1
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Tejwani L, Ravindra NG, Lee C, Cheng Y, Nguyen B, Luttik K, Ni L, Zhang S, Morrison LM, Gionco J, Xiang Y, Yoon J, Ro H, Haidery F, Grijalva RM, Bae E, Kim K, Martuscello RT, Orr HT, Zoghbi HY, McLoughlin HS, Ranum LPW, Shakkottai VG, Faust PL, Wang S, van Dijk D, Lim J. Longitudinal single-cell transcriptional dynamics throughout neurodegeneration in SCA1. Neuron 2024; 112:362-383.e15. [PMID: 38016472 PMCID: PMC10922326 DOI: 10.1016/j.neuron.2023.10.039] [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: 12/15/2022] [Revised: 09/10/2023] [Accepted: 10/27/2023] [Indexed: 11/30/2023]
Abstract
Neurodegeneration is a protracted process involving progressive changes in myriad cell types that ultimately results in the death of vulnerable neuronal populations. To dissect how individual cell types within a heterogeneous tissue contribute to the pathogenesis and progression of a neurodegenerative disorder, we performed longitudinal single-nucleus RNA sequencing of mouse and human spinocerebellar ataxia type 1 (SCA1) cerebellar tissue, establishing continuous dynamic trajectories of each cell population. Importantly, we defined the precise transcriptional changes that precede loss of Purkinje cells and, for the first time, identified robust early transcriptional dysregulation in unipolar brush cells and oligodendroglia. Finally, we applied a deep learning method to predict disease state accurately and identified specific features that enable accurate distinction of wild-type and SCA1 cells. Together, this work reveals new roles for diverse cerebellar cell types in SCA1 and provides a generalizable analysis framework for studying neurodegeneration.
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Affiliation(s)
- Leon Tejwani
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06510, USA; Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA.
| | - Neal G Ravindra
- Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Computer Science, Yale University, New Haven, CT 06510, USA
| | - Changwoo Lee
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06510, USA; Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | - Yubao Cheng
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Billy Nguyen
- University of California, San Francisco School of Medicine, San Francisco, CA 94143, USA
| | - Kimberly Luttik
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06510, USA; Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | - Luhan Ni
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Shupei Zhang
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Logan M Morrison
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - John Gionco
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA
| | - Yangfei Xiang
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA; Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06510, USA
| | | | - Hannah Ro
- Yale College, New Haven, CT 06510, USA
| | | | - Rosalie M Grijalva
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06510, USA; Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | | | - Kristen Kim
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06510, USA; Department of Psychiatry, Yale School of Medicine, New Haven, CT 06510, USA
| | - Regina T Martuscello
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA
| | - Harry T Orr
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Huda Y Zoghbi
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hayley S McLoughlin
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Laura P W Ranum
- Department of Molecular Genetics and Microbiology, Center for Neurogenetics, College of Medicine, Genetics Institute, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Vikram G Shakkottai
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY 10032, USA
| | - Siyuan Wang
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA; Department of Cell Biology, Yale School of Medicine, New Haven, CT 06510, USA.
| | - David van Dijk
- Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Computer Science, Yale University, New Haven, CT 06510, USA.
| | - Janghoo Lim
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06510, USA; Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA; Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA; Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06510, USA; Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale School of Medicine, New Haven, CT 06510, USA; Wu Tsai Institute, Yale School of Medicine, New Haven, CT 06510, USA.
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2
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Cole BA, Becker EBE. Modulation and Regulation of Canonical Transient Receptor Potential 3 (TRPC3) Channels. Cells 2023; 12:2215. [PMID: 37759438 PMCID: PMC10526463 DOI: 10.3390/cells12182215] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Canonical transient receptor potential 3 (TRPC3) channel is a non-selective cation permeable channel that plays an essential role in calcium signalling. TRPC3 is highly expressed in the brain and also found in endocrine tissues and smooth muscle cells. The channel is activated directly by binding of diacylglycerol downstream of G-protein coupled receptor activation. In addition, TRPC3 is regulated by endogenous factors including Ca2+ ions, other endogenous lipids, and interacting proteins. The molecular and structural mechanisms underlying activation and regulation of TRPC3 are incompletely understood. Recently, several high-resolution cryogenic electron microscopy structures of TRPC3 and the closely related channel TRPC6 have been resolved in different functional states and in the presence of modulators, coupled with mutagenesis studies and electrophysiological characterisation. Here, we review the recent literature which has advanced our understanding of the complex mechanisms underlying modulation of TRPC3 by both endogenous and exogenous factors. TRPC3 plays an important role in Ca2+ homeostasis and entry into cells throughout the body, and both pathological variants and downstream dysregulation of TRPC3 channels have been associated with a number of diseases. As such, TRPC3 may be a valuable therapeutic target, and understanding its regulatory mechanisms will aid future development of pharmacological modulators of the channel.
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Affiliation(s)
- Bethan A. Cole
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Esther B. E. Becker
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
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3
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Fernández de la Torre M, Fiuza-Luces C, Laine-Menéndez S, Delmiro A, Arenas J, Martín MÁ, Lucia A, Morán M. Pathophysiology of Cerebellar Degeneration in Mitochondrial Disorders: Insights from the Harlequin Mouse. Int J Mol Sci 2023; 24:10973. [PMID: 37446148 DOI: 10.3390/ijms241310973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 06/22/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
By means of a proteomic approach, we assessed the pathways involved in cerebellar neurodegeneration in a mouse model (Harlequin, Hq) of mitochondrial disorder. A differential proteomic profile study (iTRAQ) was performed in cerebellum homogenates of male Hq and wild-type (WT) mice 8 weeks after the onset of clear symptoms of ataxia in the Hq mice (aged 5.2 ± 0.2 and 5.3 ± 0.1 months for WT and Hq, respectively), followed by a biochemical validation of the most relevant changes. Additional groups of 2-, 3- and 6-month-old WT and Hq mice were analyzed to assess the disease progression on the proteins altered in the proteomic study. The proteomic analysis showed that beyond the expected deregulation of oxidative phosphorylation, the cerebellum of Hq mice showed a marked astroglial activation together with alterations in Ca2+ homeostasis and neurotransmission, with an up- and downregulation of GABAergic and glutamatergic neurotransmission, respectively, and the downregulation of cerebellar "long-term depression", a synaptic plasticity phenomenon that is a major player in the error-driven learning that occurs in the cerebellar cortex. Our study provides novel insights into the mechanisms associated with cerebellar degeneration in the Hq mouse model, including a complex deregulation of neuroinflammation, oxidative phosphorylation and glutamate, GABA and amino acids' metabolism.
