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Wodrich APK, Harris BT, Giniger E. Changes in mitochondrial distribution occur at the axon initial segment in association with neurodegeneration in Drosophila. Biol Open 2024; 13:bio060335. [PMID: 38912559 PMCID: PMC11261633 DOI: 10.1242/bio.060335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 06/17/2024] [Indexed: 06/25/2024] Open
Abstract
Changes in mitochondrial distribution are a feature of numerous age-related neurodegenerative diseases. In Drosophila, reducing the activity of Cdk5 causes a neurodegenerative phenotype and is known to affect several mitochondrial properties. Therefore, we investigated whether alterations of mitochondrial distribution are involved in Cdk5-associated neurodegeneration. We find that reducing Cdk5 activity does not alter the balance of mitochondrial localization to the somatodendritic versus axonal neuronal compartments of the mushroom body, the learning and memory center of the Drosophila brain. We do, however, observe changes in mitochondrial distribution at the axon initial segment (AIS), a neuronal compartment located in the proximal axon involved in neuronal polarization and action potential initiation. Specifically, we observe that mitochondria are partially excluded from the AIS in wild-type neurons, but that this exclusion is lost upon reduction of Cdk5 activity, concomitant with the shrinkage of the AIS domain that is known to occur in this condition. This mitochondrial redistribution into the AIS is not likely due to the shortening of the AIS domain itself but rather due to altered Cdk5 activity. Furthermore, mitochondrial redistribution into the AIS is unlikely to be an early driver of neurodegeneration in the context of reduced Cdk5 activity.
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Affiliation(s)
- Andrew P. K. Wodrich
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007, USA
- College of Medicine, University of Kentucky, Lexington, KY 40506, USA
| | - Brent T. Harris
- Department of Pathology, Georgetown University, Washington, DC 20007, USA
- Department of Neurology, Georgetown University, Washington, DC 20007, USA
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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2
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Takemura H, Kruper JA, Miyata T, Rokem A. Tractometry of Human Visual White Matter Pathways in Health and Disease. Magn Reson Med Sci 2024; 23:316-340. [PMID: 38866532 PMCID: PMC11234945 DOI: 10.2463/mrms.rev.2024-0007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024] Open
Abstract
Diffusion-weighted MRI (dMRI) provides a unique non-invasive view of human brain tissue properties. The present review article focuses on tractometry analysis methods that use dMRI to assess the properties of brain tissue within the long-range connections comprising brain networks. We focus specifically on the major white matter tracts that convey visual information. These connections are particularly important because vision provides rich information from the environment that supports a large range of daily life activities. Many of the diseases of the visual system are associated with advanced aging, and tractometry of the visual system is particularly important in the modern aging society. We provide an overview of the tractometry analysis pipeline, which includes a primer on dMRI data acquisition, voxelwise model fitting, tractography, recognition of white matter tracts, and calculation of tract tissue property profiles. We then review dMRI-based methods for analyzing visual white matter tracts: the optic nerve, optic tract, optic radiation, forceps major, and vertical occipital fasciculus. For each tract, we review background anatomical knowledge together with recent findings in tractometry studies on these tracts and their properties in relation to visual function and disease. Overall, we find that measurements of the brain's visual white matter are sensitive to a range of disorders and correlate with perceptual abilities. We highlight new and promising analysis methods, as well as some of the current barriers to progress toward integration of these methods into clinical practice. These barriers, such as variability in measurements between protocols and instruments, are targets for future development.
