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Hörner M, Groh J, Klein D, Ilg W, Schöls L, Santos SD, Bergmann A, Klebe S, Cauhape M, Branchu J, El Hachimi KH, Stevanin G, Darios F, Martini R. CNS-associated T-lymphocytes in a mouse model of Hereditary Spastic Paraplegia type 11 (SPG11) are therapeutic targets for established immunomodulators. Exp Neurol 2022; 355:114119. [DOI: 10.1016/j.expneurol.2022.114119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 11/04/2022]
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2
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Basu S, Nandy A, Biswas D. Keeping RNA polymerase II on the run: Functions of MLL fusion partners in transcriptional regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194563. [PMID: 32348849 DOI: 10.1016/j.bbagrm.2020.194563] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/13/2020] [Accepted: 04/13/2020] [Indexed: 12/21/2022]
Abstract
Since the identification of key MLL fusion partners as transcription elongation factors regulating expression of HOX cluster genes during hematopoiesis, extensive work from the last decade has resulted in significant progress in our overall mechanistic understanding of role of MLL fusion partner proteins in transcriptional regulation of diverse set of genes beyond just the HOX cluster. In this review, we are going to detail overall understanding of role of MLL fusion partner proteins in transcriptional regulation and thus provide mechanistic insights into possible MLL fusion protein-mediated transcriptional misregulation leading to aberrant hematopoiesis and leukemogenesis.
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Affiliation(s)
- Subham Basu
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India
| | - Arijit Nandy
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India.
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3
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Gstrein T, Edwards A, Přistoupilová A, Leca I, Breuss M, Pilat-Carotta S, Hansen AH, Tripathy R, Traunbauer AK, Hochstoeger T, Rosoklija G, Repic M, Landler L, Stránecký V, Dürnberger G, Keane TM, Zuber J, Adams DJ, Flint J, Honzik T, Gut M, Beltran S, Mechtler K, Sherr E, Kmoch S, Gut I, Keays DA. Mutations in Vps15 perturb neuronal migration in mice and are associated with neurodevelopmental disease in humans. Nat Neurosci 2018; 21:207-217. [PMID: 29311744 PMCID: PMC5897053 DOI: 10.1038/s41593-017-0053-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/22/2017] [Indexed: 01/31/2023]
Abstract
The formation of the vertebrate brain requires the generation, migration, differentiation and survival of neurons. Genetic mutations that perturb these critical cellular events can result in malformations of the telencephalon, providing a molecular window into brain development. Here we report the identification of an N-ethyl-N-nitrosourea-induced mouse mutant characterized by a fractured hippocampal pyramidal cell layer, attributable to defects in neuronal migration. We show that this is caused by a hypomorphic mutation in Vps15 that perturbs endosomal-lysosomal trafficking and autophagy, resulting in an upregulation of Nischarin, which inhibits Pak1 signaling. The complete ablation of Vps15 results in the accumulation of autophagic substrates, the induction of apoptosis and severe cortical atrophy. Finally, we report that mutations in VPS15 are associated with cortical atrophy and epilepsy in humans. These data highlight the importance of the Vps15-Vps34 complex and the Nischarin-Pak1 signaling hub in the development of the telencephalon.
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Affiliation(s)
- Thomas Gstrein
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Andrew Edwards
- Wellcome Trust Center for Human Genetics (WTCHG), Oxford, UK
| | - Anna Přistoupilová
- Institute of Inherited Metabolic Disorders, Charles University, Prague, Czech Republic
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Ines Leca
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Martin Breuss
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | | | - Andi H Hansen
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Ratna Tripathy
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Anna K Traunbauer
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Tobias Hochstoeger
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Gavril Rosoklija
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Marco Repic
- Institute for Molecular Biotechnology (IMBA), Vienna, Austria
| | - Lukas Landler
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Viktor Stránecký
- Institute of Inherited Metabolic Disorders, Charles University, Prague, Czech Republic
| | - Gerhard Dürnberger
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Thomas M Keane
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Johannes Zuber
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - David J Adams
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Jonathan Flint
- Wellcome Trust Center for Human Genetics (WTCHG), Oxford, UK
| | - Tomas Honzik
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Marta Gut
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Sergi Beltran
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Karl Mechtler
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Elliott Sherr
- Institute of Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Stanislav Kmoch
- Institute of Inherited Metabolic Disorders, Charles University, Prague, Czech Republic
| | - Ivo Gut
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - David A Keays
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria.
