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Kapfhammer JP, Shimobayashi E. Viewpoint: spinocerebellar ataxias as diseases of Purkinje cell dysfunction rather than Purkinje cell loss. Front Mol Neurosci 2023; 16:1182431. [PMID: 37426070 PMCID: PMC10323145 DOI: 10.3389/fnmol.2023.1182431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/22/2023] [Indexed: 07/11/2023] Open
Abstract
Spinocerebellar ataxias (SCAs) are a group of hereditary neurodegenerative diseases mostly affecting cerebellar Purkinje cells caused by a wide variety of different mutations. One subtype, SCA14, is caused by mutations of Protein Kinase C gamma (PKCγ), the dominant PKC isoform present in Purkinje cells. Mutations in the pathway in which PKCγ is active, i.e., in the regulation of calcium levels and calcium signaling in Purkinje cells, are the cause of several other variants of SCA. In SCA14, many of the observed mutations in the PKCγ gene were shown to increase the basal activity of PKCγ, raising the possibility that increased activity of PKCγ might be the cause of most forms of SCA14 and might also be involved in the pathogenesis of SCA in related subtypes. In this viewpoint and review article we will discuss the evidence for and against such a major role of PKCγ basal activity and will suggest a hypothesis of how PKCγ activity and the calcium signaling pathway may be involved in the pathogenesis of SCAs despite the different and sometimes opposing effects of mutations affecting these pathways. We will then widen the scope and propose a concept of SCA pathogenesis which is not primarily driven by cell death and loss of Purkinje cells but rather by dysfunction of Purkinje cells which are still present and alive in the cerebellum.
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Abid F, Khan K, Badshah Y, Ashraf NM, Shabbir M, Hamid A, Afsar T, Almajwal A, Razak S. Non-synonymous SNPs variants of PRKCG and its association with oncogenes predispose to hepatocellular carcinoma. Cancer Cell Int 2023; 23:123. [PMID: 37344815 PMCID: PMC10286404 DOI: 10.1186/s12935-023-02965-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/07/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND PRKCG encodes PKC γ, which is categorized under the classical protein kinase C family. No studies have specifically established the relationship between PRKCG nsSNPs with structural and functional variations in PKC γ in the context of hepatocellular carcinoma (HCC). The present study aims to uncover this link through in-silico and experimental studies. METHODS The 3D structure of PKC γ was predicted. Molecular Dynamic (MD) Simulations were run and estimates were made for interactions, stability, conservation and post-translational alterations between wild and mutant structures. The association of PRKCG levels with HCC survival rate was determined. Genotyping analyses were conducted to investigate the deleterious PRKCG nsSNP association with HCC. mRNA expression of PKC γ, HIF-1 alpha, AKT, SOCS3 and VEGF in the blood of controls and HCC patients was analyzed and a genetic cascade was constructed depicting these interactions. RESULTS The expression level of studied oncogenes was compared to tumour suppressor genes. Through Alphafold, the 3D structure of PKC γ was explored. Fifteen SNPs were narrowed down for in-silico analyses that were identified in exons 5, 10 and 18 and the regulatory and kinase domain of PKC γ. Root mean square deviation and fluctuation along with the radius of gyration unveiled potential changes between the wild and mutated variant structures. Mutant genotype AA (homozygous) corresponding to nsSNP, rs386134171 had more frequency in patients with OR (2.446), RR (1.564) and P-values (< 0.0029) that highlights its significant association with HCC compared to controls in which the wild genotype GG was found more prevalent. CONCLUSION nsSNP rs386134171 can be a genetic marker for HCC diagnosis and therapeutic studies. This study has laid down a road map for future studies to be conducted on HCC.
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Affiliation(s)
- Fizzah Abid
- Department of Healthcare Biotechnology, Atta-Ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, 44010, Pakistan
| | - Khushbukhat Khan
- Department of Healthcare Biotechnology, Atta-Ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, 44010, Pakistan
| | - Yasmin Badshah
- Department of Healthcare Biotechnology, Atta-Ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, 44010, Pakistan
| | - Naeem Mahmood Ashraf
- School of Biochemistry and Biotechnology, University of the Punjab, Lahore, 54590, Pakistan
| | - Maria Shabbir
- Department of Healthcare Biotechnology, Atta-Ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, 44010, Pakistan.