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Affiliation(s)
- Hiromasa Takemura
- Division of Sensory and Cognitive Brain Mapping, Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Hayama, Kanagawa, Japan
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Osaka, Japan
| | - John A Kruper
- Department of Psychology and eScience Institute, University of Washington, Seattle, WA, USA
| | - Toshikazu Miyata
- Division of Sensory and Cognitive Brain Mapping, Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Osaka, Japan
| | - Ariel Rokem
- Department of Psychology and eScience Institute, University of Washington, Seattle, WA, USA
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Elgendy M, Tamada H, Taira T, Iio Y, Kawamura A, Kunogi A, Mizutani Y, Kiyama H. Dynamic changes in endoplasmic reticulum morphology and its contact with the plasma membrane in motor neurons in response to nerve injury. Cell Tissue Res 2024; 396:71-84. [PMID: 38311679 PMCID: PMC10997708 DOI: 10.1007/s00441-024-03858-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 12/29/2023] [Indexed: 02/06/2024]
Abstract
The endoplasmic reticulum (ER) extends throughout a cell and plays a critical role in maintaining cellular homeostasis. Changes in ER shape could provide a clue to explore the mechanisms that underlie the fate determination of neurons after axon injury because the ER drastically changes its morphology under neuronal stress to maintain cellular homeostasis and recover from damage. Because of their tiny structures and richness in the soma, the detailed morphology of the ER and its dynamics have not been well analysed. In this study, the focused ion beam/scanning electron microscopy (FIB/SEM) analysis was performed to explore the ultra-structures of the ER in the somata of motor neuron with axon regenerative injury models. In normal motor neurons, ER in the somata is abundantly localised near the perinucleus and represents lamella-like structures. After injury, analysis of the ER volume and ER branching points indicated a collapse of the normal distribution and a transformation from lamella-like structures to mesh-like structures. Furthermore, accompanied by ER accumulation near the plasma membrane (PM), the contact between the ER and PM (ER-PM contacts) significantly increased after injury. The accumulation of extended-synaptotagmin 1 (E-Syt1), a tethering protein of the ER and PM that regulates Ca2+-dependent lipid transfer, was also identified by immunohistochemistry and quantitative Real-time PCR after injury. These morphological alterations of ER and the increase in ER-PM contacts may be crucial events that occur in motor neurons as a resilient response for the survival after axonal injury.
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Affiliation(s)
- Mahmoud Elgendy
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Damanhour University, Damanhour, 22511, Egypt
| | - Hiromi Tamada
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan.
- Anatomy, Graduate School of Medicines, University of Fukui, Matsuokashimoaizuki, Eiheiji-Cho, Yoshida-gun, Fukui, 910-1193, Japan.
| | - Takaya Taira
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Yuma Iio
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Akinobu Kawamura
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Ayusa Kunogi
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Yuka Mizutani
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Hiroshi Kiyama
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan.
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Xu Z, Angstmann CN, Wu Y, Stefen H, Parić E, Fath T, Curmi PM. Location of the axon initial segment assembly can be predicted from neuronal shape. iScience 2024; 27:109264. [PMID: 38450155 PMCID: PMC10915628 DOI: 10.1016/j.isci.2024.109264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/21/2023] [Accepted: 02/14/2024] [Indexed: 03/08/2024] Open
Abstract
The axon initial segment (AIS) is located at the proximal axon demarcating the boundary between axonal and somatodendritic compartments. The AIS facilitates the generation of action potentials and maintenance of neuronal polarity. In this study, we show that the location of AIS assembly, as marked by Ankyrin G, corresponds to the nodal plane of the lowest-order harmonic of the Laplace-Beltrami operator solved over the neuronal shape. This correlation establishes a coupling between location of AIS assembly and neuronal cell morphology. We validate this correlation for neurons with atypical morphology and neurons containing multiple AnkG clusters on distinct neurites, where the nodal plane selects the appropriate axon showing enriched Tau. Based on our findings, we propose that Turing patterning systems are candidates for dynamically governing AIS location. Overall, this study highlights the importance of neuronal cell morphology in determining the precise localization of the AIS within the proximal axon.
