1
|
Schmitz-Hübsch T, Lux S, Bauer P, Brandt AU, Schlapakow E, Greschus S, Scheel M, Gärtner H, Kirlangic ME, Gras V, Timmann D, Synofzik M, Giorgetti A, Carloni P, Shah JN, Schöls L, Kopp U, Bußenius L, Oberwahrenbrock T, Zimmermann H, Pfueller C, Kadas EM, Rönnefarth M, Grosch AS, Endres M, Amunts K, Paul F, Doss S, Minnerop M. Spinocerebellar ataxia type 14: refining clinicogenetic diagnosis in a rare adult-onset disorder. Ann Clin Transl Neurol 2021; 8:774-789. [PMID: 33739604 PMCID: PMC8045942 DOI: 10.1002/acn3.51315] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/29/2020] [Accepted: 01/13/2021] [Indexed: 12/29/2022] Open
Abstract
Objectives Genetic variant classification is a challenge in rare adult‐onset disorders as in SCA‐PRKCG (prior spinocerebellar ataxia type 14) with mostly private conventional mutations and nonspecific phenotype. We here propose a refined approach for clinicogenetic diagnosis by including protein modeling and provide for confirmed SCA‐PRKCG a comprehensive phenotype description from a German multi‐center cohort, including standardized 3D MR imaging. Methods This cross‐sectional study prospectively obtained neurological, neuropsychological, and brain imaging data in 33 PRKCG variant carriers. Protein modeling was added as a classification criterion in variants of uncertain significance (VUS). Results Our sample included 25 cases confirmed as SCA‐PRKCG (14 variants, thereof seven novel variants) and eight carriers of variants assigned as VUS (four variants) or benign/likely benign (two variants). Phenotype in SCA‐PRKCG included slowly progressive ataxia (onset at 4–50 years), preceded in some by early‐onset nonprogressive symptoms. Ataxia was often combined with action myoclonus, dystonia, or mild cognitive‐affective disturbance. Inspection of brain MRI revealed nonprogressive cerebellar atrophy. As a novel finding, a previously not described T2 hyperintense dentate nucleus was seen in all SCA‐PRKCG cases but in none of the controls. Interpretation In this largest cohort to date, SCA‐PRKCG was characterized as a slowly progressive cerebellar syndrome with some clinical and imaging features suggestive of a developmental disorder. The observed non‐ataxia movement disorders and cognitive‐affective disturbance may well be attributed to cerebellar pathology. Protein modeling emerged as a valuable diagnostic tool for variant classification and the newly described T2 hyperintense dentate sign could serve as a supportive diagnostic marker of SCA‐PRKCG.
Collapse
Affiliation(s)
- Tanja Schmitz-Hübsch
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Silke Lux
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | - Peter Bauer
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.,CENTOGENE AG, Rostock, Germany
| | - Alexander U Brandt
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Department of Neurology, University of California, Irvine, CA, USA
| | - Elena Schlapakow
- Department of Neurology, University Hospital Bonn, Bonn, Germany.,Center for Rare Diseases, University of Bonn, Bonn, Germany
| | - Susanne Greschus
- Department of Radiology, University Hospital Bonn, Bonn, Germany
| | - Michael Scheel
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Department of Neuroradiology, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Hanna Gärtner
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany
| | - Mehmet E Kirlangic
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany.,Institute for Biomedical Engineering and Computer Science, Technische Universität Ilmenau, Ilmenau, Germany
| | - Vincent Gras
- Institute of Neuroscience and Medicine (INM-4), Research Centre Juelich, Juelich, Germany
| | - Dagmar Timmann
- Department of Neurology, Essen University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Center for Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Alejandro Giorgetti
- Computational Biophysics, German Research School for Simulation Sciences, and Computational Biomedicine, Institute for Advanced Simulation (IAS-5) and Institute of Neuroscience and Medicine (INM-9), Research Centre Juelich, Juelich, Germany.,Department of Biotechnology, University of Verona, Verona, 37134, Italy
| | - Paolo Carloni
- Computational Biophysics, German Research School for Simulation Sciences, and Computational Biomedicine, Institute for Advanced Simulation (IAS-5) and Institute of Neuroscience and Medicine (INM-9), Research Centre Juelich, Juelich, Germany
| | - Jon N Shah
- Institute of Neuroscience and Medicine (INM-4), Research Centre Juelich, Juelich, Germany.,Department of Neurology, Faculty of Medicine, JARA, RWTH Aachen University, Aachen, Germany
| | - Ludger Schöls
- Department of Neurodegenerative Diseases, Center for Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Ute Kopp
- Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Lisa Bußenius
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany.,Institute for Biochemistry and Molecular Cell Biology, Center for Experimental Medicine, University Clinic Hamburg Eppendorf, Hamburg, Germany
| | - Timm Oberwahrenbrock
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany
| | - Hanna Zimmermann
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany
| | - Caspar Pfueller
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany
| | - Ella-Maria Kadas
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany
| | - Maria Rönnefarth
- Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Anne-Sophie Grosch
- Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Matthias Endres
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Berlin, Germany.,German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.,German Centre for Cardiovascular Research (DZHK), Berlin, Germany
| | - Katrin Amunts
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany.,C. and O. Vogt Institute for Brain Research, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Friedemann Paul
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Sarah Doss
- Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Movement Disorders Section, Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Martina Minnerop
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany.,Department of Neurology, Center for Movement Disorders and Neuromodulation, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany.,Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
| |
Collapse
|
2
|
Rosini F, Pretegiani E, Battisti C, Dotti MT, Federico A, Rufa A. Eye movement changes in autosomal dominant spinocerebellar ataxias. Neurol Sci 2020; 41:1719-1734. [PMID: 32130555 DOI: 10.1007/s10072-020-04318-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 02/24/2020] [Indexed: 12/15/2022]
Abstract
Oculomotor abnormalities are common findings in spinocerebellar ataxias (SCAs), a clinically heterogeneous group of neurodegenerative disorders with an autosomal dominant pattern of inheritance. Usually, cerebellar impairment accounts for most of the eye movement changes encountered; as the disease progresses, the involvement of extracerebellar structures typically seen in later stages may modify the oculomotor progression. However, ocular movement changes are rarely specific. In this regard, some important exceptions include the prominent slowing of horizontal eye movements in SCA2 and, to a lesser extent, in SCA3, SCA4, and SCA28, or the executive deficit in SCA2 and SCA17. Here, we report the eye movement abnormalities and neurological pictures of SCAs through a review of the literature. Genetic and neuropathological/neuroimaging aspects are also briefly discussed. Overall, the findings reported indicate that oculomotor analysis could be of help in differential diagnosis among SCAs and contribute to clarify the role of brain structures, particularly the cerebellum, in oculomotor control.