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Affiliation(s)
- Miguel Fernández de la Torre
- Mitochondrial and Neuromuscular Diseases Laboratory, Instituto de Investigación Sanitaria Hospital '12 de Octubre' ('imas12'), 28041 Madrid, Spain
| | - Carmen Fiuza-Luces
- Mitochondrial and Neuromuscular Diseases Laboratory, Instituto de Investigación Sanitaria Hospital '12 de Octubre' ('imas12'), 28041 Madrid, Spain
| | - Sara Laine-Menéndez
- Mitochondrial and Neuromuscular Diseases Laboratory, Instituto de Investigación Sanitaria Hospital '12 de Octubre' ('imas12'), 28041 Madrid, Spain
| | - Aitor Delmiro
- Mitochondrial and Neuromuscular Diseases Laboratory, Instituto de Investigación Sanitaria Hospital '12 de Octubre' ('imas12'), 28041 Madrid, Spain
- Spanish Network for Biomedical Research in Rare Diseases (CIBERER), U723, 28029 Madrid, Spain
- Servicio de Bioquímica Clínica, Hospital Universitario "12 de Octubre", 28041 Madrid, Spain
| | - Joaquín Arenas
- Mitochondrial and Neuromuscular Diseases Laboratory, Instituto de Investigación Sanitaria Hospital '12 de Octubre' ('imas12'), 28041 Madrid, Spain
- Spanish Network for Biomedical Research in Rare Diseases (CIBERER), U723, 28029 Madrid, Spain
| | - Miguel Ángel Martín
- Mitochondrial and Neuromuscular Diseases Laboratory, Instituto de Investigación Sanitaria Hospital '12 de Octubre' ('imas12'), 28041 Madrid, Spain
- Spanish Network for Biomedical Research in Rare Diseases (CIBERER), U723, 28029 Madrid, Spain
- Servicio de Genética, Hospital Universitario "12 de Octubre", 28041 Madrid, Spain
| | - Alejandro Lucia
- Faculty of Sports Sciences, European University of Madrid, 28670 Madrid, Spain
- Spanish Network for Biomedical Research in Fragility and Healthy Aging (CIBERFES), 28029 Madrid, Spain
| | - María Morán
- Mitochondrial and Neuromuscular Diseases Laboratory, Instituto de Investigación Sanitaria Hospital '12 de Octubre' ('imas12'), 28041 Madrid, Spain
- Spanish Network for Biomedical Research in Rare Diseases (CIBERER), U723, 28029 Madrid, Spain
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4
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Kapfhammer JP, Shimobayashi E. Viewpoint: spinocerebellar ataxias as diseases of Purkinje cell dysfunction rather than Purkinje cell loss. Front Mol Neurosci 2023; 16:1182431. [PMID: 37426070 PMCID: PMC10323145 DOI: 10.3389/fnmol.2023.1182431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/22/2023] [Indexed: 07/11/2023] Open
Abstract
Spinocerebellar ataxias (SCAs) are a group of hereditary neurodegenerative diseases mostly affecting cerebellar Purkinje cells caused by a wide variety of different mutations. One subtype, SCA14, is caused by mutations of Protein Kinase C gamma (PKCγ), the dominant PKC isoform present in Purkinje cells. Mutations in the pathway in which PKCγ is active, i.e., in the regulation of calcium levels and calcium signaling in Purkinje cells, are the cause of several other variants of SCA. In SCA14, many of the observed mutations in the PKCγ gene were shown to increase the basal activity of PKCγ, raising the possibility that increased activity of PKCγ might be the cause of most forms of SCA14 and might also be involved in the pathogenesis of SCA in related subtypes. In this viewpoint and review article we will discuss the evidence for and against such a major role of PKCγ basal activity and will suggest a hypothesis of how PKCγ activity and the calcium signaling pathway may be involved in the pathogenesis of SCAs despite the different and sometimes opposing effects of mutations affecting these pathways. We will then widen the scope and propose a concept of SCA pathogenesis which is not primarily driven by cell death and loss of Purkinje cells but rather by dysfunction of Purkinje cells which are still present and alive in the cerebellum.
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5
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Kerkhof LMC, van de Warrenburg BPC, van Roon-Mom WMC, Buijsen RAM. Therapeutic Strategies for Spinocerebellar Ataxia Type 1. Biomolecules 2023; 13:biom13050788. [PMID: 37238658 DOI: 10.3390/biom13050788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/28/2023] [Accepted: 04/29/2023] [Indexed: 05/28/2023] Open
Abstract
Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disorder that affects one or two individuals per 100,000. The disease is caused by an extended CAG repeat in exon 8 of the ATXN1 gene and is characterized mostly by a profound loss of cerebellar Purkinje cells, leading to disturbances in coordination, balance, and gait. At present, no curative treatment is available for SCA1. However, increasing knowledge on the cellular and molecular mechanisms of SCA1 has led the way towards several therapeutic strategies that can potentially slow disease progression. SCA1 therapeutics can be classified as genetic, pharmacological, and cell replacement therapies. These different therapeutic strategies target either the (mutant) ATXN1 RNA or the ataxin-1 protein, pathways that play an important role in downstream SCA1 disease mechanisms or which help restore cells that are lost due to SCA1 pathology. In this review, we will provide a summary of the different therapeutic strategies that are currently being investigated for SCA1.
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Affiliation(s)
- Laurie M C Kerkhof
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Dutch Center for RNA Therapeutics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Bart P C van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Willeke M C van Roon-Mom
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Dutch Center for RNA Therapeutics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Ronald A M Buijsen
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
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6
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Surdin T, Preissing B, Rohr L, Grömmke M, Böke H, Barcik M, Azimi Z, Jancke D, Herlitze S, Mark MD, Siveke I. Optogenetic activation of mGluR1 signaling in the cerebellum induces synaptic plasticity. iScience 2022; 26:105828. [PMID: 36632066 PMCID: PMC9826949 DOI: 10.1016/j.isci.2022.105828] [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: 04/12/2022] [Revised: 10/21/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Neuronal plasticity underlying cerebellar learning behavior is strongly associated with type 1 metabotropic glutamate receptor (mGluR1) signaling. Activation of mGluR1 leads to activation of the Gq/11 pathway, which is involved in inducing synaptic plasticity at the parallel fiber-Purkinje cell synapse (PF-PC) in form of long-term depression (LTD). To optogenetically modulate mGluR1 signaling we fused mouse melanopsin (OPN4) that activates the Gq/11 pathway to the C-termini of mGluR1 splice variants (OPN4-mGluR1a and OPN4-mGluR1b). Activation of both OPN4-mGluR1 variants showed robust Ca2+ increase in HEK cells and PCs of cerebellar slices. We provide the prove-of-concept approach to modulate synaptic plasticity via optogenetic activation of OPN4-mGluR1a inducing LTD at the PF-PC synapse in vitro. Moreover, we demonstrate that light activation of mGluR1a signaling pathway by OPN4-mGluR1a in PCs leads to an increase in intrinsic activity of PCs in vivo and improved cerebellum driven learning behavior.
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Affiliation(s)
- Tatjana Surdin
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Bianca Preissing
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Lennard Rohr
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Michelle Grömmke
- Behavioral Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | - Hanna Böke
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Maike Barcik
- Cardiovascular Research Institute Düsseldorf, Division of Cardiology, Pulmonology, and Vascular Medicine, University Duesseldorf, Medical Faculty, Duesseldorf, Germany
| | - Zohre Azimi
- Optical Imaging Group, Institut für Neuroinformatik, Ruhr-University Bochum, Bochum, Germany
| | - Dirk Jancke
- Optical Imaging Group, Institut für Neuroinformatik, Ruhr-University Bochum, Bochum, Germany
| | - Stefan Herlitze
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany,Corresponding author
| | - Melanie D. Mark
- Behavioral Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | - Ida Siveke
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany,Bridge Institute of Experimental Tumor Therapy, West German Cancer Center, University Hospital Essen, Essen, Germany,Corresponding author
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7
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Targeting mGlu1 Receptors in the Treatment of Motor and Cognitive Dysfunctions in Mice Modeling Type 1 Spinocerebellar Ataxia. Cells 2022; 11:cells11233916. [PMID: 36497172 PMCID: PMC9738505 DOI: 10.3390/cells11233916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 12/09/2022] Open
Abstract
Type 1 spinocerebellar ataxia (SCA1) is a progressive neurodegenerative disorder with no effective treatment to date. Using mice modeling SCA1, it has been demonstrated that a drug that amplifies mGlu1 receptor activation (mGlu1 receptor PAM, Ro0711401) improves motor coordination without the development of tolerance when cerebellar dysfunction manifests (i.e., in 30-week-old heterozygous ataxin-1 [154Q/2Q] transgenic mice). SCA1 is also associated with cognitive dysfunction, which may precede cerebellar motor signs. Here, we report that otherwise healthy, 8-week-old SCA1 mice showed a defect in spatial learning and memory associated with reduced protein levels of mGlu1α receptors, the GluN2B subunit of NMDA receptors, and cannabinoid CB1 receptors in the hippocampus. Systemic treatment with Ro0711401 (10 mg/kg, s.c.) partially corrected the learning deficit in the Morris water maze and restored memory retention in the SCA1 mice model. This treatment also enhanced hippocampal levels of the endocannabinoid, anandamide, without changing the levels of 2-arachidonylglycerol. These findings suggest that mGlu1 receptor PAMs may be beneficial in the treatment of motor and nonmotor signs associated with SCA1 and encourage further studies in animal models of SCA1 and other types of SCAs.
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8
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Acute Cerebellar Inflammation and Related Ataxia: Mechanisms and Pathophysiology. Brain Sci 2022; 12:brainsci12030367. [PMID: 35326323 PMCID: PMC8946185 DOI: 10.3390/brainsci12030367] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 12/11/2022] Open
Abstract
The cerebellum governs motor coordination and motor learning. Infection with external microorganisms, such as viruses, bacteria, and fungi, induces the release and production of inflammatory mediators, which drive acute cerebellar inflammation. The clinical observation of acute cerebellitis is associated with the emergence of cerebellar ataxia. In our animal model of the acute inflammation of the cerebellar cortex, animals did not show any ataxia but hyperexcitability in the cerebellar cortex and depression-like behaviors. In contrast, animal models with neurodegeneration of the cerebellar Purkinje cells and hypoexcitability of the neurons show cerebellar ataxia. The suppression of the Ca2+-activated K+ channels in vivo is associated with a type of ataxia. Therefore, there is a gap in our interpretation between the very early phase of cerebellar inflammation and the emergence of cerebellar ataxia. In this review, we discuss the hypothesized scenario concerning the emergence of cerebellar ataxia. First, compared with genetically induced cerebellar ataxias, we introduce infection and inflammation in the cerebellum via aberrant immunity and glial responses. Especially, we focus on infections with cytomegalovirus, influenza virus, dengue virus, and SARS-CoV-2, potential relevance to mitochondrial DNA, and autoimmunity in infection. Second, we review neurophysiological modulation (intrinsic excitability, excitatory, and inhibitory synaptic transmission) by inflammatory mediators and aberrant immunity. Next, we discuss the cerebellar circuit dysfunction (presumably, via maintaining the homeostatic property). Lastly, we propose the mechanism of the cerebellar ataxia and possible treatments for the ataxia in the cerebellar inflammation.