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Affiliation(s)
- Zhuang Xu
- School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
- School of Mathematics and Statistics, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Christopher N. Angstmann
- School of Mathematics and Statistics, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Yuhuang Wu
- Infection Analytics Program, Kirby Institute for Infection and Immunity, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Holly Stefen
- Dementia Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Esmeralda Parić
- Dementia Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Thomas Fath
- Dementia Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Paul M.G. Curmi
- School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
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Alkaslasi MR, Lloyd EYH, Gable AS, Silberberg H, Yarur HE, Tsai VS, Tejeda HA, Le Pichon CE. The transcriptional response of cortical neurons to concussion reveals divergent fates after injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.26.581939. [PMID: 38463961 PMCID: PMC10925231 DOI: 10.1101/2024.02.26.581939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Traumatic brain injury (TBI) is a risk factor for neurodegeneration, however little is known about how different neuron types respond to this kind of injury. In this study, we follow neuronal populations over several months after a single mild TBI (mTBI) to assess long ranging consequences of injury at the level of single, transcriptionally defined neuronal classes. We find that the stress responsive Activating Transcription Factor 3 (ATF3) defines a population of cortical neurons after mTBI. We show that neurons that activate ATF3 upregulate stress-related genes while repressing many genes, including commonly used markers for these cell types. Using an inducible reporter linked to ATF3, we genetically mark damaged cells to track them over time. Notably, we find that a population in layer V undergoes cell death acutely after injury, while another in layer II/III survives long term and retains the ability to fire action potentials. To investigate the mechanism controlling layer V neuron death, we genetically silenced candidate stress response pathways. We found that the axon injury responsive kinase MAP3K12, also known as dual leucine zipper kinase (DLK), is required for the layer V neuron death. This work provides a rationale for targeting the DLK signaling pathway as a therapeutic intervention for traumatic brain injury. Beyond this, our novel approach to track neurons after a mild, subclinical injury can inform our understanding of neuronal susceptibility to repeated impacts.
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Affiliation(s)
- Mor R. Alkaslasi
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Eliza Y. H. Lloyd
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Austin S. Gable
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Hanna Silberberg
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Hector E. Yarur
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Valerie S. Tsai
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Hugo A. Tejeda
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Claire E. Le Pichon
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Wodrich APK, Harris BT, Giniger E. Changes in mitochondrial distribution occur at the axon initial segment in association with neurodegeneration in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580288. [PMID: 38405730 PMCID: PMC10888798 DOI: 10.1101/2024.02.14.580288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Changes in mitochondrial distribution are a feature of numerous age-related neurodegenerative diseases. In Drosophila, reducing the activity of Cdk5 causes a neurodegenerative phenotype and is known to affect several mitochondrial properties. Therefore, we investigated whether alterations of mitochondrial distribution are involved in Cdk5-associated neurodegeneration. We find that reducing Cdk5 activity does not alter the balance of mitochondrial localization to the somatodendritic vs. axonal neuronal compartments of the mushroom body, the learning and memory center of the Drosophila brain. We do, however, observe changes in mitochondrial distribution at the axon initial segment (AIS), a neuronal compartment located in the proximal axon involved in neuronal polarization and action potential initiation. Specifically, we observe that mitochondria are partially excluded from the AIS in wild-type neurons, but that this exclusion is lost upon reduction of Cdk5 activity, concomitant with the shrinkage of the AIS domain that is known to occur in this condition. This mitochondrial redistribution into the AIS is not likely due to the shortening of the AIS domain itself but rather due to altered Cdk5 activity. Furthermore, mitochondrial redistribution into the AIS is unlikely to be an early driver of neurodegeneration in the context of reduced Cdk5 activity.
