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Luo M, Wang Y, Liang J, Wan X. Spastin accumulation and motor neuron defects caused by a novel SPAST splice site mutation. J Transl Med 2024; 22:872. [PMID: 39334479 DOI: 10.1186/s12967-024-05669-8] [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: 04/07/2024] [Accepted: 09/10/2024] [Indexed: 09/30/2024] Open
Abstract
BACKGROUND Hereditary spastic paraplegia (HSP) is a rare genetically heterogeneous neurodegenerative disorder. The most common type of HSP is caused by pathogenic variants in the SPAST gene. Various hypotheses regarding the pathogenic mechanisms of HSP-SPAST have been proposed. However, a single hypothesis may not be sufficient to explain HSP-SPAST. OBJECTIVE To determine the causative gene of autosomal dominant HSP-SPAST in a pure pedigree and to study its underlying pathogenic mechanism. METHODS A four-generation Chinese family was investigated. Genetic testing was performed for the causative gene, and a splice site variant was identified. In vivo and in vitro experiments were conducted separately. Western blotting and immunofluorescence were performed after transient transfection of cells with the wild-type (WT) or mutated plasmid. The developmental expression pattern of zebrafish spasts was assessed via whole-mount in situ hybridization. The designed guide RNA (gRNA) and an antisense oligo spast-MO were microinjected into Tg(hb9:GFP) zebrafish embryos, spinal cord motor neurons were observed, and a swimming behavioral analysis was conducted. RESULTS A novel heterozygous intron variant, c.1004 + 5G > A, was identified in a pure HSP-SPAST pedigree and shown to cosegregate with the disease phenotypes. This intron splice site variant skipped exon 6, causing a frameshift mutation that resulted in a premature termination codon. In vitro, the truncated protein was evenly distributed throughout the cytoplasm, formed filamentous accumulations around the nucleus, and colocalized with microtubules. Truncated proteins diffusing in the cytoplasm appeared denser. No abnormal microtubule structures were observed, and the expression levels of α-tubulin remained unchanged. In vivo, zebrafish larvae with this mutation displayed axon pathfinding defects, impaired outgrowth, and axon loss. Furthermore, spast-MO larvae exhibited unusual behavioral preferences and increased acceleration. CONCLUSION The adverse effects of premature stop codon mutations in SPAST result in insufficient levels of functional protein, and the potential toxicity arising from the intracellular accumulation of spastin serves as a contributing factor to HSP-SPAST.
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Affiliation(s)
- Min Luo
- Department of Neurology, Peking Union Medical College, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, 100730, China
| | - Yanying Wang
- Department of Neurology, Peking Union Medical College, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, 100730, China
| | - Jinxiu Liang
- Center for Genetic Medicine, The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310000, Zhejiang, China
| | - Xinhua Wan
- Department of Neurology, Peking Union Medical College, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, 100730, China.
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Raby A, Missiroli S, Sanatine P, Langui D, Pansiot J, Beaude N, Vezzana L, Saleh R, Marinello M, Laforge M, Pinton P, Buj-Bello A, Burgo A. Spastin regulates ER-mitochondrial contact sites and mitochondrial homeostasis. iScience 2024; 27:110683. [PMID: 39252960 PMCID: PMC11382127 DOI: 10.1016/j.isci.2024.110683] [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: 10/10/2023] [Revised: 05/20/2024] [Accepted: 08/05/2024] [Indexed: 09/11/2024] Open
Abstract
Mitochondria-endoplasmic reticulum (ER) contact sites (MERCs) emerged to play critical roles in numerous cellular processes, and their dysregulation has been associated to neurodegenerative disorders. Mutations in the SPG4 gene coding for spastin are among the main causes of hereditary spastic paraplegia (HSP). Spastin binds and severs microtubules, and the long isoform of this protein, namely M1, spans the outer leaflet of ER membrane where it interacts with other ER-HSP proteins. Here, we showed that overexpressed M1 spastin localizes in ER-mitochondria intersections and that endogenous spastin accumulates in MERCs. We demonstrated in different cellular models that downregulation of spastin enhances the number of MERCs, alters mitochondrial morphology, and impairs ER and mitochondrial calcium homeostasis. These effects are associated with reduced mitochondrial membrane potential, oxygen species levels, and oxidative metabolism. These findings extend our knowledge on the role of spastin in the ER and suggest MERCs deregulation as potential causes of SPG4-HSP disease.