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4
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Breuss MW, Hansen AH, Landler L, Keays DA. Brain-specific knockin of the pathogenic Tubb5 E401K allele causes defects in motor coordination and prepulse inhibition. Behav Brain Res 2017; 323:47-55. [PMID: 28130172 DOI: 10.1016/j.bbr.2017.01.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/11/2017] [Accepted: 01/17/2017] [Indexed: 01/24/2023]
Abstract
The generation, migration, and differentiation of neurons requires the functional integrity of the microtubule cytoskeleton. Mutations in the tubulin gene family are known to cause various neurological diseases including lissencephaly, ocular motor disorders, polymicrogyria and amyotrophic lateral sclerosis. We have previously reported that mutations in TUBB5 cause microcephaly that is accompanied by severe intellectual impairment and motor delay. Here we present the characterization of a Tubb5 mouse model that allows for the conditional expression of the pathogenic E401K mutation. Homozygous knockin animals exhibit a severe reduction in brain size and in body weight. These animals do not show any significant impairment in general activity, anxiety, or in the acoustic startle response, however, present with notable defects in motor coordination. When assessed on the static rod apparatus mice took longer to orient and often lost their balance completely. Interestingly, mutant animals also showed defects in prepulse inhibition, a phenotype associated with sensorimotor gating and considered an endophenotype for schizophrenia. This study provides insight into the behavioral consequences of tubulin gene mutations.
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Affiliation(s)
- Martin W Breuss
- IMP, Research Institute of Molecular Pathology, Vienna 1030, Austria.
| | - Andi H Hansen
- IMP, Research Institute of Molecular Pathology, Vienna 1030, Austria
| | - Lukas Landler
- IMP, Research Institute of Molecular Pathology, Vienna 1030, Austria
| | - David A Keays
- IMP, Research Institute of Molecular Pathology, Vienna 1030, Austria.
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5
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6
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Increased gait variability in mice with small cerebellar cortex lesions and normal rotarod performance. Behav Brain Res 2013; 241:32-7. [DOI: 10.1016/j.bbr.2012.11.034] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 11/22/2012] [Accepted: 11/24/2012] [Indexed: 02/05/2023]
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7
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Goyenvalle A, Babbs A, Wright J, Wilkins V, Powell D, Garcia L, Davies KE. Rescue of severely affected dystrophin/utrophin-deficient mice through scAAV-U7snRNA-mediated exon skipping. Hum Mol Genet 2012; 21:2559-71. [PMID: 22388933 PMCID: PMC3349427 DOI: 10.1093/hmg/dds082] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe neuromuscular disorder caused by mutations in the dystrophin gene that result in the absence of functional protein. Antisense-mediated exon skipping is one of the most promising approaches for the treatment of DMD and recent clinical trials have demonstrated encouraging results. However, antisense oligonucleotide-mediated exon skipping for DMD still faces major hurdles such as extremely low efficacy in the cardiac muscle, poor cellular uptake and relatively rapid clearance from circulation, which means that repeated administrations are required to achieve some therapeutic efficacy. To overcome these limitations, we previously proposed the use of small nuclear RNAs (snRNAs), especially U7snRNA to shuttle the antisense sequences after vectorization into adeno-associated virus (AAV) vectors. In this study, we report for the first time the efficiency of the AAV-mediated exon skipping approach in the utrophin/dystrophin double-knockout (dKO) mouse which is a very severe and progressive mouse model of DMD. Following a single intravenous injection of scAAV9-U7ex23 in dKO mice, near-normal levels of dystrophin expression were restored in all muscles examined, including the heart. This resulted in a considerable improvement of their muscle function and dystrophic pathology as well as a remarkable extension of the dKO mice lifespan. These findings suggest great potential for AAV-U7 in systemic treatment of the DMD phenotype.