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Affiliation(s)
- Andrew P. K. Wodrich
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC
- College of Medicine, University of Kentucky, Lexington, KY
| | - Brent T. Harris
- Department of Pathology, Georgetown University, Washington, DC
- Department of Neurology, Georgetown University, Washington, DC
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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Wakatsuki K, Kiryu-Seo S, Yasui M, Yokota H, Kida H, Konishi H, Kiyama H. Repeated cold stress, an animal model for fibromyalgia, elicits proprioceptor-induced chronic pain with microglial activation in mice. J Neuroinflammation 2024; 21:25. [PMID: 38238800 PMCID: PMC10795366 DOI: 10.1186/s12974-024-03018-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 01/09/2024] [Indexed: 01/22/2024] Open
Abstract
BACKGROUND Fibromyalgia is characterized by chronic pain, fatigue, and other somatic symptoms. We have recently revealed that proprioceptor hyperactivation induces chronic pain in a rat model of myalgic encephalomyelitis. The present study explores whether similar proprioceptor-induced pain is elicited in a mouse model of fibromyalgia. METHODS Repeated cold stress (RCS) was used as a fibromyalgia model. Pain behavior was examined using the von Frey test, and neuronal activation was examined immunohistochemically as activating transcription factor (ATF)3 expression. The Atf3:BAC transgenic mouse, in which mitochondria in hyperactivated neurons are specifically labeled by green fluorescent protein, was used to trace the activated neuronal circuit. PLX3397 (pexidartinib) was used for microglial suppression. RESULTS RCS elicited long-lasting pain in mice. ATF3, a marker of cellular hyperactivity and injury, was expressed in the lumbar dorsal root ganglion (DRG) 2 days after RCS initiation; the majority of ATF3-expressing DRG neurons were tropomyosin receptor kinase C- and/or vesicular glutamate transporter 1-positive proprioceptors. Microglial activation and increased numbers of microglia were observed in the medial part of the nucleus proprius 5 days after RCS initiation, and in the dorsal region of the ventral horn 7 days after RCS. In the ventral horn, only a subset of motor neurons was positive for ATF3; these neurons were surrounded by activated microglia. A retrograde tracer study revealed that ATF3-positive motor neurons projected to the intrinsic muscles of the foot (IMF). Using Atf3:BAC transgenic mice, we traced hyperactivated neuronal circuits along the reflex arc. Green fluorescent protein labeling was observed in proprioceptive DRG neurons and their processes originating from the IMF, as well as in motor neurons projecting to the IMF. Microglial activation was observed along this reflex arc, and PLX3397-induced microglial ablation significantly suppressed pain behavior. CONCLUSION Proprioceptor hyperactivation leads to local microglial activation along the reflex arc; this prolonged microglial activation may be responsible for chronic pain in the present model. Proprioceptor-induced microglial activation might be the common cause of chronic pain in both the fibromyalgia and myalgic encephalomyelitis models, although the experimental models are different.
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Affiliation(s)
- Koji Wakatsuki
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Sumiko Kiryu-Seo
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan.
| | - Masaya Yasui
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
- Department of Judo Seifuku and Health Sciences, Tokoha University, 1230 Miyakoda-Cho, Kita-Ku, Hamamatsu, Shizuoka, 431-2102, Japan
| | - Hiroki Yokota
- Department of Mechanical Engineering, Meijo University, 1-501 Shiogamaguchi, Tenpaku-Ku, Nagoya, Aichi, 468-0073, Japan
| | - Haruku Kida
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Hiroyuki Konishi
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan.
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Harley P, Kerins C, Gatt A, Neves G, Riccio F, Machado CB, Cheesbrough A, R'Bibo L, Burrone J, Lieberam I. Aberrant axon initial segment plasticity and intrinsic excitability of ALS hiPSC motor neurons. Cell Rep 2023; 42:113509. [PMID: 38019651 DOI: 10.1016/j.celrep.2023.113509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 10/06/2023] [Accepted: 11/13/2023] [Indexed: 12/01/2023] Open
Abstract
Dysregulated neuronal excitability is a hallmark of amyotrophic lateral sclerosis (ALS). We sought to investigate how functional changes to the axon initial segment (AIS), the site of action potential generation, could impact neuronal excitability in ALS human induced pluripotent stem cell (hiPSC) motor neurons. We find that early TDP-43 and C9orf72 hiPSC motor neurons show an increase in the length of the AIS and impaired activity-dependent AIS plasticity that is linked to abnormal homeostatic regulation of neuronal activity and intrinsic hyperexcitability. In turn, these hyperactive neurons drive increased spontaneous myofiber contractions of in vitro hiPSC motor units. In contrast, late hiPSC and postmortem ALS motor neurons show AIS shortening, and hiPSC motor neurons progress to hypoexcitability. At a molecular level, aberrant expression of the AIS master scaffolding protein ankyrin-G and AIS-specific voltage-gated sodium channels mirror these dynamic changes in AIS function and excitability. Our results point toward the AIS as an important site of dysfunction in ALS motor neurons.