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Affiliation(s)
- Amelie Raby
- Genethon, 91000 Evry, France
- Université Paris-Saclay, University Evry, Inserm, Genethon, Integrare Research Unit UMR_S951, 91000 Evry, France
| | - Sonia Missiroli
- Department of Medical Sciences, Section of Experimental Medicine, University of Ferrara, and Technopole of Ferrara, Laboratory for Advanced Therapies (LTTA), 44121 Ferrara, Italy
| | | | - Dominique Langui
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Julien Pansiot
- Université Paris Cité, NeuroDiderot, Inserm, 75019 Paris, France
| | - Nissai Beaude
- Genethon, 91000 Evry, France
- Université Paris-Saclay, University Evry, Inserm, Genethon, Integrare Research Unit UMR_S951, 91000 Evry, France
| | - Lucie Vezzana
- Genethon, 91000 Evry, France
- Université Paris-Saclay, University Evry, Inserm, Genethon, Integrare Research Unit UMR_S951, 91000 Evry, France
| | - Rachelle Saleh
- Université Paris Cité, NeuroDiderot, Inserm, 75019 Paris, France
| | - Martina Marinello
- Genethon, 91000 Evry, France
- Université Paris-Saclay, University Evry, Inserm, Genethon, Integrare Research Unit UMR_S951, 91000 Evry, France
| | - Mireille Laforge
- Université Paris Cité, NeuroDiderot, Inserm, 75019 Paris, France
| | - Paolo Pinton
- Department of Medical Sciences, Section of Experimental Medicine, University of Ferrara, and Technopole of Ferrara, Laboratory for Advanced Therapies (LTTA), 44121 Ferrara, Italy
| | - Ana Buj-Bello
- Genethon, 91000 Evry, France
- Université Paris-Saclay, University Evry, Inserm, Genethon, Integrare Research Unit UMR_S951, 91000 Evry, France
| | - Andrea Burgo
- Genethon, 91000 Evry, France
- Université Paris-Saclay, University Evry, Inserm, Genethon, Integrare Research Unit UMR_S951, 91000 Evry, France
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Deng K, Ruan H, Yu F, Pei Z, Xu C, Zhang S. Dominant negative effect as a novel mechanism of SPAST gene mutation in a large family with hereditary spastic paraplegia. Genes Dis 2024; 11:101152. [PMID: 38882014 PMCID: PMC11176630 DOI: 10.1016/j.gendis.2023.101152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/16/2023] [Indexed: 06/18/2024] Open
Affiliation(s)
- Ke Deng
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200000, China
| | - Haibo Ruan
- The First People's Hospital of Wenling, Wenling, Zhejiang 317500, China
| | - Feifei Yu
- Rushan Hospital of Traditional Chinese Medicine, Rushan, Shandong 264599, China
| | - Zhenle Pei
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200000, China
| | - Congjian Xu
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200000, China
- Department of Obstetrics and Gynecology, Fudan University, Shanghai 200000, China
| | - Shuo Zhang
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200000, China
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Yao L, Cao Y, Zhang C, Huang X, Tian W, Cao L. Clinical and genetic characteristics in a Chinese cohort of complex spastic paraplegia type 4. Clin Genet 2024; 106:56-65. [PMID: 38403837 DOI: 10.1111/cge.14510] [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: 12/09/2023] [Revised: 01/27/2024] [Accepted: 02/12/2024] [Indexed: 02/27/2024]
Abstract
Spastic paraplegia type 4 (SPG4), caused by SPAST mutations, is the most predominant subtype of hereditary spastic paraplegia. Most documented SPG4 patients present as pure form, with the complex form rarely reported. We described the clinical and genetic features of 20 patients with complex phenotypes of SPG4 and further explored the genotype-phenotype correlations. We collected detailed clinical data of all SPG4 patients and assessed their phenotypes. SPAST gene mutations were identified by Multiplex ligation-dependent probe amplification in combination with whole exome sequencing. We further performed statistical analysis in genotype and phenotype among patients with various manifestations and different variants. Out of 90 SPG4 patients, 20 patients (male:female = 16:4) with additional neurologic deficits, namely complex form, were included in our study. The bimodal distribution of age of onset at 0-10 and 21-40 years old is concluded. On cranial MRI, obvious white matter lesions can be observed in five patients. We identified 9 novel and 8 reported SPAST mutations, of which 11 mutations were located in AAA (ATPase associated with various cellular activities) domain. The AAA cassette of spastin is the hottest mutated region among complex SPG4. All patients with cognitive impairment (CI) are males (n = 9/9). Additionally, 80% patients with ataxia are due to frameshift mutations (n = 4/5). Overall, our study summarized and analyzed the genetic and phenotypic characteristics of complex SPG4, making up over 1/5 of in-house SPG4 cohort, among which CI and ataxia are the most common features. Further studies are expected to explore the underlying mechanisms.