Collapse
Affiliation(s)
- Francesca Rosini
- Department of Medicine Surgery and Neuroscience, Eye Tracking& Visual Application Lab EVALAB, Neurology and Neurometabolic Unit, University of Siena, Viale Bracci 2, 53100, Siena, Italy
| | - Elena Pretegiani
- Department of Medicine Surgery and Neuroscience, Eye Tracking& Visual Application Lab EVALAB, Neurology and Neurometabolic Unit, University of Siena, Viale Bracci 2, 53100, Siena, Italy
| | - Carla Battisti
- Department of Medicine, Surgery and Neuroscience, Neurology and Neurometabolic Unit, University of Siena, Siena, Italy
| | - Maria Teresa Dotti
- Department of Medicine, Surgery and Neuroscience, Neurology and Neurometabolic Unit, University of Siena, Siena, Italy
| | - Antonio Federico
- Department of Medicine, Surgery and Neuroscience, Neurology and Neurometabolic Unit, University of Siena, Siena, Italy
| | - Alessandra Rufa
- Department of Medicine Surgery and Neuroscience, Eye Tracking& Visual Application Lab EVALAB, Neurology and Neurometabolic Unit, University of Siena, Viale Bracci 2, 53100, Siena, Italy.
- Department of Medicine, Surgery and Neuroscience, Neurology and Neurometabolic Unit, University of Siena, Siena, Italy.
| |
Collapse
|
3
|
Lalonde R, Strazielle C. Motor Performances of Spontaneous and Genetically Modified Mutants with Cerebellar Atrophy. THE CEREBELLUM 2019; 18:615-634. [PMID: 30820866 DOI: 10.1007/s12311-019-01017-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Chance discovery of spontaneous mutants with atrophy of the cerebellar cortex has unearthed genes involved in optimizing motor coordination. Rotorod, stationary beam, and suspended wire tests are useful in delineating behavioral phenotypes of spontaneous mutants with cerebellar atrophy such as Grid2Lc, Grid2ho, Rorasg, Agtpbp1pcd, Relnrl, and Dab1scm. Likewise, transgenic or null mutants serving as experimental models of spinocerebellar ataxia (SCA) are phenotyped with the same tests. Among experimental models of autosomal dominant SCA, rotorod deficits were reported in SCA1 to 3, SCA5 to 8, SCA14, SCA17, and SCA27 and stationary beam deficits in SCA1 to 3, SCA5, SCA6, SCA13, SCA17, and SCA27. Beam tests are sensitive to experimental therapies of various kinds including molecules affecting glutamate signaling, mesenchymal stem cells, anti-oligomer antibodies, lentiviral vectors carrying genes, interfering RNAs, or neurotrophic factors, and interbreeding with other mutants.
Collapse
Affiliation(s)
- Robert Lalonde
- Department of Psychology, University of Rouen, 76821, Mont-Saint-Aignan Cedex, France.
| | - Catherine Strazielle
- Laboratory of Stress, Immunity, and Pathogens EA7300, and CHRU of Nancy, University of Lorraine, 54500, Vandoeuvre-les-Nancy, France
| |
Collapse
|
4
|
Doss S, Rinnenthal JL, Schmitz-Hübsch T, Brandt AU, Papazoglou S, Lux S, Maul S, Würfel J, Endres M, Klockgether T, Minnerop M, Paul F. Cerebellar neurochemical alterations in spinocerebellar ataxia type 14 appear to include glutathione deficiency. J Neurol 2015; 262:1927-35. [PMID: 26041613 DOI: 10.1007/s00415-015-7788-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 05/15/2015] [Accepted: 05/17/2015] [Indexed: 12/16/2022]
Abstract
Autosomal dominant ataxia type 14 (SCA14) is a rare usually adult-onset progressive disorder with cerebellar neurodegeneration caused by mutations in protein kinase C gamma. We set out to examine cerebellar and extracerebellar neurochemical changes in SCA14 by MR spectroscopy. In 13 SCA14 patients and 13 healthy sex- and age-matched controls, 3-T single-voxel brain proton MR spectroscopy was performed in a cerebellar voxel of interest (VOI) at TE = 30 ms to obtain a neurochemical profile of metabolites with short relaxation times. In the cerebellum and in additional VOIs in the prefrontal cortex, motor cortex, and somatosensory cortex, a second measurement was performed at TE = 144 ms to mainly extract the total N-acetyl-aspartate (tNAA) signal besides the signals for total creatine (tCr) and total choline (tCho). The cerebellar neurochemical profile revealed a decrease in glutathione (6.12E-06 ± 2.50E-06 versus 8.91E-06 ± 3.03E-06; p = 0028) and tNAA (3.78E-05 ± 5.67E-06 versus 4.25E-05 ± 5.15E-06; p = 0023) and a trend for reduced glutamate (2.63E-05 ± 6.48E-06 versus 3.15E-05 ± 7.61E-06; p = 0062) in SCA14 compared to controls. In the tNAA-focused measurement, cerebellar tNAA (296.6 ± 42.6 versus 351.7 ± 16.5; p = 0004) and tCr (272.1 ± 25.2 versus 303.2 ± 31.4; p = 0004) were reduced, while the prefrontal, somatosensory and motor cortex remained unaffected compared to controls. Neuronal pathology in SCA14 detected by MR spectroscopy was restricted to the cerebellum and did not comprise cortical regions. In the cerebellum, we found in addition to signs of neurodegeneration a glutathione reduction, which has been associated with cellular damage by oxidative stress in other neurodegenerative diseases such as Parkinson's disease and Friedreich's ataxia.
