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Jaarsma D, Birkisdóttir MB, van Vossen R, Oomen DWGD, Akhiyat O, Vermeij WP, Koekkoek SKE, De Zeeuw CI, Bosman LWJ. Different Purkinje cell pathologies cause specific patterns of progressive gait ataxia in mice. Neurobiol Dis 2024; 192:106422. [PMID: 38286390 DOI: 10.1016/j.nbd.2024.106422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 01/31/2024] Open
Abstract
Gait ataxia is one of the most common and impactful consequences of cerebellar dysfunction. Purkinje cells, the sole output neurons of the cerebellar cortex, are often involved in the underlying pathology, but their specific functions during locomotor control in health and disease remain obfuscated. We aimed to describe the effect of gradual adult-onset Purkinje cell degeneration on gaiting patterns in mice, and to determine whether two different mechanisms that both lead to Purkinje cell degeneration cause different patterns in the development of gait ataxia. Using the ErasmusLadder together with a newly developed limb detection algorithm and machine learning-based classification, we subjected mice to a challenging locomotor task with detailed analysis of single limb parameters, intralimb coordination and whole-body movement. We tested two Purkinje cell-specific mouse models, one involving stochastic cell death due to impaired DNA repair mechanisms (Pcp2-Ercc1-/-), the other carrying the mutation that causes spinocerebellar ataxia type 1 (Pcp2-ATXN1[82Q]). Both mouse models showed progressive gaiting deficits, but the sequence with which gaiting parameters deteriorated was different between mouse lines. Our longitudinal approach revealed that gradual loss of Purkinje cell function can lead to a complex pattern of loss of function over time, and that this pattern depends on the specifics of the pathological mechanisms involved. We hypothesize that this variability will also be present in disease progression in patients, and that our findings will facilitate the study of therapeutic interventions in mice, as subtle changes in locomotor abilities can be quantified by our methods.
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Affiliation(s)
- Dick Jaarsma
- Department of Neuroscience, Erasmus MC, 3015 CA, Rotterdam, the Netherlands.
| | - Maria B Birkisdóttir
- Department of Neuroscience, Erasmus MC, 3015 CA, Rotterdam, the Netherlands; Princess Máxima Center for Pediatric Oncology, 3584 CS, Utrecht, the Netherlands
| | - Randy van Vossen
- Department of Neuroscience, Erasmus MC, 3015 CA, Rotterdam, the Netherlands
| | - Demi W G D Oomen
- Department of Neuroscience, Erasmus MC, 3015 CA, Rotterdam, the Netherlands
| | - Oussama Akhiyat
- Department of Neuroscience, Erasmus MC, 3015 CA, Rotterdam, the Netherlands
| | - Wilbert P Vermeij
- Princess Máxima Center for Pediatric Oncology, 3584 CS, Utrecht, the Netherlands; Oncode Institute, 3521 AL, Utrecht, the Netherlands
| | | | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, 3015 CA, Rotterdam, the Netherlands; Netherlands Institute for Neuroscience, Royal Dutch Academy of Arts & Science, 1105 BA, Amsterdam, the Netherlands
| | - Laurens W J Bosman
- Department of Neuroscience, Erasmus MC, 3015 CA, Rotterdam, the Netherlands.
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Manto M, Cendelin J, Strupp M, Mitoma H. Advances in cerebellar disorders: pre-clinical models, therapeutic targets, and challenges. Expert Opin Ther Targets 2023; 27:965-987. [PMID: 37768297 DOI: 10.1080/14728222.2023.2263911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 09/24/2023] [Indexed: 09/29/2023]
Abstract
INTRODUCTION Cerebellar ataxias (CAs) represent neurological disorders with multiple etiologies and a high phenotypic variability. Despite progress in the understanding of pathogenesis, few therapies are available so far. Closing the loop between preclinical studies and therapeutic trials is important, given the impact of CAs upon patients' health and the roles of the cerebellum in multiple domains. Because of a rapid advance in research on CAs, it is necessary to summarize the main findings and discuss future directions. AREAS COVERED We focus our discussion on preclinical models, cerebellar reserve, the therapeutic management of CAs, and suitable surrogate markers. We searched Web of Science and PubMed using keywords relevant to cerebellar diseases, therapy, and preclinical models. EXPERT OPINION There are many symptomatic and/or disease-modifying therapeutic approaches under investigation. For therapy development, preclinical studies, standardization of disease evaluation, safety assessment, and demonstration of clinical improvements are essential. Stage of the disease and the level of the cerebellar reserve determine the goals of the therapy. Deficits in multiple categories and heterogeneity of CAs may require disease-, stage-, and symptom-specific therapies. More research is needed to clarify how therapies targeting the cerebellum influence both basal ganglia and the cerebral cortex, poorly explored domains in CAs.