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Affiliation(s)
- Li Yao
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Neurology, Suzhou Hospital of Anhui Medical University, Suzhou, China
| | - Yuwen Cao
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Neurological Rare Disease Biobank and Precision Diagnostic Technical Service Platform, Shanghai, China
| | - Chao Zhang
- Department of Neurology, Suzhou Hospital of Anhui Medical University, Suzhou, China
| | - Xiaojun Huang
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Neurological Rare Disease Biobank and Precision Diagnostic Technical Service Platform, Shanghai, China
| | - Wotu Tian
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Neurological Rare Disease Biobank and Precision Diagnostic Technical Service Platform, Shanghai, China
| | - Li Cao
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Neurological Rare Disease Biobank and Precision Diagnostic Technical Service Platform, Shanghai, China
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Damiani D, Baggiani M, Della Vecchia S, Naef V, Santorelli FM. Pluripotent Stem Cells as a Preclinical Cellular Model for Studying Hereditary Spastic Paraplegias. Int J Mol Sci 2024; 25:2615. [PMID: 38473862 DOI: 10.3390/ijms25052615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/12/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024] Open
Abstract
Hereditary spastic paraplegias (HSPs) comprise a family of degenerative diseases mostly hitting descending axons of corticospinal neurons. Depending on the gene and mutation involved, the disease could present as a pure form with limb spasticity, or a complex form associated with cerebellar and/or cortical signs such as ataxia, dysarthria, epilepsy, and intellectual disability. The progressive nature of HSPs invariably leads patients to require walking canes or wheelchairs over time. Despite several attempts to ameliorate the life quality of patients that have been tested, current therapeutical approaches are just symptomatic, as no cure is available. Progress in research in the last two decades has identified a vast number of genes involved in HSP etiology, using cellular and animal models generated on purpose. Although unanimously considered invaluable tools for basic research, those systems are rarely predictive for the establishment of a therapeutic approach. The advent of induced pluripotent stem (iPS) cells allowed instead the direct study of morphological and molecular properties of the patient's affected neurons generated upon in vitro differentiation. In this review, we revisited all the present literature recently published regarding the use of iPS cells to differentiate HSP patient-specific neurons. Most studies have defined patient-derived neurons as a reliable model to faithfully mimic HSP in vitro, discovering original findings through immunological and -omics approaches, and providing a platform to screen novel or repurposed drugs. Thereby, one of the biggest hopes of current HSP research regards the use of patient-derived iPS cells to expand basic knowledge on the disease, while simultaneously establishing new therapeutic treatments for both generalized and personalized approaches in daily medical practice.
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Affiliation(s)
- Devid Damiani
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
| | - Matteo Baggiani
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
| | - Stefania Della Vecchia
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
- Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Valentina Naef
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
| | - Filippo Maria Santorelli
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
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Wang J, Wu Y, Dong H, Ji Y, Zhang L, Liu Y, Liu Y, Gao X, Jia Y, Wang X. A novel truncated variant in SPAST results in spastin accumulation and defects in microtubule dynamics. BMC Med Genomics 2023; 16:321. [PMID: 38066582 PMCID: PMC10704811 DOI: 10.1186/s12920-023-01759-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 12/02/2023] [Indexed: 12/18/2023] Open
Abstract
OBJECTIVE Haploinsufficiency is widely accepted as the pathogenic mechanism of hereditary spastic paraplegias type 4 (SPG4). However, there are some cases that cannot be explained by reduced function of the spastin protein encoded by SPAST. The aim of this study was to identify the causative variant of SPG4 in a large Chinese family and explore its pathological mechanism. MATERIALS AND METHODS A five-generation family with 49 members including nine affected (4 males and 5 females) and 40 unaffected individuals in Mongolian nationality was recruited. Whole exome sequencing was employed to investigate the genetic etiology. Western blotting and immunofluorescence were used to analyze the effects of the mutant proteins in vitro. RESULTS A novel frameshift variant NM_014946.4: c.483_484delinsC (p.Val162Leufs*2) was identified in SPAST from a pedigree with SPG4. The variant segregated with the disease in the family and thus determined as the disease-causing variant. The c.483_484delinsC variant produced two truncated mutants (mutant M1 and M87 isoforms). They accumulated to a higher level and presented increased stability than their wild-type counterparts and may lost the microtubule severing activity. CONCLUSION SPAST mutations leading to premature stop codons do not always act through haploinsufficiency. The potential toxicity to the corticospinal tract caused by the intracellular accumulation of truncated spastin should be considered as the pathological mechanism of SPG4.
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Affiliation(s)
- Jie Wang
- Department of Genetics, Inner Mongolia Maternity and Child Health Care Hospital, Hohhot, 010020, China
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (RRBGL), Inner Mongolia University, Hohhot, 010070, China
| | - Yihan Wu
- Department of Family Medicine, Inner Mongolia People's Hospital, Hohhot, 010057, China
| | - Hong Dong
- Department of Genetics, Inner Mongolia Maternity and Child Health Care Hospital, Hohhot, 010020, China
| | - Yunpeng Ji
- Department of Genetics, Inner Mongolia Maternity and Child Health Care Hospital, Hohhot, 010020, China
| | - Lichun Zhang
- Department of Genetics, Inner Mongolia Maternity and Child Health Care Hospital, Hohhot, 010020, China
| | - Yaxian Liu
- Department of Genetics, Inner Mongolia Maternity and Child Health Care Hospital, Hohhot, 010020, China
| | - Yueshi Liu
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (RRBGL), Inner Mongolia University, Hohhot, 010070, China
| | - Xin Gao
- Department of Pediatrics, Inner Mongolia Maternity and Child Health Care Hospital, Hohhot, 010020, China
| | - Yueqi Jia
- Department of Genetics, Inner Mongolia Maternity and Child Health Care Hospital, Hohhot, 010020, China.
| | - Xiaohua Wang
- Department of Genetics, Inner Mongolia Maternity and Child Health Care Hospital, Hohhot, 010020, China.