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Mitoma H, Yamaguchi K, Honnorat J, Manto M. The Clinical Concept of LTDpathy: Is Dysregulated LTD Responsible for Prodromal Cerebellar Symptoms? Brain Sci 2022; 12:brainsci12030303. [PMID: 35326260 PMCID: PMC8946597 DOI: 10.3390/brainsci12030303] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 12/10/2022] Open
Abstract
Long-term depression at parallel fibers-Purkinje cells (PF-PC LTD) is essential for cerebellar motor learning and motor control. Recent progress in ataxiology has identified dysregulation of PF-PC LTD in the pathophysiology of certain types of immune-mediated cerebellar ataxias (IMCAs). Auto-antibodies towards voltage-gated Ca channel (VGCC), metabotropic glutamate receptor type 1 (mGluR1), and glutamate receptor delta (GluR delta) induce dysfunction of PF-PC LTD, resulting in the development of cerebellar ataxias (CAs). These disorders show a good response to immunotherapies in non-paraneoplastic conditions but are sometimes followed by cell death in paraneoplastic conditions. On the other hand, in some types of spinocerebellar ataxia (SCA), dysfunction in PF-PC LTD, and impairments of PF-PC LTD-related adaptive behaviors (including vestibulo-ocular reflex (VOR) and prism adaptation) appear during the prodromal stage, well before the manifestations of obvious CAs and cerebellar atrophy. Based on these findings and taking into account the findings of animal studies, we re-assessed the clinical concept of LTDpathy. LTDpathy can be defined as a clinical spectrum comprising etiologies associated with a functional disturbance of PF-PC LTD with concomitant impairment of related adaptative behaviors, including VOR, blink reflex, and prism adaptation. In IMCAs or degenerative CAs characterized by persistent impairment of a wide range of molecular mechanisms, these disorders are initially functional and are followed subsequently by degenerative cell processes. In such cases, adaptive disorders associated with PF-PC LTD manifest clinically with subtle symptoms and can be prodromal. Our hypothesis underlines for the first time a potential role of LTD dysfunction in the pathogenesis of the prodromal symptoms of CAs. This hypothesis opens perspectives to block the course of CAs at a very early stage.
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Affiliation(s)
- Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University, Tokyo 160-0023, Japan
- Correspondence: Japan;
| | - Kazuhiko Yamaguchi
- Department of Ultrastructural Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8511, Japan;
| | - Jerome Honnorat
- French Reference Center on Paraneoplastic Neurological Syndromes, Hospices Civils de Lyon, Hôpital Neurologique, 69677 Bron, France;
- Institut MeLis INSERM U1314/CNRS UMR 5284, Université de Lyon, Université Claude Bernard Lyon 1, 69372 Lyon, France
| | - Mario Manto
- Unité des Ataxies Cérébelleuses, Service de Neurologie, Médiathèque Jean Jacquy, CHU-Charleroi, 6000 Charleroi, Belgium;
- Service des Neurosciences, University of Mons, 7000 Mons, Belgium
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10
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mGluR1 signaling in cerebellar Purkinje cells: Subcellular organization and involvement in cerebellar function and disease. Neuropharmacology 2021; 194:108629. [PMID: 34089728 DOI: 10.1016/j.neuropharm.2021.108629] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 11/20/2022]
Abstract
The cerebellum is essential for the control, coordination, and learning of movements, and for certain aspects of cognitive function. Purkinje cells are the sole output neurons in the cerebellar cortex and therefore play crucial roles in the diverse functions of the cerebellum. The type 1 metabotropic glutamate receptor (mGluR1) is prominently enriched in Purkinje cells and triggers downstream signaling pathways that are required for functional and structural plasticity, and for synaptic responses. To understand how mGluR1 contributes to cerebellar functions, it is important to consider not only the operational properties of this receptor, but also its spatial organization and the molecular interactions that enable its proper functioning. In this review, we highlight how mGluR1 and its related signaling molecules are organized into tightly coupled microdomains to fulfill physiological functions. We also describe emerging evidence that altered mGluR1 signaling in Purkinje cells underlies cerebellar dysfunction in ataxias of human patients and mouse models.
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11
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Tellios V, Maksoud MJE, Xiang YY, Lu WY. Nitric Oxide Critically Regulates Purkinje Neuron Dendritic Development Through a Metabotropic Glutamate Receptor Type 1-Mediated Mechanism. THE CEREBELLUM 2021; 19:510-526. [PMID: 32270464 DOI: 10.1007/s12311-020-01125-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Nitric oxide (NO), specifically derived from neuronal nitric oxide synthase (nNOS), is a well-established regulator of synaptic transmission in Purkinje neurons (PNs), governing fundamental processes such as motor learning and coordination. Previous phenotypic analyses showed similar cerebellar structures between neuronal nitric oxide null (nNOS-/-) and wild-type (WT) adult male mice, despite prominent ataxic behavior within nNOS-/- mice. However, a study has yet to characterize PN molecular structure and their excitatory inputs during development in nNOS-/- mice. This study is the first to explore morphological abnormalities within the cerebellum of nNOS-/- mice, using immunohistochemistry and immunoblotting. This study sought to examine PN dendritic morphology and the expression of metabotropic glutamate receptor type 1 (mGluR1), vesicular glutamate transporter type 1 and 2 (vGluT1 and vGluT2), stromal interaction molecule 1 (STIM1), and calpain-1 within PNs of WT and nNOS-/- mice at postnatal day 7 (PD7), 2 weeks (2W), and 7 weeks (7W) of age. Results showed a decrease in PN dendritic branching at PD7 in nNOS-/- cerebella, while aberrant dendritic spine formation was noted in adult ages. Total protein expression of mGluR1 was decreased in nNOS-/- cerebella across development, while vGluT2, STIM1, and calpain-1 were significantly increased. Ex vivo treatment of WT slices with NOS inhibitor L-NAME increased calpain-1 expression, whereas treating nNOS-/- cerebellar slices with NO donor NOC-18 decreased calpain-1. Moreover, mGluR1 agonist DHPG increased calpain-1 in WT, but not in nNOS-/- slices. Together, these results indicate a novel role for nNOS/NO signaling in PN development, particularly by regulating an mGluR1-initiated calcium signaling mechanism.
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Affiliation(s)
- Vasiliki Tellios
- Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5B7, Canada.,Robarts Research Institute, London, N6A 5B7, Canada
| | - Matthew J E Maksoud
- Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5B7, Canada.,Robarts Research Institute, London, N6A 5B7, Canada
| | | | - Wei-Yang Lu
- Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5B7, Canada. .,Robarts Research Institute, London, N6A 5B7, Canada. .,Department of Physiology and Pharmacology, The University of Western Ontario, London, N6A 5B7, Canada.
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12
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Wu QW, Kapfhammer JP. Modulation of Increased mGluR1 Signaling by RGS8 Protects Purkinje Cells From Dendritic Reduction and Could Be a Common Mechanism in Diverse Forms of Spinocerebellar Ataxia. Front Cell Dev Biol 2021; 8:569889. [PMID: 33553137 PMCID: PMC7858651 DOI: 10.3389/fcell.2020.569889] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 12/30/2020] [Indexed: 12/13/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are a group of hereditary neurodegenerative diseases which are caused by diverse genetic mutations in a variety of different genes. We have identified RGS8, a regulator of G-protein signaling, as one of the genes which are dysregulated in different mouse models of SCA (e.g., SCA1, SCA2, SCA7, and SCA14). In the moment, little is known about the role of RGS8 for pathogenesis of spinocerebellar ataxia. We have studied the expression of RGS8 in the cerebellum in more detail and show that it is specifically expressed in mouse cerebellar Purkinje cells. In a mouse model of SCA14 with increased PKCγ activity, RGS8 expression was also increased. RGS8 overexpression could partially counteract the negative effects of DHPG-induced mGluR1 signaling for the expansion of Purkinje cell dendrites. Our results suggest that the increased expression of RGS8 is an important mediator of mGluR1 pathway dysregulation in Purkinje cells. These findings provide new insights in the role of RGS8 and mGluR1 signaling in Purkinje cells and for the pathology of SCAs.
