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Salzinger A, Ramesh V, Das Sharma S, Chandran S, Thangaraj Selvaraj B. Neuronal Circuit Dysfunction in Amyotrophic Lateral Sclerosis. Cells 2024; 13:792. [PMID: 38786016 PMCID: PMC11120636 DOI: 10.3390/cells13100792] [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: 03/19/2024] [Revised: 04/27/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024] Open
Abstract
The primary neural circuit affected in Amyotrophic Lateral Sclerosis (ALS) patients is the corticospinal motor circuit, originating in upper motor neurons (UMNs) in the cerebral motor cortex which descend to synapse with the lower motor neurons (LMNs) in the spinal cord to ultimately innervate the skeletal muscle. Perturbation of these neural circuits and consequent loss of both UMNs and LMNs, leading to muscle wastage and impaired movement, is the key pathophysiology observed. Despite decades of research, we are still lacking in ALS disease-modifying treatments. In this review, we document the current research from patient studies, rodent models, and human stem cell models in understanding the mechanisms of corticomotor circuit dysfunction and its implication in ALS. We summarize the current knowledge about cortical UMN dysfunction and degeneration, altered excitability in LMNs, neuromuscular junction degeneration, and the non-cell autonomous role of glial cells in motor circuit dysfunction in relation to ALS. We further highlight the advances in human stem cell technology to model the complex neural circuitry and how these can aid in future studies to better understand the mechanisms of neural circuit dysfunction underpinning ALS.
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Affiliation(s)
- Andrea Salzinger
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Vidya Ramesh
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Shreya Das Sharma
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Siddharthan Chandran
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
- Anne Rowling Regenerative Neurology Clinic (ARRNC), University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Bhuvaneish Thangaraj Selvaraj
- UK Dementia Research Institute, University of Edinburgh, Edinburgh EH16 4SB, UK; (A.S.); (V.R.); (S.D.S.); (S.C.)
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
- Anne Rowling Regenerative Neurology Clinic (ARRNC), University of Edinburgh, Edinburgh EH16 4SB, UK
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2
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Pilotto F, Douthwaite C, Diab R, Ye X, Al Qassab Z, Tietje C, Mounassir M, Odriozola A, Thapa A, Buijsen RAM, Lagache S, Uldry AC, Heller M, Müller S, van Roon-Mom WMC, Zuber B, Liebscher S, Saxena S. Early molecular layer interneuron hyperactivity triggers Purkinje neuron degeneration in SCA1. Neuron 2023; 111:2523-2543.e10. [PMID: 37321222 PMCID: PMC10431915 DOI: 10.1016/j.neuron.2023.05.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/17/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023]
Abstract
Toxic proteinaceous deposits and alterations in excitability and activity levels characterize vulnerable neuronal populations in neurodegenerative diseases. Using in vivo two-photon imaging in behaving spinocerebellar ataxia type 1 (Sca1) mice, wherein Purkinje neurons (PNs) degenerate, we identify an inhibitory circuit element (molecular layer interneurons [MLINs]) that becomes prematurely hyperexcitable, compromising sensorimotor signals in the cerebellum at early stages. Mutant MLINs express abnormally elevated parvalbumin, harbor high excitatory-to-inhibitory synaptic density, and display more numerous synaptic connections on PNs, indicating an excitation/inhibition imbalance. Chemogenetic inhibition of hyperexcitable MLINs normalizes parvalbumin expression and restores calcium signaling in Sca1 PNs. Chronic inhibition of mutant MLINs delayed PN degeneration, reduced pathology, and ameliorated motor deficits in Sca1 mice. Conserved proteomic signature of Sca1 MLINs, shared with human SCA1 interneurons, involved the higher expression of FRRS1L, implicated in AMPA receptor trafficking. We thus propose that circuit-level deficits upstream of PNs are one of the main disease triggers in SCA1.
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Affiliation(s)
- Federica Pilotto
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Christopher Douthwaite
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | - Rim Diab
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - XiaoQian Ye
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | - Zahraa Al Qassab
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Christoph Tietje
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | - Meriem Mounassir
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | | | - Aishwarya Thapa
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Ronald A M Buijsen
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Sophie Lagache
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Anne-Christine Uldry
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Manfred Heller
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Stefan Müller
- Flow Cytometry and Cell sorting, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | | | - Benoît Zuber
- Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Sabine Liebscher
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; University Hospital Cologne, Deptartment of Neurology, Cologne, Germany.
| | - Smita Saxena
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland.
