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Nan Y, Chen W, Chen F, Wei L, Zeng A, Lin X, Zhou W, Yang Y, Li Q. Endosome mediated nucleocytoplasmic trafficking and endomembrane allocation is crucial to polyglutamine toxicity. Cell Biol Toxicol 2024; 40:48. [PMID: 38900277 PMCID: PMC11189978 DOI: 10.1007/s10565-024-09891-4] [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: 12/11/2023] [Accepted: 06/03/2024] [Indexed: 06/21/2024]
Abstract
Aggregation of aberrant proteins is a common pathological hallmark in neurodegeneration such as polyglutamine (polyQ) and other repeat-expansion diseases. Here through overexpression of ataxin3 C-terminal polyQ expansion in Drosophila gut enterocytes, we generated an intestinal obstruction model of spinocerebellar ataxia type3 (SCA3) and reported a new role of nuclear-associated endosomes (NAEs)-the delivery of polyQ to the nucleoplasm. In this model, accompanied by the prominently increased RAB5-positive NAEs are abundant nucleoplasmic reticulum enriched with polyQ, abnormal nuclear envelope invagination, significantly reduced endoplasmic reticulum, indicating dysfunctional nucleocytoplasmic trafficking and impaired endomembrane organization. Consistently, Rab5 but not Rab7 RNAi further decreased polyQ-related NAEs, inhibited endomembrane disorganization, and alleviated disease model. Interestingly, autophagic proteins were enriched in polyQ-related NAEs and played non-canonical autophagic roles as genetic manipulation of autophagic molecules exhibited differential impacts on NAEs and SCA3 toxicity. Namely, the down-regulation of Atg1 or Atg12 mitigated while Atg5 RNAi aggravated the disease phenotypes both in Drosophila intestines and compound eyes. Our findings, therefore, provide new mechanistic insights and underscore the fundamental roles of endosome-centered nucleocytoplasmic trafficking and homeostatic endomembrane allocation in the pathogenesis of polyQ diseases.
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Affiliation(s)
- Yuyu Nan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410000, China
- Department of Critical Care Units, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 311121, China
| | - Wenfeng Chen
- Institute of Life Sciences, Fuzhou University, Fuzhou, Fujian Province, 350108, China
| | - Fei Chen
- Institute of Life Sciences, Fuzhou University, Fuzhou, Fujian Province, 350108, China
| | - Lili Wei
- Guangxi Clinical Research Center for Neurological Diseases, Guilin, Guangxi, 541001, China
| | - Aiyuan Zeng
- Department of Neurology, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541001, China
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin, Guangxi, 541004, China
| | - Xiaohui Lin
- Department of Neurology, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541001, China
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin, Guangxi, 541004, China
| | - Wenbin Zhou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410000, China
| | - Yufeng Yang
- Institute of Life Sciences, Fuzhou University, Fuzhou, Fujian Province, 350108, China.
| | - Qinghua Li
- Department of Neurology, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541001, China.
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin, Guangxi, 541004, China.
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2
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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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3
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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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4
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Alexander CJ, Hammer JA. An Improved Method for Differentiating Mouse Embryonic Stem Cells into Cerebellar Purkinje Neurons. THE CEREBELLUM 2019; 18:406-421. [PMID: 30729383 DOI: 10.1007/s12311-019-1007-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
While mixed primary cerebellar cultures prepared from embryonic tissue have proven valuable for dissecting structure-function relationships in cerebellar Purkinje neurons (PNs), this technique is technically challenging and often yields few cells. Recently, mouse embryonic stem cells (mESCs) have been successfully differentiated into PNs, although the published methods are very challenging as well. The focus of this study was to simplify the differentiation of mESCs into PNs. Using a recently described neural differentiation media, we generate monolayers of neural progenitor cells from mESCs and differentiate them into PN precursors using specific extrinsic factors. These PN precursors are then differentiated into mature PNs by co-culturing them with granule neuron (GN) precursors also derived from neural progenitors using different extrinsic factors. The morphology of mESC-derived PNs is indistinguishable from PNs grown in primary culture in terms of gross morphology, spine length, and spine density. Furthermore, mESC-derived PNs express Calbindin D28K, IP3R1, IRBIT, PLCβ4, PSD93, and myosin IIB-B2, all of which are either PN-specific or highly expressed in PNs. Moreover, we show that mESC-derived PNs form synapses with GN-like cells as in primary culture, express proteins driven by the PN-specific promoter Pcp2/L7, and exhibit the defect in spine ER inheritance seen in PNs isolated from dilute-lethal (myosin Va-null) mice when expressing a Pcp2/L7-driven miRNA directed against myosin Va. Finally, we define a novel extracellular matrix formulation that reproducibly yields monolayer cultures conducive for high-resolution imaging. Our improved method for differentiating mESCs into PNs should facilitate the dissection of molecular mechanisms and disease phenotypes in PNs.
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Affiliation(s)
- Christopher J Alexander
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - John A Hammer
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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5
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Alexander CJ, Wagner W, Copeland NG, Jenkins NA, Hammer JA. Creation of a myosin Va-TAP-tagged mouse and identification of potential myosin Va-interacting proteins in the cerebellum. Cytoskeleton (Hoboken) 2019; 75:395-409. [PMID: 29979496 DOI: 10.1002/cm.21474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/19/2018] [Accepted: 06/27/2018] [Indexed: 12/29/2022]
Abstract
The actin-based motor myosin Va transports numerous cargos, including the smooth endoplasmic reticulum (SER) in cerebellar Purkinje neurons (PNs) and melanosomes in melanocytes. Identifying proteins that interact with this myosin is key to understanding its cellular functions. Toward that end, we used recombineering to insert via homologous recombination a tandem affinity purification (TAP) tag composed of the immunoglobulin G-binding domain of protein A, a tobacco etch virus cleavage site, and a FLAG tag into the mouse MYO5A locus immediately after the initiation codon. Importantly, we provide evidence that the TAP-tagged version of myosin Va (TAP-MyoVa) functions normally in terms of SER transport in PNs and melanosome positioning in melanocytes. Given this and other evidence that TAP-MyoVa is fully functional, we purified it together with associated proteins directly from juvenile mouse cerebella and subjected the samples to mass spectroscopic analyses. As expected, known myosin Va-binding partners like dynein light chain were identified. Importantly, numerous novel interacting proteins were also tentatively identified, including guanine nucleotide-binding protein G(o) subunit alpha (Gnao1), a biomarker for schizophrenia. Consistently, an antibody to Gnao1 immunoprecipitates myosin Va, and Gnao1's localization to PN dendritic spines depends on myosin Va. The mouse model created here should facilitate the identification of novel myosin Va-binding partners, which in turn should advance our understanding of the roles played by this important myosin in vivo.
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Affiliation(s)
- Christopher J Alexander
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Wolfgang Wagner
- Center for Molecular Neurobiology (ZMNH), Department of Molecular Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Neal G Copeland
- The University of Texas MD Anderson, Department of Genetics, Cancer Center, Houston, Texas
| | - Nancy A Jenkins
- The University of Texas MD Anderson, Department of Genetics, Cancer Center, Houston, Texas
| | - John A Hammer
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
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6
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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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7
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Pérez Ortiz JM, Mollema N, Toker N, Adamski CJ, O'Callaghan B, Duvick L, Friedrich J, Walters MA, Strasser J, Hawkinson JE, Zoghbi HY, Henzler C, Orr HT, Lagalwar S. Reduction of protein kinase A-mediated phosphorylation of ATXN1-S776 in Purkinje cells delays onset of Ataxia in a SCA1 mouse model. Neurobiol Dis 2018; 116:93-105. [PMID: 29758256 DOI: 10.1016/j.nbd.2018.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 04/17/2018] [Accepted: 05/09/2018] [Indexed: 12/27/2022] Open
Abstract
Spinocerebellar ataxia type 1 (SCA1) is a polyglutamine (polyQ) repeat neurodegenerative disease in which a primary site of pathogenesis are cerebellar Purkinje cells. In addition to polyQ expansion of ataxin-1 protein (ATXN1), phosphorylation of ATXN1 at the serine 776 residue (ATXN1-pS776) plays a significant role in protein toxicity. Utilizing a biochemical approach, pharmacological agents and cell-based assays, including SCA1 patient iPSC-derived neurons, we examine the role of Protein Kinase A (PKA) as an effector of ATXN1-S776 phosphorylation. We further examine the implications of PKA-mediated phosphorylation at ATXN1-S776 on SCA1 through genetic manipulation of the PKA catalytic subunit Cα in Pcp2-ATXN1[82Q] mice. Here we show that pharmacologic inhibition of S776 phosphorylation in transfected cells and SCA1 patient iPSC-derived neuronal cells lead to a decrease in ATXN1. In vivo, reduction of PKA-mediated ATXN1-pS776 results in enhanced degradation of ATXN1 and improved cerebellar-dependent motor performance. These results provide evidence that PKA is a biologically important kinase for ATXN1-pS776 in cerebellar Purkinje cells.
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Affiliation(s)
- Judit M Pérez Ortiz
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, United States; Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - Nissa Mollema
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, United States; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, United States
| | - Nicholas Toker
- Skidmore College Neuroscience Program, Saratoga Springs, NY, United States
| | - Carolyn J Adamski
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, and Department of Molecular and Human Genetics, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX, United States
| | - Brennon O'Callaghan
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, United States; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, United States
| | - Lisa Duvick
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, United States; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, United States
| | - Jillian Friedrich
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, United States; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, United States
| | - Michael A Walters
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, United States
| | - Jessica Strasser
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, United States
| | - Jon E Hawkinson
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, United States
| | - Huda Y Zoghbi
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, and Department of Molecular and Human Genetics, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX, United States
| | - Christine Henzler
- RISS Bioinformatics, Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN, United States
| | - Harry T Orr
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, United States; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, United States.
| | - Sarita Lagalwar
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, United States; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, United States; Skidmore College Neuroscience Program, Saratoga Springs, NY, United States.
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8
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Pieczora L, Stracke L, Vorgerd M, Hahn S, Theiss C, Theis V. Unveiling of miRNA Expression Patterns in Purkinje Cells During Development. THE CEREBELLUM 2017; 16:376-387. [PMID: 27387430 DOI: 10.1007/s12311-016-0814-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
MicroRNAs (miRNAs) are short noncoding RNAs of 19-25 nucleotides in length that regulate gene expression at the post-transcriptional level. Dysregulation of miRNAs is associated with many disorders and neurodegenerative diseases affecting numerous different pathways and processes, of which many have not yet been completely explored. Recent studies even indicate a crucial role of miRNAs during brain development, with differential expression patterns of several miRNAs seen in both developing and mature cells. A miRNA profiling in brain tissue and the fundamental understanding of their effects might optimize the therapeutical treatment of various neurological disorders. In this study, we performed miRNA array analysis of enriched cerebellar Purkinje cell (PC) samples from both young and mature rat cerebella. We used laser microdissection (LMD) to enrich PC for a highly specific miRNA profiling. Altogether, we present the expression profile of at least 27 miRNAs expressed in rat cerebellar PC and disclose a different expression pattern of at least three of these miRNAs during development. These miRNAs are potential candidates for the regulation and control of cerebellar PC development, including neuritic and dendritic outgrowth as well as spine formation.