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Affiliation(s)
- Aurélie Goyenvalle
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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Maity B, Stewart A, Yang J, Loo L, Sheff D, Shepherd AJ, Mohapatra DP, Fisher RA. Regulator of G protein signaling 6 (RGS6) protein ensures coordination of motor movement by modulating GABAB receptor signaling. J Biol Chem 2011; 287:4972-81. [PMID: 22179605 DOI: 10.1074/jbc.m111.297218] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
γ-Aminobutyric acid (GABA) release from inhibitory interneurons located within the cerebellar cortex limits the extent of neuronal excitation in part through activation of metabotropic GABA(B) receptors. Stimulation of these receptors triggers a number of downstream signaling events, including activation of GIRK channels by the Gβγ dimer resulting in membrane hyperpolarization and inhibition of neurotransmitter release from presynaptic sites. Here, we identify RGS6, a member of the R7 subfamily of RGS proteins, as a key regulator of GABA(B)R signaling in cerebellum. RGS6 is enriched in the granule cell layer of the cerebellum along with neuronal GIRK channel subunits 1 and 2 where RGS6 forms a complex with known binding partners Gβ(5) and R7BP. Mice lacking RGS6 exhibit abnormal gait and ataxia characterized by impaired rotarod performance improved by treatment with a GABA(B)R antagonist. RGS6(-/-) mice administered baclofen also showed exaggerated motor coordination deficits compared with their wild-type counterparts. Isolated cerebellar neurons natively expressed RGS6, GABA(B)R, and GIRK channel subunits, and cerebellar granule neurons from RGS6(-/-) mice showed a significant delay in the deactivation kinetics of baclofen-induced GIRK channel currents. These results establish RGS6 as a key component of GABA(B)R signaling and represent the first demonstration of an essential role for modulatory actions of RGS proteins in adult cerebellum. Dysregulation of RGS6 expression in human patients could potentially contribute to loss of motor coordination and, thus, pharmacological manipulation of RGS6 levels might represent a viable means to treat patients with ataxias of cerebellar origin.
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Affiliation(s)
- Biswanath Maity
- Department of Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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9
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Faldini E, Stroobants S, Lüllmann-Rauch R, Eckhardt M, Gieselmann V, Balschun D, D’Hooge R. Telencephalic histopathology and changes in behavioural and neural plasticity in a murine model for metachromatic leukodystrophy. Behav Brain Res 2011; 222:309-14. [DOI: 10.1016/j.bbr.2011.03.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 03/24/2011] [Accepted: 03/27/2011] [Indexed: 11/16/2022]
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Wang L, Nomura M, Goto Y, Tanaka K, Sakamoto R, Abe I, Sakamoto S, Shibata A, Enciso PLM, Adachi M, Ohnaka K, Kawate H, Takayanagi R. Smad2 protein disruption in the central nervous system leads to aberrant cerebellar development and early postnatal ataxia in mice. J Biol Chem 2011; 286:18766-74. [PMID: 21464123 DOI: 10.1074/jbc.m111.223271] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Smad2 is a critical mediator of TGF-β signals that are known to play an important role in a wide range of biological processes in various cell types. Its role in the development of the CNS, however, is largely unknown. Mice lacking Smad2 in the CNS (Smad2-CNS-KO) were generated by a Cre-loxP approach. These mice exhibited behavioral abnormalities in motor coordination from an early postnatal stage and mortality at approximately 3 weeks of age, suggestive of severe cerebellar dysfunction. Gross observation of Smad2-CNS-KO cerebella demonstrated aberrant foliations in lobule IX and X. Further analyses revealed increased apoptotic cell death, delayed migration and maturation of granule cells, and retardation of dendritic arborization of Purkinje cells. These findings indicate that Smad2 plays a key role in cerebellar development and motor function control.
