Neurology Lab

Elucidating the pathophysiology of amyotrophic lateral sclerosis (ALS), one of the most fatal neurodegenerative diseases

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that typically develops in adulthood and leads to systemic, progressive muscle wasting and weakness, with a poor prognosis. In ALS, upper motor neurons in the motor cortex and lower motor neurons in the brainstem motor nuclei and anterior horn of the spinal cord selectively undergo cell death. Although no therapy has yet been developed that sufficiently suppresses disease progression, vigorous research in recent years has driven transformative advances in our understanding of ALS pathogenesis.

In motor neurons and glial cells in ALS, the nuclear protein TDP-43 is lost from the nucleus and accumulates in the cytoplasm as aggregates. The toxicity of these TDP-43 aggregates and the associated loss-of-function are considered central drivers of ALS onset and progression, and our group focuses on TDP-43-centered mechanisms. We have reported that the kinase IKKβ selectively reduces cytoplasmic TDP-43 aggregates (Iguchi et al., J Cell Biol, 2024), that loss of TDP-43 function directly contributes to motor neuron degeneration (Iguchi et al., Brain, 2016), and that decreased expression of the long non-coding RNA NEAT1 is one contributing factor (Kawakami et al., Brain Communications, 2025).

“Smart” research on intractable neurological diseases through interdisciplinary integration

Our group investigates disease mechanisms and develops nucleic acid therapeutics for the hereditary disorders spinal and bulbar muscular atrophy (SBMA) and spinal muscular atrophy (SMA). For SBMA, we utilize single-nucleus RNA-seq and AI-based approaches to analyze neural circuit activity, transcription/translation, cellular morphology, and intracellular structures, deepening our understanding of time-specific pathophysiology across diverse neuronal populations (Iida et al., JCI Insight, 2025). By leveraging engineering, physical sciences, and pharmaceutical sciences—together with industry–academia and international collaborations—we also promote practical development of nucleic acid medicines for polyglutamine diseases, Parkinson’s-related disorders, and motor neuron diseases (Maeda et al., Mol Ther Nucleic Acids, 2025; Hirunagi et al., J Cachexia Sarcopenia Muscle, 2024).

For SMA, we continue a nationwide registry study in collaboration with industry partners. We analyze clinical data, apply AI to patient-reported comments and imaging, and perform highly sensitive ELISA-based assessments of body fluids, aiming to develop drug efficacy evaluation batteries and biomarkers and to generate evidence for optimal treatment strategies. In addition, in collaboration with the Nagoya University Institute for Environmental Medicine, we employ long-read sequencing to analyze variants, disease modifiers, and RNA metabolism. Our overarching goal is to achieve bidirectional, mutually reinforcing outcomes from basic and clinical research, ultimately improving diagnosis and enabling the real-world implementation of new therapies for intractable neurological diseases.

Probing detailed molecular mechanisms of ALS using motor neurons derived from patient iPSCs

The iPSC Research Group uses induced pluripotent stem cells (iPSCs) to investigate ALS pathogenesis. We focus particularly on the RNA-binding proteins FUS and TDP-43, which cause ALS, and work to identify aberrant RNAs directly regulated by these proteins that drive neurodegeneration. In prior work, we discovered that FUS regulates synaptic morphology by stabilizing the mRNA of the synaptic protein SYNGAP1, and identified a novel mutation in the JaCALS ALS cohort in a region where FUS binds the SYNGAP1 mRNA (Yokoi et al., J Neurosci, 2022).

By introducing this mutation into normal iPSCs via genome editing and differentiating them into motor neurons, we showed that synapse numbers are reduced. We are currently using patient-derived iPSCs harboring mutations in RNA-binding proteins and applying technologies such as calcium live imaging to longitudinally analyze neuronal activity, with the aim of elucidating detailed molecular pathophysiology that can lead to ALS therapeutics.

Deciphering disease mechanisms and advancing drug discovery through state-of-the-art genomics and multifaceted approaches

The Genomic Analysis Group aims to elucidate genomic mechanisms underlying intractable neurological and refractory muscle diseases and conducts large-scale whole-genome analyses in close collaboration with the Nagoya University Institute for Environmental Medicine. In research on progressive supranuclear palsy (PSP), a tauopathy characterized by abnormal tau aggregation, we have expanded beyond conventional observational studies and family-based analyses to include nationwide genomic cohort collaborations, development of disease-model animals, and translational research grounded in industry–academia partnerships (Tsujikawa et al., Sci Adv, 2022).

In collaboration with multiple laboratories and institutions inside and outside the university, we also perform comprehensive analyses of structural variants using the latest long-read sequencers and pursue a physics-based understanding of pathophysiology through molecular dynamics simulations on supercomputers. We further promote AI-driven automated analyses of neuronal morphology and develop drug discovery assays using cellular models. By enabling clinician-scientists to acquire advanced bioinformatics expertise, we can accurately incorporate clinical insight and original perspectives into the interpretation of massive genomic datasets—allowing us to address key disease mechanisms that may be overlooked in analyses driven solely by engineering workflows and to translate findings more directly into clinical practice.