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Affiliation(s)
- Mario Manto
- Service des Neurosciences, University of Mons, Mons, Belgium
| | - Jan Cendelin
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Ludwig Maximilians University, Munich, Germany
| | - Hiroshi Mitoma
- Department of Medical Education, Tokyo medical University, Tokyo, Japan
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3
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Cook AA, Jayabal S, Sheng J, Fields E, Leung TCS, Quilez S, McNicholas E, Lau L, Huang S, Watt AJ. Activation of TrkB-Akt signaling rescues deficits in a mouse model of SCA6. SCIENCE ADVANCES 2022; 8:eabh3260. [PMID: 36112675 PMCID: PMC9481119 DOI: 10.1126/sciadv.abh3260] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 07/29/2022] [Indexed: 06/01/2023]
Abstract
Spinocerebellar ataxia type 6 (SCA6) is a neurodegenerative disease resulting in motor coordination deficits and cerebellar pathology. Expression of brain-derived neurotrophic factor (BDNF) is reduced in postmortem tissue from SCA6 patients. Here, we show that levels of cerebellar BDNF and its receptor, tropomyosin receptor kinase B (TrkB), are reduced at an early disease stage in a mouse model of SCA6 (SCA684Q/84Q). One month of exercise elevated cerebellar BDNF expression and improved ataxia and cerebellar Purkinje cell firing rate deficits. A TrkB agonist, 7,8-dihydroxyflavone (7,8-DHF), likewise improved motor coordination and Purkinje cell firing rate and elevated downstream Akt signaling. Prolonged 7,8-DHF administration persistently improved ataxia when treatment commenced near disease onset but was ineffective when treatment was started late. These data suggest that 7,8-DHF, which is orally bioavailable and crosses the blood-brain barrier, is a promising therapeutic for SCA6 and argue for the importance of early intervention for SCA6.
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Affiliation(s)
- Anna A. Cook
- Biology Department, McGill University, Montreal, QC, Canada
| | - Sriram Jayabal
- Biology Department, McGill University, Montreal, QC, Canada
- Integrated Neuroscience Program, McGill University, Montreal, QC, Canada
- Department of Neurobiology, Stanford School of Medicine, Stanford, CA, USA
| | - Jacky Sheng
- Biology Department, McGill University, Montreal, QC, Canada
| | - Eviatar Fields
- Biology Department, McGill University, Montreal, QC, Canada
- Integrated Neuroscience Program, McGill University, Montreal, QC, Canada
| | | | - Sabrina Quilez
- Biology Department, McGill University, Montreal, QC, Canada
| | | | - Lois Lau
- Biology Department, McGill University, Montreal, QC, Canada
| | - Shixia Huang
- Department of Molecular and Cellular Biology, Department of Education, Innovation and Technology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Alanna J. Watt
- Biology Department, McGill University, Montreal, QC, Canada
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4
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Wu YL, Chang JC, Sun HL, Cheng WL, Yen YP, Lin YS, Chao YC, Liu KH, Huang CS, Liu KL, Liu CS. Coenzyme Q10 Supplementation Increases Removal of the ATXN3 Polyglutamine Repeat, Reducing Cerebellar Degeneration and Improving Motor Dysfunction in Murine Spinocerebellar Ataxia Type 3. Nutrients 2022; 14:nu14173593. [PMID: 36079853 PMCID: PMC9459709 DOI: 10.3390/nu14173593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/29/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Coenzyme Q10 (CoQ10), a well-known antioxidant, has been explored as a treatment in several neurodegenerative diseases, but its utility in spinocerebellar ataxia type 3 (SCA3) has not been explored. Herein, the protective effect of CoQ10 was examined using a transgenic mouse model of SCA3 onset. These results demonstrated that a diet supplemented with CoQ10 significantly improved murine locomotion, revealed by rotarod and open-field tests, compared with untreated controls. Additionally, a histological analysis showed the stratification of cerebellar layers indistinguishable from that of wild-type littermates. The increased survival of Purkinje cells was reflected by the reduced abundance of TUNEL-positive nuclei and apoptosis markers of activated p53, as well as lower levels of cleaved caspase 3 and cleaved poly-ADP-ribose polymerase. CoQ10 effects were related to the facilitation of the autophagy-mediated clearance of mutant ataxin-3 protein, as evidenced by the increased expression of heat shock protein 27 and autophagic markers p62, Beclin-1 and LC3II. The expression of antioxidant enzymes heme oxygenase 1 (HO-1), glutathione peroxidase 1 (GPx1) and superoxide dismutase 1 (SOD1) and 2 (SOD2), but not of glutathione peroxidase 2 (GPx2), were restored in 84Q SCA3 mice treated with CoQ10 to levels even higher than those measured in wild-type control mice. Furthermore, CoQ10 treatment also prevented skeletal muscle weight loss and muscle atrophy in diseased mice, revealed by significantly increased muscle fiber area and upregulated muscle protein synthesis pathways. In summary, our results demonstrated biochemical and pharmacological bases for the possible use of CoQ10 in SCA3 therapy.