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Affiliation(s)
- Lixiang Wang
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
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The expression of TAG-1 in glial cells is sufficient for the formation of the juxtaparanodal complex and the phenotypic rescue of tag-1 homozygous mutants in the CNS. J Neurosci 2010; 30:13943-54. [PMID: 20962216 DOI: 10.1523/jneurosci.2574-10.2010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Myelinated fibers are organized into specialized domains that ensure the rapid propagation of action potentials and are characterized by protein complexes underlying axoglial interactions. TAG-1 (Transient Axonal Glycoprotein-1), a cell adhesion molecule of the Ig superfamily, is expressed by neurons as well as by myelinating glia. It is essential for the molecular organization of myelinated fibers as it maintains the integrity of the juxtaparanodal region through its interactions with Caspr2 and the voltage-gated potassium channels (VGKCs) on the axolemma. Since TAG-1 is the only known component of the juxtaparanodal complex expressed by the glial cell, it is important to clarify its role in the molecular organization of juxtaparanodes. For this purpose, we generated transgenic mice that exclusively express TAG-1 in oligodendrocytes and lack endogenous gene expression (Tag-1(-/-);plp(Tg(rTag-1))). Phenotypic analysis clearly demonstrates that glial TAG-1 is sufficient for the proper organization and maintenance of the juxtaparanodal domain in the CNS. Biochemical analysis shows that glial TAG-1 physically interacts with Caspr2 and VGKCs. Ultrastructural and behavioral analysis of Tag-1(-/-);plp(Tg(rTag-1)) mice shows that the expression of glial TAG-1 is sufficient to restore the axonal and myelin deficits as well as the behavioral defects observed in Tag-1(-/-) animals. Together, these data highlight the pivotal role of myelinating glia on axonal domain differentiation and organization.
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AF4 is a critical regulator of the IGF-1 signaling pathway during Purkinje cell development. J Neurosci 2010; 29:15366-74. [PMID: 20007461 DOI: 10.1523/jneurosci.5188-09.2009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Deregulation of the insulin-like growth factor 1 (IGF-1) signaling pathway is a recurrent finding in mouse models and human patients with cerebellar ataxia and thus represents a common pathological cascade in neuronal cell death that may be targeted for therapy. We have previously identified a point mutation in AF4, a transcription cofactor of RNA polymerase II elongation and chromatin remodeling, that causes progressive and highly specific Purkinje cell (PC) death in the ataxic mouse mutant robotic, leading to the accumulation of AF4 in PCs. Here we confirm that the spatiotemporal pattern of PC degeneration in the robotic cerebellum correlates with the specific profile of AF4 upregulation. To identify the underlying molecular pathways, we performed microarray gene expression analysis of PCs obtained by laser capture microdissection (LCM) at the onset of degeneration. Igf-1 was significantly downregulated in robotic PCs compared with wild-type controls before and throughout the degenerative process. Consistently, we observed a decrease in the activation of downstream signaling molecules including type 1 IGF receptor (IGF-1R) and the extracellular signal-regulated kinase (ERK) 1 and ERK2. Chromatin immunoprecipitation confirmed that Igf-1 is a direct and the first validated target of the AF4 transcriptional regulatory complex, and treatment of presymptomatic robotic mice with IGF-1 indeed markedly delayed the progression of PC death. This study demonstrates that small changes in the levels of a single transcriptional cofactor can deleteriously affect normal cerebellum function and opens new avenues of research for the manipulation of the IGF-1 pathway in the treatment of cerebellar ataxia in humans.
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How Many Ways Can Mouse Behavioral Experiments Go Wrong? Confounding Variables in Mouse Models of Neurodegenerative Diseases and How to Control Them. ADVANCES IN THE STUDY OF BEHAVIOR 2010. [DOI: 10.1016/s0065-3454(10)41007-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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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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Goyenvalle A, Babbs A, Powell D, Kole R, Fletcher S, Wilton SD, Davies KE. Prevention of dystrophic pathology in severely affected dystrophin/utrophin-deficient mice by morpholino-oligomer-mediated exon-skipping. Mol Ther 2009; 18:198-205. [PMID: 19844193 DOI: 10.1038/mt.2009.248] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe neuromuscular disorder caused by mutations in the dystrophin gene that result in the absence of functional protein. Antisense-mediated exon-skipping is one of the most promising approaches for the treatment of DMD because of its capacity to correct the reading frame and restore dystrophin expression, which has been demonstrated in vitro and in vivo. In particular, peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) have recently been shown to induce widespread high levels of dystrophin expression in the mdx mouse model. Here, we report the efficiency of the PPMO-mediated exon-skipping approach in the utrophin/dystrophin double-knockout mouse (dKO) mouse, which is a much more severe and progressive mouse model of DMD. Repeated intraperitoneal (i.p.) injections of a PPMO targeted to exon 23 of dystrophin pre-mRNA in dKO mice induce a near-normal level of dystrophin expression in all muscles examined, except for the cardiac muscle, resulting in a considerable improvement of their muscle function and dystrophic pathology. These findings suggest great potential for PPMOs in systemic treatment of the DMD phenotype.