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Fukuda H, Mizuguchi T, Doi H, Kameyama S, Kunii M, Joki H, Takahashi T, Komiya H, Sasaki M, Miyaji Y, Ohori S, Koshimizu E, Uchiyama Y, Tsuchida N, Fujita A, Hamanaka K, Misawa K, Miyatake S, Tanaka F, Matsumoto N. Long-read sequencing revealing intragenic deletions in exome-negative spastic paraplegias. J Hum Genet 2023; 68:689-697. [PMID: 37308565 DOI: 10.1038/s10038-023-01170-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 05/01/2023] [Accepted: 06/04/2023] [Indexed: 06/14/2023]
Abstract
Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders characterized by progressive spasticity and weakness in the lower extremities. To date, a total of 88 types of SPG are known. To diagnose HSP, multiple technologies, including microarray, direct sequencing, multiplex ligation-dependent probe amplification, and short-read next-generation sequencing, are often chosen based on the frequency of HSP subtypes. Exome sequencing (ES) is commonly used. We used ES to analyze ten cases of HSP from eight families. We identified pathogenic variants in three cases (from three different families); however, we were unable to determine the cause of the other seven cases using ES. We therefore applied long-read sequencing to the seven undetermined HSP cases (from five families). We detected intragenic deletions within the SPAST gene in four families, and a deletion within PSEN1 in the remaining family. The size of the deletion ranged from 4.7 to 12.5 kb and involved 1-7 exons. All deletions were entirely included in one long read. We retrospectively performed an ES-based copy number variation analysis focusing on pathogenic deletions, but were not able to accurately detect these deletions. This study demonstrated the efficiency of long-read sequencing in detecting intragenic pathogenic deletions in ES-negative HSP patients.
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Affiliation(s)
- Hiromi Fukuda
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Takeshi Mizuguchi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan.
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Shinichi Kameyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Pathology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Misako Kunii
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Hideto Joki
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Neurology, National Hospital Organization Yokohama Medical Center, Yokohama, Kanagawa, 245-8575, Japan
| | - Tatsuya Takahashi
- Department of Neurology, National Hospital Organization Yokohama Medical Center, Yokohama, Kanagawa, 245-8575, Japan
| | - Hiroyasu Komiya
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Mei Sasaki
- Department of Neurology, Yokohama Minami Kyosai Hospital, Yokohama, 236-0037, Japan
| | - Yosuke Miyaji
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Sachiko Ohori
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Clinical Genetics, Yokohama City University Hospital, Yokohama, 236-0004, Japan
- Department of Genetics, Kitasato University Hospital, Sagamihara, 252-0375, Japan
| | - Eriko Koshimizu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Yuri Uchiyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, 236-0004, Japan
| | - Naomi Tsuchida
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, 236-0004, Japan
| | - Atsushi Fujita
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Kohei Hamanaka
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Kazuharu Misawa
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- RIKEN Center for Advanced Intelligence Project, 1-4-1 Nihonbashi, Chuo-ku, Tokyo, 103-0027, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Clinical Genetics, Yokohama City University Hospital, Yokohama, 236-0004, Japan
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan.
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Chen X, Li X, Tan Y, Yang D, Lu L, Deng Y, Xu R. Identification of c.1495C > T mutation in SPAST gene in a family of Han Chinese with hereditary spastic paraplegia. Neurosci Lett 2023; 812:137399. [PMID: 37473796 DOI: 10.1016/j.neulet.2023.137399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/10/2023] [Accepted: 07/13/2023] [Indexed: 07/22/2023]
Abstract
BACKGROUND Hereditary spastic paraplegia 4 (SPG4) caused by spastin (SPAST) gene mutations accounts for 40-45% of hereditary spastic paraplegia (HSP) cases. To search for more genetic evidences for the pathogenesis of HSP, the SPAST genotype and clinical phenotype of a Chinese Han SPG4 family were analysed in this study. METHODS The clinical data of the proband and his family members were collected. Whole genomic DNA was extracted from peripheral blood, and the gene detection and pathogenicity analysis of mutations were conducted using whole-exome sequencing technology. Suspected pathogenic mutations were identified. Verification within this family was conducted by Sanger sequencing. RESULTS Eight (4 males and 4 females) of 20 members in 4 generations had SPG4. All patients presented with the high feet arches (pes cavus), the abnormal gait, the active tendon reflexes of the upper limbs, the hyperreflexia of the lower limbs, and the positive ankle clonus and Babinski's signs bilaterally. In the proband, we found a heterozygous mutation c.1495C > T in SPAST gene, which was associated with the autosomal dominant SPG4. Both the daughters and granddaughters of the proband in this family were verified to carry this mutation. The clinical characteristics of the SPG4 patients in this family are in line with the simple type of HSP. Heterozygous c.1495C > T is a pathogenic mutation in this family. CONCLUSION In this study, we identified a c.1495C > T mutation in the SPAST gene in a Han Chinese family, enriching the mutation spectrum of SPG4.