Collapse
Affiliation(s)
- Sarah Doss
- Department of Neurology, Charité, Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany,
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Lu H, Zhu L, Lian L, Chen M, Shi D, Wang K. Genetic variations in the PRKCG gene and osteosarcoma risk in a Chinese population: a case-control study. Tumour Biol 2015; 36:5241-7. [PMID: 25663494 DOI: 10.1007/s13277-015-3182-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 01/27/2015] [Indexed: 11/24/2022] Open
Abstract
Osteosarcoma is a common malignant tumor, which exists widely in the bone of children and adolescents. Protein kinase C gamma (PRKCG) gene, which encodes γPKC, plays important roles in tumor promotion, cell proliferation, differentiation, and migration. The objective of the present study was to investigate the relationship between PRKCG polymorphisms and the risk of osteosarcoma. Five tag single nucleotide polymorphisms (SNPs) of PRKCG were retrieved from the HapMap database and genotyped by the method of SNapShot in a hospital-based study containing 388 patients and 388 healthy individuals. Odds ratios (ORs) and their 95 % confidence intervals (CIs) were used to evaluate the association SPSS 20.0 statistical software package was used to analyze statistical data. Our results suggested that the T/C variant of rs454006 located in the intron 3 region of PRKCG gene was significantly associated with an increased risk of osteosarcoma (CC vs. TT, OR = 1.91; 95 % CI 1.29-2.85; P = 0.001; CC vs. TT+TC, OR = 2.14, 95 % CI = 1.48-3.09, P = 0.001; C vs. T, OR = 1.32, 95 % CI = 1.08-1.62, P = 0.008). Similarly, the rs3745406 T/C variant can also elevate the risk of osteosarcoma in the dominant model (OR = 1.45, 95 % CI = 1.08-1.96, P = 0.014), homozygous model (OR = 1.68, 95 % CI = 1.10-2.59, P = 0.002), and allelic model (OR = 1.31, 95 % CI = 1.07-1.61, P = 0.009). However, there were no significant differences in genotypes and allele frequencies of rs2547362 (T>C), rs8103851 (C>G), and rs2242245 (T>C) SNPs between osteosarcoma patients and healthy controls. The results showed that carrier of rs454006*C allele and rs3745406*C might elevate the risk of osteosarcoma. Further studies are needed to validate the coalition between PRKCG gene polymorphisms and risk of osteosarcoma relying on a larger population that included the participants in different ethnicity and hospital.
Collapse
Affiliation(s)
- Huading Lu
- Department of Orthopedics, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, China,
| | | | | | | | | | | |
Collapse
|
6
|
Yamamoto K, Seki T, Yamamoto H, Adachi N, Tanaka S, Hide I, Saito N, Sakai N. Deregulation of the actin cytoskeleton and macropinocytosis in response to phorbol ester by the mutant protein kinase C gamma that causes spinocerebellar ataxia type 14. Front Physiol 2014; 5:126. [PMID: 24744737 PMCID: PMC3978357 DOI: 10.3389/fphys.2014.00126] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/13/2014] [Indexed: 11/14/2022] Open
Abstract
Several missense mutations in the protein kinase Cγ (γPKC) gene have been found to cause spinocerebellar ataxia type 14 (SCA14), an autosomal dominant neurodegenerative disease. γPKC is a neuron-specific member of the classical PKCs and is activated and translocated to subcellular regions as a result of various stimuli, including diacylglycerol synthesis, increased intracellular Ca2+ and phorbol esters. We investigated whether SCA14 mutations affect the γPKC-related functions by stimulating HeLa cells with TPA (12-O-tetradecanoylpholbol 13-acetate), a type of phorbol ester. Wild-type (WT) γPKC-GFP was translocated to the plasma membrane within 10 min of TPA stimulation, followed by its perinuclear translocation and cell shrinkage, in a PKC kinase activity- and microtubule-dependent manner. On the other hand, although SCA14 mutant γPKC-GFP exhibited a similar translocation to the plasma membrane, the subsequent perinuclear translocation and cell shrinkage were significantly impaired in response to TPA. Translocated WT γPKC colocalized with F-actin and formed large vesicular structures in the perinuclear region. The uptake of FITC-dextran, a marker of macropinocytosis, was promoted by TPA stimulation in cells expressing WT γPKC, and FITC-dextran was surrounded by γPKC-positive vesicles. Moreover, TPA induced the phosphorylation of MARCKS, which is a membrane-substrate of PKC, resulting in the translocation of phosphorylated MARCKS to the perinuclear region, suggesting that TPA induces macropinocytosis via γPKC activation. However, TPA failed to activate macropinocytosis and trigger the translocation of phosphorylated MARCKS in cells expressing the SCA14 mutant γPKC. These findings suggest that γPKC is involved in the regulation of the actin cytoskeleton and macropinocytosis in HeLa cells, while SCA14 mutant γPKC fails to regulate these processes due to its reduced kinase activity at the plasma membrane. This property might be involved in pathogenesis of SCA14.
