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Pi BK, Chung YH, Kim HS, Nam SH, Lee AJ, Nam DE, Park HJ, Kim SB, Chung KW, Choi BO. Compound Heterozygous Mutations of SACS in a Korean Cohort Study of Charcot-Marie-Tooth Disease Concurrent Cerebellar Ataxia and Spasticity. Int J Mol Sci 2024; 25:6378. [PMID: 38928084 PMCID: PMC11204044 DOI: 10.3390/ijms25126378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
Mutations in the SACS gene are associated with autosomal recessive spastic ataxia of Charlevoix-Saguenay disease (ARSACS) or complex clinical phenotypes of Charcot-Marie-Tooth disease (CMT). This study aimed to identify SACS mutations in a Korean CMT cohort with cerebellar ataxia and spasticity by whole exome sequencing (WES). As a result, eight pathogenic SACS mutations in four families were identified as the underlying causes of these complex phenotypes. The prevalence of CMT families with SACS mutations was determined to be 0.3%. All the patients showed sensory, motor, and gait disturbances with increased deep tendon reflexes. Lower limb magnetic resonance imaging (MRI) was performed in four patients and all had fatty replacements. Of note, they all had similar fatty infiltrations between the proximal and distal lower limb muscles, different from the neuromuscular imaging feature in most CMT patients without SACS mutations who had distal dominant fatty involvement. Therefore, these findings were considered a characteristic feature in CMT patients with SACS mutations. Although further studies with more cases are needed, our results highlight lower extremity MRI findings in CMT patients with SACS mutations and broaden the clinical spectrum. We suggest screening for SACS in recessive CMT patients with complex phenotypes of ataxia and spasticity.
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Affiliation(s)
- Byung Kwon Pi
- Department of Biological Sciences, Kongju National University, Gongju 32588, Republic of Korea; (B.K.P.); (A.J.L.)
| | - Yeon Hak Chung
- Department of Neurology, Korea University Guro Hospital, College of Medicine, Korea University, 148 Gurodong-ro, Guro-gu, Seoul 08308, Republic of Korea;
| | - Hyun Su Kim
- Department of Radiology, Samsung Medical Center, School of Medicine, Sungkyunkwan University, 81 Irwon-ro, Gangnam-gu, Seoul 06351, Republic of Korea;
| | - Soo Hyun Nam
- Cell and Gene Therapy Institute, Samsung Medical Center, Gangnam-gu, Seoul 06351, Republic of Korea;
| | - Ah Jin Lee
- Department of Biological Sciences, Kongju National University, Gongju 32588, Republic of Korea; (B.K.P.); (A.J.L.)
| | - Da Eun Nam
- Department of Domestic Business, Macrogen, Inc., 238 Teheran-ro, Gangnam-gu, Seoul 06221, Republic of Korea;
| | - Hyung Jun Park
- Department of Neurology, Gangnam Severance Hospital, College of Medicine, Yonsei University, 211 Eonju-ro, Gangnam-gu, Seoul 06273, Republic of Korea;
| | - Sang Beom Kim
- Department of Neurology, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, 892 Dongnam-ro, Gangdong-gu, Seoul 05278, Republic of Korea;
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju 32588, Republic of Korea; (B.K.P.); (A.J.L.)