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Affiliation(s)
- Yu-Ling Wu
- Vascular and Genomic Center, Institute of ATP, Changhua Christian Hospital, Changhua 50091, Taiwan
- Cardiovascular and Mitochondrial Related Disease Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 97004, Taiwan
| | - Jui-Chih Chang
- Center of Regenerative Medicine and Tissue Repair, Changhua Christian Hospital, Changhua 50091, Taiwan
- General Research Laboratory of Research Department, Changhua Christian Hospital, Changhua 50091, Taiwan
| | - Hai-Lun Sun
- School of Medicine, Chung Shan Medical University, Taichung 40203, Taiwan
- Department of Pediatrics, Division of Allergy, Asthma and Rheumatology, Chung Shan Medical University Hospital, Taichung 40203, Taiwan
| | - Wen-Ling Cheng
- Vascular and Genomic Center, Institute of ATP, Changhua Christian Hospital, Changhua 50091, Taiwan
| | - Yu-Pei Yen
- Department of Nutrition, Chung Shan Medical University, Taichung 40203, Taiwan
| | - Yong-Shiou Lin
- Vascular and Genomic Center, Institute of ATP, Changhua Christian Hospital, Changhua 50091, Taiwan
| | - Yi-Chun Chao
- Inflammation Research & Drug Development Center, Changhua Christian Hospital, Changhua 50091, Taiwan
| | - Ko-Hung Liu
- Inflammation Research & Drug Development Center, Changhua Christian Hospital, Changhua 50091, Taiwan
| | - Ching-Shan Huang
- Center of Regenerative Medicine and Tissue Repair, Changhua Christian Hospital, Changhua 50091, Taiwan
| | - Kai-Li Liu
- Department of Nutrition, Chung Shan Medical University, Taichung 40203, Taiwan
- Department of Nutrition, Chung Shan Medical University Hospital, Taichung 40203, Taiwan
- Correspondence: (K.-L.L.); (C.-S.L.); Tel.: +886-4-24730022 (ext. 12136) (K.-L.L.); +886-4-7238595 (ext. 4751) (C.-S.L.)
| | - Chin-San Liu
- Vascular and Genomic Center, Institute of ATP, Changhua Christian Hospital, Changhua 50091, Taiwan
- Department of Neurology, Changhua Christian Hospital, Changhua 50094, Taiwan
- Graduate Institute of Integrated Medicine College of Chinese Medicine, China Medical University, Taichung 40447, Taiwan
- College of Medicine, National Chung Hsing University, Taichung 40227, Taiwan
- Correspondence: (K.-L.L.); (C.-S.L.); Tel.: +886-4-24730022 (ext. 12136) (K.-L.L.); +886-4-7238595 (ext. 4751) (C.-S.L.)
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5
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Sujkowski A, Richardson K, Prifti MV, Wessells RJ, Todi SV. Endurance exercise ameliorates phenotypes in Drosophila models of spinocerebellar ataxias. eLife 2022; 11:e75389. [PMID: 35170431 PMCID: PMC8871352 DOI: 10.7554/elife.75389] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/15/2022] [Indexed: 11/24/2022] Open
Abstract
Endurance exercise is a potent intervention with widespread benefits proven to reduce disease incidence and impact across species. While endurance exercise supports neural plasticity, enhanced memory, and reduced neurodegeneration, less is known about the effect of chronic exercise on the progression of movement disorders such as ataxias. Here, we focused on three different types of ataxias, spinocerebellar ataxias type (SCAs) 2, 3, and 6, belonging to the polyglutamine (polyQ) family of neurodegenerative disorders. In Drosophila models of these SCAs, flies progressively lose motor function. In this study, we observe marked protection of speed and endurance in exercised SCA2 flies and modest protection in exercised SCA6 models, with no benefit to SCA3 flies. Causative protein levels are reduced in SCA2 flies after chronic exercise, but not in SCA3 models, linking protein levels to exercise-based benefits. Further mechanistic investigation indicates that the exercise-inducible protein, Sestrin (Sesn), suppresses mobility decline and improves early death in SCA2 flies, even without exercise, coincident with disease protein level reduction and increased autophagic flux. These improvements partially depend on previously established functions of Sesn that reduce oxidative damage and modulate mTOR activity. Our study suggests differential responses of polyQ SCAs to exercise, highlighting the potential for more extensive application of exercise-based therapies in the prevention of polyQ neurodegeneration. Defining the mechanisms by which endurance exercise suppresses polyQ SCAs will open the door for more effective treatment for these diseases.