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Affiliation(s)
- Xiaohong Chen
- Department of Neurology, The First Hospital of Nanchang, Nanchang 330006, Jiangxi, China
| | - Xinming Li
- Department of Neurology, The First Hospital of Nanchang, Nanchang 330006, Jiangxi, China
| | - Yu Tan
- Department of Neurology, The First Hospital of Nanchang, Nanchang 330006, Jiangxi, China
| | - Dejiang Yang
- Department of Neurology, The First Hospital of Nanchang, Nanchang 330006, Jiangxi, China
| | - Lijun Lu
- Department of Neurology, The First Hospital of Nanchang, Nanchang 330006, Jiangxi, China
| | - Youqing Deng
- Department of Neurology, The First Hospital of Nanchang, Nanchang 330006, Jiangxi, China.
| | - Renshi Xu
- Department of Neurology, Jiangxi Provincial People's Hospital, The Clinical College of Nanchang College, The First Affiliated Hospital of Nanchang College, Nanchang 330006, Jiangxi, China.
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Costa AC, Sousa MM. The Role of Spastin in Axon Biology. Front Cell Dev Biol 2022; 10:934522. [PMID: 35865632 PMCID: PMC9294387 DOI: 10.3389/fcell.2022.934522] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/07/2022] [Indexed: 12/05/2022] Open
Abstract
Neurons are highly polarized cells with elaborate shapes that allow them to perform their function. In neurons, microtubule organization—length, density, and dynamics—are essential for the establishment of polarity, growth, and transport. A mounting body of evidence shows that modulation of the microtubule cytoskeleton by microtubule-associated proteins fine tunes key aspects of neuronal cell biology. In this respect, microtubule severing enzymes—spastin, katanin and fidgetin—a group of microtubule-associated proteins that bind to and generate internal breaks in the microtubule lattice, are emerging as key modulators of the microtubule cytoskeleton in different model systems. In this review, we provide an integrative view on the latest research demonstrating the key role of spastin in neurons, specifically in the context of axonal cell biology. We focus on the function of spastin in the regulation of microtubule organization, and axonal transport, that underlie its importance in the intricate control of axon growth, branching and regeneration.
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Affiliation(s)
- Ana Catarina Costa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação Em Saúde (i3S), University of Porto, Porto, Portugal
- Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- *Correspondence: Ana Catarina Costa, ; Monica Mendes Sousa,
| | - Monica Mendes Sousa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação Em Saúde (i3S), University of Porto, Porto, Portugal
- *Correspondence: Ana Catarina Costa, ; Monica Mendes Sousa,
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Genetic architecture of motor neuron diseases. J Neurol Sci 2021; 434:120099. [PMID: 34965490 DOI: 10.1016/j.jns.2021.120099] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/26/2021] [Accepted: 12/14/2021] [Indexed: 12/18/2022]
Abstract
Motor neuron diseases (MNDs) are rare and frequently fatal neurological disorders in which motor neurons within the brainstem and spinal cord regions slowly die. MNDs are primarily caused by genetic mutations, and > 100 different mutant genes in humans have been discovered thus far. Given the fact that many more MND-related genes have yet to be discovered, the growing body of genetic evidence has offered new insights into the diverse cellular and molecular mechanisms involved in the aetiology and pathogenesis of MNDs. This search may aid in the selection of potential candidate genes for future investigation and, eventually, may open the door to novel interventions to slow down disease progression. In this review paper, we have summarized detailed existing research findings of different MNDs, such as amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), spinal bulbar muscle atrophy (SBMA) and hereditary spastic paraplegia (HSP) in relation to their complex genetic architecture.