| | - Byung-Ok Choi
- Cell and Gene Therapy Institute, Samsung Medical Center, Gangnam-gu, Seoul 06351, Republic of Korea;
- Department of Neurology, Samsung Medical Center, School of Medicine, Sungkyunkwan University, 81 Irwonr-ro, Gangnam-gu, Seoul 06351, Republic of Korea
- Department of Health Science and Technology, Samsung Advanced Institute for Health Sciences and Technology, 81 Irwon-ro, Gangnam-gu, Seoul 06351, Republic of Korea
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Chen C, Merrill RA, Jong CJ, Strack S. Driving Mitochondrial Fission Improves Cognitive, but not Motor Deficits in a Mouse Model of Ataxia of Charlevoix-Saguenay. CEREBELLUM (LONDON, ENGLAND) 2024:10.1007/s12311-024-01701-1. [PMID: 38735882 DOI: 10.1007/s12311-024-01701-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/01/2024] [Indexed: 05/14/2024]
Abstract
Autosomal-recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is caused by loss-of-function mutation in the SACS gene, which encodes sacsin, a putative HSP70-HSP90 co-chaperone. Previous studies with Sacs knock-out (KO) mice and patient-derived fibroblasts suggested that SACSIN mutations inhibit the function of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1). This in turn resulted in mitochondrial hyperfusion and dysfunction. We experimentally tested this hypothesis by genetically manipulating the mitochondrial fission/fusion equilibrium, creating double KO (DKO) mice that also lack positive (PP2A/Bβ2) and negative (PKA/AKAP1) regulators of Drp1. Neither promoting mitochondrial fusion (Bβ2 KO) nor fission (Akap1 KO) influenced progression of motor symptoms in Sacs KO mice. However, our studies identified profound learning and memory deficits in aged Sacs KO mice. Moreover, this cognitive impairment was rescued in a gene dose-dependent manner by deletion of the Drp1 inhibitor PKA/Akap1. Our results are inconsistent with mitochondrial dysfunction as a primary pathogenic mechanism in ARSACS. Instead, they imply that promoting mitochondrial fission may be beneficial at later stages of the disease when pathology extends to brain regions subserving learning and memory.
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Affiliation(s)
- Chunling Chen
- Department of Neuroscience and Pharmacology, University of Iowa, Carver College of Medicine, Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA
| | - Ronald A Merrill
- Department of Molecular Physiology and Biophysics, University of Iowa, Carver College of Medicine, Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA
| | - Chian Ju Jong
- Department of Neuroscience and Pharmacology, University of Iowa, Carver College of Medicine, Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, University of Iowa, Carver College of Medicine, Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA.
- Iowa Neuroscience Institute, Intellectual and Developmental Disabilities Research Center, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA.
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Chen C, Merrill RA, Jong CJ, Strack S. Driving mitochondrial fission improves cognitive, but not motor deficits in a mouse model of Ataxia of Charlevoix-Saguenay. RESEARCH SQUARE 2024:rs.3.rs-4178088. [PMID: 38659734 PMCID: PMC11042405 DOI: 10.21203/rs.3.rs-4178088/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Autosomal-recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is caused by loss-of-function mutation in the SACS gene, which encodes sacsin, a putative HSP70-HSP90 co-chaperone. Previous studies with Sacs knock-out (KO) mice and patient-derived fibroblasts suggested that SACSIN mutations inhibit the function of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1). This in turn resulted in mitochondrial hyperfusion and dysfunction. We experimentally tested this hypothesis by genetically manipulating the mitochondrial fission/fusion equilibrium, creating double KO (DKO) mice that also lack positive (PP2A/Bβ2) and negative (PKA/AKAP1) regulators of Drp1. Neither promoting mitochondrial fusion (Bβ2 KO) nor fission (Akap1 KO) influenced progression of motor symptoms in Sacs KO mice. However, our studies identified profound learning and memory deficits in aged Sacs KO mice. Moreover, this cognitive impairment was rescued in a gene dose-dependent manner by deletion of the Drp1 inhibitor PKA/Akap1. Our results are inconsistent with mitochondrial dysfunction as a primary pathogenic mechanism in ARSACS. Instead, they imply that promoting mitochondrial fission may be beneficial at later stages of the disease when pathology extends to brain regions subserving learning and memory.