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Affiliation(s)
- Qin-Wei Wu
- Institute of Anatomy, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Josef P Kapfhammer
- Institute of Anatomy, Department of Biomedicine, University of Basel, Basel, Switzerland
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13
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Neves-Carvalho A, Duarte-Silva S, Teixeira-Castro A, Maciel P. Polyglutamine spinocerebellar ataxias: emerging therapeutic targets. Expert Opin Ther Targets 2020; 24:1099-1119. [PMID: 32962458 DOI: 10.1080/14728222.2020.1827394] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Six of the most frequent dominantly inherited spinocerebellar ataxias (SCAs) worldwide - SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17 - are caused by an expansion of a polyglutamine (polyQ) tract in the corresponding proteins. While the identification of the causative mutation has advanced knowledge on the pathogenesis of polyQ SCAs, effective therapeutics able to mitigate the severe clinical manifestation of these highly incapacitating disorders are not yet available. AREAS COVERED This review provides a comprehensive and critical perspective on well-established and emerging therapeutic targets for polyQ SCAs; it aims to inspire prospective drug discovery efforts. EXPERT OPINION The landscape of polyQ SCAs therapeutic targets and strategies includes (1) the mutant genes and proteins themselves, (2) enhancement of endogenous protein quality control responses, (3) abnormal protein-protein interactions of the mutant proteins, (4) disturbed neuronal function, (5) mitochondrial function, energy availability and oxidative stress, and (6) glial dysfunction, growth factor or hormone imbalances. Challenges include gaining a clearer definition of therapeutic targets for the drugs in clinical development, the discovery of novel drug-like molecules for challenging key targets, and the attainment of a stronger translation of preclinical findings to the clinic.
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Affiliation(s)
- Andreia Neves-Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho , Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory , Braga, Guimarães, Portugal
| | - Sara Duarte-Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho , Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory , Braga, Guimarães, Portugal
| | - Andreia Teixeira-Castro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho , Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory , Braga, Guimarães, Portugal
| | - Patrícia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho , Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory , Braga, Guimarães, Portugal
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14
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Robinson KJ, Watchon M, Laird AS. Aberrant Cerebellar Circuitry in the Spinocerebellar Ataxias. Front Neurosci 2020; 14:707. [PMID: 32765211 PMCID: PMC7378801 DOI: 10.3389/fnins.2020.00707] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/11/2020] [Indexed: 12/11/2022] Open
Abstract
The spinocerebellar ataxias (SCAs) are a heterogeneous group of neurodegenerative diseases that share convergent disease features. A common symptom of these diseases is development of ataxia, involving impaired balance and motor coordination, usually stemming from cerebellar dysfunction and neurodegeneration. For most spinocerebellar ataxias, pathology can be attributed to an underlying gene mutation and the impaired function of the encoded protein through loss or gain-of-function effects. Strikingly, despite vast heterogeneity in the structure and function of disease-causing genes across the SCAs and the cellular processes affected, the downstream effects have considerable overlap, including alterations in cerebellar circuitry. Interestingly, aberrant function and degeneration of Purkinje cells, the major output neuronal population present within the cerebellum, precedes abnormalities in other neuronal populations within many SCAs, suggesting that Purkinje cells have increased vulnerability to cellular perturbations. Factors that are known to contribute to perturbed Purkinje cell function in spinocerebellar ataxias include altered gene expression resulting in altered expression or functionality of proteins and channels that modulate membrane potential, downstream impairments in intracellular calcium homeostasis and changes in glutamatergic input received from synapsing climbing or parallel fibers. This review will explore this enhanced vulnerability and the aberrant cerebellar circuitry linked with it in many forms of SCA. It is critical to understand why Purkinje cells are vulnerable to such insults and what overlapping pathogenic mechanisms are occurring across multiple SCAs, despite different underlying genetic mutations. Enhanced understanding of disease mechanisms will facilitate the development of treatments to prevent or slow progression of the underlying neurodegenerative processes, cerebellar atrophy and ataxic symptoms.
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Affiliation(s)
| | | | - Angela S. Laird
- Centre for Motor Neuron Disease Research, Department of Biomedical Science, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
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15
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Cook AA, Fields E, Watt AJ. Losing the Beat: Contribution of Purkinje Cell Firing Dysfunction to Disease, and Its Reversal. Neuroscience 2020; 462:247-261. [PMID: 32554108 DOI: 10.1016/j.neuroscience.2020.06.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 02/06/2023]
Abstract
The cerebellum is a brain structure that is highly interconnected with other brain regions. There are many contributing factors to cerebellar-related brain disease, such as altered afferent input, local connectivity, and/or cerebellar output. Purkinje cells (PC) are the principle cells of the cerebellar cortex, and fire intrinsically; that is, they fire spontaneous action potentials at high frequencies. This review paper focuses on PC intrinsic firing activity, which is altered in multiple neurological diseases, including ataxia, Huntington Disease (HD) and autism spectrum disorder (ASD). Notably, there are several cases where interventions that restore or rescue PC intrinsic activity also improve impaired behavior in these mouse models of disease. These findings suggest that rescuing PC firing deficits themselves may be sufficient to improve impairment in cerebellar-related behavior in disease. We propose that restoring PC intrinsic firing represents a good target for drug development that might be of therapeutic use for several disorders.
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Affiliation(s)
- Anna A Cook
- Department of Biology, McGill University, Montreal, Canada
| | - Eviatar Fields
- Department of Biology, McGill University, Montreal, Canada; Integrated Program in Neuroscience, McGill University, Montreal, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, Canada.
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16
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Volovikov EA, Davidenko AV, Lagarkova MA. Molecular Mechanisms of Spinocerebellar Ataxia Type 1. RUSS J GENET+ 2020. [DOI: 10.1134/s102279542002012x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Sathyanesan A, Zhou J, Scafidi J, Heck DH, Sillitoe RV, Gallo V. Emerging connections between cerebellar development, behaviour and complex brain disorders. Nat Rev Neurosci 2019; 20:298-313. [PMID: 30923348 DOI: 10.1038/s41583-019-0152-2] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The human cerebellum has a protracted developmental timeline compared with the neocortex, expanding the window of vulnerability to neurological disorders. As the cerebellum is critical for motor behaviour, it is not surprising that most neurodevelopmental disorders share motor deficits as a common sequela. However, evidence gathered since the late 1980s suggests that the cerebellum is involved in motor and non-motor function, including cognition and emotion. More recently, evidence indicates that major neurodevelopmental disorders such as intellectual disability, autism spectrum disorder, attention-deficit hyperactivity disorder and Down syndrome have potential links to abnormal cerebellar development. Out of recent findings from clinical and preclinical studies, the concept of the 'cerebellar connectome' has emerged that can be used as a framework to link the role of cerebellar development to human behaviour, disease states and the design of better therapeutic strategies.
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Affiliation(s)
- Aaron Sathyanesan
- Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, DC, USA.
| | - Joy Zhou
- Department of Pathology and Immunology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Joseph Scafidi
- Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, DC, USA.,George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Detlef H Heck
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
| | - Vittorio Gallo
- Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, DC, USA. .,George Washington University School of Medicine and Health Sciences, Washington, DC, USA.
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18
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Srinivasan SR, Shakkottai VG. Moving Towards Therapy in SCA1: Insights from Molecular Mechanisms, Identification of Novel Targets, and Planning for Human Trials. Neurotherapeutics 2019; 16:999-1008. [PMID: 31338702 PMCID: PMC6985354 DOI: 10.1007/s13311-019-00763-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The spinocerebellar ataxias (SCAs) are a group of neurodegenerative disorders inherited in an autosomal dominant fashion. The SCAs result in progressive gait imbalance, incoordination of the limbs, speech changes, and oculomotor dysfunction, among other symptoms. Over the past few decades, significant strides have been made in understanding the pathogenic mechanisms underlying these diseases. Although multiple efforts using a combination of genetics and pharmacology with small molecules have been made towards developing new therapeutics, no FDA approved treatment currently exists. In this review, we focus on SCA1, a common SCA subtype, in which some of the greatest advances have been made in understanding disease biology, and consequently potential therapeutic targets. Understanding of the underlying basic biology and targets of therapy in SCA1 is likely to give insight into treatment strategies in other SCAs. The diversity of the biology in the SCAs, and insight from SCA1 suggests, however, that both shared treatment strategies and specific approaches tailored to treat distinct genetic causes of SCA are likely needed for this group of devastating neurological disorders.