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Affiliation(s)
- Alyson Sujkowski
- Department of Physiology, Wayne State University School of MedicineDetroitUnited States
- Department of Pharmacology, Wayne State University School of MedicineDetroitUnited States
| | - Kristin Richardson
- Department of Physiology, Wayne State University School of MedicineDetroitUnited States
| | - Matthew V Prifti
- Department of Pharmacology, Wayne State University School of MedicineDetroitUnited States
| | - Robert J Wessells
- Department of Physiology, Wayne State University School of MedicineDetroitUnited States
| | - Sokol V Todi
- Department of Pharmacology, Wayne State University School of MedicineDetroitUnited States
- Department of Neurology, Wayne State University School of MedicineDetroitUnited States
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6
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Sujkowski A, Hong L, Wessells RJ, Todi SV. The protective role of exercise against age-related neurodegeneration. Ageing Res Rev 2022; 74:101543. [PMID: 34923167 PMCID: PMC8761166 DOI: 10.1016/j.arr.2021.101543] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/01/2021] [Accepted: 12/14/2021] [Indexed: 02/08/2023]
Abstract
Endurance exercise is a widely accessible, low-cost intervention with a variety of benefits to multiple organ systems. Exercise improves multiple indices of physical performance and stimulates pronounced health benefits reducing a range of pathologies including metabolic, cardiovascular, and neurodegenerative disorders. Endurance exercise delays brain aging, preserves memory and cognition, and improves symptoms of neurodegenerative pathologies like Amyotrophic Lateral Sclerosis, Alzheimer's disease, Parkinson's disease, Huntington's disease, and various ataxias. Potential mechanisms underlying the beneficial effects of exercise include neuronal survival and plasticity, neurogenesis, epigenetic modifications, angiogenesis, autophagy, and the synthesis and release of neurotrophins and cytokines. In this review, we discuss shared benefits and molecular pathways driving the protective effects of endurance exercise on various neurodegenerative diseases in animal models and in humans.
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Affiliation(s)
- Alyson Sujkowski
- Department of Physiology, Wayne State University School of Medicine, USA; Department of Pharmacology, Wayne State University School of Medicine, USA
| | - Luke Hong
- Department of Pharmacology, Wayne State University School of Medicine, USA; Department of Neurology, Wayne State University School of Medicine, USA
| | - R J Wessells
- Department of Physiology, Wayne State University School of Medicine, USA
| | - Sokol V Todi
- Department of Pharmacology, Wayne State University School of Medicine, USA; Department of Neurology, Wayne State University School of Medicine, USA.
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7
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Affiliation(s)
- Francesca Gelfo
- Department of Human Sciences, Guglielmo Marconi University; IRCCS Fondazione Santa Lucia, Rome, Italy
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8
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Cendelin J, Cvetanovic M, Gandelman M, Hirai H, Orr HT, Pulst SM, Strupp M, Tichanek F, Tuma J, Manto M. Consensus Paper: Strengths and Weaknesses of Animal Models of Spinocerebellar Ataxias and Their Clinical Implications. THE CEREBELLUM 2021; 21:452-481. [PMID: 34378174 DOI: 10.1007/s12311-021-01311-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 01/02/2023]
Abstract
Spinocerebellar ataxias (SCAs) represent a large group of hereditary degenerative diseases of the nervous system, in particular the cerebellum, and other systems that manifest with a variety of progressive motor, cognitive, and behavioral deficits with the leading symptom of cerebellar ataxia. SCAs often lead to severe impairments of the patient's functioning, quality of life, and life expectancy. For SCAs, there are no proven effective pharmacotherapies that improve the symptoms or substantially delay disease progress, i.e., disease-modifying therapies. To study SCA pathogenesis and potential therapies, animal models have been widely used and are an essential part of pre-clinical research. They mainly include mice, but also other vertebrates and invertebrates. Each animal model has its strengths and weaknesses arising from model animal species, type of genetic manipulation, and similarity to human diseases. The types of murine and non-murine models of SCAs, their contribution to the investigation of SCA pathogenesis, pathological phenotype, and therapeutic approaches including their advantages and disadvantages are reviewed in this paper. There is a consensus among the panel of experts that (1) animal models represent valuable tools to improve our understanding of SCAs and discover and assess novel therapies for this group of neurological disorders characterized by diverse mechanisms and differential degenerative progressions, (2) thorough phenotypic assessment of individual animal models is required for studies addressing therapeutic approaches, (3) comparative studies are needed to bring pre-clinical research closer to clinical trials, and (4) mouse models complement cellular and invertebrate models which remain limited in terms of clinical translation for complex neurological disorders such as SCAs.