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Affiliation(s)
- Lukas Pieczora
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Lara Stracke
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Matthias Vorgerd
- Department of Neurology, Neuromuscular Center Ruhrgebiet, University Hospital Bergmannsheil, Ruhr-University Bochum, Buerkle-de-la-Camp-Platz 1, 44789, Bochum, Germany
| | - Stephan Hahn
- Department of Molecular Gastrointestinal Oncology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Carsten Theiss
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany.
| | - Verena Theis
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
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9
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Prolonged Type 1 Metabotropic Glutamate Receptor Dependent Synaptic Signaling Contributes to Spino-Cerebellar Ataxia Type 1. J Neurosci 2017; 36:4910-6. [PMID: 27147646 DOI: 10.1523/jneurosci.3953-15.2016] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 04/02/2016] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED Type 1 metabotropic glutamate receptor (mGluR1)-dependent signaling at parallel fiber to Purkinje neuron synapses is critical for cerebellar function. In a mouse model of human spino-cerebellar ataxia type 1 (early SCA1, 12 weeks) we find prolonged parallel fiber mGluR1-dependent synaptic currents and calcium signaling. Acute treatment with a low dose of the potent and specific activity-dependent mGluR1-negative allosteric modulator JNJ16259685 shortened the prolonged mGluR1 currents and rescued the moderate ataxia. Our results provide exciting new momentum for developing mGluR1-based pharmacology to treat ataxia. SIGNIFICANCE STATEMENT Ataxia is a progressive and devastating degenerative movement disorder commonly associated with loss of cerebellar function and with no known cure. In the early stages of a mouse model of human spinocerebellar ataxia type 1, SCA1, where mice exhibit only moderate motor impairment, we detect excess "gain of function" of metabotropic glutamate receptor signaling at an important cerebellar synapse. Because careful control of this type of signaling is critical for cerebellar function in mice and humans, we sought to remove the excess signaling with a powerful, readily available pharmacological modulator. Remarkably, this pharmacological treatment acutely restored normal motor function in the ataxic mice. Our results pave the way for exploring a new avenue for early treatment of human ataxias.
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10
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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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11
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Leto K, Arancillo M, Becker EBE, Buffo A, Chiang C, Ding B, Dobyns WB, Dusart I, Haldipur P, Hatten ME, Hoshino M, Joyner AL, Kano M, Kilpatrick DL, Koibuchi N, Marino S, Martinez S, Millen KJ, Millner TO, Miyata T, Parmigiani E, Schilling K, Sekerková G, Sillitoe RV, Sotelo C, Uesaka N, Wefers A, Wingate RJT, Hawkes R. Consensus Paper: Cerebellar Development. CEREBELLUM (LONDON, ENGLAND) 2016; 15:789-828. [PMID: 26439486 PMCID: PMC4846577 DOI: 10.1007/s12311-015-0724-2] [Citation(s) in RCA: 245] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The development of the mammalian cerebellum is orchestrated by both cell-autonomous programs and inductive environmental influences. Here, we describe the main processes of cerebellar ontogenesis, highlighting the neurogenic strategies used by developing progenitors, the genetic programs involved in cell fate specification, the progressive changes of structural organization, and some of the better-known abnormalities associated with developmental disorders of the cerebellum.
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Affiliation(s)
- Ketty Leto
- Department of Neuroscience Rita Levi Montalcini, University of Turin, via Cherasco 15, 10026, Turin, Italy.
- Neuroscience Institute Cavalieri-Ottolenghi, University of Turin, Regione Gonzole 10, 10043, Orbassano, Torino, Italy.
| | - Marife Arancillo
- Departments of Pathology & Immunology and Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA
| | - Esther B E Becker
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Annalisa Buffo
- Department of Neuroscience Rita Levi Montalcini, University of Turin, via Cherasco 15, 10026, Turin, Italy
- Neuroscience Institute Cavalieri-Ottolenghi, University of Turin, Regione Gonzole 10, 10043, Orbassano, Torino, Italy
| | - Chin Chiang
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, 4114 MRB III, Nashville, TN, 37232, USA
| | - Baojin Ding
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605-2324, USA
| | - William B Dobyns
- Seattle Children's Research Institute, Center for Integrative Brain Research, Seattle, WA, USA
- Department of Pediatrics, Genetics Division, University of Washington, Seattle, WA, USA
| | - Isabelle Dusart
- Sorbonne Universités, Université Pierre et Marie Curie Univ Paris 06, Institut de Biologie Paris Seine, France, 75005, Paris, France
- Centre National de la Recherche Scientifique, CNRS, UMR8246, INSERM U1130, Neuroscience Paris Seine, France, 75005, Paris, France
| | - Parthiv Haldipur
- Seattle Children's Research Institute, Center for Integrative Brain Research, Seattle, WA, USA
| | - Mary E Hatten
- Laboratory of Developmental Neurobiology, The Rockefeller University, New York, NY, 10065, USA
| | - Mikio Hoshino
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan
| | - Alexandra L Joyner
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, 10065, USA
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Daniel L Kilpatrick
- Department of Microbiology and Physiological Systems and Program in Neuroscience, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605-2324, USA
| | - Noriyuki Koibuchi
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Silvia Marino
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London, E1 2AT, UK
| | - Salvador Martinez
- Department Human Anatomy, IMIB-Arrixaca, University of Murcia, Murcia, Spain
| | - Kathleen J Millen
- Seattle Children's Research Institute, Center for Integrative Brain Research, Seattle, WA, USA
| | - Thomas O Millner
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London, E1 2AT, UK
| | - Takaki Miyata
- Department of Anatomy and Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Elena Parmigiani
- Department of Neuroscience Rita Levi Montalcini, University of Turin, via Cherasco 15, 10026, Turin, Italy
- Neuroscience Institute Cavalieri-Ottolenghi, University of Turin, Regione Gonzole 10, 10043, Orbassano, Torino, Italy
| | - Karl Schilling
- Anatomie und Zellbiologie, Anatomisches Institut, Rheinische Friedrich-Wilhelms-Universität, Bonn, Germany
| | - Gabriella Sekerková
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Roy V Sillitoe
- Departments of Pathology & Immunology and Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA
| | - Constantino Sotelo
- Institut de la Vision, UPMC Université de Paris 06, Paris, 75012, France
| | - Naofumi Uesaka
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Annika Wefers
- Center for Neuropathology, Ludwig-Maximilians-University, Munich, Germany
| | - Richard J T Wingate
- MRC Centre for Developmental Neurobiology, King's College London, London, UK
| | - Richard Hawkes
- Department of Cell Biology & Anatomy and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, T2N 4NI, AB, Canada
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12
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Keiser MS, Monteys AM, Corbau R, Gonzalez-Alegre P, Davidson BL. RNAi prevents and reverses phenotypes induced by mutant human ataxin-1. Ann Neurol 2016; 80:754-765. [PMID: 27686464 PMCID: PMC5115960 DOI: 10.1002/ana.24789] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/18/2016] [Accepted: 09/25/2016] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Spinocerebellar ataxia type 1 is an autosomal dominant fatal neurodegenerative disease caused by a polyglutamine expansion in the coding region of ATXN1. We showed previously that partial suppression of mutant ataxin-1 (ATXN1) expression, using virally expressed RNAi triggers, could prevent disease symptoms in a transgenic mouse model and a knockin mouse model of the disease, using a single dose of virus. Here, we set out to test whether RNAi triggers targeting ATXN1 could not only prevent, but also reverse disease readouts when delivered after symptom onset. METHODS We administered recombinant adeno-associated virus (rAAV) expressing miS1, an artificial miRNA targeting human ATXN1 mRNA (rAAV.miS1), to a mouse model of spinocerebellar ataxia type 1 (SCA1; B05 mice). Viruses were delivered prior to or after symptom onset at multiple doses. Control B05 mice were treated with rAAVs expressing a control artificial miRNA, or with saline. Animal behavior, molecular phenotypes, neuropathology, and magnetic resonance spectroscopy were done on all groups, and data were compared to wild-type littermates. RESULTS We found that SCA1 phenotypes could be reversed by partial suppression of human mutant ATXN1 mRNA by rAAV.miS1 when delivered after symptom onset. We also identified the therapeutic range of rAAV.miS1 that could prevent or reverse disease readouts. INTERPRETATION SCA1 disease may be reversible by RNAi therapy, and the doses required for advancing this therapy to humans are delineated. Ann Neurol 2016;80:754-765.
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Affiliation(s)
- Megan S Keiser
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Alejandro Mas Monteys
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Romuald Corbau
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA.,Spark Therapeutics, Philadelphia, PA
| | - Pedro Gonzalez-Alegre
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Neurology, University of Pennsylvania, Philadelphia, PA
| | - Beverly L Davidson
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA
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13
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Shuvaev AN, Hosoi N, Sato Y, Yanagihara D, Hirai H. Progressive impairment of cerebellar mGluR signalling and its therapeutic potential for cerebellar ataxia in spinocerebellar ataxia type 1 model mice. J Physiol 2016; 595:141-164. [PMID: 27440721 DOI: 10.1113/jp272950] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 07/11/2016] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS Spinocerebellar ataxia type 1 (SCA1) is a progressive neurodegenerative disease caused by a gene defect, leading to movement disorder such as cerebellar ataxia. It remains largely unknown which functional defect contributes to the cerebellar ataxic phenotype in SCA1. In this study, we report progressive dysfunction of metabotropic glutamate receptor (mGluR) signalling, which leads to smaller slow synaptic responses, reduced dendritic Ca2+ signals and impaired synaptic plasticity at cerebellar synapses, in the early disease stage of SCA1 model mice. We also show that enhancement of mGluR signalling by a clinically available drug, baclofen, leads to improvement of motor performance in SCA1 mice. SCA1 is an incurable disease with no effective treatment, and our results may provide mechanistic grounds for targeting mGluRs and a novel drug therapy with baclofen to treat SCA1 patients in the future. ABSTRACT Spinocerebellar ataxia type 1 (SCA1) is a progressive neurodegenerative disease that presents with cerebellar ataxia and motor learning defects. Previous studies have indicated that the pathology of SCA1, as well as other ataxic diseases, is related to signalling pathways mediated by the metabotropic glutamate receptor type 1 (mGluR1), which is indispensable for proper motor coordination and learning. However, the functional contribution of mGluR signalling to SCA1 pathology is unclear. In the present study, we show that SCA1 model mice develop a functional impairment of mGluR signalling which mediates slow synaptic responses, dendritic Ca2+ signals, and short- and long-term synaptic plasticity at parallel fibre (PF)-Purkinje cell (PC) synapses in a progressive manner from the early disease stage (5 postnatal weeks) prior to PC death. Notably, impairment of mGluR-mediated dendritic Ca2+ signals linearly correlated with a reduction of PC capacitance (cell surface area) in disease progression. Enhancement of mGluR signalling by baclofen, a clinically available GABAB receptor agonist, led to an improvement of motor performance in SCA1 mice and the improvement lasted ∼1 week after a single application of baclofen. Moreover, the restoration of motor performance in baclofen-treated SCA1 mice matched the functional recovery of mGluR-mediated slow synaptic currents and mGluR-dependent short- and long-term synaptic plasticity. These results suggest that impairment of synaptic mGluR cascades is one of the important contributing factors to cerebellar ataxia in early and middle stages of SCA1 pathology, and that modulation of mGluR signalling by baclofen or other clinical interventions may be therapeutic targets to treat SCA1.