| | - Arslan Hamid
- LIMES Institute (AG-Netea), University of Bonn, Carl-Troll-Str. 31, 53115, Bonn, Germany
| | - Tayyaba Afsar
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Ali Almajwal
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Suhail Razak
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
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Sun R, Tang X, Cao X, Shao X, Sun H. Novel mutation in exon11 of PRKCG (SCA14): A case report. Front Genet 2023; 14:1129988. [PMID: 36968593 PMCID: PMC10031122 DOI: 10.3389/fgene.2023.1129988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/13/2023] [Indexed: 03/29/2023] Open
Abstract
Introduction: PRKCG mutations have been implicated in the pathogenesis of spinocerebellar ataxia type 14 (SCA14), which is a rare autosomal dominant disease marked by cerebellar degeneration, dysarthria, and nystagmus. Until now, there has never been a report of patients with mutations of c.1232G>C worldwide. Case description: We report a case of a 30-year-old Chinese man with episodic dystaxia, speech disorder, and cognitive impairment; however, his father exclusively exhibited a speech disorder regardless of the same mutation. Whole-exome sequencing revealed a heterozygous c.1232G>C (p.G411A) variant of PRKCG. Conclusion: This case presents an extended genotype and phenotype of SCA14, and emphasizes the importance of gene sequencing in patients with spinocerebellar ataxia.
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Affiliation(s)
- Rong Sun
- Department of Endocrinology and Metabolism, Dushu Lake Hospital Affiliated to Soochow University, Medical Center of Soochow University, Suzhou, Jiangsu, China
| | - Xiang Tang
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Xueqin Cao
- Department of Endocrinology and Metabolism, Dushu Lake Hospital Affiliated to Soochow University, Medical Center of Soochow University, Suzhou, Jiangsu, China
| | - Xinyu Shao
- Department of Endocrinology and Metabolism, Dushu Lake Hospital Affiliated to Soochow University, Medical Center of Soochow University, Suzhou, Jiangsu, China
- *Correspondence: Hong Sun, ; Xinyu Shao,
| | - Hong Sun
- Department of Endocrinology and Metabolism, Dushu Lake Hospital Affiliated to Soochow University, Medical Center of Soochow University, Suzhou, Jiangsu, China
- *Correspondence: Hong Sun, ; Xinyu Shao,
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Wu QW, Kapfhammer JP. The Emerging Key Role of the mGluR1-PKCγ Signaling Pathway in the Pathogenesis of Spinocerebellar Ataxias: A Neurodevelopmental Viewpoint. Int J Mol Sci 2022; 23:ijms23169169. [PMID: 36012439 PMCID: PMC9409119 DOI: 10.3390/ijms23169169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 12/19/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are a heterogeneous group of autosomal dominantly inherited progressive disorders with degeneration and dysfunction of the cerebellum. Although different subtypes of SCAs are classified according to the disease-associated causative genes, the clinical syndrome of the ataxia is shared, pointing towards a possible convergent pathogenic pathway among SCAs. In this review, we summarize the role of SCA-associated gene function during cerebellar Purkinje cell development and discuss the relationship between SCA pathogenesis and neurodevelopment. We will summarize recent studies on molecules involved in SCA pathogenesis and will focus on the mGluR1-PKCγ signaling pathway evaluating the possibility that this might be a common pathway which contributes to these diseases.
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Pilo CA, Newton AC. Two Sides of the Same Coin: Protein Kinase C γ in Cancer and Neurodegeneration. Front Cell Dev Biol 2022; 10:929510. [PMID: 35800893 PMCID: PMC9253466 DOI: 10.3389/fcell.2022.929510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/23/2022] [Indexed: 12/23/2022] Open
Abstract
Protein kinase C (PKC) isozymes transduce myriad signals within the cell in response to the generation of second messengers from membrane phospholipids. The conventional isozyme PKCγ reversibly binds Ca2+ and diacylglycerol, which leads to an open, active conformation. PKCγ expression is typically restricted to neurons, but evidence for its expression in certain cancers has emerged. PKC isozymes have been labeled as oncogenes since the discovery that they bind tumor-promoting phorbol esters, however, studies of cancer-associated PKC mutations and clinical trial data showing that PKC inhibitors have worsened patient survival have reframed PKC as a tumor suppressor. Aberrant expression of PKCγ in certain cancers suggests a role outside the brain, although whether PKCγ also acts as a tumor suppressor remains to be established. On the other hand, PKCγ variants associated with spinocerebellar ataxia type 14 (SCA14), a neurodegenerative disorder characterized by Purkinje cell degeneration, enhance basal activity while preventing phorbol ester-mediated degradation. Although the basis for SCA14 Purkinje cell degeneration remains unknown, studies have revealed how altered PKCγ activity rewires cerebellar signaling to drive SCA14. Importantly, enhanced basal activity of SCA14-associated mutants inversely correlates with age of onset, supporting that enhanced PKCγ activity drives SCA14. Thus, PKCγ activity should likely be inhibited in SCA14, whereas restoring PKC activity should be the goal in cancer therapies. This review describes how PKCγ activity can be lost or gained in disease and the overarching need for a PKC structure as a powerful tool to predict the effect of PKCγ mutations in disease.