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3
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Gautam M, Genç B, Helmold B, Ahrens A, Kuka J, Makrecka-Kuka M, Günay A, Koçak N, Aguilar-Wickings IR, Keefe D, Zheng G, Swaminathan S, Redmon M, Zariwala HA, Özdinler PH. SBT-272 improves TDP-43 pathology in ALS upper motor neurons by modulating mitochondrial integrity, motility, and function. Neurobiol Dis 2023; 178:106022. [PMID: 36716828 DOI: 10.1016/j.nbd.2023.106022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/09/2023] [Accepted: 01/25/2023] [Indexed: 01/28/2023] Open
Abstract
Mitochondrial defects are one of the common underlying causes of neuronal vulnerability in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), and TDP-43 pathology is the most commonly observed proteinopathy. Disrupted inner mitochondrial membrane (IMM) reported in the upper motor neurons (UMNs) of ALS patients with TDP-43 pathology is recapitulated in the UMNs of well-characterized hTDP-43 mouse model of ALS. The construct validity, such as shared and common cellular pathology in mice and human, offers a unique opportunity to test treatment strategies that may translate to patients. SBT-272 is a well-tolerated brain-penetrant small molecule that stabilizes cardiolipin, a phospholipid found in IMM, thereby restoring mitochondrial structure and respiratory function. We investigated whether SBT-272 can improve IMM structure and health in UMNs diseased with TDP-43 pathology in our well-characterized UMN reporter line for ALS. We found that SBT-272 significantly improved mitochondrial structural integrity and restored mitochondrial motility and function. This led to improved health of diseased UMNs in vitro. In comparison to edaravone and AMX0035, SBT-272 appeared more effective in restoring health of diseased UMNs. Chronic treatment of SBT-272 for sixty days starting at an early symptomatic stage of the disease in vivo led to a significant reduction in astrogliosis, microgliosis, and TDP-43 pathology in the ALS motor cortex. Our results underscore the therapeutic potential of SBT-272, especially within the context of TDP-43 pathology and mitochondrial dysfunction.
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Affiliation(s)
- Mukesh Gautam
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611, USA
| | - Barış Genç
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611, USA
| | - Benjamin Helmold
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611, USA
| | - Angela Ahrens
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611, USA
| | - Janis Kuka
- Latvian Institute of Organic Synthesis (LIOS), Aizkraukles Street 21, LV-2006 Riga, Latvia
| | - Marina Makrecka-Kuka
- Latvian Institute of Organic Synthesis (LIOS), Aizkraukles Street 21, LV-2006 Riga, Latvia
| | - Aksu Günay
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611, USA
| | - Nuran Koçak
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611, USA
| | - Izaak R Aguilar-Wickings
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611, USA
| | - Dennis Keefe
- Stealth BioTherapeutics, 140 Kendrick St Building C, Needham, MA 02494, USA
| | - Guozhu Zheng
- Stealth BioTherapeutics, 140 Kendrick St Building C, Needham, MA 02494, USA
| | - Suchitra Swaminathan
- Division of Rheumatology, Department of Medicine, Feinberg School of Medicine, Northwestern University, 420 E Superior St, Chicago, IL 60611, USA.; Robert H. Lurie Comprehensive Cancer Research Center, Feinberg School of Medicine, Northwestern University, 675 N St Clair Fl 21 Ste 100, Chicago, IL 60611, USA
| | - Martin Redmon
- Stealth BioTherapeutics, 140 Kendrick St Building C, Needham, MA 02494, USA
| | - Hatim A Zariwala
- Stealth BioTherapeutics, 140 Kendrick St Building C, Needham, MA 02494, USA
| | - P Hande Özdinler
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611, USA; Robert H. Lurie Comprehensive Cancer Research Center, Feinberg School of Medicine, Northwestern University, 675 N St Clair Fl 21 Ste 100, Chicago, IL 60611, USA; Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Center for Developmental Therapeutics, Northwestern University, 2205 Tech Dr, Evanston, IL 60208, USA..