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Affiliation(s)
- Anton N Shuvaev
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan.,Research Institute of Molecular Medicine and Pathobiochemistry, Krasnoyarsk State Medical University named after Prof. V. F. Voino-Yasenetsky, Krasnoyarsk, 660022, Russia
| | - Nobutake Hosoi
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan
| | - Yamato Sato
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, 153-8902, Japan
| | - Dai Yanagihara
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, 153-8902, Japan
| | - Hirokazu Hirai
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan.,Research Program for Neural Signalling, Division of Endocrinology, Metabolism and Signal Research, Gunma University Initiative for Advanced Research, Maebashi, Gunma, 371-8511, Japan
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14
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Meera P, Pulst SM, Otis TS. Cellular and circuit mechanisms underlying spinocerebellar ataxias. J Physiol 2016; 594:4653-60. [PMID: 27198167 DOI: 10.1113/jp271897] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/13/2016] [Indexed: 12/12/2022] Open
Abstract
Degenerative ataxias are a common form of neurodegenerative disease that affect about 20 individuals per 100,000. The autosomal dominant spinocerebellar ataxias (SCAs) are caused by a variety of protein coding mutations (single nucleotide changes, deletions and expansions) in single genes. Affected genes encode plasma membrane and intracellular ion channels, membrane receptors, protein kinases, protein phosphatases and proteins of unknown function. Although SCA-linked genes are quite diverse they share two key features: first, they are highly, although not exclusively, expressed in cerebellar Purkinje neurons (PNs), and second, when mutated they lead ultimately to the degeneration of PNs. In this review we summarize ataxia-related changes in PN neurophysiology that have been observed in various mouse knockout lines and in transgenic models of human SCA. We also highlight emerging evidence that altered metabotropic glutamate receptor signalling and disrupted calcium homeostasis in PNs form a common, early pathophysiological mechanism in SCAs. Together these findings indicate that aberrant calcium signalling and profound changes in PN neurophysiology precede PN cell loss and are likely to lead to cerebellar circuit dysfunction that explains behavioural signs of ataxia characteristic of the disease.
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Affiliation(s)
- Pratap Meera
- Department of Neurobiology, Geffen School of Medicine, University of California, 650 Charles Young Drive, Los Angeles, CA, 90095, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, 175 N Medical Drive E, Salt Lake City, UT, 84132, USA
| | - Thomas S Otis
- Department of Neurobiology, Geffen School of Medicine, University of California, 650 Charles Young Drive, Los Angeles, CA, 90095, USA.,Roche Pharmaceutical Research and Early Development (pRED), Neuroscience, Ophthalmology and Rare Diseases (NORD), Grenzacherstrasse 124, CH-4070, Basel, Switzerland
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15
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Kohiyama MF, Lagalwar S. Stabilization and Degradation Mechanisms of Cytoplasmic Ataxin-1. J Exp Neurosci 2016; 9:123-9. [PMID: 27168726 PMCID: PMC4859447 DOI: 10.4137/jen.s25469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 04/11/2016] [Accepted: 04/13/2016] [Indexed: 12/24/2022] Open
Abstract
Aggregation-prone proteins in neurodegenerative disease disrupt cellular protein stabilization and degradation pathways. The neurodegenerative disease spinocerebellar ataxia type 1 (SCA1) is caused by a coding polyglutamine expansion in the Ataxin-1 gene (ATXN1), which gives rise to the aggregation-prone mutant form of ATXN1 protein. Cerebellar Purkinje neurons, preferentially vulnerable in SCA1, produce ATXN1 protein in both cytoplasmic and nuclear compartments. Cytoplasmic stabilization of ATXN1 by phosphorylation and 14-3-3-mediated mechanisms ultimately drive translocation of the protein to the nucleus where aggregation may occur. However, experimental inhibition of phosphorylation and 14-3-3 binding results in rapid degradation of ATXN1, thus preventing nuclear translocation and cellular toxicity. The exact mechanism of cytoplasmic ATXN1 degradation is currently unknown; further investigation of degradation may provide future therapeutic targets. This review examines the present understanding of cytoplasmic ATXN1 stabilization and potential degradation mechanisms during normal and pathogenic states.
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Affiliation(s)
- Mayumi F Kohiyama
- B.A., Skidmore College Neuroscience Program, Saratoga Springs, NY, USA
| | - Sarita Lagalwar
- Assistant Professor of Neuroscience, Williamson Chair in Neuroscience, Skidmore College Neuroscience Program, Saratoga Springs, NY, USA
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16
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Watson LM, Wong MMK, Becker EBE. Induced pluripotent stem cell technology for modelling and therapy of cerebellar ataxia. Open Biol 2016; 5:150056. [PMID: 26136256 PMCID: PMC4632502 DOI: 10.1098/rsob.150056] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Induced pluripotent stem cell (iPSC) technology has emerged as an important tool in understanding, and potentially reversing, disease pathology. This is particularly true in the case of neurodegenerative diseases, in which the affected cell types are not readily accessible for study. Since the first descriptions of iPSC-based disease modelling, considerable advances have been made in understanding the aetiology and progression of a diverse array of neurodegenerative conditions, including Parkinson's disease and Alzheimer's disease. To date, however, relatively few studies have succeeded in using iPSCs to model the neurodegeneration observed in cerebellar ataxia. Given the distinct neurodevelopmental phenotypes associated with certain types of ataxia, iPSC-based models are likely to provide significant insights, not only into disease progression, but also to the development of early-intervention therapies. In this review, we describe the existing iPSC-based disease models of this heterogeneous group of conditions and explore the challenges associated with generating cerebellar neurons from iPSCs, which have thus far hindered the expansion of this research.
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Affiliation(s)
- Lauren M Watson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Maggie M K Wong
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Esther B E Becker
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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17
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Power EM, English NA, Empson RM. Are Type 1 metabotropic glutamate receptors a viable therapeutic target for the treatment of cerebellar ataxia? J Physiol 2016; 594:4643-52. [PMID: 26748626 DOI: 10.1113/jp271153] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 12/19/2015] [Indexed: 12/13/2022] Open
Abstract
The cerebellum is a key brain structure for accurate coordination of sensory and motor function. Compared with other brain regions, the cerebellum expresses a particularly high level of Type 1 metabotropic glutamate receptors (mGluR1). In this review we aim to explore the significance of these receptors for cerebellar synapse function and their potential for treating cerebellar ataxia, a poorly treated degenerative motor disorder that is often hereditary. We find a significant and historical literature showing pivotal mechanisms linking mGluR1 activity with healthy cerebellar synaptic function and motor coordination. This is best illustrated by the impaired motor behaviour in mGluR1 knockout mice that bears strong resemblance to human ataxias. More recent literature also indicates that an imbalance of mGluR1 signalling is as critical as its removal. Too much, as well as too little, mGluR1 activity contributes to ataxia in several clinically relevant mouse models, and perhaps also in humans. Given the availability and ongoing refinement of selective pharmacological tools to either reduce (negative allosteric modulation) or boost (positive allosteric modulation) mGluR1 activity, our findings suggest that pharmacological manipulation of these receptors should be explored as an exciting new approach for the treatment of a variety of human cerebellar ataxias.
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Affiliation(s)
- Emmet M Power
- Department of Physiology, Brain Research New Zealand, Brain Health Research Centre, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand, 9054
| | - Natalya A English
- Department of Physiology, Brain Research New Zealand, Brain Health Research Centre, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand, 9054
| | - Ruth M Empson
- Department of Physiology, Brain Research New Zealand, Brain Health Research Centre, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand, 9054
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18
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Jarius S, Wildemann B. 'Medusa head ataxia': the expanding spectrum of Purkinje cell antibodies in autoimmune cerebellar ataxia. Part 2: Anti-PKC-gamma, anti-GluR-delta2, anti-Ca/ARHGAP26 and anti-VGCC. J Neuroinflammation 2015; 12:167. [PMID: 26377184 PMCID: PMC4574118 DOI: 10.1186/s12974-015-0357-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/02/2015] [Indexed: 01/18/2023] Open
Abstract
Serological testing for anti-neural autoantibodies is important in patients presenting with idiopathic cerebellar ataxia, since these autoantibodies may indicate cancer, determine treatment and predict prognosis. While some of them target nuclear antigens present in all or most CNS neurons (e.g. anti-Hu, anti-Ri), others more specifically target antigens present in the cytoplasm or plasma membrane of Purkinje cells (PC). In this series of articles, we provide a detailed review of the clinical and paraclinical features, oncological, therapeutic and prognostic implications, pathogenetic relevance, and differential laboratory diagnosis of the 12 most common PC autoantibodies (often referred to as 'Medusa head antibodies' due their characteristic somatodendritic binding pattern when tested by immunohistochemistry). To assist immunologists and neurologists in diagnosing these disorders, typical high-resolution immunohistochemical images of all 12 reactivities are presented, diagnostic pitfalls discussed and all currently available assays reviewed. Of note, most of these antibodies target antigens involved in the mGluR1/calcium pathway essential for PC function and survival. Many of the antigens also play a role in spinocerebellar ataxia. Part 1 focuses on anti-metabotropic glutamate receptor 1-, anti-Homer protein homolog 3-, anti-Sj/inositol 1,4,5-trisphosphate receptor- and anti-carbonic anhydrase-related protein VIII-associated autoimmune cerebellar ataxia (ACA); part 2 covers anti-protein kinase C gamma-, anti-glutamate receptor delta-2-, anti-Ca/RhoGTPase-activating protein 26- and anti-voltage-gated calcium channel-associated ACA; and part 3 reviews the current knowledge on anti-Tr/delta notch-like epidermal growth factor-related receptor-, anti-Nb/AP3B2-, anti-Yo/cerebellar degeneration-related protein 2- and Purkinje cell antibody 2-associated ACA, discusses differential diagnostic aspects, and provides a summary and outlook.
