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University of Groningen Genetic and molecular mechanisms ... · PDF file Genetic and molecular mechanisms underlying spinocerebellar ataxias. Justyna Jezierska Phd thesis – Department

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  • University of Groningen

    Genetic and molecular mechanisms underlying spinocerebellar ataxias Jezierska, Justyna

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    Publication date: 2013

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    Citation for published version (APA): Jezierska, J. (2013). Genetic and molecular mechanisms underlying spinocerebellar ataxias. Groningen: s.n.

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  • Genetic and molecular mechanisms underlying spinocerebellar ataxias

    Justyna Jezierska

    Phd thesis – Department of Genetics

    University Medical Center Groningen, University of Groningen

    Groningen, The Netherlands

    This study was financially supported by University of Groningen and Research Institute GUIDE.

    Cover design and book layout: Lovebird design and printing solutions (

    Printed by: EIKON

    Printing of the thesis was financially supported by University of Groningen, GUIDE and Department of Genetics, UMCG.

    Copyright ©2013 Justyna Jezierska. All rights reserved.

    No part of this book may be reproduced, stored in retrieval system, or transmitted in any form or by any means, without prior permission of the author.

    JJezierska.indd 2 8/16/2013 9:46:34 AM


    Genetic and molecular mechanisms underlying spinocerebellar ataxias


    ter verkrijging van het doctoraat in de Medische Wetenschappen

    aan de Rijksuniversiteit Groningen op gezag van de

    Rector Magnificus, dr. E. Sterken, in het openbaar te verdedigen op

    maandag 23 september 2013 om 11.00 uur


    Justyna Jezierska

    geboren op 10 april 1985

    te Warszawa, Polen

    JJezierska.indd 3 8/16/2013 9:46:34 AM

  • Promotores: Prof. dr R. Sinke

    Prof. dr H.H. Kampinga

    Co-Promotor: Dr. D.S. Verbeek

    Beoordelingscommissie: Prof.dr H. van Bokhoven

    Prof.dr H.P.H. Kremer

    Prof.dr O.C.M. Sibon

    ISBN: 978-90-367-6373-8

    JJezierska.indd 4 8/16/2013 9:46:34 AM


    CHAPTER 1:

    General introduction and outline of the thesis 7

    CHAPTER 2:

    SCA14 mutation V138E leads to partly unfolded PKCγ associated with an exposed C-terminus, altered kinetics, phosphorylation and enhanced insolubilization 27

    CHAPTER 3:

    Mutations in potassium channel KCND3 cause spinocerebellar ataxia type 19 45

    CHAPTER 4:

    Prodynorphin mutations cause the neurodegenerative disorder spinocerebellar ataxia type 23 63

    CHAPTER 5:

    Identification and characterization of novel PDYN mutations in dominant cerebellar ataxia cases 81

    CHAPTER 6:

    Elevated Dynorphin A levels lead to Purkinje cell loss in spinocerebellar ataxia type 23 mice 91

    CHAPTER 7:

    SCA23-mutant Dynorphin A peptides cause cell death via non-opioid excitotoxic mechanisms 101

    CHAPTER 8:

    Conclusions, General Discussion and Future Perspectives 129



    SUMMARY 149


    JJezierska.indd 5 8/16/2013 9:46:34 AM

  • List of Abbreviations

    AD = Alzheimer’s disease ADCA = autosomal dominant ataxia ALS = amyotrophic lateral sclerosis AMPAR = α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor Ca2+ = calcium CF = climbing fiber DAG = diacylglycerol Dyn = dynorphin EAAT = excitatory amino acid transporter ER = endoplasmic reticulum ERAD = endoplasmic reticulum-associated degradation GC = granule cell HD = Huntington’s disease IP3 = inositol-triphosphate IP3R = inositol-triphosphate receptor iPS = induced pluripotent KChIP = Kv channel-interacting protein KOR = kappa-opioid receptor Kv = voltage-gated potassium channel LTD= long-term depression LTP = long-term potentiation mGluR = Group I metabotropic glutamate receptors ML = molecular layer NAc = nucleus accumbens NGS = next-generation sequencing NMDAR = N-methyl-D-aspartate receptor NSC = neuronal stem cell PC = Purkinje cell PD = Parkinson’s disease PDK1 = Phosphoinositide-dependent kinase-1 PDYN = prodynorphin PF = parallel fiber PFC = prefrontal cortex PI = propidium iodide PKC = protein kinase C PKCγ = protein kinase C gamma PLC = phospholipase C polyQ = polyglutamine SCA = spinocerebellar ataxia UTR = untranslated region WT = wild type