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Affiliation(s)
- Caila A. Pilo
- Department of Pharmacology, University of California, San Diego, San Diego, CA, United States
- Biomedical Sciences Graduate Program, University of California, San Diego, San Diego, CA, United States
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, San Diego, San Diego, CA, United States
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Wu QW, Kapfhammer JP. Serine/threonine kinase 17b (STK17B) signalling regulates Purkinje cell dendritic development and is altered in multiple spinocerebellar ataxias. Eur J Neurosci 2021; 54:6673-6684. [PMID: 34536317 PMCID: PMC9292345 DOI: 10.1111/ejn.15465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 09/07/2021] [Accepted: 09/11/2021] [Indexed: 11/28/2022]
Abstract
Serine/threonine kinase 17b (STK17B, also known as DRAK2) is known to be a downstream effector of protein kinase C (PKC) in the immune system, in particular T lymphocytes. PKC activity also plays a critical role for dendritic development and synaptic maturation and plasticity in cerebellar Purkinje cells. We present evidence that STK17B is strongly expressed in mouse cerebellar Purkinje cells starting in the early postnatal period and remaining highly expressed throughout adult stages and that STK17B is a target of PKC phosphorylation in the cerebellum. STK17B overexpression potentiates the morphological changes of Purkinje cells seen after PKC activation, suggesting that it is a downstream effector of PKC. A phosphorylation mimetic STK17B variant induced a marked reduction of Purkinje cell dendritic tree size, whereas the inhibition of STK17B with the novel compound 16 (Cpd16) could partially rescue the morphological changes of the Purkinje cell dendritic tree after PKC activation. These findings show that STK17B signalling is an important downstream effector of PKC activation in Purkinje cells. Furthermore, STK17B was identified as a molecule being transcriptionally downregulated in mouse models of SCA1, SCA7, SCA14 and SCA41. The reduced expression of STK17B in these mouse models might protect Purkinje cell dendrites from the negative effects of overactivated PKC signalling. Our findings provide new insights in the role of STK17B for Purkinje cell dendritic development and the pathology of SCAs.
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Affiliation(s)
- Qin-Wei Wu
- Institute of Anatomy, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Josef P Kapfhammer
- Institute of Anatomy, Department of Biomedicine, University of Basel, Basel, Switzerland
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7
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Wu QW, Kapfhammer JP. Conditional gene silencing via a CRISPR system in cerebellar Purkinje cells. Biochim Biophys Acta Gen Subj 2021; 1865:129869. [PMID: 33581252 DOI: 10.1016/j.bbagen.2021.129869] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 12/26/2022]
Abstract
• Specific gene knockdown in cerebellar Purkinje cells is a major challenge because Purkinje cells only make up a small fraction of the cerebellum and off-target effects of shRNA occur.
• Little is known about the application of CRISPR-Cas13 and the resulting protein expression levels in Purkinje cells, a type of developing postmitotic neuron.
• We explored the possibility of a Cas13-mediated conditional knockdown system for cerebellar Purkinje cells. This system can achieve a suppression of the target proteins restricted to Purkinje cells in mixed cerebellar cultures.
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Affiliation(s)
- Qin-Wei Wu
- Institute of Anatomy, Department of Biomedicine, University of Basel, Pestalozzistr. 20, 4056 Basel, Switzerland.
| | - Josef P Kapfhammer
- Institute of Anatomy, Department of Biomedicine, University of Basel, Pestalozzistr. 20, 4056 Basel, Switzerland.
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8
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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.