Through these multifaceted efforts, we aim to integrate basic medicine, clinical medicine, and information science to ultimately deliver innovative diagnostic and therapeutic solutions to patients suffering from intractable neurological and refractory muscle diseases.

Identifying therapeutic seeds and advancing clinical translation for motor neuron diseases

Our group conducts clinical research and clinical trials (including investigator-initiated trials) focused primarily on SBMA and ALS. For SBMA, building on our translational research experience that led to the regulatory approval of leuprorelin acetate in 2017 (based on research achievements from Nagoya University Neurology), we are currently pursuing clinical development of mexiletine hydrochloride.

Many patients with SBMA experience worsening motor paralysis and impaired fine motor function following cold exposure. Based on studies inspired by this observation, we are conducting an investigator-initiated trial of mexiletine hydrochloride for SBMA (the Med-SBMA trial). In addition, because it has been suggested that molecular pathology progresses before clinical symptoms appear in many neurodegenerative diseases, we are investigating ultra-early pathophysiology and biomarkers in SBMA (Torii et al., Neurology, 2023).

For ALS, we focus on analyses of biospecimens obtained from patients to identify biomarkers associated with disease progression and biomarkers that change prior to symptom onset. We employ comprehensive “omics” approaches (transcriptomics, proteomics, metabolomics, exosomal miRNAs, and more) and analyze data using methods such as machine learning. Ultimately, we aim to integrate multi-omics results to clarify what is occurring in the patient’s body. We also advance reverse translational research (rTR), in which clinically derived findings are tested and validated in basic research, to promote mechanistic studies and therapeutic development.

Cohort studies capturing prodromal stages through health screening to enable prognostic prediction and preemptive medicine

Since 2017, the Lewy Body Disease Group has conducted a high-risk cohort study for Lewy body disease onset (the NaT-PROBE study) based on questionnaire surveys of individuals undergoing routine health checkups. Our analyses have shown that approximately 6% of checkup participants aged 50 years and older have multiple prodromal symptoms—autonomic dysfunction, REM sleep behavior disorder, and olfactory impairment—placing them at high risk of developing Lewy body disease (Hattori et al., J Neurol, 2020). We further found that about one-third of these individuals show reduced uptake on DaT-SPECT or MIBG myocardial scintigraphy (Hattori et al., npj Parkinson’s Disease, 2023), and that approximately half exhibit elevated plasma neurofilament light chain (NfL), a marker of neurodegeneration (Hiraga et al., npj Parkinson’s Disease, 2024).

In addition, we developed a new questionnaire to capture subtle motor symptoms prior to onset (Tamakoshi et al., J Parkinson’s Disease, 2025) and are working to identify diverse prodromal populations. Collectively, these findings provide important evidence that neurodegeneration progresses in high-risk individuals even before clinical symptoms emerge and form a foundation for identifying target populations for preemptive treatment. Building on these insights, we are developing stratification and prognostic prediction models for the prodromal stage of Lewy body disease, with the goal of establishing an academic basis for realizing preemptive medicine.

Movement disorder research spanning pathophysiology to advanced therapies through multidisciplinary approaches

The Parkinson’s Disease & Movement Disorders Group conducts a broad range of research from both clinical and engineering perspectives to improve the diagnosis and treatment of Parkinson’s disease and tremor disorders. In advanced Parkinson’s disease, we evaluate the multifaceted effects—motor and non-motor—of rapidly evolving device-aided therapies such as deep brain stimulation (DBS), levodopa intestinal gel therapy, and continuous subcutaneous levodopa infusion, accumulating evidence that supports appropriate patient selection and improved treatment outcomes (Tsuboi et al., J Neural Transm, 2025).

For essential tremor and dystonic tremor, we provide individualized surgical treatments including focused ultrasound (FUS) and DBS, while advancing pathophysiological studies that integrate detailed clinical observation with physiological and imaging analyses. We are also developing diagnostic support technologies, including analyses of visual cognitive function using Tobii eye-tracking devices in Parkinson’s disease (Uematsu et al., Parkinsonism Relat Disord, 2024) and approaches using facial expression and voice data obtained during speech tasks and natural conversation. Leveraging collaborative frameworks with neurosurgery, engineering, and other disciplines, we aim to generate clinically impactful outcomes while approaching the essence of movement disorders from multiple angles.

