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Sekerková G, Kilic S, Cheng YH, Fredrick N, Osmani A, Kim H, Opal P, Martina M. Phenotypical, genotypical and pathological characterization of the moonwalker mouse, a model of ataxia. Neurobiol Dis 2024; 195:106492. [PMID: 38575093 PMCID: PMC11089908 DOI: 10.1016/j.nbd.2024.106492] [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: 11/01/2023] [Revised: 03/13/2024] [Accepted: 04/01/2024] [Indexed: 04/06/2024] Open
Abstract
We performed a comprehensive study of the morphological, functional, and genetic features of moonwalker (MWK) mice, a mouse model of spinocerebellar ataxia caused by a gain of function of the TRPC3 channel. These mice show numerous behavioral symptoms including tremor, altered gait, circling behavior, impaired motor coordination, impaired motor learning and decreased limb strength. Cerebellar pathology is characterized by early and almost complete loss of unipolar brush cells as well as slowly progressive, moderate loss of Purkinje cell (PCs). Structural damage also includes loss of synaptic contacts from parallel fibers, swollen ER structures, and degenerating axons. Interestingly, no obvious correlation was observed between PC loss and severity of the symptoms, as the phenotype stabilizes around 2 months of age, while the cerebellar pathology is progressive. This is probably due to the fact that PC function is severely impaired much earlier than the appearance of PC loss. Indeed, PC firing is already impaired in 3 weeks old mice. An interesting feature of the MWK pathology that still remains to be explained consists in a strong lobule selectivity of the PC loss, which is puzzling considering that TRPC is expressed in every PC. Intriguingly, genetic analysis of MWK cerebella shows, among other alterations, changes in the expression of both apoptosis inducing and resistance factors possibly suggesting that damaged PCs initiate specific cellular pathways that protect them from overt cell loss.
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Affiliation(s)
- Gabriella Sekerková
- Department of Neuroscience, Northwestern University, Feinberg School of Medicine, 300 E. Superior, Chicago, IL 60611, USA.
| | - Sumeyra Kilic
- Department of Neuroscience, Northwestern University, Feinberg School of Medicine, 300 E. Superior, Chicago, IL 60611, USA
| | - Yen-Hsin Cheng
- Department of Neuroscience, Northwestern University, Feinberg School of Medicine, 300 E. Superior, Chicago, IL 60611, USA
| | - Natalie Fredrick
- Department of Neurology, Northwestern University, Feinberg School of Medicine, 300 E. Superior, Chicago, IL 60611, USA
| | - Anne Osmani
- Department of Neuroscience, Northwestern University, Feinberg School of Medicine, 300 E. Superior, Chicago, IL 60611, USA
| | - Haram Kim
- Department of Neuroscience, Northwestern University, Feinberg School of Medicine, 300 E. Superior, Chicago, IL 60611, USA
| | - Puneet Opal
- Department of Neurology, Northwestern University, Feinberg School of Medicine, 300 E. Superior, Chicago, IL 60611, USA
| | - Marco Martina
- Department of Neuroscience, Northwestern University, Feinberg School of Medicine, 300 E. Superior, Chicago, IL 60611, USA.
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Ruff DS, Balbo I, Lai R, Dieng D, Hennessey C, Vennam K, Dwork AJ, McCreary M, Louis ED, Faust PL, Kuo S. Reduced Bergmann glial process terminations and lateral appendages in essential tremor. Ann Clin Transl Neurol 2024; 11:377-388. [PMID: 38098226 PMCID: PMC10863904 DOI: 10.1002/acn3.51958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/29/2023] [Accepted: 11/12/2023] [Indexed: 02/15/2024] Open
Abstract
OBJECTIVE Postmortem examination of the essential tremor cerebellum has revealed a variety of pathological changes centered in and around Purkinje cells. Studies have predominantly focused on cerebellar neuronal connections. Bergmann glial morphology has not yet been studied in essential tremor. Among their many roles, Bergmann glia in the cerebellar cortex ensheath Purkinje cell synapses and provide neuroprotection. Specifically, the complex radial processes and lateral appendages of Bergmann glia are structural domains that modulate Purkinje cell synaptic transmission. In this study, we investigate whether Bergmann glia morphology is altered in the essential tremor cerebellum. METHODS We applied the Golgi-Kopsch method and used computerized three-dimensional cell reconstruction to visualize Bergmann glia in the postmortem cerebellum of 34 cases and 17 controls. We quantified morphology of terminal structures (number of terminations and lateral appendage density) and morphology of radial processes (total process length, branch length, branch order, and branch volume) in each glial cell. We quantified number of branches and volume as well. RESULTS Essential tremor cases had a 31.9% decrease in process terminations and a 35.7% decrease in lateral appendage density in Bergmann glia. Total process length and branch length did not differ between essential tremor cases and controls. We found also a reduction in number of secondary and tertiary branches and tertiary branches volume. INTERPRETATION These findings suggest that Bergmann glia in essential tremor cases have more alterations in their terminal structures, with a relative preservation of radial processes, and highlight a potential role for these astrocytes in the disease pathophysiology.