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Affiliation(s)
- S Jarius
- Molecular Neuroimmunology Group, Department of Neurology, University of Heidelberg, Otto Meyerhof Center, Im Neuenheimer Feld 350, D-69120, Heidelberg, Germany.
| | - B Wildemann
- Molecular Neuroimmunology Group, Department of Neurology, University of Heidelberg, Otto Meyerhof Center, Im Neuenheimer Feld 350, D-69120, Heidelberg, Germany.
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19
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Jarius S, Wildemann B. 'Medusa-head ataxia': the expanding spectrum of Purkinje cell antibodies in autoimmune cerebellar ataxia. Part 1: Anti-mGluR1, anti-Homer-3, anti-Sj/ITPR1 and anti-CARP VIII. J Neuroinflammation 2015; 12:166. [PMID: 26377085 PMCID: PMC4574226 DOI: 10.1186/s12974-015-0356-y] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/02/2015] [Indexed: 01/09/2023] Open
Abstract
Serological testing for anti-neural autoantibodies is important in patients presenting with idiopathic cerebellar ataxia, since these autoantibodies may indicate cancer, determine treatment and predict prognosis. While some of them target nuclear antigens present in all or most CNS neurons (e.g. anti-Hu, anti-Ri), others more specifically target antigens present in the cytoplasm or plasma membrane of Purkinje cells (PC). In this series of articles, we provide a detailed review of the clinical and paraclinical features, oncological, therapeutic and prognostic implications, pathogenetic relevance, and differential laboratory diagnosis of the 12 most common PC autoantibodies (often referred to as 'Medusa-head antibodies' due to their characteristic somatodendritic binding pattern when tested by immunohistochemistry). To assist immunologists and neurologists in diagnosing these disorders, typical high-resolution immunohistochemical images of all 12 reactivities are presented, diagnostic pitfalls discussed and all currently available assays reviewed. Of note, most of these antibodies target antigens involved in the mGluR1/calcium pathway essential for PC function and survival. Many of the antigens also play a role in spinocerebellar ataxia. Part 1 focuses on anti-metabotropic glutamate receptor 1-, anti-Homer protein homolog 3-, anti-Sj/inositol 1,4,5-trisphosphate receptor- and anti-carbonic anhydrase-related protein VIII-associated autoimmune cerebellar ataxia (ACA); part 2 covers anti-protein kinase C gamma-, anti-glutamate receptor delta-2-, anti-Ca/RhoGTPase-activating protein 26- and anti-voltage-gated calcium channel-associated ACA; and part 3 reviews the current knowledge on anti-Tr/delta notch-like epidermal growth factor-related receptor-, anti-Nb/AP3B2-, anti-Yo/cerebellar degeneration-related protein 2- and Purkinje cell antibody 2-associated ACA, discusses differential diagnostic aspects and provides a summary and outlook.
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Affiliation(s)
- S Jarius
- Molecular Neuroimmunology Group, Department of Neurology, University of Heidelberg, Otto Meyerhof Center, Im Neuenheimer Feld 350, D-69120, Heidelberg, Germany.
| | - B Wildemann
- Molecular Neuroimmunology Group, Department of Neurology, University of Heidelberg, Otto Meyerhof Center, Im Neuenheimer Feld 350, D-69120, Heidelberg, Germany.
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20
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Hearst SM, Shao Q, Lopez M, Raucher D, Vig PJS. Focused cerebellar laser light induced hyperthermia improves symptoms and pathology of polyglutamine disease SCA1 in a mouse model. THE CEREBELLUM 2015; 13:596-606. [PMID: 24930030 DOI: 10.1007/s12311-014-0576-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Spinocerebellar ataxia 1 (SCA1) results from pathologic glutamine expansion in the ataxin-1 protein (ATXN1). This misfolded ATXN1 causes severe Purkinje cell (PC) loss and cerebellar ataxia in both humans and mice with the SCA1 disease. The molecular chaperone heat-shock proteins (HSPs) are known to modulate polyglutamine protein aggregation and are neuroprotective. Since HSPs are induced under stress, we explored the effects of focused laser light induced hyperthermia (HT) on HSP-mediated protection against ATXN1 toxicity. We first tested the effects of HT in a cell culture model and found that HT induced Hsp70 and increased its localization to nuclear inclusions in HeLa cells expressing GFP-ATXN1[82Q]. HT treatment decreased ATXN1 aggregation by making GFP-ATXN1[82Q] inclusions smaller and more numerous compared to non-treated cells. Further, we tested our HT approach in vivo using a transgenic (Tg) mouse model of SCA1. We found that our laser method increased cerebellar temperature from 38 to 40 °C without causing any neuronal damage or inflammatory response. Interestingly, mild cerebellar HT stimulated the production of Hsp70 to a significant level. Furthermore, multiple exposure of focused cerebellar laser light induced HT to heterozygous SCA1 transgenic (Tg) mice significantly suppressed the SCA1 phenotype as compared to sham-treated control animals. Moreover, in treated SCA1 Tg mice, the levels of PC calcium signaling/buffering protein calbindin-D28k markedly increased followed by a reduction in PC neurodegenerative morphology. Taken together, our data suggest that laser light induced HT is a novel non-invasive approach to treat SCA1 and maybe other polyglutamine disorders.
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Affiliation(s)
- Scoty M Hearst
- Department of Neurology, University of Mississippi Medical Center, 2500 N State St, Jackson, MS, 39216, USA
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21
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Animal Models of Spinocerebellar Ataxia Type 1. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00063-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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22
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Penetrating the cell membrane, thermal targeting and novel anticancer drugs: the development of thermally targeted, elastin-like polypeptide cancer therapeutics. Ther Deliv 2014; 5:429-45. [PMID: 24856169 DOI: 10.4155/tde.14.14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Therapeutic peptides offer important cancer treatment approaches. Designed to inhibit oncogenes and other oncoproteins, early therapeutic peptides applications were hampered by pharmacokinetic properties now addressed through tumor targeting strategies. Active targeting with environmentally responsive biopolymers or macromolecules enhances therapeutics accumulation at tumor sites; passive targeting with macromolecules, or liposomes, exploits angiogenesis and poor lymphatic drainage to preferentially accumulate therapeutics within tumors. Genetically engineered, thermally-responsive, elastin-like polypeptides use both strategies and cell-penetrating peptides to further intratumoral cell uptake. This review describes the development and application of cell-penetrating peptide-elastin-like polypeptide therapeutics for the thermally targeted delivery of therapeutic peptides.
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23
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Hearst SM, Shao Q, Lopez M, Raucher D, Vig PJS. The design and delivery of a PKA inhibitory polypeptide to treat SCA1. J Neurochem 2014; 131:101-14. [PMID: 24903464 DOI: 10.1111/jnc.12782] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 05/13/2014] [Accepted: 06/02/2014] [Indexed: 01/28/2023]
Abstract
Spinocerebellar ataxia-1 (SCA1) is a neurodegenerative disease that primarily targets Purkinje cells (PCs) of the cerebellum. The exact mechanism of PC degeneration is unknown, however, it is widely believed that mutant ataxin-1 becomes toxic because of the phosphorylation of its serine 776 (S776) residue by cAMP-dependent protein kinase A (PKA). Therefore, to directly modulate mutant ATXN1 S776 phosphorylation and aggregation, we designed a therapeutic polypeptide to inhibit PKA. This polypeptide comprised of a thermally responsive elastin-like peptide (ELP) carrier, which increases peptide half-life, a PKA inhibitory peptide (PKI), and a cell-penetrating peptide (Synb1). We observed that our therapeutic polypeptide, Synb1-ELP-PKI, inhibited PKA activity at concentrations similar to the PKI peptide. Additionally, Synb1-ELP-PKI significantly suppressed mutant ATXN1 S776 phosphorylation and intranuclear inclusion formation in cell culture. Further, Synb1-ELP-PKI treatment improved SCA1 PC morphology in cerebellar slice cultures. Furthermore, the Synb1-ELP peptide carrier crossed the blood-brain barrier and localized to the cerebellum via the i.p. or intranasal route. Here, we show the intranasal delivery of ELP-based peptides to the brain as a novel delivery strategy. We also demonstrate that our therapeutic polypeptide has a great potential to target the neurotoxic S776 phosphorylation pathway in the SCA1 disease.
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Affiliation(s)
- Scoty M Hearst
- Department of Neurology, University of Mississippi Medical Center, Jackson, Mississippi, USA; Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi, USA
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24
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Age-dependent decrease in chaperone activity impairs MANF expression, leading to Purkinje cell degeneration in inducible SCA17 mice. Neuron 2014; 81:349-65. [PMID: 24462098 DOI: 10.1016/j.neuron.2013.12.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2013] [Indexed: 12/14/2022]
Abstract
Although protein-misfolding-mediated neurodegenerative diseases have been linked to aging, how aging contributes to selective neurodegeneration remains unclear. We established spinocerebellar ataxia 17 (SCA17) knockin mice that inducibly express one copy of mutant TATA box binding protein (TBP) at different ages by tamoxifen-mediated Cre recombination. We find that more mutant TBP accumulates in older mouse and that this accumulation correlates with age-related decreases in Hsc70 and chaperone activity. Consistently, older SCA17 mice experienced earlier neurological symptom onset and more severe Purkinje cell degeneration. Mutant TBP shows decreased association with XBP1s, resulting in the reduced transcription of mesencephalic astrocyte-derived neurotrophic factor (MANF), which is enriched in Purkinje cells. Expression of Hsc70 improves the TBP-XBP1s interaction and MANF transcription, and overexpression of MANF ameliorates mutant TBP-mediated Purkinje cell degeneration via protein kinase C (PKC)-dependent signaling. These findings suggest that the age-related decline in chaperone activity affects polyglutamine protein function that is important for the viability of specific types of neurons.