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Affiliation(s)
| | - Vikram G Shakkottai
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA.
- Department of Molecular and Integrative Physiology, University of Michigan, 4009 BSRB, 109 Zina Pitcher Place, Ann Arbor, Michigan, 48109, USA.
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19
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Abstract
The spinocerebellar ataxias (SCAs) comprise more than 40 autosomal dominant neurodegenerative disorders that present principally with progressive ataxia. Within the past few years, studies of pathogenic mechanisms in the SCAs have led to the development of promising therapeutic strategies, especially for SCAs caused by polyglutamine-coding CAG repeats. Nucleotide-based gene-silencing approaches that target the first steps in the pathogenic cascade are one promising approach not only for polyglutamine SCAs but also for the many other SCAs caused by toxic mutant proteins or RNA. For these and other emerging therapeutic strategies, well-coordinated preparation is needed for fruitful clinical trials. To accomplish this goal, investigators from the United States and Europe are now collaborating to share data from their respective SCA cohorts. Increased knowledge of the natural history of SCAs, including of the premanifest and early symptomatic stages of disease, will improve the prospects for success in clinical trials of disease-modifying drugs. In addition, investigators are seeking validated clinical outcome measures that demonstrate responsiveness to changes in SCA populations. Findings suggest that MRI and magnetic resonance spectroscopy biomarkers will provide objective biological readouts of disease activity and progression, but more work is needed to establish disease-specific biomarkers that track target engagement in therapeutic trials. Together, these efforts suggest that the development of successful therapies for one or more SCAs is not far away.
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20
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Abstract
PURPOSE OF REVIEW This survey takes into consideration the most recent advances in both human degenerative ataxias, disorders with a well established cerebellar origin, and discoveries from dystonia rodent models aimed at discussing the pathogenesis of dystonia. RECENT FINDINGS One common recurrent term that emerges when describing dystonia is heterogeneity. Indeed, dystonia encompasses a wide group of 'hyperkinetic' movement disorders, with heterogeneous causes, classification, anatomical and physiological substrates. In addition, the clinical heterogeneity of age at onset, symptom distribution and appearance of non-motor symptoms has supported the concept of dystonia as 'network' disorder. Pathophysiological alterations are thought to arise from dysfunction at cortico-thalamic-basal ganglia level, whereas, more recently, a role for cerebellar pathways emerged. Results from human and animal studies thus fuel the evolving concept of the network disorder. SUMMARY Current evidence suggests the involvement of multiple brain regions and cellular mechanisms, as part of the neural dysfunction observed at system level in dystonia.
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21
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Chopra R, Wasserman AH, Pulst SM, De Zeeuw CI, Shakkottai VG. Protein kinase C activity is a protective modifier of Purkinje neuron degeneration in cerebellar ataxia. Hum Mol Genet 2019; 27:1396-1410. [PMID: 29432535 DOI: 10.1093/hmg/ddy050] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 02/05/2018] [Indexed: 11/13/2022] Open
Abstract
Among the many types of neurons expressing protein kinase C (PKC) enzymes, cerebellar Purkinje neurons are particularly reliant on appropriate PKC activity for maintaining homeostasis. The importance of PKC enzymes in Purkinje neuron health is apparent as mutations in PRKCG (encoding PKCγ) cause cerebellar ataxia. PRKCG has also been identified as an important node in ataxia gene networks more broadly, but the functional role of PKC in other forms of ataxia remains unexplored, and the mechanisms by which PKC isozymes regulate Purkinje neuron health are not well understood. Here, we investigated how PKC activity influences neurodegeneration in inherited ataxia. Using mouse models of spinocerebellar ataxia type 1 (SCA1) and 2 (SCA2) we identify an increase in PKC-mediated substrate phosphorylation in two different forms of inherited cerebellar ataxia. Normalizing PKC substrate phosphorylation in SCA1 and SCA2 mice accelerates degeneration, suggesting that the increased activity observed in these models is neuroprotective. We also find that increased phosphorylation of PKC targets limits Purkinje neuron membrane excitability, suggesting that PKC activity may support Purkinje neuron health by moderating excitability. These data suggest a functional role for PKC enzymes in ataxia gene networks, and demonstrate that increased PKC activity is a protective modifier of degeneration in inherited cerebellar ataxia.
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Affiliation(s)
- Ravi Chopra
- Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Aaron H Wasserman
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA
| | - Chris I De Zeeuw
- Netherlands Institute for Neuroscience, Amsterdam 1105 CA, The Netherlands.,Department of Neuroscience, Erasmus MC, Rotterdam 3015 GE, The Netherlands
| | - Vikram G Shakkottai
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
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22
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Coarelli G, Brice A, Durr A. Recent advances in understanding dominant spinocerebellar ataxias from clinical and genetic points of view. F1000Res 2018; 7. [PMID: 30473770 PMCID: PMC6234732 DOI: 10.12688/f1000research.15788.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/02/2018] [Indexed: 12/12/2022] Open
Abstract
Abstract Spinocerebellar ataxias (SCAs) are rare types of cerebellar ataxia with a dominant mode of inheritance. To date, 47 SCA subtypes have been identified, and the number of genes implicated in SCAs is continually increasing. Polyglutamine (polyQ) expansion diseases (
ATXN1/SCA1,
ATXN2/SCA2,
ATXN3/SCA3,
CACNA1A/SCA6,
ATXN7/SCA7,
TBP/SCA17, and
ATN1/DRPLA) are the most common group of SCAs. No preventive or curative treatments are currently available, but various therapeutic approaches, including RNA-targeting treatments, such as antisense oligonucleotides (ASOs), are being developed. Clinical trials of ASOs in SCA patients are already planned. There is, therefore, a need to identify valid outcome measures for such studies. In this review, we describe recent advances towards identifying appropriate biomarkers, which are essential for monitoring disease progression and treatment efficacy. Neuroimaging biomarkers are the most powerful markers identified to date, making it possible to reduce sample sizes for clinical trials. Changes on brain MRI are already evident at the premanifest stage in SCA1 and SCA2 carriers and are correlated with CAG repeat size. Other potential biomarkers have also been developed, based on neurological examination, oculomotor study, cognitive assessment, and blood and cerebrospinal fluid analysis. Longitudinal studies based on multimodal approaches are required to establish the relationships between parameters and to validate the biomarkers identified.
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Affiliation(s)
- Giulia Coarelli
- Assistance Publique-Hôpitaux de Paris (AP-HP), Department of Neurology, Avicenne Hospital, Paris 13 University, Bobigny, 93000, France.,Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Paris, 75013, France
| | - Alexis Brice
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Paris, 75013, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Genetic department, Pitié-Salpêtrière University Hospital, Paris, 75013, France
| | - Alexandra Durr
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Paris, 75013, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Genetic department, Pitié-Salpêtrière University Hospital, Paris, 75013, France
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23
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Pilotto F, Saxena S. Epidemiology of inherited cerebellar ataxias and challenges in clinical research. CLINICAL AND TRANSLATIONAL NEUROSCIENCE 2018. [DOI: 10.1177/2514183x18785258] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Federica Pilotto
- Department of Neurology, Inselspital University Hospital, University of Bern, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, Switzerland
- Regenerative Neuroscience Cluster, University of Bern, Bern, Switzerland
| | - Smita Saxena
- Department of Neurology, Inselspital University Hospital, University of Bern, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, Switzerland
- Regenerative Neuroscience Cluster, University of Bern, Bern, Switzerland
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24
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Perkins EM, Clarkson YL, Suminaite D, Lyndon AR, Tanaka K, Rothstein JD, Skehel PA, Wyllie DJA, Jackson M. Loss of cerebellar glutamate transporters EAAT4 and GLAST differentially affects the spontaneous firing pattern and survival of Purkinje cells. Hum Mol Genet 2018; 27:2614-2627. [PMID: 29741614 PMCID: PMC6049029 DOI: 10.1093/hmg/ddy169] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/30/2018] [Accepted: 05/01/2018] [Indexed: 12/20/2022] Open
Abstract
Loss of excitatory amino acid transporters (EAATs) has been implicated in a number of human diseases including spinocerebellar ataxias, Alzhiemer's disease and motor neuron disease. EAAT4 and GLAST/EAAT1 are the two predominant EAATs responsible for maintaining low extracellular glutamate levels and preventing neurotoxicity in the cerebellum, the brain region essential for motor control. Here using genetically modified mice we identify new critical roles for EAAT4 and GLAST/EAAT1 as modulators of Purkinje cell (PC) spontaneous firing patterns. We show high EAAT4 levels, by limiting mGluR1 signalling, are essential in constraining inherently heterogeneous firing of zebrin-positive PCs. Moreover mGluR1 antagonists were found to restore regular spontaneous PC activity and motor behaviour in EAAT4 knockout mice. In contrast, GLAST/EAAT1 expression is required to sustain normal spontaneous simple spike activity in low EAAT4 expressing (zebrin-negative) PCs by restricting NMDA receptor activation. Blockade of NMDA receptor activity restores spontaneous activity in zebrin-negative PCs of GLAST knockout mice and furthermore alleviates motor deficits. In addition both transporters have differential effects on PC survival, with zebrin-negative PCs more vulnerable to loss of GLAST/EAAT1 and zebrin-positive PCs more vulnerable to loss of EAAT4. These findings reveal that glutamate transporter dysfunction through elevated extracellular glutamate and the aberrant activation of extrasynaptic receptors can disrupt cerebellar output by altering spontaneous PC firing. This expands our understanding of disease mechanisms in cerebellar ataxias and establishes EAATs as targets for restoring homeostasis in a variety of neurological diseases where altered cerebellar output is now thought to play a key role in pathogenesis.