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Affiliation(s)
- David S. Ruff
- Department of NeurologyColumbia UniversityNew YorkNew York10032USA
- Initiative for Columbia Ataxia and TremorColumbia UniversityNew YorkNew York10032USA
| | - Ilaria Balbo
- Department of NeurologyColumbia UniversityNew YorkNew York10032USA
- Initiative for Columbia Ataxia and TremorColumbia UniversityNew YorkNew York10032USA
| | - Ruo‐Yah Lai
- Department of NeurologyColumbia UniversityNew YorkNew York10032USA
- Initiative for Columbia Ataxia and TremorColumbia UniversityNew YorkNew York10032USA
| | - Diarra Dieng
- Department of NeurologyColumbia UniversityNew YorkNew York10032USA
- Initiative for Columbia Ataxia and TremorColumbia UniversityNew YorkNew York10032USA
| | - Charlotte Hennessey
- Department of NeurologyColumbia UniversityNew YorkNew York10032USA
- Initiative for Columbia Ataxia and TremorColumbia UniversityNew YorkNew York10032USA
| | - Krish Vennam
- Department of NeurologyColumbia UniversityNew YorkNew York10032USA
- Initiative for Columbia Ataxia and TremorColumbia UniversityNew YorkNew York10032USA
| | - Andrew J. Dwork
- Department of Pathology and Cell BiologyColumbia University Medical Center, The New York Presbyterian HospitalNew YorkNew York10032USA
- Department of PsychiatryColumbia UniversityNew YorkNew YorkUSA
| | - Morgan McCreary
- Department of NeurologyUniversity of Texas SouthwesternDallasTexas75390USA
| | - Elan D. Louis
- Department of NeurologyUniversity of Texas SouthwesternDallasTexas75390USA
| | - Phyllis L. Faust
- Initiative for Columbia Ataxia and TremorColumbia UniversityNew YorkNew York10032USA
- Department of Pathology and Cell BiologyColumbia University Medical Center, The New York Presbyterian HospitalNew YorkNew York10032USA
| | - Sheng‐Han Kuo
- Department of NeurologyColumbia UniversityNew YorkNew York10032USA
- Initiative for Columbia Ataxia and TremorColumbia UniversityNew YorkNew York10032USA
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Olmos V, Thompson EN, Gogia N, Luttik K, Veeranki V, Ni L, Sim S, Chen K, Krause DS, Lim J. Dysregulation of alternative splicing in spinocerebellar ataxia type 1. Hum Mol Genet 2024; 33:138-149. [PMID: 37802886 PMCID: PMC10979408 DOI: 10.1093/hmg/ddad170] [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: 06/30/2023] [Revised: 09/29/2023] [Accepted: 10/02/2023] [Indexed: 10/08/2023] Open
Abstract
Spinocerebellar ataxia type 1 is caused by an expansion of the polyglutamine tract in ATAXIN-1. Ataxin-1 is broadly expressed throughout the brain and is involved in regulating gene expression. However, it is not yet known if mutant ataxin-1 can impact the regulation of alternative splicing events. We performed RNA sequencing in mouse models of spinocerebellar ataxia type 1 and identified that mutant ataxin-1 expression abnormally leads to diverse splicing events in the mouse cerebellum of spinocerebellar ataxia type 1. We found that the diverse splicing events occurred in a predominantly cell autonomous manner. A majority of the transcripts with misregulated alternative splicing events were previously unknown, thus allowing us to identify overall new biological pathways that are distinctive to those affected by differential gene expression in spinocerebellar ataxia type 1. We also provide evidence that the splicing factor Rbfox1 mediates the effect of mutant ataxin-1 on misregulated alternative splicing and that genetic manipulation of Rbfox1 expression modifies neurodegenerative phenotypes in a Drosophila model of spinocerebellar ataxia type 1 in vivo. Together, this study provides novel molecular mechanistic insight into the pathogenesis of spinocerebellar ataxia type 1 and identifies potential therapeutic strategies for spinocerebellar ataxia type 1.