Collapse
Affiliation(s)
- Kazuhiro Yamamoto
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan
| | - Takahiro Seki
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan ; Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University Kumamoto, Japan
| | - Hikaru Yamamoto
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan ; Biosignal Research Center, Kobe University Kobe, Japan
| | - Naoko Adachi
- Biosignal Research Center, Kobe University Kobe, Japan
| | - Shigeru Tanaka
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan
| | - Izumi Hide
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan
| | - Naoaki Saito
- Biosignal Research Center, Kobe University Kobe, Japan
| | - Norio Sakai
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan
| |
Collapse
|
7
|
Wedding IM, Koht J, Dietrichs E, Landrø NI, Tallaksen CME. Cognition is only minimally impaired in Spinocerebellar ataxia type 14 (SCA14): a neuropsychological study of ten Norwegian subjects compared to intrafamilial controls and population norm. BMC Neurol 2013; 13:186. [PMID: 24289098 PMCID: PMC4219450 DOI: 10.1186/1471-2377-13-186] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 11/22/2013] [Indexed: 11/21/2022] Open
Abstract
Background There is an increasing awareness of the role of the cerebellum not only in motor, but also in cognitive and emotional functions. Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant hereditary ataxia characterized by a relatively pure cerebellar phenotype. Cognitive impairment has been reported in studies with phenotype descriptions of SCA14, but previous studies have been small without control groups, and no homogeneous and systematic test panel has been used. The objective of this study was to thoroughly characterize the neuropsychological profile in ten Norwegian SCA14 subjects compared to unaffected family members and population norm data. Methods Ten SCA14 subjects and ten intrafamilial unaffected age- and education-matched controls from two Norwegian families were included. The unaffected intrafamilial controls included six first degree relatives, two second degree relatives, and two spouses. General intellectual ability, memory, visuoperceptive skills, psychomotor speed, executive functions, depression and anxiety were examined using internationally standardized tests, with minimal need for manual response to avoid motor bias. Results No significant cognitive deficit was found in SCA14 subjects compared to intrafamilial controls. Verbal IQ, verbal executive function and psychomotor speed tended to be reduced in affected subjects, but previously reported non-verbal executive dysfunction was not confirmed in this study. Conclusion Only subtle cognitive impairment was found in SCA14 affected subjects. The current findings do not confirm earlier reports of cognitive dysfunction in SCA14, but does shows a mild impairment in specific verbal executive functions. Genotypic differences may partly account for this discrepancy, and further studies on larger materials are needed to verify the findings.
Collapse
|
8
|
Hekman KE, Yu GY, Brown CD, Zhu H, Du X, Gervin K, Undlien DE, Peterson A, Stevanin G, Clark HB, Pulst SM, Bird TD, White KP, Gomez CM. A conserved eEF2 coding variant in SCA26 leads to loss of translational fidelity and increased susceptibility to proteostatic insult. Hum Mol Genet 2012; 21:5472-83. [PMID: 23001565 DOI: 10.1093/hmg/dds392] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The autosomal dominant spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of disorders exhibiting cerebellar atrophy and Purkinje cell degeneration whose subtypes arise from 31 distinct genetic loci. Our group previously published the locus for SCA26 on chromosome 19p13.3. In this study, we performed targeted deep sequencing of the critical interval in order to identify candidate causative variants in individuals from the SCA26 family. We identified a single variant that co-segregates with the disease phenotype that produces a single amino acid substitution in eukaryotic elongation factor 2. This substitution, P596H, sits in a domain critical for maintaining reading frame during translation. The yeast equivalent, P580H EF2, demonstrated impaired translocation, detected as an increased rate of -1 programmed ribosomal frameshift read-through in a dual-luciferase assay for observing translational recoding. This substitution also results in a greater susceptibility to proteostatic disruption, as evidenced by a more robust activation of a reporter gene driven by unfolded protein response activation upon challenge with dithiothreitol or heat shock in our yeast model system. Our results present a compelling candidate mutation and mechanism for the pathogenesis of SCA26 and further support the role of proteostatic disruption in neurodegenerative diseases.
Collapse
Affiliation(s)
- Katherine E Hekman
- Department of Neurology, Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL 60637, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Establishment of a novel fluorescence-based method to evaluate chaperone-mediated autophagy in a single neuron. PLoS One 2012; 7:e31232. [PMID: 22363588 PMCID: PMC3280339 DOI: 10.1371/journal.pone.0031232] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Accepted: 01/04/2012] [Indexed: 11/19/2022] Open
Abstract
Background Chaperone-mediated autophagy (CMA) is a selective autophagy-lysosome protein degradation pathway. The role of CMA in normal neuronal functions and in neural disease pathogenesis remains unclear, in part because there is no available method to monitor CMA activity at the single-cell level. Methodology/Principal Findings We sought to establish a single-cell monitoring method by visualizing translocation of CMA substrates from the cytosol to lysosomes using the HaloTag (HT) system. GAPDH, a CMA substrate, was fused to HT (GAPDH-HT); this protein accumulated in the lysosomes of HeLa cells and cultured cerebellar Purkinje cells (PCs) after labeling with fluorescent dye-conjugated HT ligand. Lysosomal accumulation was enhanced by treatments that activate CMA and prevented by siRNA-mediated knockdown of LAMP2A, a lysosomal receptor for CMA, and by treatments that inactivate CMA. These results suggest that lysosomal accumulation of GAPDH-HT reflects CMA activity. Using this method, we revealed that mutant γPKC, which causes spinocerebellar ataxia type 14, decreased CMA activity in cultured PCs. Conclusion/Significance In the present study, we established a novel fluorescent-based method to evaluate CMA activity in a single neuron. This novel method should be useful and valuable for evaluating the role of CMA in various neuronal functions and neural disease pathogenesis.
Collapse
|
10
|
Koht J, Stevanin G, Durr A, Mundwiller E, Brice A, Tallaksen CME. SCA14 in Norway, two families with autosomal dominant cerebellar ataxia and a novel mutation in the PRKCG gene. Acta Neurol Scand 2012; 125:116-22. [PMID: 21434874 DOI: 10.1111/j.1600-0404.2011.01504.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Despite a similar prevalence of autosomal dominant cerebellar ataxia (ADCA) in Norway compared to other European countries, less than 10% of the families are explained by the CAG trinucleotide expansions. We wanted to find the occurence of SCA14 in the dominant ataxia population and describe the phenotype. METHODS We screened a large dominant cerebellar ataxia cohort for mutations in the PRKCG gene. Patients were evaluated according to a standard clinical protocol for ataxia patients. RESULTS A novel mutation was found in two families, a C to A transversion altering Histidine to a Glutamine at codon 139, located in a highly concerved region in the gene. It completely co-segregated with the affected family members and was not seen in 576 control chromosomes. Genetic analysis revealed common alleles at three microsatellite markers between these two families suggesting a shared ancestral chromosome. Affected subjects displayed a mild, slowly progressive cerebellar syndrome that included gait and limb ataxia and saccadic pursuit and head tremor in one. Age at onset ranged from 10 to 45 years. CONCLUSIONS These are the first families with SCA14 reported from Scandinavia and a new mutation in the PRKCG gene. The occurrence in the Norwegian dominant ataxia cohort is 3.5%.
