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Chen JM, Chen SK, Jin PP, Sun SC. Identification of the ataxin-1 interaction network and its impact on spinocerebellar ataxia type 1. Hum Genomics 2022; 16:29. [PMID: 35906672 PMCID: PMC9335979 DOI: 10.1186/s40246-022-00404-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 07/22/2022] [Indexed: 12/03/2022] Open
Abstract
Background Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disease caused by a polyglutamine expansion in the ataxin-1 protein. The pathogenic mechanism resulting in SCA1 is still unclear. Protein–protein interactions affect the function and stability of ataxin-1. Methods Wild-type and mutant ataxin-1 were expressed in HEK-293T cells. The levels of expression were assessed using real-time polymerase chain reaction (PCR) and Western blots. Co-immunoprecipitation was done in HEK-293T cells expressing exogenous wild-type and mutant ataxin-1 using anti-Flag antibody following by tandem affinity purification in order to study protein–protein interactions. The candidate interacting proteins were validated by immunoprecipitation. Chromatin immunoprecipitation and high-throughput sequencing and RNA immunoprecipitation and high-throughput sequencing were performed using HEK-293T cells expressing wild-type or mutant ataxin-1. Results In this study using HEK-293T cells, we found that wild-type ataxin-1 interacted with MCM2, GNAS, and TMEM206, while mutant ataxin-1 lost its interaction with MCM2, GNAS, and TMEM206. Two ataxin-1 binding targets containing the core GGAG or AAAT were identified in HEK-293T cells using ChIP-seq. Gene Ontology analysis of the top ataxin-1 binding genes identified SLC6A15, NTF3, KCNC3, and DNAJC6 as functional genes in neurons in vitro. Ataxin-1 also was identified as an RNA-binding protein in HEK-293T cells using RIP-seq, but the polyglutamine expansion in the ataxin-1 had no direct effects on the RNA-binding activity of ataxin-1. Conclusions An expanded polyglutamine tract in ataxin-1 might interfere with protein–protein or protein–DNA interactions but had little effect on protein–RNA interactions. This study suggested that the dysfunction of protein–protein or protein–DNA interactions is involved in the pathogenesis of SCA1.
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Affiliation(s)
- Jiu-Ming Chen
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201801, China
| | - Shi-Kai Chen
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201801, China
| | - Pei-Pei Jin
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201801, China
| | - Shun-Chang Sun
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201801, China.
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Gunthorpe MJ. Timing is everything: structural insights into the disease-linked Kv3 channels controlling fast action-potential firing in the brain. Nat Commun 2022; 13:4086. [PMID: 35840565 PMCID: PMC9287389 DOI: 10.1038/s41467-022-31537-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/21/2022] [Indexed: 11/09/2022] Open
Affiliation(s)
- Martin J Gunthorpe
- Autifony Therapeutics Ltd, Stevenage Bioscience Catalyst, Gunnels Wood Road, Stevenage, SG1 2FX, UK.
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Tada Y, Kume K, Matsuda Y, Kurashige T, Kanaya Y, Ohsawa R, Morino H, Tabu H, Kaneko S, Suenaga T, Kakizuka A, Kawakami H. Genetic screening for potassium channel mutations in Japanese autosomal dominant spinocerebellar ataxia. J Hum Genet 2020; 65:363-369. [PMID: 31907387 DOI: 10.1038/s10038-019-0717-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 12/04/2019] [Accepted: 12/19/2019] [Indexed: 01/17/2023]
Abstract
Spinocerebellar ataxia (SCA) is a genetically heterogeneous disease characterized by cerebellar ataxia. Many causative genes have been identified to date, the most common etiology being the abnormal expansion of repeat sequences, and the mutation of ion channel genes also play an important role in the development of SCA. Some of them encode calcium and potassium channels. However, due to limited reports about potassium genes in SCA, we screened 192 Japanese individuals with dominantly inherited SCA who had no abnormal repeat expansions of causative genes for potassium channel mutations (KCNC3 for SCA13 and KCND3 for SCA19/SCA22) by target sequencing. As a result, two variants were identified from two patients: c.1973G>A, p.R658Q and c.1018G>A, p.V340M for KCNC3, and no pathogenic variant was identified for KCND3. The newly identified p.V340M exists in the extracellular domain, and p.R658Q exists in the intracellular domain on the C-terminal side, although most of the reported KCNC3 mutations are present at the transmembrane site. Adult-onset and slowly progressive cerebellar ataxia are the main clinical features of SCA13 and SCA19 caused by potassium channel mutations, which was similar in our cases. SCA13 caused by KCNC3 mutations may present with deep sensory loss and cognitive impairment in addition to cerebellar ataxia. In this study, mild deep sensory loss was observed in one case. SCA caused by potassium channel gene mutations is extremely rare, and more cases should be accumulated in the future to elucidate its pathogenesis due to channel dysfunction.