Functional network research to explore early diagnosis, treatment response, and neural substrates in healthy individuals

The Dementia & Neuroimaging Analysis Group uses functional MRI (fMRI) to investigate changes in brain functional networks in Alzheimer’s disease and preclinical dementia. Through large-scale network analyses of resting-state fMRI, we aim to capture subtle abnormalities in neural substrates before clinical symptoms appear and thereby contribute to early diagnosis and improved understanding of disease mechanisms.

Going forward, we plan to integrate plasma biomarker measurements and proteomic analyses to identify new indicators useful for early diagnosis, progression prediction, and evaluation of treatment response. By combining imaging with biomarkers, these efforts are expected to contribute to personalized medicine and the development of novel therapies.

In addition, through industry–academia collaborations, we conduct joint studies involving other faculties and companies, including research in healthy participants. Using brain functional imaging and physiological assessments, we pursue interdisciplinary research themes such as perception, autonomic function, cognition, and decision-making. Beyond disease-focused research, we aim to deepen understanding of the brain and mind and to generate and apply knowledge that will be valuable in future societies.

Biomarker research in immune-mediated neuropathies focusing on autoantibodies, complement, and glycans

Our group investigates immune-mediated peripheral nerve disorders such as chronic inflammatory demyelinating polyneuropathy (CIDP), autoimmune nodopathies, and anti-MAG antibody neuropathy, with the goal of elucidating mechanisms and identifying biomarkers directly linked to diagnosis and treatment. We focus particularly on autoantibodies (including anti-NF155, anti-CNTN1, anti-Caspr1, and anti-MAG antibodies), complement activity, and glycans on neuronal membranes (N-linked glycans, gangliosides, HNK-1, and others), and we analyze associations between molecular pathophysiology and clinical phenotypes from multiple perspectives (Furukawa et al., Eur J Neurol, 2025; Fukami et al., Neurol Neuroimmunol Neuroinflamm, 2024).

Methodologically, we apply immunoassays (ELISA, Simoa, etc.) to serum, cerebrospinal fluid, and peripheral nerve biopsy tissue; complement activity assays; glycan analyses (mass spectrometry); and transcriptomic analyses via RNA sequencing to extract disease-specific molecular signatures. By assembling case cohorts through domestic and international collaborative networks and integrating clinical information with biomarker data, we aim to realize precision diagnosis and prediction of treatment responses. In addition, to meet the needs of many clinicians, our department performs pathological diagnosis of peripheral nerves through a joint research program with Saga University. Ultimately, we seek to contribute to personalized medicine in peripheral nerve and neuroimmunological diseases by scientifically clarifying “who responds best to which treatment, and when.

Solving the mysteries of muscle disease and advancing therapy through clinical practice and multi-layer omics

Our group performs approximately 80–100 muscle biopsies annually upon request from Nagoya University Hospital and affiliated hospitals, and utilizes obtained specimens for both diagnosis and research. We also collaborate with the National Hospital Organization Suzuka Hospital to provide care for refractory neuromuscular diseases and to promote research grounded in clinical practice.

In addition to pathological evaluation of muscle biopsy tissue and blood samples, we combine cutting-edge comprehensive analyses—including genomic, transcriptomic, and metabolomic profiling—to elucidate disease mechanisms at the molecular level. Our research has included multifaceted studies such as characterization of clinicopathological features and metabolic abnormalities in inclusion body myositis (IBM), identification of features of refractory muscle diseases including post-transplant GVHD myositis, and evaluation of rehabilitation effects using robotic suits (Kazuta et al., Ann Clin Transl Neurol, 2024).

Through translational research that bridges basic and clinical studies, we continue to disseminate insights that improve diagnostic accuracy and support the development of novel therapies. Moving forward, we will pursue collaborations with diverse research institutions to help realize medical care that benefits patients and their families.

Advancing clinical neurophysiology grounded in extensive testing experience and a long tradition of autonomic research

This group is responsible for clinical neurophysiology testing at the hospital and conducts research primarily focused on autonomic nervous system function. Each year, we perform approximately 400 nerve conduction studies and needle electromyography examinations, interpret around 350 EEGs, and read approximately 500 additional neurophysiological tests. We also provide education for medical and clinical laboratory science students, as well as training for physicians from affiliated hospitals, offering abundant opportunities to learn from a wide range of cases through diagnostic testing.

We also place strong emphasis on testing and research related to autonomic dysfunction. For example, we perform approximately 120 head-up tilt tests annually, which are essential for diagnosing orthostatic hypotension. Autonomic research in our department has long been recognized nationwide; around 30 years ago, we were the first to report abnormalities in MIBG myocardial scintigraphy in neurodegenerative diseases. We have continued to publish numerous findings on autonomic disorders. More recently, we have investigated heart rate variability in Parkinson’s disease using wearable devices and examined relationships between autonomic function and imaging findings, enabling broad learning of clinically relevant knowledge (Suzuki et al., Parkinsonism Relat Disord, 2024).