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Affiliation(s)
- Peter Harley
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK; UCL Queen Square Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Caoimhe Kerins
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK; Centre for Craniofacial & Regenerative Biology, King's College London, London SE1 9RT, UK
| | - Ariana Gatt
- Queen Square Brain Bank, Department of Neurodegenerative Disease, Institute of Neurology, University College London, London WC1N 1PJ, UK
| | - Guilherme Neves
- Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Federica Riccio
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Carolina Barcellos Machado
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Aimee Cheesbrough
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Lea R'Bibo
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK
| | - Juan Burrone
- Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK; MRC Centre for Neurodevelopmental Disorders, Kings College London, London SE1 1UL, UK.
| | - Ivo Lieberam
- Centre for Gene Therapy & Regenerative Medicine, Kings College London, London SE1 9RT, UK; Centre for Developmental Neurobiology, Kings College London, London SE1 1UL, UK; MRC Centre for Neurodevelopmental Disorders, Kings College London, London SE1 1UL, UK.
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Gilloteaux J, De Swert K, Suain V, Nicaise C. Thalamic Neuron Resilience during Osmotic Demyelination Syndrome (ODS) Is Revealed by Primary Cilium Outgrowth and ADP-ribosylation factor-like protein 13B Labeling in Axon Initial Segment. Int J Mol Sci 2023; 24:16448. [PMID: 38003639 PMCID: PMC10671465 DOI: 10.3390/ijms242216448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
A murine osmotic demyelinating syndrome (ODS) model was developed through chronic hyponatremia, induced by desmopressin subcutaneous implants, followed by precipitous sodium restoration. The thalamic ventral posterolateral (VPL) and ventral posteromedial (VPM) relay nuclei were the most demyelinated regions where neuroglial damage could be evidenced without immune response. This report showed that following chronic hyponatremia, 12 h and 48 h time lapses after rebalancing osmolarity, amid the ODS-degraded outskirts, some resilient neuronal cell bodies built up primary cilium and axon hillock regions that extended into axon initial segments (AIS) where ADP-ribosylation factor-like protein 13B (ARL13B)-immunolabeled rod-like shape content was revealed. These AIS-labeled shaft lengths appeared proportional with the distance of neuronal cell bodies away from the ODS damaged epicenter and time lapses after correction of hyponatremia. Fine structure examination verified these neuron abundant transcriptions and translation regions marked by the ARL13B labeling associated with cell neurotubules and their complex cytoskeletal macromolecular architecture. This necessitated energetic transport to organize and restore those AIS away from the damaged ODS core demyelinated zone in the murine model. These labeled structures could substantiate how thalamic neuron resilience occurred as possible steps of a healing course out of ODS.
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Affiliation(s)
- Jacques Gilloteaux
- URPhyM, NARILIS, Université de Namur, Rue de Bruxelles 61, B-5000 Namur, Belgium; (J.G.); (K.D.S.)
- Department of Anatomical Sciences, St George’s University School of Medicine, Newcastle upon Tyne NE1 JG8, UK
| | - Kathleen De Swert
- URPhyM, NARILIS, Université de Namur, Rue de Bruxelles 61, B-5000 Namur, Belgium; (J.G.); (K.D.S.)
| | - Valérie Suain
- Laboratoire d’Histologie Générale, Université Libre de Bruxelles, Route de Lennik 808, B-1070 Bruxelles, Belgium;
| | - Charles Nicaise
- URPhyM, NARILIS, Université de Namur, Rue de Bruxelles 61, B-5000 Namur, Belgium; (J.G.); (K.D.S.)