Collapse
|
11
|
Parker JL, Santiago M. Oculomotor aspects of the hereditary cerebellar ataxias. HANDBOOK OF CLINICAL NEUROLOGY 2012; 103:63-83. [PMID: 21827881 DOI: 10.1016/b978-0-444-51892-7.00003-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- J Larry Parker
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS 39216-4505, USA.
| | | |
Collapse
|
12
|
Abstract
SCA14 is an autosomal dominant hereditary cerebellar ataxia that usually has an onset in early to mid adult life, with slow progression and normal lifespan. Although generally an uncomplicated cerebellar ataxia with gait imbalance, dysarthria, and nystagmus, there is occasionally sensory loss, hyperactive tendon reflexes, cognitive decline, or myoclonus. Brain MRI shows cerebellar atrophy. A single autopsy has shown loss of cerebellar Purkinje cells. The disease is caused by mutations in the protein kinase C gamma (PKCγ, PRKCG) gene with a hotspot for mutations in exon 4. Genetic testing for SCA14 is clinically available.
Collapse
Affiliation(s)
- Dong-Hui Chen
- Department of Neurology, University of Washington, Seattle, WA, USA
| | | | | |
Collapse
|
13
|
Sakai N, Saito N, Seki T. Molecular pathophysiology of neurodegenerative disease caused by γPKC mutations. World J Biol Psychiatry 2011; 12 Suppl 1:95-8. [PMID: 21906004 DOI: 10.3109/15622975.2011.598688] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant neurodegenerative disorder, which is caused by missense mutations of PRKCG gene encoding γ type protein kinase C (γPKC). To elucidate the pathophysiology of SCA14, we have analyzed the character of mutant γPKC causing SCA14, expressed in cultured cells. RESULTS We found that most of mutant γPKCs were susceptible to cytoplasmic aggregation, suggesting that this aggregate-prone is involved in the etiology of SCA14. When expressed in cultured Purkinje cells, mutant γPKC inhibited the development of dendrites in a manner independent of its aggregate-prone, suggesting that other mechanism is implicated in the pathogenesis of SCA14. FRAP (fluorescence recovery after photobleaching) analysis demonstrated that mobility of mutant γPKC was slower than that of wild type in Purkinje cells. Furthermore, translocation of mutant PKC was attenuated when the cells was treated with high potassium solution. These results suggest that mutant γPKC forms oligomers in Purkinje cells. In addition, enzymological studies revealed that most of mutant γPKC had higher basal activity than wild one. However, the imaging analysis of γPKC demonstrated that mutations slowed the translocation of γPKC, which may explain the low accessibility of mutant γPKC to the plasma membrane. CONCLUSION We propose that variety of mutant γPKC characters integrally and complicatedly participate in the pathophysiology of SCA 14.
Collapse
Affiliation(s)
- Norio Sakai
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
| | | | | |
Collapse
|
14
|
Seki T, Adachi N, Abe-Seki N, Shimahara T, Takahashi H, Yamamoto K, Saito N, Sakai N. Elucidation of the molecular mechanism and exploration of novel therapeutics for spinocerebellar ataxia caused by mutant protein kinase Cγ. J Pharmacol Sci 2011; 116:239-47. [PMID: 21666345 DOI: 10.1254/jphs.11r04cp] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Spinocerebellar ataxia (SCA) is an inherited neurodegenerative disorder that is characterized by cerebellar atrophy and progressive ataxia and is classified into 31 types by the genetic locus. Recently, missense mutations of PRKCG genes that code protein kinase Cγ (γPKC) have been identified as a causal gene of SCA14. To explore the molecular mechanism of SCA14 pathogenesis, we investigated how mutant γPKC causes the neurodegeneration of cerebellar Purkinje cells (PCs) by expressing mutant γPKC-GFP in cell lines and primary cultured PCs. Mutant γPKC was susceptible to aggregation in the cytoplasm, which led to an impairment of the ubiquitin-proteasome system and apoptosis. Furthermore, mutant γPKC induced improper dendritic development of cultured PCs in an aggregation-independent manner. Stimulation-induced translocation of mutant γPKC in PC dendrites was prominently attenuated by the reduced mobility of oligomerized mutant γPKC, which resulted in attenuated signal transduction and the improper morphology of PC dendrites. These findings suggested that the oligomerization and aggregation of mutant γPKC caused improper dendritic development and apoptosis of PCs, which led to cerebellar dysfunction and SCA14 pathogenesis. We screened the chemicals that improved these cellular dysfunctions and identified several compounds, including trehalose and Congo red, which could be novel therapeutics for SCA14.