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Affiliation(s)
- Aurélie Goyenvalle
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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16
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A point mutation in TRPC3 causes abnormal Purkinje cell development and cerebellar ataxia in moonwalker mice. Proc Natl Acad Sci U S A 2009; 106:6706-11. [PMID: 19351902 DOI: 10.1073/pnas.0810599106] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The hereditary ataxias are a complex group of neurological disorders characterized by the degeneration of the cerebellum and its associated connections. The molecular mechanisms that trigger the loss of Purkinje cells in this group of diseases remain incompletely understood. Here, we report a previously undescribed dominant mouse model of cerebellar ataxia, moonwalker (Mwk), that displays motor and coordination defects and loss of cerebellar Purkinje cells. Mwk mice harbor a gain-of-function mutation (T635A) in the Trpc3 gene encoding the nonselective transient receptor potential cation channel, type C3 (TRPC3), resulting in altered TRPC3 channel gating. TRPC3 is highly expressed in Purkinje cells during the phase of dendritogenesis. Interestingly, growth and differentiation of Purkinje cell dendritic arbors are profoundly impaired in Mwk mice. Our findings define a previously unknown role for TRPC3 in both dendritic development and survival of Purkinje cells, and provide a unique mechanism underlying cerebellar ataxia.
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Bitoun E, Davies KE. The robotic mouse: understanding the role of AF4, a cofactor of transcriptional elongation and chromatin remodelling, in purkinje cell function. THE CEREBELLUM 2009; 8:175-83. [PMID: 19340490 DOI: 10.1007/s12311-009-0101-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Accepted: 03/11/2009] [Indexed: 10/20/2022]
Abstract
Neurological disorders represent a large share of the disease burden worldwide, and the incidence of age-related forms will continue to rise with life expectancy. Gene targeting has been and will remain a valuable approach to the generation of clinically relevant mouse models from which to elucidate the underlying molecular basis. However, as the aetiology of the majority of these conditions is still unknown, a reverse approach based on large-scale random chemical mutagenesis is now being used in an attempt to identify new genes and associated signalling pathways that control neuronal cell death and survival. Here, we review the characterisation of a novel model of autosomal dominant cerebellar ataxia which shows general growth retardation and develops adult-onset region-specific Purkinje cell loss as well as cataracts and defects in early T-cell maturation. We have previously established that the mutated protein Af4, which is a member of the AF4/LAF4/FMR2 (ALF) family of transcription cofactors frequently translocated in childhood leukaemia, undergoes slower proteasomal turnover through the ubiquitin pathway and abnormally accumulates in Purkinje cells of the cerebellum. We have also shown that Af4 functions as part of a large multiprotein complex that stimulates RNA polymerase II elongation and mediates chromatin remodelling during transcription. With the forthcoming identification of the gene targets that trigger Purkinje cell death in the robotic cerebellum, and the functional conservation among the ALF proteins, the robotic mouse promises to deliver important insights into the pathogenesis of human ataxia, but also of mental retardation to which FMR2 and LAF4 have been linked.