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11
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Piermarini E, Akarsu S, Connors T, Kneussel M, Lane MA, Morfini G, Karabay A, Baas PW, Qiang L. Modeling gain-of-function and loss-of-function components of SPAST-based hereditary spastic paraplegia using transgenic mice. Hum Mol Genet 2021; 31:1844-1859. [PMID: 34935948 PMCID: PMC9169457 DOI: 10.1093/hmg/ddab367] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 12/24/2022] Open
Abstract
Hereditary spastic paraplegia (HSP) is a disease in which dieback degeneration of corticospinal tracts, accompanied by axonal swellings, leads to gait deficiencies. SPG4-HSP, the most common form of the disease, results from mutations of human spastin gene (SPAST), which is the gene that encodes spastin, a microtubule-severing protein. The lack of a vertebrate model that recapitulates both the etiology and symptoms of SPG4-HSP has stymied the development of effective therapies for the disease. hSPAST-C448Y mice, which express human mutant spastin at the ROSA26 locus, display corticospinal dieback and gait deficiencies but not axonal swellings. On the other hand, mouse spastin gene (Spast)-knockout (KO) mice display axonal swellings but not corticospinal dieback or gait deficiencies. One possibility is that reduced spastin function, resulting in axonal swellings, is not the cause of the disease but exacerbates the toxic effects of the mutant protein. To explore this idea, Spast-KO and hSPAST-C448Y mice were crossbred, and the offspring were compared with the parental lines via histological and behavioral analyses. The crossbred animals displayed axonal swellings as well as earlier onset, worsened gait deficiencies and corticospinal dieback compared with the hSPAST-C448Y mouse. These results, together with observations on changes in histone deacetylases 6 and tubulin modifications in the axon, indicate that each of these three transgenic mouse lines is valuable for investigating a different component of the disease pathology. Moreover, the crossbred mice are the best vertebrate model to date for testing potential therapies for SPG4-HSP.
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Affiliation(s)
- Emanuela Piermarini
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Seyma Akarsu
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA,Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul 34469, Turkey
| | - Theresa Connors
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Matthias Kneussel
- Department of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
| | - Michael A Lane
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Gerardo Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Arzu Karabay
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul 34469, Turkey
| | - Peter W Baas
- To whom correspondence should be addressed at: Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA. Tel: +1 2159918311; Fax: +1 2158439082; ; Tel: +1 2159918298;
| | - Liang Qiang
- To whom correspondence should be addressed at: Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA. Tel: +1 2159918311; Fax: +1 2158439082; ; Tel: +1 2159918298;
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12
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Chen R, Du S, Yao Y, Zhang L, Luo J, Shen Y, Xu Z, Zeng X, Zhang L, Liu M, Yin C, Tang B, Tan J, Xu X, Liu JY. A Novel SPAST Mutation Results in Spastin Accumulation and Defects in Microtubule Dynamics. Mov Disord 2021; 37:598-607. [PMID: 34927746 PMCID: PMC9300132 DOI: 10.1002/mds.28885] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 11/24/2021] [Accepted: 11/27/2021] [Indexed: 11/25/2022] Open
Abstract
Background Haploinsufficiency is widely accepted as the pathogenic mechanism of spastic paraplegia type 4 (SPG4). However, there are some cases that cannot be explained by reduced function of the spastin protein encoded by SPAST. Objectives To identify the causative gene of autosomal dominant hereditary spastic paraplegia in three large Chinese families and explore the pathological mechanism of a spastin variant. Methods Three large Chinese hereditary spastic paraplegia families with a total of 247 individuals (67 patients) were investigated, of whom 59 members were recruited to the study. Genetic testing was performed to identify the causative gene. Western blotting and immunofluorescence were used to analyze the effects of the mutant proteins in vitro. Results In the three hereditary spastic paraplegia families, of whom three index cases were misdiagnosed as other types of neurological diseases, a novel c.985dupA (p.Met329Asnfs*3) variant in SPAST was identified and was shown to cosegregate with the phenotype in the three families. The c.985dupA mutation produced two truncated mutants (mutant M1 and M87 isoforms) that accumulated to a higher level than their wild‐type counterparts. Furthermore, the mutant M1 isoform heavily decorated the microtubules and rendered them resistant to depolymerization. In contrast, the mutant M87 isoform was diffusely localized in both the nucleus and the cytoplasm, could not decorate microtubules, and was not able to promote microtubule disassembly. Conclusions SPAST mutations leading to premature stop codons do not always act through haploinsufficiency. The truncated spastin may damage the corticospinal tracts through an isoform‐specific toxic effect.
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Affiliation(s)
- Rui Chen
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Shiyue Du
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Yanyi Yao
- Medical Genetics Center, Maternal and Child Health Hospital of Hubei Province, Wuhan, China
| | - Lu Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Junyu Luo
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Yinhua Shen
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Zhenping Xu
- College of Life Science and Technology, Xinxiang Medical University, Xinxiang, China
| | - Xiaomei Zeng
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Luoying Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Mugen Liu
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Chuang Yin
- Department of Neurology, Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Jun Tan
- Department of Neurology, Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Xuan Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Jing Yu Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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13
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Zou J, Cai Z, Liang Z, Liang Y, Zhang G, Yang J, Zhang Y, Lin H, Tan M. Different fusion tags affect the activity of ubiquitin overexpression on spastin protein stability. Eur J Histochem 2021; 65. [PMID: 34873900 PMCID: PMC8678624 DOI: 10.4081/ejh.2021.3352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 11/23/2021] [Indexed: 11/23/2022] Open
Abstract
Spastin is one of the proteins which lead to hereditary spastic paraplegia (HSP), whose dysfunction towards microtubule severing and membrane transporting is critically important. The present study is to elucidate the mechanisms of the protein stability regulation of spastin. The ubiquitin encoding plasmids were transfected into COS-7 cells with different fusion tags including Green Fluorescent Protein (GFP), mCherry and Flag. The expression level of spastin was detected, microtubule severing activity and neurite outgrowth were quantified. The data showed that ubiquitin overexpression significantly induced the decreased expression of spastin, suppressed the activity of microtubule severing in COS-7 cells and inhibited the promoting effect on neurite outgrowth in cultured hippocampal neurons. Furthermore, when modulating the overexpression experiments of ubiquitin, it was found that relatively small tag like Flag, but not large tags such as GFP or mCherry fused with ubiquitin, retained the activity on spastin stability. The present study investigated the effects of small/large tags addition to ubiquitin and the novel mechanisms of post-transcriptional modifications of spastin on regulating neurite outgrowth, in the attempt to experimentally elucidate the mechanisms that control the level or stability of spastin in hereditary spastic paraplegia.