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Notartomaso S, Zappulla C, Biagioni F, Cannella M, Bucci D, Mascio G, Scarselli P, Fazio F, Weisz F, Lionetto L, Simmaco M, Gradini R, Battaglia G, Signore M, Puliti A, Nicoletti F. Pharmacological enhancement of mGlu1 metabotropic glutamate receptors causes a prolonged symptomatic benefit in a mouse model of spinocerebellar ataxia type 1. Mol Brain 2013; 6:48. [PMID: 24252411 PMCID: PMC4225515 DOI: 10.1186/1756-6606-6-48] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/28/2013] [Indexed: 11/10/2022] Open
Abstract
Background Spinocerebellar ataxia type 1 (SCA1) is a genetic disorder characterized by severe ataxia associated with progressive loss of cerebellar Purkinje cells. The mGlu1 metabotropic glutamate receptor plays a key role in mechanisms of activity-dependent synaptic plasticity in the cerebellum, and its dysfunction is linked to the pathophysiology of motor symptoms associated with SCA1. We used SCA1 heterozygous transgenic mice (Q154/Q2) as a model for testing the hypothesis that drugs that enhance mGlu1 receptor function may be good candidates for the medical treatment of SCA1. Results Symptomatic 30-week old SCA1 mice showed reduced mGlu1 receptor mRNA and protein levels in the cerebellum. Interestingly, these mice also showed an intense expression of mGlu5 receptors in cerebellar Purkinje cells, which normally lack these receptors. Systemic treatment of SCA1 mice with the mGlu1 receptor positive allosteric modulator (PAM), Ro0711401 (10 mg/kg, s.c.), caused a prolonged improvement of motor performance on the rotarod and the paw-print tests. A single injection of Ro0711401 improved motor symptoms for several days, and no tolerance developed to the drug. In contrast, the mGlu5 receptor PAM, VU0360172 (10 mg/kg, s.c.), caused only a short-lasting improvement of motor symptoms, whereas the mGlu1 receptor antagonist, JNJ16259685 (2.5 mg/kg, i.p.), further impaired motor performance in SCA1 mice. The prolonged symptomatic benefit caused by Ro0711401 outlasted the time of drug clearance from the cerebellum, and was associated with neuroadaptive changes in the cerebellum, such as a striking reduction of the ectopically expressed mGlu5 receptors in Purkinje cells, increases in levels of total and Ser880-phosphorylated GluA2 subunit of AMPA receptors, and changes in the length of spines in the distal dendrites of Purkinje cells. Conclusions These data demonstrate that pharmacological enhancement of mGlu1 receptors causes a robust and sustained motor improvement in SCA1 mice, and lay the groundwork for the development of mGlu1 receptor PAMs as novel “cerebellum-specific”, effective, and safe symptomatic drugs for the treatment of SCA1 in humans.
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Gupta M, Kamynina E, Morley S, Chung S, Muakkassa N, Wang H, Brathwaite S, Sharma G, Manor D. Plekhg4 is a novel Dbl family guanine nucleotide exchange factor protein for rho family GTPases. J Biol Chem 2013; 288:14522-14530. [PMID: 23572525 DOI: 10.1074/jbc.m112.430371] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the PLEKHG4 (puratrophin-1) gene are associated with the heritable neurological disorder autosomal dominant spinocerebellar ataxia. However, the biochemical functions of this gene product have not been described. We report here that expression of Plekhg4 in the murine brain is developmentally regulated, with pronounced expression in the newborn midbrain and brainstem that wanes with age and maximal expression in the cerebellar Purkinje neurons in adulthood. We show that Plekhg4 is subject to ubiquitination and proteasomal degradation, and its steady-state expression levels are regulated by the chaperones Hsc70 and Hsp90 and by the ubiquitin ligase CHIP. On the functional level, we demonstrate that Plekhg4 functions as a bona fide guanine nucleotide exchange factor (GEF) that facilitates activation of the small GTPases Rac1, Cdc42, and RhoA. Overexpression of Plekhg4 in NIH3T3 cells induces rearrangements of the actin cytoskeleton, specifically enhanced formation of lamellopodia and fillopodia. These findings indicate that Plekhg4 is an aggregation-prone member of the Dbl family GEFs and that regulation of GTPase signaling is critical for proper cerebellar function.
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Affiliation(s)
- Meghana Gupta
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | | | - Samantha Morley
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Stacey Chung
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | | | - Hong Wang
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Shayna Brathwaite
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | | | - Danny Manor
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106; Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
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G-substrate: the cerebellum and beyond. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 106:381-416. [PMID: 22340725 DOI: 10.1016/b978-0-12-396456-4.00004-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The discovery of nitric oxide (NO) as an activator of soluble guanylate cyclase (sGC) has stimulated extensive research on the NO-sGC-3':5'-cyclic guanosine monophosphate (cGMP)-cGMP-dependent protein kinase (PKG) pathway. However, the restricted localization of pathway components and the lack of information on PKG substrates have hindered research seeking to examine the physiological roles of the NO-sGC-cGMP-PKG pathway. An excellent substrate for PKG is the G-substrate, which was originally discovered in the cerebellum. The role of G-substrate in the cerebellum and other brain structures has been revealed in recent years. This review discusses the relationship between the G-substrate and other components of the NO-sGC-cGMP-PKG pathway and describes the characteristics of the G-substrate gene and protein related to diseases. Finally, we discuss the physiological role of G-substrate in the cerebellum, where it regulates cerebellum-dependent long-term memory, and its role in the ventral tegmental area and retina, where it acts as an effective neuroprotectant.
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Vig PJS, Hearst S, Shao Q, Lopez ME, Murphy HA, Safaya E. Glial S100B protein modulates mutant ataxin-1 aggregation and toxicity: TRTK12 peptide, a potential candidate for SCA1 therapy. THE CEREBELLUM 2011; 10:254-66. [PMID: 21384195 DOI: 10.1007/s12311-011-0262-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Non-cell autonomous involvement of glial cells in the pathogenesis of polyglutamine diseases is gaining recognition in the ataxia field. We previously demonstrated that Purkinje cells (PCs) in polyglutamine disease spinocerebellar ataxia-1 (SCA1) contain cytoplasmic vacuoles rich in Bergmann glial protein S100B. The vacuolar formation in SCA1 PCs is accompanied with an abnormal morphology of dendritic spines. In addition, S100B messenger RNA (mRNA) expression levels are significantly high in the cerebella of asymptomatic SCA1 transgenic (Tg) mice and increase further with age when compared with the age-matched wild-type animals. This higher S100B mRNA expression positively correlates with an increase in the number of vacuoles. To further characterize the function of S100B in SCA1 pathology, we explored the effects of S100B protein on GFP-ataxin-1 (ATXN1) with expanded polyglutamines [82Q] in HEK stable cell line. Externally added S100B protein to these cells induced S100B-positive vacuoles similar to those seen in SCA1 PCs in vivo. Further, we found that both externally added and internally expressed S100B significantly reduced GFP-ATXN1[82Q] inclusion body formation. In contrast, the addition of S100B inhibitory peptide TRTK12 reversed S100B-mediated effects. Interestingly, in SCA1 Tg mice, PCs containing S100B vacuoles also showed the lack of nuclear inclusions, whereas PCs without vacuoles contained nuclear inclusions. Additionally, TRTK12 treatment reduced abnormal dendritic growth and morphology of PCs in cerebellar slice cultures prepared from SCA1 Tg mice. Moreover, intranasal administration of TRTK12 to SCA1 Tg mice reduced cerebellar S100B levels in the particulate fractions, and these mice displayed a significant improvement in their performance deficit on the Rotarod test. Taken together, our results suggest that glial S100B may augment degenerative changes in SCA1 PCs by modulating mutant ataxin-1 toxicity/solubility through an unknown signaling pathway.
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Affiliation(s)
- Parminder J S Vig
- Department of Neurology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
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Hearst SM, Walker LR, Shao Q, Lopez M, Raucher D, Vig PJS. The design and delivery of a thermally responsive peptide to inhibit S100B-mediated neurodegeneration. Neuroscience 2011; 197:369-80. [PMID: 21958864 DOI: 10.1016/j.neuroscience.2011.09.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 09/10/2011] [Accepted: 09/12/2011] [Indexed: 11/13/2022]
Abstract
S100B, a glial-secreted protein, is believed to play a major role in neurodegeneration in Alzheimer's disease, Down syndrome, traumatic brain injury, and spinocerebellar ataxia type 1 (SCA1). SCA1 is a trinucleotide repeat disorder in which the expanded polyglutamine mutation in the protein ataxin-1 primarily targets Purkinje cells of the cerebellum. Currently, the exact mechanism of S100B-mediated Purkinje cell damage in SCA1 is not clear. However, here we show that S100B may act via the activation of the receptor for advanced glycation end product (RAGE) signaling pathway, resulting in oxidative stress-mediated injury to mutant ataxin-1-expressing neurons. To combat S100B-mediated neurodegeneration, we have designed a selective thermally responsive S100B inhibitory peptide, Synb1-ELP-TRTK. Our therapeutic polypeptide was developed using three key elements: (1) the elastin-like polypeptide (ELP), a thermally responsive polypeptide, (2) the TRTK12 peptide, a known S100B inhibitory peptide, and (3) a cell-penetrating peptide, Synb1, to enhance intracellular delivery. Binding studies revealed that our peptide, Synb1-ELP-TRTK, interacts with its molecular target S100B and maintains a high S100B binding affinity as comparable with the TRTK12 peptide alone. In addition, in vitro studies revealed that Synb1-ELP-TRTK treatment reduces S100B uptake in SHSY5Y cells. Furthermore, the Synb1-ELP-TRTK peptide decreased S100B-induced oxidative damage to mutant ataxin-1-expressing neurons. To test the delivery capabilities of ELP-based therapeutic peptides to the cerebellum, we treated mice with fluorescently labeled Synb1-ELP and observed that thermal targeting enhanced peptide delivery to the cerebellum. Here, we have laid the framework for thermal-based therapeutic targeting to regions of the brain, particularly the cerebellum. Overall, our data suggest that thermal targeting of ELP-based therapeutic peptides to the cerebellum is a novel treatment strategy for cerebellar neurodegenerative disorders.
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Affiliation(s)
- S M Hearst
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, USA
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30
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Solodkin A, Peri E, Chen EE, Ben-Jacob E, Gomez CM. Loss of intrinsic organization of cerebellar networks in spinocerebellar ataxia type 1: correlates with disease severity and duration. CEREBELLUM (LONDON, ENGLAND) 2011; 10:218-32. [PMID: 20886327 PMCID: PMC3091958 DOI: 10.1007/s12311-010-0214-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of cerebellar degenerative disorders, characterized by progressive gait unsteadiness, hand incoordination, and dysarthria. The mutational mechanism in SCA1, a dominantly inherited form of SCA, consists of an expanded trinucleotide CAG repeat. In SCA1, there is loss of Purkinje cells, neuronal loss in dentate nucleus, olives, and pontine nuclei. In the present study, we sought to apply intrinsic functional connectivity analysis combined with diffusion tensor imaging to define the state of cerebellar connectivity in SCA1. Our results on the intrinsic functional connectivity in lateral cerebellum and thalamus showed progressive organizational changes in SCA1 noted as a progressive increase in the absolute value of the correlation coefficients. In the lateral cerebellum, the anatomical organization of functional clusters seen as parasagittal bands in controls is lost, changing to a patchy appearance in SCA1. Lastly, only fractional anisotropy in the superior peduncle and changes in functional organization in thalamus showed a linear dependence to duration and severity of disease. The present pilot work represents an initial effort describing connectivity biomarkers of disease progression in SCA1. The functional changes detected with intrinsic functional analysis and diffusion tensor imaging suggest that disease progression can be analyzed as a disconnection syndrome.
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Affiliation(s)
- Ana Solodkin
- Department of Neurology, MC 2030, The University of Chicago Hospitals, Chicago, IL, USA.