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Affiliation(s)
- Emma M Perkins
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - Yvonne L Clarkson
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - Daumante Suminaite
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - Alastair R Lyndon
- School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, John Muir Building, Riccarton, Edinburgh, UK
| | - Kohichi Tanaka
- Laboratory of Molecular Neuroscience, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-Ku, Tokyo, Japan
| | - Jeffrey D Rothstein
- Department of Neurology and Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Paul A Skehel
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
| | - David J A Wyllie
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Mandy Jackson
- The Centre for Discovery Brain Sciences, The University of Edinburgh, Hugh Robson Building, Edinburgh, UK
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25
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Kim JH, Lukowicz A, Qu W, Johnson A, Cvetanovic M. Astroglia contribute to the pathogenesis of spinocerebellar ataxia Type 1 (SCA1) in a biphasic, stage-of-disease specific manner. Glia 2018; 66:1972-1987. [PMID: 30043530 DOI: 10.1002/glia.23451] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 04/11/2018] [Accepted: 04/11/2018] [Indexed: 12/22/2022]
Abstract
Spinocerebellar ataxia type 1 (SCA1) is a fatal, dominantly inherited neurodegenerative disease caused by the expansion of CAG repeats in the Ataxin-1 (ATXN1) gene. SCA1 is characterized by balance and coordination deficits due to the predominant loss of Purkinje neurons in the cerebellum. We previously demonstrated that cerebellar astrogliosis beings during the early stages of SCA1, prior to onset of motor deficits and loss of Purkinje neurons. We communicate here that cerebellar astrogliosis contributes to SCA1 pathogenesis in a biphasic, stage of disease dependent manner. We modulated astrogliosis by selectively reducing pro-inflammatory transcriptional regulator nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) signaling in astroglia via a Cre-lox mouse genetic approach. Our results indicate that inhibition of astroglial NF-κB signaling, prior to motor deficit onset, exacerbates disease severity. This is suggestive of a neuroprotective role mediated by astroglia during early stage SCA1. In contrast, inhibition of astroglial NF-κB signaling during late stage of disease ameliorated motor deficits, indicating a potentially harmful role of astroglia late in SCA1. These results indicate that astrogliosis may have a critical and dual role in disease. If so, our results imply that anti-inflammatory astroglia-based therapeutic approaches may need to consider disease progression to achieve therapeutic efficacy.
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Affiliation(s)
- Joo Hyun Kim
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota 2101 6th Street SE, Minneapolis, Minnesota
| | - Abigail Lukowicz
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota 2101 6th Street SE, Minneapolis, Minnesota
| | - Wenhui Qu
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota 2101 6th Street SE, Minneapolis, Minnesota
| | - Andrea Johnson
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota 2101 6th Street SE, Minneapolis, Minnesota
| | - Marija Cvetanovic
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota 2101 6th Street SE, Minneapolis, Minnesota
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Ady V, Toscano-Márquez B, Nath M, Chang PK, Hui J, Cook A, Charron F, Larivière R, Brais B, McKinney RA, Watt AJ. Altered synaptic and firing properties of cerebellar Purkinje cells in a mouse model of ARSACS. J Physiol 2018; 596:4253-4267. [PMID: 29928778 DOI: 10.1113/jp275902] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 06/19/2018] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodegenerative human disease characterized in part by ataxia and Purkinje cell loss in anterior cerebellar lobules. A knock-out mouse model has been developed that recapitulates several features of ARSACS. Using this ARSACS mouse model, we report changes in synaptic input and intrinsic firing in cerebellar Purkinje cells, as well as in their synaptic output in the deep cerebellar nuclei. Changes in firing are observed in anterior lobules that later exhibit Purkinje cell death, but not in posterior lobules that do not. Our results show that both synaptic and intrinsic alterations in Purkinje cell properties likely contribute to disease manifestation in ARSACS; these findings resemble pathophysiological changes reported in several other ataxias. ABSTRACT Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodegenerative disease that includes a pronounced and progressive cerebellar dysfunction. ARSACS is caused by an autosomal recessive loss-of-function mutation in the Sacs gene that encodes the protein sacsin. To better understand the cerebellar pathophysiology in ARSACS, we studied synaptic and firing properties of Purkinje cells from a mouse model of ARSACS, Sacs-/- mice. We found that excitatory synaptic drive was reduced onto Sacs-/- Purkinje cells, and that Purkinje cell firing rate, but not regularity, was reduced at postnatal day (P)40, an age when ataxia symptoms were first reported. Firing rate deficits were limited to anterior lobules that later display Purkinje cell death, and were not observed in posterior lobules where Purkinje cells are not lost. Mild firing deficits were observed as early as P20, prior to the manifestation of motor deficits, suggesting that a critical level of cerebellar dysfunction is required for motor coordination to emerge. Finally, we observed a reduction in Purkinje cell innervation onto target neurons in the deep cerebellar nuclei (DCN) in Sacs-/- mice. Together, these findings suggest that multiple alterations in the cerebellar circuit including Purkinje cell input and output contribute to cerebellar-related disease onset in ARSACS.
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Affiliation(s)
- Visou Ady
- Department of Biology, McGill University, Montréal, Canada
| | | | - Moushumi Nath
- Department of Biology, McGill University, Montréal, Canada
| | - Philip K Chang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Jeanette Hui
- Department of Biology, McGill University, Montréal, Canada
| | - Anna Cook
- Department of Biology, McGill University, Montréal, Canada
| | - François Charron
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Roxanne Larivière
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Canada
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Canada
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montréal, Canada
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27
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Ca 2+ signaling and spinocerebellar ataxia. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1733-1744. [PMID: 29777722 DOI: 10.1016/j.bbamcr.2018.05.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/07/2018] [Accepted: 05/09/2018] [Indexed: 11/22/2022]
Abstract
Spinocerebellar ataxia (SCA) is a neural disorder, which is caused by degenerative changes in the cerebellum. SCA is primarily characterized by gait ataxia, and additional clinical features include nystagmus, dysarthria, tremors and cerebellar atrophy. Forty-four hereditary SCAs have been identified to date, along with >35 SCA-associated genes. Despite the great diversity and distinct functionalities of the SCA-related genes, accumulating evidence supports the occurrence of a common pathophysiological event among several hereditary SCAs. Altered calcium (Ca2+) homeostasis in the Purkinje cells (PCs) of the cerebellum has been proposed as a possible pathological SCA trigger. In support of this, signaling events that are initiated from or lead to aberrant Ca2+ release from the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1), which is highly expressed in cerebellar PCs, seem to be closely associated with the pathogenesis of several SCA types. In this review, we summarize the current research on pathological hereditary SCA events, which involve altered Ca2+ homeostasis in PCs, through IP3R1 signaling.