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Gelon PA, Dutchak PA, Sephton CF. Synaptic dysfunction in ALS and FTD: anatomical and molecular changes provide insights into mechanisms of disease. Front Mol Neurosci 2022; 15:1000183. [PMID: 36263379 PMCID: PMC9575515 DOI: 10.3389/fnmol.2022.1000183] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/01/2022] [Indexed: 11/29/2022] Open
Abstract
Synaptic loss is a pathological feature of all neurodegenerative diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). ALS is a disease of the cortical and spinal motor neurons resulting in fatal paralysis due to denervation of muscles. FTD is a form of dementia that primarily affects brain regions controlling cognition, language and behavior. Once classified as two distinct diseases, ALS and FTD are now considered as part of a common disease spectrum based on overlapping clinical, pathological and genetic evidence. At the cellular level, aggregation of common proteins and overlapping gene susceptibilities are shared in both ALS and FTD. Despite the convergence of these two fields of research, the underlying disease mechanisms remain elusive. However, recent discovers from ALS and FTD patient studies and models of ALS/FTD strongly suggests that synaptic dysfunction is an early event in the disease process and a unifying hallmark of these diseases. This review provides a summary of the reported anatomical and cellular changes that occur in cortical and spinal motor neurons in ALS and FTD tissues and models of disease. We also highlight studies that identify changes in the proteome and transcriptome of ALS and FTD models and provide a conceptual overview of the processes that contribute to synaptic dysfunction in these diseases. Due to space limitations and the vast number of publications in the ALS and FTD fields, many articles have not been discussed in this review. As such, this review focuses on the three most common shared mutations in ALS and FTD, the hexanucleuotide repeat expansion within intron 1 of chromosome 9 open reading frame 72 (C9ORF72), transactive response DNA binding protein 43 (TARDBP or TDP-43) and fused in sarcoma (FUS), with the intention of highlighting common pathways that promote synaptic dysfunction in the ALS-FTD disease spectrum.
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Lu WZ, Lin HA, Hou SK, Lee CF, Bai CH, Lin SF. Split-hand index for amyotrophic lateral sclerosis diagnosis: A frequentist and Bayesian meta-analysis. Clin Neurophysiol 2022; 143:56-66. [PMID: 36116424 DOI: 10.1016/j.clinph.2022.08.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 08/02/2022] [Accepted: 08/21/2022] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Preferential wasting of the thenar muscles, the split-hand sign, may be used for early diagnosis of amyotrophic lateral sclerosis (ALS). METHODS Electronic databases were searched for studies assessing the split-hand index (SHI) and the compound muscle action potential (CMAP) amplitudes of abductor pollicis brevis (APB), first dorsal interosseous (FDI), and abductor digiti minimi (ADM). The SHI was obtained by multiplying CMAP amplitudes of APB and FDI and dividing the product by the CMAP amplitude of ADM. The Bayesian analysis was used for validation. RESULTS In total, 17 studies and 1635 patients were included. Our meta-analysis revealed that ALS patients had significantly decreased SHI (standardized mean difference [SMD], -1.60, P < 0.001), CMAP of the APB (SMD, -1.67, P < 0.001), FDI (SMD, -1.12, P < 0.001), and ADM (SMD, -1.09, P < 0.001). The binormal receiver operating characteristic curve analysis showed a threshold of < 7.4 for SHI, and cutoff values of < 6.4 mV for APB and < 8.4 mV for FDI, respectively. The Bayesian analysis validated decreased SHI in ALS patients (posterior mean difference of - 5.91). CONCLUSIONS An SHI of < 7.4 can be used facilitating earlier diagnosis of ALS. SIGNIFICANCE SHI can be used as a standard neurophysiological biomarker for early diagnosis.