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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
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9
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Wu QW, Kapfhammer JP. Modulation of Increased mGluR1 Signaling by RGS8 Protects Purkinje Cells From Dendritic Reduction and Could Be a Common Mechanism in Diverse Forms of Spinocerebellar Ataxia. Front Cell Dev Biol 2021; 8:569889. [PMID: 33553137 PMCID: PMC7858651 DOI: 10.3389/fcell.2020.569889] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 12/30/2020] [Indexed: 12/13/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are a group of hereditary neurodegenerative diseases which are caused by diverse genetic mutations in a variety of different genes. We have identified RGS8, a regulator of G-protein signaling, as one of the genes which are dysregulated in different mouse models of SCA (e.g., SCA1, SCA2, SCA7, and SCA14). In the moment, little is known about the role of RGS8 for pathogenesis of spinocerebellar ataxia. We have studied the expression of RGS8 in the cerebellum in more detail and show that it is specifically expressed in mouse cerebellar Purkinje cells. In a mouse model of SCA14 with increased PKCγ activity, RGS8 expression was also increased. RGS8 overexpression could partially counteract the negative effects of DHPG-induced mGluR1 signaling for the expansion of Purkinje cell dendrites. Our results suggest that the increased expression of RGS8 is an important mediator of mGluR1 pathway dysregulation in Purkinje cells. These findings provide new insights in the role of RGS8 and mGluR1 signaling in Purkinje cells and for the pathology of SCAs.
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Affiliation(s)
- Qin-Wei Wu
- Institute of Anatomy, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Josef P Kapfhammer
- Institute of Anatomy, Department of Biomedicine, University of Basel, Basel, Switzerland
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10
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Winkler SC, Shimobayashi E, Kapfhammer JP. PKCγ-Mediated Phosphorylation of CRMP2 Regulates Dendritic Outgrowth in Cerebellar Purkinje Cells. Mol Neurobiol 2020; 57:5150-5166. [PMID: 32860158 PMCID: PMC7541385 DOI: 10.1007/s12035-020-02038-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/22/2020] [Indexed: 11/02/2022]
Abstract
The signalling protein PKCγ is a major regulator of Purkinje cell development and synaptic function. We have shown previously that increased PKCγ activity impairs dendritic development of cerebellar Purkinje cells. Mutations in the protein kinase Cγ gene (PRKCG) cause spinocerebellar ataxia type 14 (SCA14). In a transgenic mouse model of SCA14 expressing the human S361G mutation, Purkinje cell dendritic development is impaired in cerebellar slice cultures similar to pharmacological activation of PKC. The mechanisms of PKCγ-driven inhibition of dendritic growth are still unclear. Using immunoprecipitation-coupled mass spectrometry analysis, we have identified collapsin response mediator protein 2 (CRMP2) as a protein interacting with constitutive active PKCγ(S361G) and confirmed the interaction with the Duolink™ proximity ligation assay. We show that in cerebellar slice cultures from PKCγ(S361G)-mice, phosphorylation of CRMP2 at the known PKC target site Thr555 is increased in Purkinje cells confirming phosphorylation of CRMP2 by PKCγ. miRNA-mediated CRMP2 knockdown decreased Purkinje cell dendritic outgrowth in dissociated cerebellar cultures as did the transfection of CRMP2 mutants with a modified Thr555 site. In contrast, dendritic development was normal after wild-type CRMP2 overexpression. In a novel knock-in mouse expressing only the phospho-defective T555A-mutant CRMP2, Purkinje cell dendritic development was reduced in dissociated cultures. This reduction could be rescued by transfecting wild-type CRMP2 but only partially by the phospho-mimetic T555D-mutant. Our findings establish CRMP2 as an important target of PKCγ phosphorylation in Purkinje cells mediating its control of dendritic development. Dynamic regulation of CRMP2 phosphorylation via PKCγ is required for its correct function.
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Affiliation(s)
- Sabine C Winkler
- Anatomical Institute, Department of Biomedicine, University of Basel, Pestalozzistrasse 20, CH - 4056, Basel, Switzerland
| | - Etsuko Shimobayashi
- Anatomical Institute, Department of Biomedicine, University of Basel, Pestalozzistrasse 20, CH - 4056, Basel, Switzerland
| | - Josef P Kapfhammer
- Anatomical Institute, Department of Biomedicine, University of Basel, Pestalozzistrasse 20, CH - 4056, Basel, Switzerland.