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Affiliation(s)
- Jan Cendelin
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic. .,Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.
| | - Marija Cvetanovic
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mandi Gandelman
- Department of Neurology, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Hirokazu Hirai
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, 3-39-22, Gunma, 371-8511, Japan.,Viral Vector Core, Gunma University Initiative for Advanced Research (GIAR), Gunma, 371-8511, Japan
| | - Harry T Orr
- Department of Laboratory Medicine and Pathology, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Hospital of the Ludwig-Maximilians University, Munich, Campus Grosshadern, Marchioninistr. 15, 81377, Munich, Germany
| | - Filip Tichanek
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.,Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic
| | - Jan Tuma
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.,The Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7843, San Antonio, TX, 78229, USA
| | - Mario Manto
- Unité des Ataxies Cérébelleuses, Service de Neurologie, CHU-Charleroi, Charleroi, Belgium.,Service des Neurosciences, Université de Mons, UMons, Mons, Belgium
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White JJ, Bosman LWJ, Blot FGC, Osório C, Kuppens BW, Krijnen WHJJ, Andriessen C, De Zeeuw CI, Jaarsma D, Schonewille M. Region-specific preservation of Purkinje cell morphology and motor behavior in the ATXN1[82Q] mouse model of spinocerebellar ataxia 1. Brain Pathol 2021; 31:e12946. [PMID: 33724582 PMCID: PMC8412070 DOI: 10.1111/bpa.12946] [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: 07/23/2020] [Revised: 01/27/2021] [Accepted: 02/16/2021] [Indexed: 01/09/2023] Open
Abstract
Purkinje cells are the primary processing units of the cerebellar cortex and display molecular heterogeneity that aligns with differences in physiological properties, projection patterns, and susceptibility to disease. In particular, multiple mouse models that feature Purkinje cell degeneration are characterized by incomplete and patterned Purkinje cell degeneration, suggestive of relative sparing of Purkinje cell subpopulations, such as those expressing Aldolase C/zebrinII (AldoC) or residing in the vestibulo‐cerebellum. Here, we investigated a well‐characterized Purkinje cell‐specific mouse model for spinocerebellar ataxia type 1 (SCA1) that expresses human ATXN1 with a polyQ expansion (82Q). Our pathological analysis confirms previous findings that Purkinje cells of the vestibulo‐cerebellum, i.e., the flocculonodular lobes, and crus I are relatively spared from key pathological hallmarks: somatodendritic atrophy, and the appearance of p62/SQSTM1‐positive inclusions. However, immunohistological analysis of transgene expression revealed that spared Purkinje cells do not express mutant ATXN1 protein, indicating the sparing of Purkinje cells can be explained by an absence of transgene expression. Additionally, we found that Purkinje cells in other cerebellar lobules that typically express AldoC, not only display severe pathology but also show loss of AldoC expression. The relatively preserved flocculonodular lobes and crus I showed a substantial fraction of Purkinje cells that expressed the mutant protein and displayed pathology as well as loss of AldoC expression. Despite considerable pathology in these lobules, behavioral analyses demonstrated a relative sparing of related functions, suggestive of sufficient functional cerebellar reserve. Together, the data indicate that mutant ATXN1 affects both AldoC‐positive and AldoC‐negative Purkinje cells and disrupts normal parasagittal AldoC expression in Purkinje cells. Our results show that, in a mouse model otherwise characterized by widespread Purkinje cell degeneration, sparing of specific subpopulations is sufficient to maintain normal performance of specific behaviors within the context of the functional, modular map of the cerebellum.
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Affiliation(s)
- Joshua J White
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | | | - Catarina Osório
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Bram W Kuppens
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | | | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Dick Jaarsma
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
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