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Affiliation(s)
- Victor Olmos
- Department of Genetics, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, United States
| | - Evrett N Thompson
- Department of Cell Biology, Yale School of Medicine, 10 Amistad Street, New Haven, CT 06510, United States
- Yale Stem Cell Center, Yale School of Medicine, 10 Amistad Street, New Haven, CT 06510, United States
| | - Neha Gogia
- Department of Genetics, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, United States
| | - Kimberly Luttik
- Interdepartmental Neuroscience Program, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, United States
- Department of Neuroscience, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, USA
| | - Vaishnavi Veeranki
- Department of Genetics, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, United States
| | - Luhan Ni
- Department of Genetics, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, United States
| | - Serena Sim
- Yale College, 433 Temple Street, New Haven, CT 06510, United States
| | - Kelly Chen
- Yale College, 433 Temple Street, New Haven, CT 06510, United States
| | - Diane S Krause
- Department of Cell Biology, Yale School of Medicine, 10 Amistad Street, New Haven, CT 06510, United States
- Yale Stem Cell Center, Yale School of Medicine, 10 Amistad Street, New Haven, CT 06510, United States
- Department of Pathology, Yale School of Medicine, 10 Amistad Street, New Haven, CT 06510, United States
- Department of Laboratory Medicine, Yale School of Medicine, 10 Amistad Street, New Haven, CT 06510, United States
| | - Janghoo Lim
- Department of Genetics, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, United States
- Yale Stem Cell Center, Yale School of Medicine, 10 Amistad Street, New Haven, CT 06510, United States
- Interdepartmental Neuroscience Program, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, United States
- Department of Neuroscience, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06510, United States
- Wu Tsai Institute, Yale School of Medicine, 100 College, New Haven, CT 06510, United States
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Nanclares C, Noriega-Prieto JA, Labrada-Moncada FE, Cvetanovic M, Araque A, Kofuji P. Altered calcium signaling in Bergmann glia contributes to spinocerebellar ataxia type-1 in a mouse model of SCA1. Neurobiol Dis 2023; 187:106318. [PMID: 37802154 PMCID: PMC10624966 DOI: 10.1016/j.nbd.2023.106318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/28/2023] [Accepted: 10/04/2023] [Indexed: 10/08/2023] Open
Abstract
Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disease caused by an abnormal expansion of glutamine (Q) encoding CAG repeats in the ATAXIN1 (ATXN1) gene and characterized by progressive cerebellar ataxia, dysarthria, and eventual deterioration of bulbar functions. SCA1 shows severe degeneration of cerebellar Purkinje cells (PCs) and activation of Bergmann glia (BG), a type of cerebellar astroglia closely associated with PCs. Combining electrophysiological recordings, calcium imaging techniques, and chemogenetic approaches, we have investigated the electrical intrinsic and synaptic properties of PCs and the physiological properties of BG in SCA1 mouse model expressing mutant ATXN1 only in PCs. PCs of SCA1 mice displayed lower spontaneous firing rate and larger slow afterhyperpolarization currents (sIAHP) than wildtype mice, whereas the properties of the synaptic inputs were unaffected. BG of SCA1 mice showed higher calcium hyperactivity and gliotransmission, manifested by higher frequency of NMDAR-mediated slow inward currents (SICs) in PC. Preventing the BG calcium hyperexcitability of SCA1 mice by loading BG with the calcium chelator BAPTA restored sIAHP and spontaneous firing rate of PCs to similar levels of wildtype mice. Moreover, mimicking the BG hyperactivity by activating BG expressing Gq-DREADDs in wildtype mice reproduced the SCA1 pathological phenotype of PCs, i.e., enhancement of sIAHP and decrease of spontaneous firing rate. These results indicate that the intrinsic electrical properties of PCs, but not their synaptic properties, were altered in SCA1 mice and that these alterations were associated with the hyperexcitability of BG. Moreover, preventing BG hyperexcitability in SCA1 mice and promoting BG hyperexcitability in wildtype mice prevented and mimicked, respectively, the pathological electrophysiological phenotype of PCs. Therefore, BG plays a relevant role in the dysfunction of the electrical intrinsic properties of PCs in SCA1 mice, suggesting that they may serve as potential targets for therapeutic approaches to treat the spinocerebellar ataxia type 1.
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Affiliation(s)
- Carmen Nanclares
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | | | | | - Marija Cvetanovic
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
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Cvetanovic M, Gray M. Contribution of Glial Cells to Polyglutamine Diseases: Observations from Patients and Mouse Models. Neurotherapeutics 2023; 20:48-66. [PMID: 37020152 PMCID: PMC10119372 DOI: 10.1007/s13311-023-01357-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2023] [Indexed: 04/07/2023] Open
Abstract
Neurodegenerative diseases are broadly characterized neuropathologically by the degeneration of vulnerable neuronal cell types in a specific brain region. The degeneration of specific cell types has informed on the various phenotypes/clinical presentations in someone suffering from these diseases. Prominent neurodegeneration of specific neurons is seen in polyglutamine expansion diseases including Huntington's disease (HD) and spinocerebellar ataxias (SCA). The clinical manifestations observed in these diseases could be as varied as the abnormalities in motor function observed in those who have Huntington's disease (HD) as demonstrated by a chorea with substantial degeneration of striatal medium spiny neurons (MSNs) or those with various forms of spinocerebellar ataxia (SCA) with an ataxic motor presentation primarily due to degeneration of cerebellar Purkinje cells. Due to the very significant nature of the degeneration of MSNs in HD and Purkinje cells in SCAs, much of the research has centered around understanding the cell autonomous mechanisms dysregulated in these neuronal cell types. However, an increasing number of studies have revealed that dysfunction in non-neuronal glial cell types contributes to the pathogenesis of these diseases. Here we explore these non-neuronal glial cell types with a focus on how each may contribute to the pathogenesis of HD and SCA and the tools used to evaluate glial cells in the context of these diseases. Understanding the regulation of supportive and harmful phenotypes of glia in disease could lead to development of novel glia-focused neurotherapeutics.
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Affiliation(s)
- Marija Cvetanovic
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, USA
| | - Michelle Gray
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, AL, USA.
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