role in synucleinopathies such as PD and dementia with Lewy bodies. However, the mechanism underlying aSyn propagation and disease progression in PD are still unclear.
To identify the mechanism of αSyn propagation, we prepared these proteins from iPS cells of PD patients. We already collaborated with Prof. Okano to create iPS cells from PD patients, especially Park4 patients. We also started the project with Prof. Okano to prepare the genetically modified marmoset and/or drug induced model as suitable models for PD. We will inject the diseased proteins from patients into PD marmoset models. As the final goal of this project, we will establish the new drugs to prevent the αSyn propagation for PD patients.
Name Yohei Okada
Affiliation / Position Aichi Medical University, School of Medicine, Department of Neurology
Associate Professor
Research Project The analysis of stress signals which induce abnormal protein aggregations in patient iPSC-derived neurons
Research Outline Disease specific human iPSCs, established from patients’ somatic cells, may provide valuable disease models by patient-derived cells, and could faithfully recapitulate disease onset and progression when differentiated into the cells affected by the disease. In this study, focusing on the abnormal protein aggregations that could cause neurodegeneration in neurological disorders, we would establish disease specific iPSCs from patients of neurodegenerative diseases, and differentiate them into neural cells. We would perform detailed analysis of the differentiation process of iPSCs to clarify the underlying pathogenesis of disease onset and early disease progression, as well as the process of abnormal protein aggregation and neurodegeneration. By these analyses, we would investigate aging related ‘stress signals’ causing disease progression, which could be a novel therapeutic target.