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10
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Tamada H. Three-dimensional ultrastructure analysis of organelles in injured motor neuron. Anat Sci Int 2023:10.1007/s12565-023-00720-y. [PMID: 37071350 DOI: 10.1007/s12565-023-00720-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/23/2023] [Indexed: 04/19/2023]
Abstract
Morphological analysis of organelles is one of the important clues for understanding the cellular conditions and mechanisms occurring in cells. In particular, nanoscale information within crowded intracellular organelles of tissues provide more direct implications when compared to analyses of cells in culture or isolation. However, there are some difficulties in detecting individual shape using light microscopy, including super-resolution microscopy. Transmission electron microscopy (TEM), wherein the ultrastructure can be imaged at the membrane level, cannot determine the whole structure, and analyze it quantitatively. Volume EM, such as focused ion beam/scanning electron microscopy (FIB/SEM), can be a powerful tool to explore the details of three-dimensional ultrastructures even within a certain volume, and to measure several parameters from them. In this review, the advantages of FIB/SEM analysis in organelle studies are highlighted along with the introduction of mitochondrial analysis in injured motor neurons. This would aid in understanding the morphological details of mitochondria, especially those distributed in the cell bodies as well as in the axon initial segment (AIS) in mouse tissues. These regions have not been explored thus far due to the difficulties encountered in accessing their images by conditional microscopies. Some mechanisms of nerve regeneration have also been discussed with reference to the obtained findings. Finally, future perspectives on FIB/SEM are introduced. The combination of biochemical and genetic understanding of organelle structures and a nanoscale understanding of their three-dimensional distribution and morphology will help to match achievements in genomics and structural biology.
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Affiliation(s)
- Hiromi Tamada
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan.
- Anatomy, Graduate School of Medicines, University of Fukui, Matsuokashimoaizuki, Eiheiji-Cho, Yoshida-Gun, Fukui, 910-1193, Japan.
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Fan Q, Takarada-Iemata M, Okitani N, Tamatani T, Ishii H, Hattori T, Kiryu-Seo S, Kiyama H, Hori O. Brain injury triggers cell-type-specific and time-dependent endoplasmic reticulum stress responses. Glia 2023; 71:667-681. [PMID: 36412235 DOI: 10.1002/glia.24303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 10/29/2022] [Accepted: 11/03/2022] [Indexed: 11/23/2022]
Abstract
The unfolded protein response (UPR) is a signal transduction network that responds to endoplasmic reticulum (ER) stress by coordinating protein homeostasis to maintain cell viability. The UPR can also trigger cell death when adaptive responses fail to improve protein homeostasis. Despite accumulating evidence suggesting that the UPR plays a role in neurodegenerative diseases and brain insults, our understanding of how ER stress is induced under neuropathological conditions is limited. Here, we investigated the cell- and time-specific patterns of the ER stress response after brain injury using ER stress-activated indicator (ERAI) mice, which enable monitoring of the UPR in vivo via increased fluorescence of a spliced XBP-1 protein fused with the green fluorescent protein (GFP) variant Venus. Following cortical stab injury of ERAI mice, the GFP signal and number of GFP+ cells increased in the ipsilateral cortex throughout the observation period (6 h to 7 days post-injury), confirming the induction of the UPR. GFP signals were observed in injured neurons early (from 6 h) after brain injury. However, non-neuronal cells, mainly endothelial cells followed by astrocytes, accounted for the majority of GFP+ cells after brain injury. Similar results were obtained in a mouse model of focal cerebral ischemia. These findings suggest that activation of the UPR in both neuronal and non-neuronal cells, especially endothelial cells and astrocytes, may play an important role in and could be a potential therapeutic target for acute brain injuries.
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Affiliation(s)
- Qiyan Fan
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Mika Takarada-Iemata
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Nahoko Okitani
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Takashi Tamatani
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Hiroshi Ishii
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Tsuyoshi Hattori
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Sumiko Kiryu-Seo
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Osamu Hori
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
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