Collapse
Affiliation(s)
- Takahiro Seki
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Whaley NR, Fujioka S, Wszolek ZK. Autosomal dominant cerebellar ataxia type I: a review of the phenotypic and genotypic characteristics. Orphanet J Rare Dis 2011; 6:33. [PMID: 21619691 PMCID: PMC3123548 DOI: 10.1186/1750-1172-6-33] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 05/28/2011] [Indexed: 12/26/2022] Open
Abstract
Type I autosomal dominant cerebellar ataxia (ADCA) is a type of spinocerebellar ataxia (SCA) characterized by ataxia with other neurological signs, including oculomotor disturbances, cognitive deficits, pyramidal and extrapyramidal dysfunction, bulbar, spinal and peripheral nervous system involvement. The global prevalence of this disease is not known. The most common type I ADCA is SCA3 followed by SCA2, SCA1, and SCA8, in descending order. Founder effects no doubt contribute to the variable prevalence between populations. Onset is usually in adulthood but cases of presentation in childhood have been reported. Clinical features vary depending on the SCA subtype but by definition include ataxia associated with other neurological manifestations. The clinical spectrum ranges from pure cerebellar signs to constellations including spinal cord and peripheral nerve disease, cognitive impairment, cerebellar or supranuclear ophthalmologic signs, psychiatric problems, and seizures. Cerebellar ataxia can affect virtually any body part causing movement abnormalities. Gait, truncal, and limb ataxia are often the most obvious cerebellar findings though nystagmus, saccadic abnormalities, and dysarthria are usually associated. To date, 21 subtypes have been identified: SCA1-SCA4, SCA8, SCA10, SCA12-SCA14, SCA15/16, SCA17-SCA23, SCA25, SCA27, SCA28 and dentatorubral pallidoluysian atrophy (DRPLA). Type I ADCA can be further divided based on the proposed pathogenetic mechanism into 3 subclasses: subclass 1 includes type I ADCA caused by CAG repeat expansions such as SCA1-SCA3, SCA17, and DRPLA, subclass 2 includes trinucleotide repeat expansions that fall outside of the protein-coding regions of the disease gene including SCA8, SCA10 and SCA12. Subclass 3 contains disorders caused by specific gene deletions, missense mutation, and nonsense mutation and includes SCA13, SCA14, SCA15/16, SCA27 and SCA28. Diagnosis is based on clinical history, physical examination, genetic molecular testing, and exclusion of other diseases. Differential diagnosis is broad and includes secondary ataxias caused by drug or toxic effects, nutritional deficiencies, endocrinopathies, infections and post-infection states, structural abnormalities, paraneoplastic conditions and certain neurodegenerative disorders. Given the autosomal dominant pattern of inheritance, genetic counseling is essential and best performed in specialized genetic clinics. There are currently no known effective treatments to modify disease progression. Care is therefore supportive. Occupational and physical therapy for gait dysfunction and speech therapy for dysarthria is essential. Prognosis is variable depending on the type of ADCA and even among kindreds.
Collapse
|
16
|
Seki T, Takahashi H, Yamamoto K, Ogawa K, Onji T, Adachi N, Tanaka S, Hide I, Saito N, Sakai N. Congo red, an amyloid-inhibiting compound, alleviates various types of cellular dysfunction triggered by mutant protein kinase cγ that causes spinocerebellar ataxia type 14 (SCA14) by inhibiting oligomerization and aggregation. J Pharmacol Sci 2011; 114:206-16. [PMID: 20938103 DOI: 10.1254/jphs.10170fp] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Several missense mutations in the protein kinase Cγ (γPKC) gene have been found to cause spinocerebellar ataxia type 14 (SCA14), an autosomal dominant neurodegenerative disease. We previously demonstrated that the mutant γPKC found in SCA14 is susceptible to aggregation that induces apoptotic cell death. Congo red is widely used as a histological dye for amyloid detection. Recent evidence has revealed that Congo red has the property to inhibit amyloid oligomers and fibril formation of misfolded proteins. In the present study, we examine whether Congo red inhibits aggregate formation and cytotoxicity of mutant γPKC. Congo red likely inhibits aggregate formation of mutant γPKC – green fluorescent protein (GFP) without affecting its expression level in SH-SY5Y cells. Congo red counteracts the insolubilization of recombinant mutant γPKC, suggesting that the dye inhibits aggregation of mutant γPKC by a direct mechanism. Congo red also inhibits aggregation and oligomerization of mutant γPKC-GFP in primary cultured cerebellar Purkinje cells. Moreover, the dye reverses the improper development of dendrites and inhibits apoptotic cell death in Purkinje cells that express mutant γPKC-GFP. These results indicate that amyloid-inhibiting compounds like Congo red may be novel therapeutics for SCA14.
Collapse
Affiliation(s)
- Takahiro Seki
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Seki T, Abe-Seki N, Kikawada T, Takahashi H, Yamamoto K, Adachi N, Tanaka S, Hide I, Saito N, Sakai N. Effect of trehalose on the properties of mutant {gamma}PKC, which causes spinocerebellar ataxia type 14, in neuronal cell lines and cultured Purkinje cells. J Biol Chem 2010; 285:33252-33264. [PMID: 20705605 DOI: 10.1074/jbc.m110.146704] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Several missense mutations in the protein kinase Cγ (γPKC) gene have been found to cause spinocerebellar ataxia type 14 (SCA14), an autosomal dominant neurodegenerative disease. We previously demonstrated that the mutant γPKC found in SCA14 is susceptible to aggregation, which induces apoptotic cell death. The disaccharide trehalose has been reported to inhibit aggregate formation and to alleviate symptoms in cellular and animal models of Huntington disease, Alzheimer disease, and prion disease. Here, we show that trehalose can be incorporated into SH-SY5Y cells and reduces the aggregation of mutant γPKC-GFP, thereby inhibiting apoptotic cell death in SH-SY5Y cells and primary cultured Purkinje cells (PCs). Trehalose acts by directly stabilizing the conformation of mutant γPKC without affecting protein turnover. Trehalose was also found to alleviate the improper development of dendrites in PCs expressing mutant γPKC-GFP without aggregates but not in PCs with aggregates. In PCs without aggregates, trehalose improves the mobility and translocation of mutant γPKC-GFP, probably by inhibiting oligomerization and thereby alleviating the improper development of dendrites. These results suggest that trehalose counteracts various cellular dysfunctions that are triggered by mutant γPKC in both neuronal cell lines and primary cultured PCs by inhibiting oligomerization and aggregation of mutant γPKC.