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    General introduction and outline of the thesis

    JJezierska.indd 7 8/16/2013 9:47:27 AM

  • JJezierska.indd 8 8/16/2013 9:47:27 AM

  • Introduction


    Spinocerebellar ataxias Neurodegenerative disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS), and spinocerebellar ataxias (SCAs), are a group of diseases that remain incurable despite the enormous research effort into the underlying pathological mechanisms. The pathology includes progressive neuronal cell death, hence the name “neurodegeneration”, but the underlying cause is still mainly unknown.

    SCAs are autosomal dominant disorders that lead to the atrophy of Purkinje cells (PCs) in the cerebellar cortex and successive neuronal loss in spinocerebellar tracks. The disease pathology is characterized by cerebellar ataxia, which means unsteady gait, clumsiness and eye movement defects (dysarthria). This ataxic disorder can be accompanied by various other symptoms including cognitive impairment, epilepsy, peripheral neuropathy or psychiatric problems, correlated with neuronal loss in other brain regions. Onset of the disease symptoms is usually in third or fourth decade of life [1].

    The first neurological ataxic phenotype classification was proposed by Harding and it divides the autosomal dominant ataxias (ADCA) into three clinical subgroups (ADCA I-III; Table 1) [1]. This classification is sometimes still used, but it is not that useful as not all SCA phenotypes fit exactly into the three defined subgroups. Additionally, the genetic mechanisms underlying particular types of SCA do not correlate with Harding’s classification. For instance, the ADCA I subgroup comprises SCA types caused by coding and non-coding repeat expansions and conventional mutations. The current classification of the SCAs is therefore based on the underlying genetic defect and the definitive diagnosis relies on the outcome of the genetic analysis.

    Table 1 The autosomal dominant cerebellar ataxia (ADCA) classification of Harding (1982) [2] SCA type Clinical manifestations

    ADCA I 1-4, 8, 10, 12-23, 25, 27, 28,

    DRPLA Complex (spinal cord syndromes, peripheral nerve disease, cognitive impairment, ophthalmologic signs, psychiatric problems and seizures)

    ADCA II 7 Pigmentary maculopathy

    ADCA III 5, 6, 11, 26, 29, 30, 31 “Pure” cerebellar

    SCA is genetically a very heterogeneous group of diseases (Fig. 1), and to date 32 different subtypes of SCA have been recognized (SCA9 and SCA33 are unassigned, SCA15 and 16 were proved to be allelic, also SCA19 and 22 were linked to the same gene, and SCA24 was proved to be recessively inherited) (Table 2). The disease gene has been identified for 22 SCA types. Phenotypically similar SCAs are not only caused by mutations in various genes, but the mutation mechanism can also be different, including coding and non-coding repeat expansions, missense and nonsense mutations, deletions and duplications.

    JJezierska.indd 9 8/16/2013 9:48:19 AM

  • 1 CH

    A PT



    Fig. 1 Localization of various spinocerebellar ataxias-associated mutations in different gene regions.

    Despite the recent advances in genetic techniques, the genetic diagnosis for SCA remains problematic. Screening of the more common SCA genes (SCA types 1-3, 6, 7, 12, 14, and 17) yields mutations in only 60-70% of the cases. Additionally, the identification of new disease genes is not always straightforward, as even after the disease locus has been mapped, the disease genes cannot always be found in the li

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