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31
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Marelli C, Cazeneuve C, Brice A, Stevanin G, Dürr A. Autosomal dominant cerebellar ataxias. Rev Neurol (Paris) 2011; 167:385-400. [PMID: 21546047 DOI: 10.1016/j.neurol.2011.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 01/27/2011] [Indexed: 12/30/2022]
Abstract
Cerebellar ataxias with autosomal dominant transmission (ADCA) are far rarer than sporadic cases of cerebellar ataxia. The identification of genes involved in dominant forms has confirmed the genetic heterogeneity of these conditions and of the underlying mechanisms and pathways. To date, at least 28 genetic loci and, among them, 20 genes have been identified. In many instances, the phenotype is not restricted to cerebellar dysfunction but includes more complex multisystemic neurological deficits. Seven ADCA (SCA1, 2, 3, 6, 7, 17, and dentatorubro-pallido-luysian atrophy) are caused by repeat expansions in the corresponding proteins; phenotype-genotype correlations have shown that repeat size influences the progression of the disease, its severity and clinical differences among patients, including the phenomenon of anticipation between generations. All other ADCA are caused either by non-coding repeat expansions, conventional mutations or large rearrangements in genes with different functions. This review will focus on the genetic features of ADCA and on the clinical differences among the different forms.
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Affiliation(s)
- C Marelli
- Département de génétique et cytogénétique, consultation de génétique clinique, CHU Pitié-Salpêtrière, AP-HP, 47, boulevard de l'Hôpital, 75013 Paris, France
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32
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Chen KA, Cruz PE, Lanuto DJ, Flotte TR, Borchelt DR, Srivastava A, Zhang J, Steindler DA, Zheng T. Cellular fusion for gene delivery to SCA1 affected Purkinje neurons. Mol Cell Neurosci 2011; 47:61-70. [PMID: 21420496 DOI: 10.1016/j.mcn.2011.03.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 03/03/2011] [Accepted: 03/04/2011] [Indexed: 01/10/2023] Open
Abstract
Cerebellar Purkinje neurons (PNs) possess a well characterized propensity to fuse with bone marrow-derived cells (BMDCs), producing heterokaryons with Purkinje cell identities. This offers the potential to rescue/repair at risk or degenerating PNs in the inherited ataxias, including Spinocerebellar Ataxia 1 (SCA1), by introducing therapeutic factors through BMDCs to potentially halt or reverse disease progression. In this study, we combined gene therapy and a stem cell-based treatment to attempt repair of at-risk PNs through cell-cell fusion in a Sca1(154Q/2Q) knock-in mouse model. BMDCs enriched for the hematopoietic stem cell (HSC) population were genetically modified using adeno-associated viral vector 7 (AAV7) to carry SCA1 modifier genes and transplanted into irradiated Sca1(154Q/2Q) mice. Binucleated Purkinje heterokaryons with sex-mismatched donor Y chromosomes were detected and successfully expressed the modifier genes in vivo. Potential effects of the new genome within Purkinje heterokaryons were evaluated using nuclear inclusions (NIs) as a biological marker to reflect possible modifications of the SCA1 disease process. An overall decrease in number of NIs and an increase in the number of surviving PNs were observed in treated Sca1(154Q/2Q). Furthermore, Bergmann glia were found to have fusogenic potential with the donor population and reveal another potential route of therapeutic entry into at-risk cells of the SCA1 cerebellum. This study presents a first step towards a proof-of-principle that combines somatic cellular fusion events with a neuroprotective gene therapy approach for providing potential neuronal protection/repair in a variety of neurodegenerative disorders.
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Affiliation(s)
- K Amy Chen
- Department of Neuroscience, The Evelyn F. and William L. McKnight Brain Institute of the University of Florida, USA
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33
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Abstract
The spinocerebellar ataxias (SCA) are a large group of inherited disorders affecting the cerebellum and its afferent and efferent pathways. Their hallmark symptom is slowly progressive, symmetrical, midline, and appendicular ataxia. Some may also have associated hyperkinetic movements (chorea, dystonia, myoclonus, postural/action tremor, restless legs, rubral tremor, tics), which may aid in differential diagnosis and provide treatable targets to improve performance and quality of life in these progressive, incurable conditions. The typical dominant ataxias with associated hyperkinetic movements are SCA1-3, 6-8, 12, 14, 15, 17, 19-21, and 27. The common recessive ataxias with associated hyperkinetic movements are ataxia telangiectasia and Friedreich's ataxia. Fragile X tremor-ataxia syndrome (FXTAS) and multiple-system atrophy (a sporadic ataxia which is felt to have a genetic substrate) also have hyperkinetic features. A careful work-up should be done in all apparently sporadic cases, to rule out acquired causes of ataxia, some of which can cause hyperkinetic movements in addition to ataxia. Some testing should be done even in individuals with a confirmed genetic cause, as the presence of a secondary factor (nutritional deficiency, thyroid dysfunction) can contribute to the phenotype.
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Affiliation(s)
- Susan L Perlman
- David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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Hearst SM, Lopez ME, Shao Q, Liu Y, Vig PJS. Dopamine D2 receptor signaling modulates mutant ataxin-1 S776 phosphorylation and aggregation. J Neurochem 2010; 114:706-16. [PMID: 20477910 PMCID: PMC2921766 DOI: 10.1111/j.1471-4159.2010.06791.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Spinocerebellar ataxia 1 (SCA1) is a dominantly inherited neurodegenerative disease associated with progressive ataxia resulting from the loss of cerebellar Purkinje cells (PCs) and neurons in the brainstem. In PCs of SCA1 transgenic mice, the disease causing ataxin-1 protein mediates the formation of S100B containing cytoplasmic vacuoles and further self-aggregates to form intranuclear inclusions. The exact function of the ataxin-1 protein is not fully understood. However, the aggregation and neurotoxicity of the mutant ataxin-1 protein is dependent on the phosphorylation at serine 776 (S776). Although protein kinase A (PKA) has been implicated as the S776 kinase, the mechanism of PKA/ataxin-1 regulation in SCA1 is still not clear. We propose that a dopamine D(2) receptor (D2R)/S100B pathway may be involved in modulating PKA activity in PCs. Using a D2R/S100B HEK stable cell line transiently transfected with GFP-ataxin-1[82Q], we demonstrate that stimulation of the D2R/S100B pathway caused a reduction in mutant ataxin-1 S776 phosphorylation and ataxin-1 aggregation. Activation of PKA by forskolin resulted in an enhanced S776 phosphorylation and increased ataxin-1 nuclear aggregation, which was suppressed by treatment with D2R agonist bromocriptine and PKA inhibitor H89. Furthermore, treating SCA1 transgenic PC slice cultures with forskolin induced neurodegenerative morphological abnormalities in PC dendrites consistent with those observed in vivo. Taken together our data support a mechanism where PKA dependent mutant ataxin-1 phosphorylation and aggregation can be regulated by D2R/S100B signaling.
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Affiliation(s)
- SM Hearst
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS
| | - ME Lopez
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS
| | - Q Shao
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS
| | - Y Liu
- Department of Behavioral Neuroscience, Oregon Health & Science University and Portland Veterans Affairs Medical Center, Portland, OR
| | - PJS Vig
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS
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Zhang C, Browne A, Child D, Divito JR, Stevenson JA, Tanzi RE. Loss of function of ATXN1 increases amyloid beta-protein levels by potentiating beta-secretase processing of beta-amyloid precursor protein. J Biol Chem 2010; 285:8515-26. [PMID: 20097758 DOI: 10.1074/jbc.m109.079079] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alzheimer disease (AD) is a devastating neurodegenerative disease with complex and strong genetic inheritance. Four genes have been established to either cause familial early onset AD (APP, PSEN1, and PSEN2) or to increase susceptibility for late onset AD (APOE). To date approximately 80% of the late onset AD genetic variance remains elusive. Recently our genome-wide association screen identified four novel late onset AD candidate genes. Ataxin 1 (ATXN1) is one of these four AD candidate genes and has been indicated to be the disease gene for spinocerebellar ataxia type 1, which is also a neurodegenerative disease. Mounting evidence suggests that the excessive accumulation of Abeta, the proteolytic product of beta-amyloid precursor protein (APP), is the primary AD pathological event. In this study, we ask whether ATXN1 may lead to AD pathogenesis by affecting Abeta and APP processing utilizing RNA interference in a human neuronal cell model and mouse primary cortical neurons. We show that knock-down of ATXN1 significantly increases the levels of both Abeta40 and Abeta42. This effect could be rescued with concurrent overexpression of ATXN1. Moreover, overexpression of ATXN1 decreased Abeta levels. Regarding the underlying molecular mechanism, we show that the effect of ATXN1 expression on Abeta levels is modulated via beta-secretase cleavage of APP. Taken together, ATXN1 functions as a genetic risk modifier that contributes to AD pathogenesis through a loss-of-function mechanism by regulating beta-secretase cleavage of APP and Abeta levels.
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Affiliation(s)
- Can Zhang
- Department of Neurology, Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129-2060, USA
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Animal models of human cerebellar ataxias: a cornerstone for the therapies of the twenty-first century. THE CEREBELLUM 2009; 8:137-54. [PMID: 19669387 DOI: 10.1007/s12311-009-0127-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cerebellar ataxias represent a group of disabling neurological disorders. Our understanding of the pathogenesis of cerebellar ataxias is continuously expanding. A considerable number of laboratory animals with neurological mutations have been reported and numerous relevant animal models mimicking the phenotype of cerebellar ataxias are becoming available. These models greatly help dissecting the numerous mechanisms of cerebellar dysfunction, a major step for the assessment of therapeutics targeting a given deleterious pathway and for the screening of old or newly synthesized chemical compounds. Nevertheless, differences between animal models and human disorders should not be overlooked and difficulties in terms of characterization should not be occulted. The identification of the mutations of many hereditary ataxias, the development of valuable animal models, and the recent identifications of the molecular mechanisms underlying cerebellar disorders represent a combination of key factors for the development of anti-ataxic innovative therapies. It is anticipated that the twenty-first century will be the century of effective therapies in the field of cerebellar ataxias. The animal models are a cornerstone to reach this goal.