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Affiliation(s)
- Jianyu Zou
- Department of Orthopaedics, The First Affiliated Hospital of Jinan University, Guangzhou.
| | - Zhenbin Cai
- Department of Orthopaedics, The First Affiliated Hospital of Jinan University, Guangzhou.
| | - Zhi Liang
- Department of Orthopaedics, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen.
| | - Yaozhong Liang
- Department of Orthopaedics, The First Affiliated Hospital of Jinan University, Guangzhou.
| | - Guowei Zhang
- Department of Orthopaedics, The First Affiliated Hospital of Jinan University, Guangzhou.
| | - Jie Yang
- Department of Orthopaedics, The First Affiliated Hospital of Jinan University, Guangzhou.
| | - Yunlong Zhang
- Department of Orthopaedics, The First Affiliated Hospital of Jinan University, Guangzhou.
| | - Hongsheng Lin
- Department of Orthopaedics, The First Affiliated Hospital of Jinan University, Guangzhou.
| | - Minghui Tan
- Department of Orthopaedics, The First Affiliated Hospital of Jinan University, Guangzhou.
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14
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Elsayed LEO, Eltazi IZ, Ahmed AE, Stevanin G. Insights into Clinical, Genetic, and Pathological Aspects of Hereditary Spastic Paraplegias: A Comprehensive Overview. Front Mol Biosci 2021; 8:690899. [PMID: 34901147 PMCID: PMC8662366 DOI: 10.3389/fmolb.2021.690899] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 10/19/2021] [Indexed: 12/31/2022] Open
Abstract
Hereditary spastic paraplegias (HSP) are a heterogeneous group of motor neurodegenerative disorders that have the core clinical presentation of pyramidal syndrome which starts typically in the lower limbs. They can present as pure or complex forms with all classical modes of monogenic inheritance reported. To date, there are more than 100 loci/88 spastic paraplegia genes (SPG) involved in the pathogenesis of HSP. New patterns of inheritance are being increasingly identified in this era of huge advances in genetic and functional studies. A wide range of clinical symptoms and signs are now reported to complicate HSP with increasing overall complexity of the clinical presentations considered as HSP. This is especially true with the emergence of multiple HSP phenotypes that are situated in the borderline zone with other neurogenetic disorders. The genetic diagnostic approaches and the utilized techniques leave a diagnostic gap of 25% in the best studies. In this review, we summarize the known types of HSP with special focus on those in which spasticity is the principal clinical phenotype ("SPGn" designation). We discuss their modes of inheritance, clinical phenotypes, underlying genetics, and molecular pathways, providing some observations about therapeutic opportunities gained from animal models and functional studies. This review may pave the way for more analytic approaches that take into consideration the overall picture of HSP. It will shed light on subtle associations that can explain the occurrence of the disease and allow a better understanding of its observed variations. This should help in the identification of future biomarkers, predictors of disease onset and progression, and treatments for both better functional outcomes and quality of life.
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Affiliation(s)
- Liena E. O. Elsayed
- Department of Basic Sciences, College of Medicine, Princess Nourah bint Abdulrahman University [PNU], Riyadh, Saudi Arabia
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | | | - Ammar E. Ahmed
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Giovanni Stevanin
- Institut du Cerveau – Paris Brain Institute - ICM, Sorbonne Université, INSERM, CNRS, APHP, Paris, France
- CNRS, INCIA, Université de Bordeaux, Bordeaux, France
- Ecole Pratique des Hautes Etudes, EPHE, PSL Research University, Paris, France
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15
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Verriello L, Lonigro IR, Pessa ME, Betto E, Pauletto G, Fogolari F, Gigli GL, Curcio F. Amplifying the spectrum of SPAST gene mutations. ACTA BIO-MEDICA : ATENEI PARMENSIS 2021; 92:e2021220. [PMID: 35132972 PMCID: PMC10523053 DOI: 10.23750/abm.v92is1.11608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 06/14/2023]
Abstract
Hereditary spastic paraplegias (HSPs) include a group of neurodegenerative disorders characterized by slowly progressive spasticity and weakness of the lower extremities, caused by axon degeneration of corticospinal tracts. Spastic paraplegia type 4 (SPG4) is the most common autosomal dominant form of HSP and is caused by mutations in the SPAST gene. SPAST gene encodes for the protein spastin, a member of the ATPases Associated with a variety of cellular Activity (AAA) family.We describe a newly variant in SPAST gene, within an Italian family affected by pure HSP. In particular, we found a heterozygous intragenic microdeletion of 3T in exon 13 of SPG4 gene. The 3T deletion results in a mutated protein with a unique leucine residues deletion at the protein position 508, in the AAA ATPase domain. This variant is not registered in any public database either as rare normal variant nor as mutation in SPAST gene and the importance of this aminoacid is confirmed by the absolute conservation in multiple alignments with diverse species. We conclude that the novel SPAST gene variant identified is probably pathogenic and destabilizes the precise arrangement of the nucleotide binding domain, with a consequent loss-of-function of the mutated spastin protein.
