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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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Márquez BT, Leung TCS, Hui J, Charron F, McKinney RA, Watt AJ. A mitochondrial-targeted antioxidant (MitoQ) improves motor coordination and reduces Purkinje cell death in a mouse model of ARSACS. Neurobiol Dis 2023; 183:106157. [PMID: 37209925 DOI: 10.1016/j.nbd.2023.106157] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 05/10/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023] Open
Abstract
Mitochondrial deficits have been observed in animal models of Autosomal-recessive spastic ataxia of the Charlevoix-Saguenay (ARSACS) and in patient-derived fibroblasts. We investigated whether mitochondrial function could be restored in Sacs-/- mice, a mouse model of ARSACS, using the mitochondrial-targeted antioxidant ubiquinone MitoQ. After 10 weeks of chronic MitoQ administration in drinking water, we partially reversed motor coordination deficits in Sacs-/- mice but did not affect litter-matched wild-type control mice. MitoQ administration led to a restoration of superoxide dismutase 2 (SOD2) in cerebellar Purkinje cell somata without altering Purkinje cell firing deficits. Purkinje cells in anterior vermis of Sacs-/- mice normally undergo cell death in ARSACS; however, Purkinje cells numbers were elevated after chronic MitoQ treatment. Furthermore, Purkinje cell innervation of target neurons in the cerebellar nuclei of Sacs-/- mice were also partially restored with MitoQ treatment. Our data suggest that MitoQ is a potential therapeutic treatment for ARSACS and that it improves motor coordination via increasing cerebellar Purkinje cell mitochondria function and reducing Purkinje cell death.
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Affiliation(s)
| | | | - Jeanette Hui
- Department of Biology, McGill University, Montreal, QC, Canada
| | - François Charron
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada.
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, QC, Canada.
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Apsley EJ, Becker EBE. Purkinje Cell Patterning-Insights from Single-Cell Sequencing. Cells 2022; 11:cells11182918. [PMID: 36139493 PMCID: PMC9497131 DOI: 10.3390/cells11182918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/08/2022] [Accepted: 09/13/2022] [Indexed: 11/21/2022] Open
Abstract
Despite their homogeneous appearance, Purkinje cells are remarkably diverse with respect to their molecular phenotypes, physiological properties, afferent and efferent connectivity, as well as their vulnerability to insults. Heterogeneity in Purkinje cells arises early in development, with molecularly distinct embryonic cell clusters present soon after Purkinje cell specification. Traditional methods have characterized cerebellar development and cell types, including Purkinje cell subtypes, based on knowledge of selected markers. However, recent single-cell RNA sequencing studies provide vastly increased resolution of the whole cerebellar transcriptome. Here we draw together the results of multiple single-cell transcriptomic studies in developing and adult cerebellum in both mouse and human. We describe how this detailed transcriptomic data has increased our understanding of the intricate development and function of Purkinje cells and provides first clues into features specific to human cerebellar development.
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Affiliation(s)
- Elizabeth J. Apsley
- 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
- Correspondence:
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Chang HHV, Cook AA, Watt AJ, Cullen KE. Loss of Flocculus Purkinje Cell Firing Precision Leads to Impaired Gaze Stabilization in a Mouse Model of Spinocerebellar Ataxia Type 6 (SCA6). Cells 2022; 11:cells11172739. [PMID: 36078147 PMCID: PMC9454745 DOI: 10.3390/cells11172739] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Abstract
Spinocerebellar Ataxia Type 6 (SCA6) is a mid-life onset neurodegenerative disease characterized by progressive ataxia, dysarthria, and eye movement impairment. This autosomal dominant disease is caused by the expansion of a CAG repeat tract in the CACNA1A gene that encodes the α1A subunit of the P/Q type voltage-gated Ca2+ channel. Mouse models of SCA6 demonstrate impaired locomotive function and reduced firing precision of cerebellar Purkinje in the anterior vermis. Here, to further assess deficits in other cerebellar-dependent behaviors, we characterized the oculomotor phenotype of a knock-in mouse model with hyper-expanded polyQ repeats (SCA684Q). We found a reduction in the efficacy of the vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) in SCA6 mutant mice, without a change in phase, compared to their litter-matched controls. Additionally, VOR motor learning was significantly impaired in SCA684Q mice. Given that the floccular lobe of the cerebellum plays a vital role in the generation of OKR and VOR calibration and motor learning, we investigated the firing behavior and morphology of floccular cerebellar Purkinje cells. Overall, we found a reduction in the firing precision of floccular lobe Purkinje cells but no morphological difference between SCA684Q and wild-type mice. Taken together, our findings establish that gaze stabilization and motor learning are impaired in SCA684Q mice and suggest that altered cerebellar output contributes to these deficits.
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Affiliation(s)
| | - Anna A. Cook
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Alanna J. Watt
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Kathleen E. Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, USA
- Correspondence:
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Mayoral-Palarz K, Neves-Carvalho A, Duarte-Silva S, Monteiro-Fernandes D, Maciel P, Khodakhah K. Cerebellar neuronal dysfunction accompanies early motor symptoms in spinocerebellar ataxia type 3. Dis Model Mech 2022; 15:275597. [PMID: 35660856 PMCID: PMC9367011 DOI: 10.1242/dmm.049514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 05/25/2022] [Indexed: 11/30/2022] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3) is an adult-onset, progressive ataxia. SCA3 presents with ataxia before any gross neuropathology. A feature of many cerebellar ataxias is aberrant cerebellar output that contributes to motor dysfunction. We examined whether abnormal cerebellar output was present in the CMVMJD135 SCA3 mouse model and, if so, whether it correlated with the disease onset and progression. In vivo recordings showed that the activity of deep cerebellar nuclei neurons, the main output of the cerebellum, was altered. The aberrant activity correlated with the onset of ataxia. However, although the severity of ataxia increased with age, the severity of the aberrant cerebellar output was not progressive. The abnormal cerebellar output, however, was accompanied by non-progressive abnormal activity of their upstream synaptic inputs, the Purkinje cells. In vitro recordings indicated that alterations in intrinsic Purkinje cell pacemaking and in their synaptic inputs contributed to abnormal Purkinje cell activity. These findings implicate abnormal cerebellar physiology as an early, consistent contributor to pathophysiology in SCA3, and suggest that the aberrant cerebellar output could be an appropriate therapeutic target in SCA3. Summary: In a mouse model of spinocerebellar ataxia type 3 (SCA3), aberrant cerebellar physiology is apparent early in disease, prior to cerebellar neuronal pathology. Aberrant cerebellar output could be a therapeutic target in SCA3.
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Affiliation(s)
- Kristin Mayoral-Palarz
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Andreia Neves-Carvalho
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.,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
| | - Daniela Monteiro-Fernandes
- 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
| | - Kamran Khodakhah
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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