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Bains M, Florez-McClure ML, Heidenreich KA. Insulin-like growth factor-I prevents the accumulation of autophagic vesicles and cell death in Purkinje neurons by increasing the rate of autophagosome-to-lysosome fusion and degradation. J Biol Chem 2009; 284:20398-407. [PMID: 19509289 PMCID: PMC2740464 DOI: 10.1074/jbc.m109.011791] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 06/02/2009] [Indexed: 01/02/2023] Open
Abstract
Continuous macroautophagic activity is critical for the maintenance of neuronal homeostasis; however, unchecked or dysregulated autophagy can lead to cell death. Cultured Purkinje neurons die by an autophagy-associated cell death mechanism when deprived of trophic support. Here, we report that insulin-like growth factor-I (IGF-I) completely blocked the autophagy-associated cell death of Purkinje neurons. To examine the mechanism by which IGF-I influences autophagy, neurons were infected with adeno-RFP-LC3 and subjected to trophic factor withdrawal, and the size and number of autophagosomes were analyzed by live-cell fluorescence imaging. In control neurons, autophagy occurred at a constitutive low level with most autophagosomes measuring less than 0.75 microm. Trophic factor withdrawal increased the number and size of autophagosomes with most autophagosomes ranging between 0.75 and 1.5 microm and some reaching 1.5-2.25 microm. IGF-I added at the time of trophic factor withdrawal prevented the accumulation of the larger autophagosomes; however, it had no effect on the conversion of LC3, an indicator of autophagy induction. Instead, the rate of autophagosome-to-lysosome fusion measured by colocalization of RFP-LC3 and LysoSensor Green was accelerated by IGF-I. Treating the neurons with bafilomycin A(1) in the presence of IGF-I led to the accumulation of autophagosomes even larger than those induced by trophic factor withdrawal alone, indicating that IGF-I regulates autophagic vesicle turnover. Finally, the effect of IGF-I on autophagy was mediated by an Akt/mTOR-de pend ent and an ERK-independent pathway. These data suggest a novel role for IGF-I in protecting Purkinje neurons from autophagy-associated cell death by increasing autophagy efficiency downstream of autophagy induction.
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Affiliation(s)
- Mona Bains
- From the Department of Pharmacology, University of Colorado Denver, Aurora, Colorado 80045
| | - Maria L. Florez-McClure
- Neuroscience Research, Discovery Martek Biosciences Corporation, Boulder, Colorado 80301, and
| | - Kim A. Heidenreich
- From the Department of Pharmacology, University of Colorado Denver, Aurora, Colorado 80045
- the Denver Veterans Affairs Medical Center, Denver, Colorado 80262
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Vig PJS, Shao Q, Subramony SH, Lopez ME, Safaya E. Bergmann glial S100B activates myo-inositol monophosphatase 1 and Co-localizes to purkinje cell vacuoles in SCA1 transgenic mice. THE CEREBELLUM 2009; 8:231-44. [PMID: 19593677 DOI: 10.1007/s12311-009-0125-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 06/19/2009] [Indexed: 12/13/2022]
Abstract
Spinocerebellar ataxia-1 (SCA1) is a late onset neurodegenerative disease caused by the expansion of a polyglutamine repeat within ataxin-1 protein. The toxic effects triggered by mutant ataxin-1 result in degeneration of the neurons in cerebellum, brain stem and spinocerebellar tracts. The targeted overexpression of mutant ataxin-1 in cerebellar Purkinje cells (PCs) of the SCA1 transgenic mice results in the formation of cytoplasmic vacuoles in PCs. These vacuoles appear early on before the onset of behavioral abnormalities. Interestingly, we found that vacoules contain S100B and vimentin proteins, which normally localize to neighboring Bergmann glia (BG). Further, immunohistochemical and specialized silver stain analysis revealed that vacuolar formation is associated with alterations in the morphology of dendritic spines of PCs. To gain insights into the mechanisms of vacuolar formation, we investigated if vacuoles in SCA1 PCs have an autophagic origin or are a consequence of some other event. We examined the expression levels (by Western blotting) of microtubule-associated protein light chain 3 (LC3)-I and LC3-II, and the degradation levels of p62 (a LC3 partner) in the cerebellar fractions prepared from pre-symptomatic SCA1 and age-matched wild-type mice. No p62 degradation was observed; however, LC3-II/(LC3-I + LC3-II) ratios were significantly altered in SCA1 mice indicating changes in the autophagic flux. In addition, LC3 localized to PC vacuoles. Further, we observed a co-localization of myo-inositol monophosphatase 1 (IMPA1) with S100B in PC vacuoles. IMPA1 is present in PC spines and has been implicated in autophagy. In vitro studies using purified IMPA1 and S100B demonstrated that S100B interacted with and activated IMPA1. Both apo and Ca(2+)-bound S100B were found to activate IMPA1, depending on substrate concentration. IMPA1 is regulated by another calcium-binding protein calbindin-D28k (CaB), since we reported earlier that the CaB levels are reduced in SCA1 PCs, the activation of IMPA1 by S100B may modulate CaB-dependent inositol signaling. This may cause BG-PC interface to degenerate resulting in vacuolar formation. In sum, these data indicate that vacuoles appearing early in SCA1 PCs could be developing through some unknown autophagic mechanism.
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Affiliation(s)
- Parminder J S Vig
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS 39216, USA.
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Ferraguti F, Crepaldi L, Nicoletti F. Metabotropic glutamate 1 receptor: current concepts and perspectives. Pharmacol Rev 2009; 60:536-81. [PMID: 19112153 DOI: 10.1124/pr.108.000166] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Almost 25 years after the first report that glutamate can activate receptors coupled to heterotrimeric G-proteins, tremendous progress has been made in the field of metabotropic glutamate receptors. Now, eight members of this family of glutamate receptors, encoded by eight different genes that share distinctive structural features have been identified. The first cloned receptor, the metabotropic glutamate (mGlu) receptor mGlu1 has probably been the most extensively studied mGlu receptor, and in many respects it represents a prototypical subtype for this family of receptors. Its biochemical, anatomical, physiological, and pharmacological characteristics have been intensely investigated. Together with subtype 5, mGlu1 receptors constitute a subgroup of receptors that couple to phospholipase C and mobilize Ca(2+) from intracellular stores. Several alternatively spliced variants of mGlu1 receptors, which differ primarily in the length of their C-terminal domain and anatomical localization, have been reported. Use of a number of genetic approaches and the recent development of selective antagonists have provided a means for clarifying the role played by this receptor in a number of neuronal systems. In this article we discuss recent advancements in the pharmacology and concepts about the intracellular transduction and pathophysiological role of mGlu1 receptors and review earlier data in view of these novel findings. The impact that this new and better understanding of the specific role of these receptors may have on novel treatment strategies for a variety of neurological and psychiatric disorders is considered.
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Affiliation(s)
- Francesco Ferraguti
- Department of Pharmacology, Innsbruck Medical University, Peter-Mayr Strasse 1a, Innsbruck A-6020, Austria.
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Intracellular degradation of misfolded proteins in polyglutamine neurodegenerative diseases. ACTA ACUST UNITED AC 2008; 59:245-52. [PMID: 18773920 DOI: 10.1016/j.brainresrev.2008.08.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2008] [Revised: 08/15/2008] [Accepted: 08/17/2008] [Indexed: 01/15/2023]
Abstract
A number of neurodegenerative diseases, including Alzheimer's, Parkinson's, and polyglutamine diseases, are characterized by the age-dependent formation of intracellular protein aggregates and neurodegeneration. Although there is some debate surrounding the role of these aggregates in neurotoxicity, the formation of aggregates is known to reflect the accumulation of misfolded and toxic proteins. The degradation of misfolded proteins occurs mainly via the ubiquitin-proteasome and autophagy pathways. In neuronal cells, polyglutamine protein inclusions are present predominantly in the nucleus, which is not accessible to autophagy. It remains unclear how the ubiquitin-proteasomal and autophagy pathways remove misfolded proteins in the different subcellular regions of neurons, where disease proteins become misfolded and aggregated in an age-dependent manner. Here we discuss the key findings to date about the roles of the ubiquitin-proteasome system and autophagy in polyglutamine diseases. Understanding how these two pathways function to clear mutant polyglutamine proteins will further the development of effective treatments for polyglutamine and other neurodegenerative diseases.
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41
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Abstract
G-protein-coupled receptors (GPCR) are the largest family of receptors with over 500 members. Evaluation of GPCR gene expression in primary human tumors identified over-expression of GPCR in several tumor types. Analysis of cancer samples in different disease stages also suggests that some GPCR may be involved in early tumor progression and others may play a critical role in tumor invasion and metastasis. Currently, >50% of drug targets to various human diseases are based on GPCR. In this review, the relationships between several GPCR and melanoma development and/or progression will be discussed. Finally, the possibility of using one or more of these GPCR as therapeutic targets in melanoma will be summarized.
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Affiliation(s)
- Hwa Jin Lee
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
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42
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Activation of mutant protein kinase Cgamma leads to aberrant sequestration and impairment of its cellular function. Biochem Biophys Res Commun 2008; 372:447-53. [PMID: 18503760 DOI: 10.1016/j.bbrc.2008.05.072] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Accepted: 05/11/2008] [Indexed: 11/21/2022]
Abstract
Mutations in protein kinase Cgamma (PKCgamma) cause the neurodegenerative disease spinocerebellar ataxia type 14 (SCA14). In this study, expression of an extensive panel of known SCA14-associated PKCgamma mutations as fusion proteins in cell culture led to the consistent formation of cytoplasmic aggregates in response to purinoceptor stimulation. Aggregates co-stained with antibodies to phosphorylated PKCgamma and the early endosome marker EEA1 but failed to redistribute to the cell membrane under conditions of oxidative stress. These studies suggest that Purkinje cell damage in SCA14 may result from a reduction of PKCgamma activity due its aberrant sequestration in the early endosome compartment.
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Tsirigotis M, Baldwin RM, Tang MY, Lorimer IAJ, Gray DA. Activation of p38MAPK contributes to expanded polyglutamine-induced cytotoxicity. PLoS One 2008; 3:e2130. [PMID: 18461158 PMCID: PMC2330164 DOI: 10.1371/journal.pone.0002130] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 03/27/2008] [Indexed: 01/30/2023] Open
Abstract
Background The signaling pathways that may modulate the pathogenesis of diseases induced by expanded polyglutamine proteins are not well understood. Methodologies/Principal Findings Herein we demonstrate that expanded polyglutamine protein cytotoxicity is mediated primarily through activation of p38MAPK and that the atypical PKC iota (PKCι) enzyme antagonizes polyglutamine-induced cell death through induction of the ERK signaling pathway. We show that pharmacological blockade of p38MAPK rescues cells from polyglutamine-induced cell death whereas inhibition of ERK recapitulates the sensitivity observed in cells depleted of PKCι by RNA interference. We provide evidence that two unrelated proteins with expanded polyglutamine repeats induce p38MAPK in cultured cells, and demonstrate induction of p38MAPK in an in vivo model of neurodegeneration (spinocerebellar ataxia 1, or SCA-1). Conclusions/Significance Taken together, our data implicate activated p38MAPK in disease progression and suggest that its inhibition may represent a rational strategy for therapeutic intervention in the polyglutamine disorders.