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28
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Type 1 metabotropic glutamate receptor and its signaling molecules as therapeutic targets for the treatment of cerebellar disorders. Curr Opin Pharmacol 2018. [DOI: 10.1016/j.coph.2018.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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29
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Bushart DD, Chopra R, Singh V, Murphy GG, Wulff H, Shakkottai VG. Targeting potassium channels to treat cerebellar ataxia. Ann Clin Transl Neurol 2018; 5:297-314. [PMID: 29560375 PMCID: PMC5846455 DOI: 10.1002/acn3.527] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/14/2017] [Accepted: 12/18/2017] [Indexed: 12/22/2022] Open
Abstract
Objective Purkinje neuron dysfunction is associated with cerebellar ataxia. In a mouse model of spinocerebellar ataxia type 1 (SCA1), reduced potassium channel function contributes to altered membrane excitability resulting in impaired Purkinje neuron spiking. We sought to determine the relationship between altered membrane excitability and motor dysfunction in SCA1 mice. Methods Patch-clamp recordings in acute cerebellar slices and motor phenotype testing were used to identify pharmacologic agents which improve Purkinje neuron physiology and motor performance in SCA1 mice. Additionally, we retrospectively reviewed records of patients with SCA1 and other autosomal-dominant SCAs with prominent Purkinje neuron involvement to determine whether currently approved potassium channel activators were tolerated. Results Activating calcium-activated and subthreshold-activated potassium channels improved Purkinje neuron spiking impairment in SCA1 mice (P < 0.05). Additionally, dendritic hyperexcitability was improved by activating subthreshold-activated potassium channels but not calcium-activated potassium channels (P < 0.01). Improving spiking and dendritic hyperexcitability through a combination of chlorzoxazone and baclofen produced sustained improvements in motor dysfunction in SCA1 mice (P < 0.01). Retrospective review of SCA patient records suggests that co-treatment with chlorzoxazone and baclofen is tolerated. Interpretation Targeting both altered spiking and dendritic membrane excitability is associated with sustained improvements in motor performance in SCA1 mice, while targeting altered spiking alone produces only short-term improvements in motor dysfunction. Potassium channel activators currently in clinical use are well tolerated and may provide benefit in SCA patients. Future clinical trials with potassium channel activators are warranted in cerebellar ataxia.
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Affiliation(s)
- David D Bushart
- Department of Molecular & Integrative Physiology University of Michigan Ann Arbor Michigan
| | - Ravi Chopra
- Department of Neurology University of Michigan Ann Arbor Michigan
| | - Vikrant Singh
- Department of Pharmacology University of California Davis California
| | - Geoffrey G Murphy
- Department of Molecular & Integrative Physiology University of Michigan Ann Arbor Michigan.,Molecular & Behavioral Neuroscience Institute University of Michigan Ann Arbor Michigan
| | - Heike Wulff
- Department of Pharmacology University of California Davis California
| | - Vikram G Shakkottai
- Department of Molecular & Integrative Physiology University of Michigan Ann Arbor Michigan.,Department of Neurology University of Michigan Ann Arbor Michigan
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30
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Ibrahim MF, Power EM, Potapov K, Empson RM. Motor and Cerebellar Architectural Abnormalities during the Early Progression of Ataxia in a Mouse Model of SCA1 and How Early Prevention Leads to a Better Outcome Later in Life. Front Cell Neurosci 2017; 11:292. [PMID: 28979190 PMCID: PMC5611386 DOI: 10.3389/fncel.2017.00292] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/05/2017] [Indexed: 12/04/2022] Open
Abstract
Exposing developing cerebellar Purkinje neurons (PNs) to mutant Ataxin1 (ATXN1) in 82Q spinocerebellar ataxia type 1 (SCA1) mice disrupts motor behavior and cerebellar climbing fiber (CF) architecture from as early as 4 weeks of age. In contrast, if mutant ATXN1 expression is silenced until after cerebellar development is complete, then its impact on motor behavior and cerebellar architecture is greatly reduced. Under these conditions even 6 month old SCA1 mice exhibit largely intact motor behavior and molecular layer (ML) and CF architecture but show a modest reduction in PN soma area as a first sign of cerebellar disruption. Our results contrast the sensitivity of the developing cerebellum and remarkable resilience of the adult cerebellum to mutant ATXN1 and imply that SCA1 in this mouse model is both a developmental and neurodegenerative disorder.
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Affiliation(s)
- Mohamed F Ibrahim
- Department of Physiology, School of Biomedical Sciences, Brain Health Research Centre, Brain Research New Zealand, University of OtagoDunedin, New Zealand
| | - Emmet M Power
- Department of Physiology, School of Biomedical Sciences, Brain Health Research Centre, Brain Research New Zealand, University of OtagoDunedin, New Zealand
| | - Kay Potapov
- Department of Physiology, School of Biomedical Sciences, Brain Health Research Centre, Brain Research New Zealand, University of OtagoDunedin, New Zealand
| | - Ruth M Empson
- Department of Physiology, School of Biomedical Sciences, Brain Health Research Centre, Brain Research New Zealand, University of OtagoDunedin, New Zealand
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31
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Watson LM, Bamber E, Schnekenberg RP, Williams J, Bettencourt C, Lickiss J, Jayawant S, Fawcett K, Clokie S, Wallis Y, Clouston P, Sims D, Houlden H, Becker EB, Németh AH. Dominant Mutations in GRM1 Cause Spinocerebellar Ataxia Type 44. Am J Hum Genet 2017; 101:451-458. [PMID: 28886343 PMCID: PMC5591020 DOI: 10.1016/j.ajhg.2017.08.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 07/25/2017] [Indexed: 12/15/2022] Open
Abstract
The metabotropic glutamate receptor 1 (mGluR1) is abundantly expressed in the mammalian central nervous system, where it regulates intracellular calcium homeostasis in response to excitatory signaling. Here, we describe heterozygous dominant mutations in GRM1, which encodes mGluR1, that are associated with distinct disease phenotypes: gain-of-function missense mutations, linked in two different families to adult-onset cerebellar ataxia, and a de novo truncation mutation resulting in a dominant-negative effect that is associated with juvenile-onset ataxia and intellectual disability. Crucially, the gain-of-function mutations could be pharmacologically modulated in vitro using an existing FDA-approved drug, Nitazoxanide, suggesting a possible avenue for treatment, which is currently unavailable for ataxias.
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32
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Abstract
The dominantly inherited spinocerebellar ataxias (SCAs) are a large and diverse group of neurodegenerative diseases. The most prevalent SCAs (SCA1, SCA2, SCA3, SCA6 and SCA7) are caused by expansion of a glutamine-encoding CAG repeat in the affected gene. These SCAs represent a substantial portion of the polyglutamine neurodegenerative disorders and provide insight into this class of diseases as a whole. Recent years have seen considerable progress in deciphering the clinical, pathological, physiological and molecular aspects of the polyglutamine SCAs, with these advances establishing a solid base from which to pursue potential therapeutic approaches.
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33
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Yashiro S, Seki K. Association of social defeat stress-induced anhedonia-like symptoms with mGluR1-dependent decrease in membrane-bound AMPA-GluR1 in the mouse ventral midbrain. Stress 2017; 20:404-418. [PMID: 28554247 DOI: 10.1080/10253890.2017.1336534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Anhedonia is a core symptom of social defeat stress (SDS)-induced depression associated with the reward system. We previously reported that decreased membrane-bound AMPA-GluR1 in the reward system is associated with lipopolysaccharide-induced anhedonia-like symptoms. Since group I metabotropic glutamate receptor (mGluR) activation reduces the surface density of GluR1, we examined whether group I mGluR-dependent decrease in membrane-bound GluR1 in the reward system is involved in SDS-induced anhedonia-like symptoms. Mice exposed to SDS for 4 consecutive days had markedly decreased membrane-bound GluR1 and GluR2 in the prefrontal cortex (PFC) and membrane-bound GluR1 in the ventral midbrain (VM) along with lower sucrose preference (SP). Intra-PFC injection of the group I mGluR agonist (S)-3,5-dihydroxyphenylglycine (DHPG; 100 μmol) demonstrated decrease in membrane-bound GluR1 and GluR2 in the PFC 2 and 24 h and membrane-bound GluR1 in the VM 24 h after injection. Moreover, intra-PFC injection of DHPG decreased SP only in the second 24-h (24-48 h) period. Conversely, intra-VM injection of DHPG decreased SP in both the first and second 24-h period and decreased membrane-bound GluR1 in the VM 2 and 24 h after injection. Pre-treatment with the mGluR1 antagonist JNJ16259685 (30 mg/kg, subcutaneous) prevented SDS-decreased SP and membrane-bound GluR1 in the VM. The mGluR5 antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP; 10 mg/kg, subcutaneous) prevented SDS-induced decrease in membrane-bound GluR1 and GluR2 in the PFC, whereas MPEP did not affect SDS-induced decrease in SP and membrane-bound GluR1 in the VM. These results suggest that mGluR1-mediated decrease in membrane-bound GluR1 in VM is involved in SDS-induced anhedonia-like symptoms.