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PDK1 Regulates the Maintenance of Cell Body and the Development of Dendrites of Purkinje Cells by pS6 and PKCγ. J Neurosci 2020; 40:5531-5548. [PMID: 32487697 DOI: 10.1523/jneurosci.2496-19.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 01/09/2023] Open
Abstract
3-Phosphoinositide-dependent protein kinase-1 (PDK1) plays a critical role in the development of mammalian brain. Here, we investigated the role of PDK1 in Purkinje cells (PCs) by generating the PDK1-conditional knock-out mice (cKO) through crossing PV-cre or Pcp2-cre mice with Pdk1fl/fl mice. The male mice were used in the behavioral testing, and the other experiments were performed on mice of both sexes. These PDK1-cKO mice displayed decreased cerebellar size and impaired motor balance and coordination. By the electrophysiological recording, we observed the reduced spontaneous firing of PCs from the cerebellar slices of the PDK1-cKO mice. Moreover, the cell body size of PCs in the PDK1-cKO mice was time dependently reduced compared with that in the control mice. And the morphologic complexity of PCs was also decreased after PDK1 deletion. These effects may have contributed to the reduction of the rpS6 (reduced ribosomal protein S6) phosphorylation and the PKCγ expression in PDK1-cKO mice since the upregulation of pS6 by treatment of 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-1, the agonist of mTOR1, partly rescued the reduction in the cell body size of the PCs, and the delivery of recombinant adeno-associated virus-PKCγ through cerebellar injection rescued the reduced complexity of the dendritic arbor in PDK1-cKO mice. Together, our data suggest that PDK1, by regulating rpS6 phosphorylation and PKCγ expression, controls the cell body maintenance and the dendritic development in PCs and is critical for cerebellar motor coordination.SIGNIFICANCE STATEMENT Here, we show the role of 3-phosphoinositide-dependent protein kinase-1 (PDK1) in Purkinje cells (PCs). The ablation of PDK1 in PCs resulted in a reduction of cell body size, and dendritic complexity and abnormal spontaneous firing, which attributes to the motor defects in PDK1-conditional knock-out (cKO) mice. Moreover, the ribosomal protein S6 (rpS6) phosphorylation and the expression of PKCγ are downregulated after the ablation of PDK1. Additionally, upregulation of rpS6 phosphorylation by3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-1 partly rescued the reduction in cell body size of PCs, and the overexpression of PKCγ in PDK1-KO PCs rescued the reduction in the dendritic complexity. These findings indicate that PDK1 contributes to the maintenance of the cell body and the dendritic development of PCs by regulating rpS6 phosphorylation and PKCγ expression.
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12
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The CRISPR-Cas13a system interferes with Purkinje cell dendritic development. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118710. [DOI: 10.1016/j.bbamcr.2020.118710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/18/2020] [Accepted: 03/24/2020] [Indexed: 12/26/2022]
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13
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Alexander CJ, Hammer JA. An Improved Method for Differentiating Mouse Embryonic Stem Cells into Cerebellar Purkinje Neurons. THE CEREBELLUM 2019; 18:406-421. [PMID: 30729383 DOI: 10.1007/s12311-019-1007-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
While mixed primary cerebellar cultures prepared from embryonic tissue have proven valuable for dissecting structure-function relationships in cerebellar Purkinje neurons (PNs), this technique is technically challenging and often yields few cells. Recently, mouse embryonic stem cells (mESCs) have been successfully differentiated into PNs, although the published methods are very challenging as well. The focus of this study was to simplify the differentiation of mESCs into PNs. Using a recently described neural differentiation media, we generate monolayers of neural progenitor cells from mESCs and differentiate them into PN precursors using specific extrinsic factors. These PN precursors are then differentiated into mature PNs by co-culturing them with granule neuron (GN) precursors also derived from neural progenitors using different extrinsic factors. The morphology of mESC-derived PNs is indistinguishable from PNs grown in primary culture in terms of gross morphology, spine length, and spine density. Furthermore, mESC-derived PNs express Calbindin D28K, IP3R1, IRBIT, PLCβ4, PSD93, and myosin IIB-B2, all of which are either PN-specific or highly expressed in PNs. Moreover, we show that mESC-derived PNs form synapses with GN-like cells as in primary culture, express proteins driven by the PN-specific promoter Pcp2/L7, and exhibit the defect in spine ER inheritance seen in PNs isolated from dilute-lethal (myosin Va-null) mice when expressing a Pcp2/L7-driven miRNA directed against myosin Va. Finally, we define a novel extracellular matrix formulation that reproducibly yields monolayer cultures conducive for high-resolution imaging. Our improved method for differentiating mESCs into PNs should facilitate the dissection of molecular mechanisms and disease phenotypes in PNs.