Collapse
Affiliation(s)
- Takahiro Seki
- From the Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551
| | - Nana Abe-Seki
- From the Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551
| | - Takahiro Kikawada
- National Institute of Agrobiological Sciences, Ohwashi 1-2, Tsukuba, Ibaraki 305-8634
| | - Hideyuki Takahashi
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Kazuhiro Yamamoto
- From the Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551
| | - Naoko Adachi
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Shigeru Tanaka
- From the Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551
| | - Izumi Hide
- From the Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551
| | - Naoaki Saito
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Norio Sakai
- From the Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551.
| |
Collapse
|
18
|
Yamamoto K, Seki T, Adachi N, Takahashi T, Tanaka S, Hide I, Saito N, Sakai N. Mutant protein kinase C gamma that causes spinocerebellar ataxia type 14 (SCA14) is selectively degraded by autophagy. Genes Cells 2010; 15:425-38. [PMID: 20398063 DOI: 10.1111/j.1365-2443.2010.01395.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several causal missense mutations in the protein kinase Cgamma (gammaPKC) gene have been found in spinocerebellar ataxia type 14 (SCA14), an autosomal dominant neurodegenerative disease. We previously showed that mutant gammaPKC found in SCA14 is susceptible to aggregation and causes apoptosis. Aggregation of misfolded proteins is generally involved in the pathogenesis of many neurodegenerative diseases. Growing evidence indicates that macroautophagy (autophagy) is important for the degradation of misfolded proteins and the prevention of neurodegenerative diseases. In the present study, we examined whether autophagy is involved in the degradation of the mutant gammaPKC that causes SCA14. Mutant gammaPKC-GFP was transiently expressed in SH-SY5Y cells by using an adenoviral tetracycline-regulated system. Subsequently, temporal changes in clearance of aggregates and degradation of gammaPKC-GFP were evaluated. Rapamycin, an autophagic inducer, accelerated clearance of aggregates and promoted degradation of mutant gammaPKC-GFP, but it did not affect degradation of wild-type gammaPKC-GFP. These effects of rapamycin were not observed in embryonic fibroblast cells from Atg5-deficient mice, which are not able to perform autophagy. Furthermore, lithium, another type of autophagic inducer, also promoted the clearance of mutant gammaPKC aggregates. These results indicate that autophagy contributes to the degradation of mutant gammaPKC, suggesting that autophagic inducers could provide therapeutic potential for SCA14.
Collapse
Affiliation(s)
- Kazuhiro Yamamoto
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi Minami-ku, Hiroshima 734-8551, Japan
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Seki T, Shimahara T, Yamamoto K, Abe N, Amano T, Adachi N, Takahashi H, Kashiwagi K, Saito N, Sakai N. Mutant γPKC found in spinocerebellar ataxia type 14 induces aggregate-independent maldevelopment of dendrites in primary cultured Purkinje cells. Neurobiol Dis 2009; 33:260-73. [DOI: 10.1016/j.nbd.2008.10.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Accepted: 10/18/2008] [Indexed: 12/23/2022] Open
|
20
|
Zhang Y, Snider A, Willard L, Takemoto DJ, Lin D. Loss of Purkinje cells in the PKCgamma H101Y transgenic mouse. Biochem Biophys Res Commun 2008; 378:524-8. [PMID: 19056342 DOI: 10.1016/j.bbrc.2008.11.082] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Accepted: 11/16/2008] [Indexed: 11/25/2022]
Abstract
Spinocerebellar ataxia type 14 (SCA14) is an autosomal, dominant neurodegenerative disorder caused by mutations in PKCgamma. The objective of this study was to determine effects of PKCgamma H101Y SCA14 mutation on Purkinje cells in the transgenic mouse. Results demonstrated that wild type PKCgamma-like Purkinje cell localization of HA-tagged PKCgamma H101Y mutant proteins, altered morphology and loss of Purkinje cells were observed in the PKCgamma H101Y SCA14 transgenic mouse at four weeks of age. Failure of stereotypical clasping responses in the hind limbs of transgenic mice was also observed. Further, PKCgamma H101Y SCA14 mutation caused lack of total cellular PKCgamma enzyme activity, loss of connexin 57 phosphorylation on serines, and activation of caspase-12 in the PKCgamma H101Y SCA14 transgenic mouse. Results clearly demonstrate a need for PKCgamma control of gap junctions for maintenance of Purkinje cells. This is the first transgenic mouse to our knowledge which models a human SCA14 mutation.
Collapse
Affiliation(s)
- Yunong Zhang
- Department of Human Nutrition, Kansas State University, 212 Justin Hall, Manhattan, KS 66506, USA
| | | | | | | | | |
Collapse
|
21
|
Miura S, Nakagawara H, Kaida H, Sugita M, Noda K, Motomura K, Ohyagi Y, Ayabe M, Aizawa H, Ishibashi M, Taniwaki T. Expansion of the phenotypic spectrum of SCA14 caused by the Gly128Asp mutation in PRKCG. Clin Neurol Neurosurg 2008; 111:211-5. [PMID: 18986758 DOI: 10.1016/j.clineuro.2008.09.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 09/11/2008] [Accepted: 09/14/2008] [Indexed: 11/16/2022]
Abstract
Two cases of spinocerebellar ataxia type 14 (SCA14) with a G128D mutation in the protein kinase C gamma gene (PRKCG) without a definite family history have been reported previously. Here, we describe the first familial cases of SCA14 with a G128D mutation in PRKCG. Among three family members, the chief complaints varied and included ataxic gait, cervical dystonia, and positional vertigo. Moreover, retinal degeneration and facial muscle weakness were observed, although these are not expected to be present in SCA14. Cerebral blood flow evaluation using single photon emission computed tomography (SPECT) also differed among family members. It is possible that patients with the G128D mutation suffering from SCA14 may sometimes be classified as unaffected due to the varying clinical signs among family members.
Collapse
Affiliation(s)
- Shiroh Miura
- Division of Respirology, Neurology and Rheumatology, Department of Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Adachi N, Kobayashi T, Takahashi H, Kawasaki T, Shirai Y, Ueyama T, Matsuda T, Seki T, Sakai N, Saito N. Enzymological analysis of mutant protein kinase Cgamma causing spinocerebellar ataxia type 14 and dysfunction in Ca2+ homeostasis. J Biol Chem 2008; 283:19854-63. [PMID: 18499672 DOI: 10.1074/jbc.m801492200] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant neurodegenerative disease caused by mutations in protein kinase Cgamma (PKCgamma). Interestingly, 18 of 22 mutations are concentrated in the C1 domain, which binds diacylglycerol and is necessary for translocation and regulation of PKCgamma kinase activity. To determine the effect of these mutations on PKCgamma function and the pathology of SCA14, we investigated the enzymological properties of the mutant PKCgammas. We found that wild-type PKCgamma, but not C1 domain mutants, inhibits Ca2+ influx in response to muscarinic receptor stimulation. The sustained Ca2+ influx induced by muscarinic receptor ligation caused prolonged membrane localization of mutant PKCgamma. Pharmacological experiments showed that canonical transient receptor potential (TRPC) channels are responsible for the Ca2+ influx regulated by PKCgamma. Although in vitro kinase assays revealed that most C1 domain mutants are constitutively active, they could not phosphorylate TRPC3 channels in vivo. Single molecule observation by the total internal reflection fluorescence microscopy revealed that the membrane residence time of mutant PKCgammas was significantly shorter than that of the wild-type. This fact indicated that, although membrane association of the C1 domain mutants was apparently prolonged, these mutants have a reduced ability to bind diacylglycerol and be retained on the plasma membrane. As a result, they fail to phosphorylate TRPC channels, resulting in sustained Ca2+ entry. Such an alteration in Ca2+ homeostasis and Ca2+-mediated signaling in Purkinje cells may contribute to the neurodegeneration characteristic of SCA14.