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Gullulu O, Ozcelik E, Tuzlakoglu Ozturk M, Karagoz MS, Tazebay UH. A multi-faceted approach to unravel coding and non-coding gene fusions and target chimeric proteins in ataxia. J Biomol Struct Dyn 2024:1-21. [PMID: 38411012 DOI: 10.1080/07391102.2024.2321510] [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: 09/12/2023] [Accepted: 02/15/2024] [Indexed: 02/28/2024]
Abstract
Ataxia represents a heterogeneous group of neurodegenerative disorders characterized by a loss of balance and coordination, often resulting from mutations in genes vital for cerebellar function and maintenance. Recent advances in genomics have identified gene fusion events as critical contributors to various cancers and neurodegenerative diseases. However, their role in ataxia pathogenesis remains largely unexplored. Our study Hdelved into this possibility by analyzing RNA sequencing data from 1443 diverse samples, including cell and mouse models, patient samples, and healthy controls. We identified 7067 novel gene fusions, potentially pivotal in disease onset. These fusions, notably in-frame, could produce chimeric proteins, disrupt gene regulation, or introduce new functions. We observed conservation of specific amino acids at fusion breakpoints and identified potential aggregate formations in fusion proteins, known to contribute to ataxia. Through AI-based protein structure prediction, we identified topological changes in three high-confidence fusion proteins-TEN1-ACOX1, PEX14-NMNAT1, and ITPR1-GRID2-which could potentially alter their functions. Subsequent virtual drug screening identified several molecules and peptides with high-affinity binding to fusion sites. Molecular dynamics simulations confirmed the stability of these protein-ligand complexes at fusion breakpoints. Additionally, we explored the role of non-coding RNA fusions as miRNA sponges. One such fusion, RP11-547P4-FLJ33910, showed strong interaction with hsa-miR-504-5p, potentially acting as its sponge. This interaction correlated with the upregulation of hsa-miR-504-5p target genes, some previously linked to ataxia. In conclusion, our study unveils new aspects of gene fusions in ataxia, suggesting their significant role in pathogenesis and opening avenues for targeted therapeutic interventions.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Omer Gullulu
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Emrah Ozcelik
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
- Central Research Laboratory (GTU-MAR), Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Merve Tuzlakoglu Ozturk
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
- Central Research Laboratory (GTU-MAR), Gebze Technical University, Gebze, Kocaeli, Turkey
| | - Mustafa Safa Karagoz
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Uygar Halis Tazebay
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Kocaeli, Turkey
- Central Research Laboratory (GTU-MAR), Gebze Technical University, Gebze, Kocaeli, Turkey
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Awuah WA, Tan JK, Shkodina AD, Ferreira T, Adebusoye FT, Mazzoleni A, Wellington J, David L, Chilcott E, Huang H, Abdul-Rahman T, Shet V, Atallah O, Kalmanovich J, Jiffry R, Madhu DE, Sikora K, Kmyta O, Delva MY. Hereditary spastic paraplegia: Novel insights into the pathogenesis and management. SAGE Open Med 2023; 12:20503121231221941. [PMID: 38162912 PMCID: PMC10757446 DOI: 10.1177/20503121231221941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 11/28/2023] [Indexed: 01/03/2024] Open
Abstract
Hereditary spastic paraplegia is a genetically heterogeneous neurodegenerative disorder characterised primarily by muscle stiffness in the lower limbs. Neurodegenerative disorders are conditions that result from cellular and metabolic abnormalities, many of which have strong genetic ties. While ageing is a known contributor to these changes, certain neurodegenerative disorders can manifest early in life, progressively affecting a person's quality of life. Hereditary spastic paraplegia is one such condition that can appear in individuals of any age. In hereditary spastic paraplegia, a distinctive feature is the degeneration of long nerve fibres in the corticospinal tract of the lower limbs. This degeneration is linked to various cellular and metabolic processes, including mitochondrial dysfunction, remodelling of the endoplasmic reticulum membrane, autophagy, abnormal myelination processes and alterations in lipid metabolism. Additionally, hereditary spastic paraplegia affects processes like endosome membrane trafficking, oxidative stress and mitochondrial DNA polymorphisms. Disease-causing genetic loci and associated genes influence the progression and severity of hereditary spastic paraplegia, potentially affecting various cellular and metabolic functions. Although hereditary spastic paraplegia does not reduce a person's lifespan, it significantly impairs their quality of life as they age, particularly with more severe symptoms. Regrettably, there are currently no treatments available to halt or reverse the pathological progression of hereditary spastic paraplegia. This review aims to explore the metabolic mechanisms underlying the pathophysiology of hereditary spastic paraplegia, emphasising the interactions of various genes identified in recent network studies. By comprehending these associations, targeted molecular therapies that address these biochemical processes can be developed to enhance treatment strategies for hereditary spastic paraplegia and guide clinical practice effectively.