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Affiliation(s)
- Christopher J Alexander
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - John A Hammer
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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14
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Calcium-dependent kinases in the brain have site-specific associations with locomotion and rearing impairments in rats with bile duct ligation. Behav Brain Res 2019; 372:112009. [DOI: 10.1016/j.bbr.2019.112009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/15/2019] [Accepted: 06/03/2019] [Indexed: 12/31/2022]
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15
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Chelban V, Wiethoff S, Fabian-Jessing BK, Haridy NA, Khan A, Efthymiou S, Becker EBE, O'Connor E, Hersheson J, Newland K, Hojland AT, Gregersen PA, Lindquist SG, Petersen MB, Nielsen JE, Nielsen M, Wood NW, Giunti P, Houlden H. Genotype-phenotype correlations, dystonia and disease progression in spinocerebellar ataxia type 14. Mov Disord 2018; 33:1119-1129. [PMID: 29603387 PMCID: PMC6175136 DOI: 10.1002/mds.27334] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/16/2018] [Accepted: 01/21/2018] [Indexed: 12/11/2022] Open
Abstract
Background: Spinocerebellar ataxia type 14 is a rare form of autosomal dominant cerebellar ataxia caused by mutations in protein kinase Cγ gene. Clinically, it presents with a slowly progressive, mainly pure cerebellar ataxia. Methods: Using next generation sequencing, we screened 194 families with autosomal dominant cerebellar ataxia and normal polyglutamine repeats. In‐depth phenotyping was performed using validated clinical rating scales neuroimaging and electrophysiological investigations. Results: We identified 25 individuals from 13 families carrying pathogenic mutations in protein kinase Cγ gene. A total of 10 unique protein kinase Cγ gene mutations have been confirmed of which 5 are novel and 5 were previously described. Our data suggest that the age at onset is highly variable; disease course is slowly progressive and rarely associated with severe disability. However, one third of patients presented with a complex ataxia comprising severe focal and/or task‐induced dystonia, peripheral neuropathy, parkinsonism, myoclonus, and pyramidal syndrome. The most complex phenotype is related to a missense mutation in the catalytic domain in exon 11. Conclusion: We present one of the largest genetically confirmed spinocerebellar ataxia type 14 cohorts contributing novel variants and clinical characterisation. We show that although protein kinase Cγ gene mutations present mainly as slowly progressive pure ataxia, more than a third of cases had a complex phenotype. Overall, our case series extends the phenotype and suggests that protein kinase Cγ gene mutations should be considered in patients with slowly progressive autosomal dominant cerebellar ataxia, particularly when myoclonus, dystonia, or mild cognitive impairment are present in the absence of polyglutamine expansion. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Viorica Chelban
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK.,National Hospital for Neurology and Neurosurgery, London, UK.,Department of Neurology and Neurosurgery, Institute of Emergency Medicine, Chisinau, Republic of Moldova
| | - Sarah Wiethoff
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK.,Center for Neurology and Hertie Institute for Clinical Brain Research, Eberhard-Karls-University, Tübingen, Germany
| | | | - Nourelhoda A Haridy
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK.,Department of Neurology and Psychiatry, Assiut University Hospital, Faculty of Medicine, Assiut, Egypt
| | - Alaa Khan
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK
| | - Stephanie Efthymiou
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK
| | - Esther B E Becker
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Emer O'Connor
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK
| | - Joshua Hersheson
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK
| | - Katrina Newland
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK
| | | | | | - Suzanne G Lindquist
- Danish Dementia Research Centre, Neurogenetics Clinic, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Genetics, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Michael B Petersen
- Department of Clinical Genetics, Aalborg University Hospital, Aalborg, Denmark
| | - Jørgen E Nielsen
- Danish Dementia Research Centre, Neurogenetics Clinic, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Michael Nielsen
- Department of Neurology, Aalborg University Hospital, Aalborg, Denmark
| | - Nicholas W Wood
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK.,National Hospital for Neurology and Neurosurgery, London, UK
| | - Paola Giunti
- Deparmtent of Molecular Neuroscience, Ataxia Centre UCL, Institute of Neurology, London, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, University College London, Institute of Neurology, London, UK.,National Hospital for Neurology and Neurosurgery, London, UK
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