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Affiliation(s)
- Yui Tada
- Department of Epidemiology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan.,Laboratory of Functional Biology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kodai Kume
- Department of Epidemiology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Yukiko Matsuda
- Department of Epidemiology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Takashi Kurashige
- Department of Neurology, National Hospital Organization Kure Medical Center and Chugoku Cancer Center, Kure, Japan
| | - Yuhei Kanaya
- Department of Epidemiology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Ryosuke Ohsawa
- Department of Epidemiology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Hiroyuki Morino
- Department of Epidemiology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Hayato Tabu
- Department of Neurology, Kitano Hospital, Osaka, Japan
| | - Satoshi Kaneko
- Department of Neurology, Kansai Medical University, Osaka, Japan
| | | | - Akira Kakizuka
- Laboratory of Functional Biology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Hideshi Kawakami
- Department of Epidemiology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan.
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Szpisjak L, Zadori D, Klivenyi P, Vecsei L. Clinical Characteristics and Possible Drug Targets in Autosomal Dominant Spinocerebellar Ataxias. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2019; 18:279-293. [DOI: 10.2174/1871527318666190311155846] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/10/2018] [Accepted: 01/31/2019] [Indexed: 12/28/2022]
Abstract
Background & Objective:
The autosomal dominant spinocerebellar ataxias (SCAs) belong
to a large and expanding group of neurodegenerative disorders. SCAs comprise more than 40 subtypes
characterized by progressive ataxia as a common feature. The most prevalent diseases among SCAs
are caused by CAG repeat expansions in the coding-region of the causative gene resulting in polyglutamine
(polyQ) tract formation in the encoded protein. Unfortunately, there is no approved therapy to
treat cerebellar motor dysfunction in SCA patients. In recent years, several studies have been conducted
to recognize the clinical and pathophysiological aspects of the polyQ SCAs more accurately.
This scientific progress has provided new opportunities to develop promising gene therapies, including
RNA interference and antisense oligonucleotides.
Conclusion:
The aim of the current work is to give a brief summary of the clinical features of SCAs
and to review the cardinal points of pathomechanisms of the most common polyQ SCAs. In addition,
we review the last few year’s promising gene suppression therapies of the most frequent polyQ SCAs
in animal models, on the basis of which human trials may be initiated in the near future.
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Affiliation(s)
- Laszlo Szpisjak
- Department of Neurology, University of Szeged, Szeged, Hungary
| | - Denes Zadori
- Department of Neurology, University of Szeged, Szeged, Hungary
| | - Peter Klivenyi
- Department of Neurology, University of Szeged, Szeged, Hungary
| | - Laszlo Vecsei
- Department of Neurology, University of Szeged, Szeged, Hungary
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Abstract
The spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of autosomal dominantly inherited progressive disorders, the clinical hallmark of which is loss of balance and coordination accompanied by slurred speech; onset is most often in adult life. Genetically, SCAs are grouped as repeat expansion SCAs, such as SCA3/Machado-Joseph disease (MJD), and rare SCAs that are caused by non-repeat mutations, such as SCA5. Most SCA mutations cause prominent damage to cerebellar Purkinje neurons with consecutive cerebellar atrophy, although Purkinje neurons are only mildly affected in some SCAs. Furthermore, other parts of the nervous system, such as the spinal cord, basal ganglia and pontine nuclei in the brainstem, can be involved. As there is currently no treatment to slow or halt SCAs (many SCAs lead to premature death), the clinical care of patients with SCA focuses on managing the symptoms through physiotherapy, occupational therapy and speech therapy. Intense research has greatly expanded our understanding of the pathobiology of many SCAs, revealing that they occur via interrelated mechanisms (including proteotoxicity, RNA toxicity and ion channel dysfunction), and has led to the identification of new targets for treatment development. However, the development of effective therapies is hampered by the heterogeneity of the SCAs; specific therapeutic approaches may be required for each disease.
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