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Affiliation(s)
| | | | - Anastasiia D Shkodina
- Department of Neurological Diseases, Poltava State Medical University, Poltava, Ukraine
| | - Tomas Ferreira
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | | | - Adele Mazzoleni
- Barts and the London School of Medicine and Dentistry, London, UK
| | - Jack Wellington
- Cardiff University School of Medicine, Cardiff University, Wales, UK
| | - Lian David
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Ellie Chilcott
- Cardiff University School of Medicine, Cardiff University, Wales, UK
| | - Helen Huang
- Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | | | - Vallabh Shet
- Faculty of Medicine, Bangalore Medical College and Research Institute, Karnataka, India
| | - Oday Atallah
- Department of Neurosurgery, Hannover Medical School, Hannover, Germany
| | | | - Riaz Jiffry
- Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | | | | | | | - Mykhailo Yu Delva
- Department of Neurological Diseases, Poltava State Medical University, Poltava, Ukraine
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Matsugi A, Ohtsuka H, Bando K, Kondo Y, Kikuchi Y. Effects of non-invasive brain stimulation for degenerative cerebellar ataxia: a protocol for a systematic review and meta-analysis. BMJ Open 2023; 13:e073526. [PMID: 37385745 PMCID: PMC10314638 DOI: 10.1136/bmjopen-2023-073526] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 06/21/2023] [Indexed: 07/01/2023] Open
Abstract
INTRODUCTION To date, the medical and rehabilitation needs of people with degenerative cerebellar ataxia (DCA) are not fully met because no curative treatment has yet been established. Movement disorders such as cerebellar ataxia and balance and gait disturbance are common symptoms of DCA. Recently, non-invasive brain stimulation (NIBS) techniques, including repetitive transcranial magnetic stimulation and transcranial electrical stimulation, have been reported as possible intervention methods to improve cerebellar ataxia. However, evidence of the effects of NIBS on cerebellar ataxia, gait ability, and activity of daily living is insufficient. This study will aim to systematically evaluate the clinical effects of NIBS on patients with DCA. METHODS AND ANALYSIS We will conduct a preregistered systematic review and meta-analysis based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We will include randomised controlled trials to assess the effects of NIBS on patients with DCA. The primary clinical outcome will be cerebellar ataxia, as measured by the Scale for Assessment and Rating of Ataxia and the International Cooperative Ataxia Rating Scale. The secondary outcomes will include gait speed, functional ambulatory capacity and functional independence measure, as well as any other reported outcomes that the reviewer considers important. The following databases will be searched: PubMed, Cochrane Central Register of Controlled Trials, CINAHL and PEDro. We will assess the strength of the evidence included in the studies and estimate the effects of NIBS. ETHICS AND DISSEMINATION Because of the nature of systematic reviews, no ethical issues are anticipated. This systematic review will provide evidence on the effects of NIBS in patients with DCA. The findings of this review are expected to contribute to clinical decision-making towards selecting NIBS techniques for treatment and generating new clinical questions to be addressed. PROSPERO REGISTRATION NUMBER CRD42023379192.
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Affiliation(s)
- Akiyoshi Matsugi
- Faculty of Rehabilitation, Shijonawate Gakuen University, Daito, Japan
| | - Hiroyuki Ohtsuka
- Department of Rehabilitation, School of Nursing and Rehabilitation Sciences, Showa University, Midoriku, Yokohama-shi, Kanagawa, Japan
| | - Kyota Bando
- Department of Physical Rehabilitation, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Yuki Kondo
- Department of Physical Rehabilitation, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Yutaka Kikuchi
- Department of Rehabilitation for Intractable Neurological Disorders, Mihara Memorial Hospital, Isesaki, Gunma, Japan
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