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Affiliation(s)
- Wei-Zhen Lu
- Department of Emergency Medicine, Taipei Medical University-Shuang Ho Hospital, New Taipei, Taiwan
| | - Hui-An Lin
- Department of Emergency Medicine, Taipei Medical University Hospital, Taipei, Taiwan; Department of Emergency Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Sen-Kuang Hou
- Department of Emergency Medicine, Taipei Medical University Hospital, Taipei, Taiwan; Department of Emergency Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Cheng-Fan Lee
- Department of Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Chyi-Huey Bai
- School of Public Health, College of Public Health, Taipei Medical University, Taipei, Taiwan; Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Nutrition Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Sheng-Feng Lin
- Department of Emergency Medicine, Taipei Medical University Hospital, Taipei, Taiwan; School of Public Health, College of Public Health, Taipei Medical University, Taipei, Taiwan; Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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Monteverdi A, Palesi F, Costa A, Vitali P, Pichiecchio A, Cotta Ramusino M, Bernini S, Jirsa V, Gandini Wheeler-Kingshott CAM, D’Angelo E. Subject-specific features of excitation/inhibition profiles in neurodegenerative diseases. Front Aging Neurosci 2022; 14:868342. [PMID: 35992607 PMCID: PMC9391060 DOI: 10.3389/fnagi.2022.868342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 07/05/2022] [Indexed: 11/26/2022] Open
Abstract
Brain pathologies are characterized by microscopic changes in neurons and synapses that reverberate into large scale networks altering brain dynamics and functional states. An important yet unresolved issue concerns the impact of patients' excitation/inhibition profiles on neurodegenerative diseases including Alzheimer's Disease, Frontotemporal Dementia, and Amyotrophic Lateral Sclerosis. In this work, we used The Virtual Brain (TVB) simulation platform to simulate brain dynamics in healthy and neurodegenerative conditions and to extract information about the excitatory/inhibitory balance in single subjects. The brain structural and functional connectomes were extracted from 3T-MRI (Magnetic Resonance Imaging) scans and TVB nodes were represented by a Wong-Wang neural mass model endowing an explicit representation of the excitatory/inhibitory balance. Simulations were performed including both cerebral and cerebellar nodes and their structural connections to explore cerebellar impact on brain dynamics generation. The potential for clinical translation of TVB derived biophysical parameters was assessed by exploring their association with patients' cognitive performance and testing their discriminative power between clinical conditions. Our results showed that TVB biophysical parameters differed between clinical phenotypes, predicting higher global coupling and inhibition in Alzheimer's Disease and stronger N-methyl-D-aspartate (NMDA) receptor-dependent excitation in Amyotrophic Lateral Sclerosis. These physio-pathological parameters allowed us to perform an advanced analysis of patients' conditions. In backward regressions, TVB-derived parameters significantly contributed to explain the variation of neuropsychological scores and, in discriminant analysis, the combination of TVB parameters and neuropsychological scores significantly improved the discriminative power between clinical conditions. Moreover, cluster analysis provided a unique description of the excitatory/inhibitory balance in individual patients. Importantly, the integration of cerebro-cerebellar loops in simulations improved TVB predictive power, i.e., the correlation between experimental and simulated functional connectivity in all pathological conditions supporting the cerebellar role in brain function disrupted by neurodegeneration. Overall, TVB simulations reveal differences in the excitatory/inhibitory balance of individual patients that, combined with cognitive assessment, can promote the personalized diagnosis and therapy of neurodegenerative diseases.
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Affiliation(s)
- Anita Monteverdi
- Brain Connectivity Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Fulvia Palesi
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Alfredo Costa
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Unit of Behavioral Neurology, IRCCS Mondino Foundation, Pavia, Italy
| | - Paolo Vitali
- Department of Radiology, IRCCS Policlinico San Donato, Milan, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Anna Pichiecchio
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Advanced Imaging and Radiomic Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Matteo Cotta Ramusino
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Unit of Behavioral Neurology, IRCCS Mondino Foundation, Pavia, Italy
| | - Sara Bernini
- Dementia Research Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Viktor Jirsa
- Institut de Neurosciences des Systèmes, INSERM, INS, Aix-Marseille University, Marseille, France
| | - Claudia A. M. Gandini Wheeler-Kingshott
- Brain Connectivity Center, IRCCS Mondino Foundation, Pavia, Italy
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, University College London (UCL) Queen Square Institute of Neurology, London, United Kingdom
| | - Egidio D’Angelo
- Brain Connectivity Center, IRCCS Mondino Foundation, Pavia, Italy
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
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Acute Colon Inflammation Triggers Primary Motor Cortex Glial Activation, Neuroinflammation, Neuronal Hyperexcitability, and Motor Coordination Deficits. Int J Mol Sci 2022; 23:ijms23105347. [PMID: 35628158 PMCID: PMC9141031 DOI: 10.3390/ijms23105347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/28/2022] [Accepted: 05/07/2022] [Indexed: 02/05/2023] Open
Abstract
Neuroinflammation underlies neurodegenerative diseases. Herein, we test whether acute colon inflammation activates microglia and astrocytes, induces neuroinflammation, disturbs neuron intrinsic electrical properties in the primary motor cortex, and alters motor behaviors. We used a rat model of acute colon inflammation induced by dextran sulfate sodium. Inflammatory mediators and microglial activation were assessed in the primary motor cortex by PCR and immunofluorescence assays. Electrophysiological properties of the motor cortex neurons were determined by whole-cell patch-clamp recordings. Motor behaviors were examined using open-field and rotarod tests. We show that the primary motor cortex of rats with acute colon inflammation exhibited microglial and astrocyte activation and increased mRNA abundance of interleukin-6, tumor necrosis factor-alpha, and both inducible and neuronal nitric oxide synthases. These changes were accompanied by a reduction in resting membrane potential and rheobase and increased input resistance and action potential frequency, indicating motor neuron hyperexcitability. In addition, locomotion and motor coordination were impaired. In conclusion, acute colon inflammation induces motor cortex microglial and astrocyte activation and inflammation, which led to neurons’ hyperexcitability and reduced motor coordination performance. The described disturbances resembled some of the early features found in amyotrophic lateral sclerosis patients and animal models, suggesting that colon inflammation might be a risk factor for developing this disease.