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Affiliation(s)
- Maria Tsirigotis
- Centre for Cancer Therapeutics, Ottawa Health Research Institute, Ottawa, Ontario, Canada
| | - R. Mitchell Baldwin
- Centre for Cancer Therapeutics, Ottawa Health Research Institute, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Matthew Y. Tang
- Centre for Cancer Therapeutics, Ottawa Health Research Institute, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Ian A. J. Lorimer
- Centre for Cancer Therapeutics, Ottawa Health Research Institute, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Douglas A. Gray
- Centre for Cancer Therapeutics, Ottawa Health Research Institute, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
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Matilla-Dueñas A, Goold R, Giunti P. Clinical, genetic, molecular, and pathophysiological insights into spinocerebellar ataxia type 1. THE CEREBELLUM 2008; 7:106-14. [DOI: 10.1007/s12311-008-0009-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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45
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McCray BA, Taylor JP. The role of autophagy in age-related neurodegeneration. Neurosignals 2007; 16:75-84. [PMID: 18097162 DOI: 10.1159/000109761] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Most age-related neurodegenerative diseases are characterized by accumulation of aberrant protein aggregates in affected brain regions. In many cases, these proteinaceous deposits are composed of ubiquitin conjugates, suggesting a failure in the clearance of proteins targeted for degradation. The 2 principal routes of intracellular protein catabolism are the ubiquitin proteasome system and the autophagy-lysosome system (autophagy). Both of these degradation pathways have been implicated as playing important roles in the pathogenesis of neurodegenerative disease. Here we describe autophagy and review the evidence suggesting that impairment of autophagy contributes to the initiation or progression of age-related neurodegeneration. We also review recent evidence indicating that autophagy may be exploited to remove toxic protein species, suggesting novel strategies for therapeutic intervention for a class of diseases for which no effective treatments presently exist.
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Affiliation(s)
- Brett A McCray
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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46
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Jorgensen ND, Andresen JM, Pitt JE, Swenson MA, Zoghbi HY, Orr HT. Hsp70/Hsc70 regulates the effect phosphorylation has on stabilizing ataxin-1. J Neurochem 2007; 102:2040-2048. [PMID: 17540008 DOI: 10.1111/j.1471-4159.2007.04678.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Spinocerebellar ataxia type 1 (SCA1) is an inherited neurodegenerative disorder. The mutation causing SCA1 is an expansion in the polyglutamine tract of the ATXN1 protein. Previous work demonstrated that phosphorylation of mutant ATXN1 at serine 776 (S776), a putative Akt phosphorylation site, is critical for pathogenesis. To examine this pathway further, we utilized a cell-transfection system that allowed the targeting of Akt to either the cytoplasm or the nucleus. In contrast to HeLa cells, we found that Akt targeted to the cytoplasm increased the degradation of ATXN1 in Chinese hamster ovary cells. However, Akt targeted to the cytoplasm failed to destabilize ATXN1 if Hsp70/Hsc70 was present. Thus, Hsp70/Hsc70 can regulate ATXN1 levels in concert with phosphorylation of ATXN1 at S776.
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Affiliation(s)
- Nathan D Jorgensen
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, USAInstitute of Human Genetics, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USAHoward Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, USA
| | - J Michael Andresen
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, USAInstitute of Human Genetics, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USAHoward Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, USA
| | - Jason E Pitt
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, USAInstitute of Human Genetics, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USAHoward Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, USA
| | - Melissa A Swenson
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, USAInstitute of Human Genetics, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USAHoward Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, USA
| | - Huda Y Zoghbi
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, USAInstitute of Human Genetics, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USAHoward Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, USA
| | - Harry T Orr
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, USAInstitute of Human Genetics, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USAHoward Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, USA
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47
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Latouche M, Lasbleiz C, Martin E, Monnier V, Debeir T, Mouatt-Prigent A, Muriel MP, Morel L, Ruberg M, Brice A, Stevanin G, Tricoire H. A conditional pan-neuronal Drosophila model of spinocerebellar ataxia 7 with a reversible adult phenotype suitable for identifying modifier genes. J Neurosci 2007; 27:2483-92. [PMID: 17344386 PMCID: PMC6672519 DOI: 10.1523/jneurosci.5453-06.2007] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Spinocerebellar ataxia 7 (SCA7) is a neurodegenerative disease caused by a polyglutamine (polyQ) expansion in the ataxin 7 (ATXN7) protein, a member of a multiprotein complex involved in histone acetylation. We have created a conditional Drosophila model of SCA7 in which expression of truncated ATXN7 (ATXN7T) with a pathogenic polyQ expansion is induced in neurons in adult flies. In this model, mutant ATXN7T accumulated in neuronal intranuclear inclusions containing ubiquitin, the 19S proteasome subunit, and HSP70 (heat shock protein 70), as in patients. Aggregation was accompanied by a decrease in locomotion and lifespan but limited neuronal death. Disaggregation of the inclusions, when expression of expanded ATXN7T was stopped, correlated with improved locomotor function and increased lifespan, suggesting that the pathology may respond to treatment. Lifespan was then used as a quantitative marker in a candidate gene approach to validate the interest of the model and to identify generic modulators of polyQ toxicity and specific modifiers of SCA7. Several molecular pathways identified in this focused screen (proteasome function, unfolded protein stress, caspase-dependent apoptosis, and histone acetylation) were further studied in primary neuronal cultures. Sodium butyrate, a histone deacetylase inhibitor, improved the survival time of the neurons. This model is therefore a powerful tool for studying SCA7 and for the development of potential therapies for polyQ diseases.
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Affiliation(s)
- Morwena Latouche
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Christelle Lasbleiz
- Centre National de la Rechereche Scientifique, UMR 7592, Insititut Jacques Monod, Campus Universitaire de Jussieu, Paris F-75251, France, and
| | - Elodie Martin
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Véronique Monnier
- Centre National de la Rechereche Scientifique, UMR 7592, Insititut Jacques Monod, Campus Universitaire de Jussieu, Paris F-75251, France, and
| | - Thomas Debeir
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Annick Mouatt-Prigent
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Marie-Paule Muriel
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Lydie Morel
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
| | - Merle Ruberg
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Alexis Brice
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
- Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Départment de Génétique, Cytogénétique, et Embryologie, Paris F-75013, France
| | - Giovanni Stevanin
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
- Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Départment de Génétique, Cytogénétique, et Embryologie, Paris F-75013, France
| | - Hérvé Tricoire
- Centre National de la Rechereche Scientifique, UMR 7592, Insititut Jacques Monod, Campus Universitaire de Jussieu, Paris F-75251, France, and
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Sikora J, Harzer K, Elleder M. Neurolysosomal pathology in human prosaposin deficiency suggests essential neurotrophic function of prosaposin. Acta Neuropathol 2007; 113:163-75. [PMID: 17024494 PMCID: PMC2956888 DOI: 10.1007/s00401-006-0148-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 08/15/2006] [Accepted: 08/29/2006] [Indexed: 01/27/2023]
Abstract
A neuropathologic study of three cases of prosaposin (pSap) deficiency (ages at death 27, 89 and 119 days), carried out in the standard autopsy tissues, revealed a neurolysosomal pathology different from that in the non-neuronal cells. Non-neuronal storage is represented by massive lysosomal accumulation of glycosphingolipids (glucosyl-, galactosyl-, lactosyl-, globotriaosylceramides, sulphatide, and ceramide). The lysosomes in the central and peripheral neurons were distended by pleomorphic non-lipid aggregates lacking specific staining and autofluorescence. Lipid storage was borderline in case 1, and at a low level in the other cases. Neurolysosomal storage was associated with massive ubiquitination, which was absent in the non-neuronal cells and which did not display any immunohistochemical aggresomal properties. Confocal microscopy and cross-correlation function analyses revealed a positive correlation between the ubiquitin signal and the late endosomal/lysosomal markers. We suppose that the neuropathology most probably reflects excessive influx of non-lipid material (either in bulk or as individual molecules) into the neurolysosomes. The cortical neurons appeared to be uniquely vulnerable to pSap deficiency. Whereas in case 1 they populated the cortex, in cases 2 and 3 they had been replaced by dense populations of both phagocytic microglia and astrocytes. We suggest that this massive neuronal loss reflects a cortical neuronal survival crisis precipitated by the lack of pSap. The results of our study may extend the knowledge of the neurotrophic function of pSap, which should be considered essential for the survival and maintenance of human cortical neurons.
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Affiliation(s)
- Jakub Sikora
- Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University and General Teaching Hospital, Ke Karlovu 2, Prague 2, 12808 Czech Republic
| | - Klaus Harzer
- Neurometabolic Laboratory, Department of Pediatrics and Child Development (Universitäts-Kinderklinik), University of Tübingen, Tübingen, 72076 Germany
| | - Milan Elleder
- Institute of Inherited Metabolic Disorders, 1st Faculty of Medicine, Charles University and General Teaching Hospital, Ke Karlovu 2, Prague 2, 12808 Czech Republic
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Sabater L, Bataller L, Carpentier AF, Aguirre-Cruz ML, Saiz A, Benyahia B, Dalmau J, Graus F. Protein kinase Cgamma autoimmunity in paraneoplastic cerebellar degeneration and non-small-cell lung cancer. J Neurol Neurosurg Psychiatry 2006; 77:1359-62. [PMID: 16801349 PMCID: PMC2077410 DOI: 10.1136/jnnp.2006.097188] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND The clinical and immunological profiles of patients with paraneoplastic cerebellar degeneration (PCD) and non-small-cell lung cancer (NSCLC) are not well known. OBJECTIVE To review the clinical and immunological features of patients with PCD, NSCLC and without well-characterised onconeural antibodies. METHODS The clinical features of nine patients with the diagnosis of classical PCD and NSCLC, included in our archives, were retrospectively reviewed. The presence of antibodies to cerebellar components was determined by immunohistochemistry and immunoblot of rat cerebellum. A cDNA library of human cerebellum was screened with the positive sera to identify the antigen. RESULTS Nine patients with PCD and NSCLC were identified. Six patients were men, and the median age at diagnosis of PCD was 63 (range 47-73) years. PCD was completely reversed in two patients, and partially in one, after treatment of the tumour. The serum of one of the patients with PCD showed a unique reactivity with Purkinje cells. The screening of a cerebellar-expression library resulted in the isolation of protein kinase Cgamma (PKCgamma). PKCgamma immunoreactivity was not observed in the serum of 170 patients with non-paraneoplastic neurological syndromes, 27 patients with PCD, no onconeural antibodies and small-cell lung cancer, and 52 patients with NSCLC without paraneoplastic neurological syndromes. The NSCLC from 11 patients without PCD did not express PKCgamma at either the RNA or protein level. However, many cells of the NSCLC of the patient with PKCgamma antibodies expressed PKCgamma. CONCLUSION PCD occurs in patients with NSCLC without typical onconeural antibodies and is associated with immune reactions against key proteins of the Purkinje cells.
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Affiliation(s)
- L Sabater
- Service of Neurology, Hospital Clinic, and Institut d' Investigació Biomèdica August Pi i Sunyer, Barcelona, Spain
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50
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Abstract
Antibodies as diagnostic markers of ataxia
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