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Affiliation(s)
- Emmanuelle Bitoun
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
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18
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Yin H, Moulton HM, Seow Y, Boyd C, Boutilier J, Iverson P, Wood MJ. Cell-penetrating peptide-conjugated antisense oligonucleotides restore systemic muscle and cardiac dystrophin expression and function. Hum Mol Genet 2008; 17:3909-18. [PMID: 18784278 PMCID: PMC7108561 DOI: 10.1093/hmg/ddn293] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Antisense oligonucleotides (AOs) have the potential to induce functional dystrophin protein expression via exon skipping by restoring in-frame transcripts in the majority of patients suffering from Duchenne muscular dystrophy (DMD). AOs of morpholino phosphoroamidate (PMO) and 2'-O-methyl phosphorothioate RNA (2'Ome RNA) chemistry have been shown to restore dystrophin expression in skeletal muscle but not in heart, following high-dose systemic delivery in murine models of muscular dystrophy (mdx). Exploiting the cell transduction properties of two basic arginine-rich cell penetrating peptides, we demonstrate widespread systemic correction of dystrophin expression in body-wide muscles and cardiac tissue in adult dystrophic mdx mice, with a single low-dose injection of peptide-conjugated PMO AO. This approach was sufficient to restore uniform, high-level dystrophin protein expression in peripheral muscle and cardiac tissue, with robust sarcolemmal relocalization of the dystrophin-associated protein complex and functional improvement in muscle. Peptide-conjugated AOs therefore have significant potential for systemic correction of the DMD phenotype.
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MESH Headings
- Animals
- Cell Membrane Permeability/drug effects
- Cell Membrane Permeability/genetics
- Dose-Response Relationship, Drug
- Dystrophin/biosynthesis
- Dystrophin/genetics
- Dystrophin/physiology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Heart Injuries/drug therapy
- Heart Injuries/metabolism
- Heart Injuries/physiopathology
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Morpholines/pharmacokinetics
- Morpholines/therapeutic use
- Morpholinos
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/physiology
- Muscular Dystrophy, Animal/drug therapy
- Muscular Dystrophy, Animal/genetics
- Muscular Dystrophy, Animal/metabolism
- Oligonucleotides, Antisense/chemistry
- Oligonucleotides, Antisense/genetics
- Oligonucleotides, Antisense/pharmacokinetics
- Peptides/genetics
- Peptides/pharmacokinetics
- Peptides/therapeutic use
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Affiliation(s)
- HaiFang Yin
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | | | - Yiqi Seow
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Corinne Boyd
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | | | | | - Matthew J.A. Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
- To whom correspondence should be addressed. Tel: +44 1865272419; Fax: +44 1865272420;
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Savvaki M, Panagiotaropoulos T, Stamatakis A, Sargiannidou I, Karatzioula P, Watanabe K, Stylianopoulou F, Karagogeos D, Kleopa KA. Impairment of learning and memory in TAG-1 deficient mice associated with shorter CNS internodes and disrupted juxtaparanodes. Mol Cell Neurosci 2008; 39:478-90. [PMID: 18760366 DOI: 10.1016/j.mcn.2008.07.025] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2008] [Revised: 07/29/2008] [Accepted: 07/31/2008] [Indexed: 10/21/2022] Open
Abstract
The cell adhesion molecule TAG-1 is expressed by neurons and glial cells and plays a role in axon outgrowth, migration and fasciculation during development. TAG-1 is also required for the clustering of Kv1.1/1.2 potassium channels and Caspr2 at the juxtaparanodes of myelinated fibers. Behavioral examination of TAG-1 deficient mice (Tag-1(-/-)) showed cognitive impairments in the Morris water maze and novel object recognition tests, reduced spontaneous motor activity, abnormal gait coordination and increased response latency to noxious stimulation. Investigation at the molecular level revealed impaired juxtaparanodal clustering of Caspr2 and Kv1.1/1.2 in the hippocampus, entorhinal cortex, cerebellum and olfactory bulb, with diffusion into the internode. Caspr2 and Kv1.1 levels were reduced in the cerebellum and olfactory bulb. Moreover, Tag-1(-/-) mice had shorter internodes in the cerebral and cerebellar white matter. The detected molecular alterations may account for the behavioural deficits and hyperexcitability in these animals.
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Affiliation(s)
- Maria Savvaki
- Department of Basic Science, University of Crete Medical School, and Institute of Molecular Biology and Biotechnology, Heraklion, Greece
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