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Zakharova MN, Bakulin IS, Abramova AA. Toxic Damage to Motor Neurons. NEUROCHEM J+ 2021. [DOI: 10.1134/s1819712421040164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract—Amyotrophic lateral sclerosis (ALS) is a multifactor disease in the development of which both genetic and environmental factors play a role. Specifically, the effects of organic and inorganic toxic substances can result in an increased risk of ALS development and the acceleration of disease progression. It was described that some toxins can induce potentially curable ALS-like syndromes. In this case, the specific treatment for the prevention of the effects of the toxic factor may result in positive clinical dynamics. In this article, we review the main types of toxins that can damage motor neurons in the brain and spinal cord leading to the development of the clinical manifestation of ALS, briefly present historical data on studies on the role of toxic substances, and describe the main mechanisms of the pathogenesis of motor neuron disease associated with their action.
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Dyer MS, Woodhouse A, Blizzard CA. Cytoplasmic Human TDP-43 Mislocalization Induces Widespread Dendritic Spine Loss in Mouse Upper Motor Neurons. Brain Sci 2021; 11:brainsci11070883. [PMID: 34209287 PMCID: PMC8301870 DOI: 10.3390/brainsci11070883] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/25/2021] [Accepted: 06/27/2021] [Indexed: 11/16/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is defined by the destruction of upper- and lower motor neurons. Post-mortem, nearly all ALS cases are positive for cytoplasmic aggregates containing the DNA/RNA binding protein TDP-43. Recent studies indicate that this pathogenic mislocalization of TDP-43 may participate in generating hyperexcitability of the upper motor neurons, the earliest detectable change in ALS patients, yet the mechanisms driving this remain unclear. We investigated how mislocalisation of TDP-43 could initiate network dysfunction in ALS. We employed a tetracycline inducible system to express either human wildtype TDP-43 (TDP-43WT) or human TDP-43 that cannot enter the nucleus (TDP-43ΔNLS) in excitatory neurons (Camk2α promoter), crossed Thy1-YFPH mice to visualize dendritic spines, the major site of excitatory synapses. In comparison to both TDP-43WT and controls, TDP-43ΔNLS drove a robust loss in spine density in all the dendrite regions of the upper motor neurons, most affecting thin spines. This indicates that TDP-43 is involved in the generation of network dysfunction in ALS likely through impacting the formation or durability of excitatory synapses. These findings are relevant to the vast majority of ALS cases, and provides further evidence that upper motor neurons may need to be protected from TDP-43 mediated synaptic excitatory changes early in disease.
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Affiliation(s)
- Marcus S. Dyer
- Menzies Institute for Medical Research, College Health and Medicine, University of Tasmania, Hobart, TAS 7000, Australia;
| | - Adele Woodhouse
- Wicking Dementia Research and Education Centre, College Health and Medicine, University of Tasmania, Hobart, TAS 7000, Australia;
| | - Catherine A. Blizzard
- Menzies Institute for Medical Research, College Health and Medicine, University of Tasmania, Hobart, TAS 7000, Australia;
- Correspondence:
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