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Affiliation(s)
- Sayori Yashiro
- a Department of Pharmacology, School of Pharmaceutical Science , Ohu University , Tomitamachi, Koriyama , Fukushima , Japan
| | - Kenjiro Seki
- a Department of Pharmacology, School of Pharmaceutical Science , Ohu University , Tomitamachi, Koriyama , Fukushima , Japan
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34
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Meera P, Pulst S, Otis T. A positive feedback loop linking enhanced mGluR function and basal calcium in spinocerebellar ataxia type 2. eLife 2017; 6. [PMID: 28518055 PMCID: PMC5444899 DOI: 10.7554/elife.26377] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/16/2017] [Indexed: 12/11/2022] Open
Abstract
Metabotropic glutamate receptor 1 (mGluR1) function in Purkinje neurons (PNs) is essential for cerebellar development and for motor learning and altered mGluR1 signaling causes ataxia. Downstream of mGluR1, dysregulation of calcium homeostasis has been hypothesized as a key pathological event in genetic forms of ataxia but the underlying mechanisms remain unclear. We find in a spinocerebellar ataxia type 2 (SCA2) mouse model that calcium homeostasis in PNs is disturbed across a broad range of physiological conditions. At parallel fiber synapses, mGluR1-mediated excitatory postsynaptic currents (EPSCs) and associated calcium transients are increased and prolonged in SCA2 PNs. In SCA2 PNs, enhanced mGluR1 function is prevented by buffering [Ca2+] at normal resting levels while in wildtype PNs mGluR1 EPSCs are enhanced by elevated [Ca2+]. These findings demonstrate a deleterious positive feedback loop involving elevated intracellular calcium and enhanced mGluR1 function, a mechanism likely to contribute to PN dysfunction and loss in SCA2. DOI:http://dx.doi.org/10.7554/eLife.26377.001
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Affiliation(s)
- Pratap Meera
- Department of Neurobiology, Geffen School of Medicine, University of California, Los Angeles, United States
| | - Stefan Pulst
- Department of Neurology, University of Utah, Salt Lake, United States
| | - Thomas Otis
- Department of Neurobiology, Geffen School of Medicine, University of California, Los Angeles, United States.,Neuroscience, Ophthalmology, and Rare Diseases, Roche Pharmaceutical Research and Early Development, Basel, Switzerland
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35
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Kano M, Watanabe T. Type-1 metabotropic glutamate receptor signaling in cerebellar Purkinje cells in health and disease. F1000Res 2017; 6:416. [PMID: 28435670 PMCID: PMC5381626 DOI: 10.12688/f1000research.10485.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/30/2017] [Indexed: 01/28/2023] Open
Abstract
The cerebellum is a brain structure involved in coordination, control, and learning of movements, as well as certain aspects of cognitive function. Purkinje cells are the sole output neurons from the cerebellar cortex and therefore play crucial roles in the overall function of the cerebellum. The type-1 metabotropic glutamate receptor (mGluR1) is a key “hub” molecule that is critically involved in the regulation of synaptic wiring, excitability, synaptic response, and synaptic plasticity of Purkinje cells. In this review, we aim to highlight how mGluR1 controls these events in Purkinje cells. We also describe emerging evidence that altered mGluR1 signaling in Purkinje cells underlies cerebellar dysfunctions in several clinically relevant mouse models of human ataxias.
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Affiliation(s)
- Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takaki Watanabe
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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36
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Affiliation(s)
- Visou Ady
- Department of Biology, McGill University, Montreal, H3G 0B1, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, H3G 0B1, Canada
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37
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Hoxha E, Tempia F, Lippiello P, Miniaci MC. Modulation, Plasticity and Pathophysiology of the Parallel Fiber-Purkinje Cell Synapse. Front Synaptic Neurosci 2016; 8:35. [PMID: 27857688 PMCID: PMC5093118 DOI: 10.3389/fnsyn.2016.00035] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 10/19/2016] [Indexed: 12/24/2022] Open
Abstract
The parallel fiber-Purkinje cell (PF-PC) synapse represents the point of maximal signal divergence in the cerebellar cortex with an estimated number of about 60 billion synaptic contacts in the rat and 100,000 billions in humans. At the same time, the Purkinje cell dendritic tree is a site of remarkable convergence of more than 100,000 parallel fiber synapses. Parallel fiber activity generates fast postsynaptic currents via α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, and slower signals, mediated by mGlu1 receptors, resulting in Purkinje cell depolarization accompanied by sharp calcium elevation within dendritic regions. Long-term depression (LTD) and long-term potentiation (LTP) have been widely described for the PF-PC synapse and have been proposed as mechanisms for motor learning. The mechanisms of induction for LTP and LTD involve different signaling mechanisms within the presynaptic terminal and/or at the postsynaptic site, promoting enduring modification in the neurotransmitter release and change in responsiveness to the neurotransmitter. The PF-PC synapse is finely modulated by several neurotransmitters, including serotonin, noradrenaline and acetylcholine. The ability of these neuromodulators to gate LTP and LTD at the PF-PC synapse could, at least in part, explain their effect on cerebellar-dependent learning and memory paradigms. Overall, these findings have important implications for understanding the cerebellar involvement in a series of pathological conditions, ranging from ataxia to autism. For example, PF-PC synapse dysfunctions have been identified in several murine models of spino-cerebellar ataxia (SCA) types 1, 3, 5 and 27. In some cases, the defect is specific for the AMPA receptor signaling (SCA27), while in others the mGlu1 pathway is affected (SCA1, 3, 5). Interestingly, the PF-PC synapse has been shown to be hyper-functional in a mutant mouse model of autism spectrum disorder, with a selective deletion of Pten in Purkinje cells. However, the full range of methodological approaches, that allowed the discovery of the physiological principles of PF-PC synapse function, has not yet been completely exploited to investigate the pathophysiological mechanisms of diseases involving the cerebellum. We, therefore, propose to extend the spectrum of experimental investigations to tackle this problem.
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Affiliation(s)
- Eriola Hoxha
- Neuroscience Institute Cavalieri Ottolenghi (NICO) and Department of Neuroscience, University of TorinoTorino, Italy
| | - Filippo Tempia
- Neuroscience Institute Cavalieri Ottolenghi (NICO) and Department of Neuroscience, University of TorinoTorino, Italy
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38
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Mark MD, Schwitalla JC, Groemmke M, Herlitze S. Keeping Our Calcium in Balance to Maintain Our Balance. Biochem Biophys Res Commun 2016; 483:1040-1050. [PMID: 27392710 DOI: 10.1016/j.bbrc.2016.07.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 07/04/2016] [Indexed: 01/13/2023]
Abstract
Calcium is a key signaling molecule and ion involved in a variety of diverse processes in our central nervous system (CNS) which include gene expression, synaptic transmission and plasticity, neuronal excitability and cell maintenance. Proper control of calcium signaling is not only vital for neuronal physiology but also cell survival. Mutations in fundamental channels, transporters and second messenger proteins involved in orchestrating the balance of our calcium homeostasis can lead to severe neurodegenerative disorders, such as Spinocerebellar (SCA) and Episodic (EA) ataxias. Hereditary ataxias make up a remarkably diverse group of neurological disorders clinically characterized by gait ataxia, nystagmus, dysarthria, trunk and limb ataxia and often atrophy of the cerebellum. The largest family of hereditary ataxias is SCAs which consists of a growing family of 42 members. A relatively smaller family of 8 members compose the EAs. The gene mutations responsible for half of the EA members and over 35 of the SCA subtypes have been identified, and several have been found to be responsible for cerebellar atrophy, abnormal intracellular calcium levels, dysregulation of Purkinje cell pacemaking, altered cerebellar synaptic transmission and/or ataxia in mouse models. Although the genetic diversity and affected cellular pathways of hereditary ataxias are broad, one common theme amongst these genes is their effects on maintaining calcium balance in primarily the cerebellum. There is emerging evidence that the pathogenesis of hereditary ataxias may be caused by imbalances in intracellular calcium due to genetic mutations in calcium-mediating proteins. In this review we will discuss the current evidence supporting the role of deranged calcium as the culprit to neurodegenerative diseases with a primary focus on SCAs and EAs.
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Affiliation(s)
- Melanie D Mark
- Department of Zoology and Neurobiology, ND7/31, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
| | - Jan Claudius Schwitalla
- Department of Zoology and Neurobiology, ND7/31, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Michelle Groemmke
- Department of Zoology and Neurobiology, ND7/31, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Stefan Herlitze
- Department of Zoology and Neurobiology, ND7/31, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
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