Collapse
Affiliation(s)
- Naoko Adachi
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Seki T, Takahashi H, Adachi N, Abe N, Shimahara T, Saito N, Sakai N. Aggregate formation of mutant protein kinase C gamma found in spinocerebellar ataxia type 14 impairs ubiquitin-proteasome system and induces endoplasmic reticulum stress. Eur J Neurosci 2007; 26:3126-40. [DOI: 10.1111/j.1460-9568.2007.05933.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
24
|
Basri R, Yabe I, Soma H, Sasaki H. Spectrum and prevalence of autosomal dominant spinocerebellar ataxia in Hokkaido, the northern island of Japan: a study of 113 Japanese families. J Hum Genet 2007; 52:848-855. [PMID: 17805477 DOI: 10.1007/s10038-007-0182-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Accepted: 07/31/2007] [Indexed: 11/28/2022]
Abstract
Autosomal dominant cerebellar ataxia (ADCA) is a genetically heterogeneous group of neurodegenerative disorders. To shed further light on the clinical and genetic spectrum of ADCA in Japan, we conducted a study to determine the frequency of a new variety of different subtypes of SCAs among ADCA patients. This current study was carried out from April 1999 to December 2006 on the basis of patients with symptoms and signs of ADCA disorders. PCR and/or direct sequencing were evaluated in a total of 113 families. Among them, 35 families were found to have the mutation associated with SCA6, 30 with SCA3, 11 with SCA1, five with SCA2, five with DRPLA, and one with SCA14. We also detected the heterozygous -16C --> T single nucleotide substitution within the puratrophin-1 gene responsible for 16q22.1-linked ADCA in ten families. In this study, unusual varieties of SCA, including 27, 13, 5, 7, 8, 12, 17, and 16 were not found. Of the 113 patients, 14% had as yet unidentified ADCA mutations. The present study validates the prevalence of genetically distinct ADCA subtypes based on ethnic origin and geographical variation, and shows that 16q-linked ADCA has strong hereditary effects in patients with ADCAs in Japan.
Collapse
Affiliation(s)
- Rehana Basri
- Department of Neurology, Graduate School of Medicine, Hokkaido University, N15W7. Kita-Ku, Sapporo, 060-8368, Japan
| | - Ichiro Yabe
- Department of Neurology, Graduate School of Medicine, Hokkaido University, N15W7. Kita-Ku, Sapporo, 060-8368, Japan.
| | - Hiroyuki Soma
- Department of Neurology, Graduate School of Medicine, Hokkaido University, N15W7. Kita-Ku, Sapporo, 060-8368, Japan
| | - Hidenao Sasaki
- Department of Neurology, Graduate School of Medicine, Hokkaido University, N15W7. Kita-Ku, Sapporo, 060-8368, Japan
| |
Collapse
|
25
|
Nolte D, Landendinger M, Schmitt E, Müller U. Spinocerebellar ataxia 14: Novel mutation in exon 2 ofPRKCG in a German family. Mov Disord 2007; 22:265-7. [PMID: 17149711 DOI: 10.1002/mds.21269] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
We describe a novel mutation in the gene coding for protein kinase C gamma (PRKCG) in patients of a German family affected with slowly progressive gait ataxia, dysarthria, and nystagmus. The G/T missense mutation occurred in exon 2 of PRKCG and results in a substitution of glycine by valine (G63V) in the evolutionarily highly conserved cysteine-rich region 1/C1 domain of PRKCG. Among the 20 mutations described to date, this is the first mutation located in exon 2 of PRKCG.
Collapse
Affiliation(s)
- Dagmar Nolte
- Institut für Humangenetik, Justus-Liebig Universität Giessen, Germany.
| | | | | | | |
Collapse
|
26
|
Morita H, Yoshida K, Suzuki K, Ikeda SI. A Japanese case of SCA14 with the Gly128Asp mutation. J Hum Genet 2006; 51:1118-1121. [PMID: 17024314 DOI: 10.1007/s10038-006-0063-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Accepted: 08/22/2006] [Indexed: 12/28/2022]
Abstract
Spinocerebellar ataxia type 14 (SCA14) is a rare form of autosomal dominant cerebellar ataxias caused by mutations in the protein kinase Cgamma gene (PRKCG). We have identified a Japanese patient with SCA14 who carried the Gly128Asp mutation in PRKCG. She first noticed gait unsteadiness at around age 42, and then her gait ataxia worsened very slowly for more than 20 years. At age 62, she was still ambulatory, although cerebellar ataxia was clinically evident. She is the second patient identified with the G128D mutation. Both patients with this mutation showed pure cerebellar ataxia. With only two families with SCA14 found in Japan prior to this study, the clinical features and disease-causing mutations in PRKCG are heterogeneous in the same ethnic background.
Collapse
Affiliation(s)
- Hiroshi Morita
- Department of Medicine (Neurology), Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
| | - Kunihiro Yoshida
- Department of Medicine (Neurology), Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Kayo Suzuki
- Department of Instrumental Analysis, Research Center for Human and Environmental Science, Shinshu University, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
| | - Shu-Ichi Ikeda
- Department of Medicine (Neurology), Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
| |
Collapse
|