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Affiliation(s)
- Lorenzo Verriello
- Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy.
| | - Incoronata Renata Lonigro
- Institute of Clinical Pathology, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy.
| | - Maria Elena Pessa
- a:1:{s:5:"en_US";s:49:"Azienda ospedaliero universitaria Friuli centrale";}.
| | - Elena Betto
- Institute of Clinical Pathology, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy.
| | - Giada Pauletto
- Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy.
| | - Federico Fogolari
- Department of Mathematics, Informatics and Physics (DMIF), University of Udine, Italy.
| | - Gian Luigi Gigli
- Clinical Neurology Unit, Department of Neurosciences, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy.
| | - Francesco Curcio
- Institute of Clinical Pathology, Santa Maria della Misericordia University Hospital, ASUFC, Udine, Italy.
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16
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ER Morphology in the Pathogenesis of Hereditary Spastic Paraplegia. Cells 2021; 10:cells10112870. [PMID: 34831093 PMCID: PMC8616106 DOI: 10.3390/cells10112870] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 12/18/2022] Open
Abstract
The endoplasmic reticulum (ER) is the most abundant and widespread organelle in cells. Its peculiar membrane architecture, formed by an intricate network of tubules and cisternae, is critical to its multifaceted function. Regulation of ER morphology is coordinated by a few ER-specific membrane proteins and is thought to be particularly important in neurons, where organized ER membranes are found even in the most distant neurite terminals. Mutation of ER-shaping proteins has been implicated in the neurodegenerative disease hereditary spastic paraplegia (HSP). In this review we discuss the involvement of these proteins in the pathogenesis of HSP, focusing on the experimental evidence linking their molecular function to disease onset. Although the precise biochemical activity of some ER-related HSP proteins has been elucidated, the pathological mechanism underlying ER-linked HSP is still undetermined and needs to be further investigated.
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17
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Liu Q, Zhang G, Ji Z, Lin H. Molecular and cellular mechanisms of spastin in neural development and disease (Review). Int J Mol Med 2021; 48:218. [PMID: 34664680 PMCID: PMC8547542 DOI: 10.3892/ijmm.2021.5051] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/29/2021] [Indexed: 12/26/2022] Open
Abstract
Spastin is a microtubule (MT)‑severing enzyme identified from mutations of hereditary spastic paraplegia in 1999 and extensive studies indicate its vital role in various cellular activities. In the past two decades, efforts have been made to understand the underlying molecular mechanisms of how spastin is linked to neural development and disease. Recent studies on spastin have unraveled the mechanistic processes of its MT‑severing activity and revealed that spastin acts as an MT amplifier to mediate its remodeling, thus providing valuable insight into the molecular roles of spastin under physiological conditions. In addition, recent research has revealed multiple novel molecular mechanisms of spastin in cellular biological pathways, including endoplasmic reticulum shaping, calcium trafficking, fatty acid trafficking, as well as endosomal fission and trafficking. These processes are closely involved in axonal and dendritic development and maintenance. The current review presents recent biological advances regarding the molecular mechanisms of spastin at the cellular level and provides insight into how it affects neural development and disease.
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Affiliation(s)
- Qiuling Liu
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
| | - Guowei Zhang
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
| | - Zhisheng Ji
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
| | - Hongsheng Lin
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
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18
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Mohan N, Qiang L, Morfini G, Baas PW. Therapeutic Strategies for Mutant SPAST-Based Hereditary Spastic Paraplegia. Brain Sci 2021; 11:brainsci11081081. [PMID: 34439700 PMCID: PMC8394973 DOI: 10.3390/brainsci11081081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/13/2021] [Accepted: 08/16/2021] [Indexed: 12/16/2022] Open
Abstract
Mutations of the SPAST gene that encodes the microtubule-severing enzyme called spastin are the chief cause of Hereditary Spastic Paraplegia. Growing evidence indicates that pathogenic mutations functionally compromise the spastin protein and endow it with toxic gain-of-function properties. With each of these two factors potentially relevant to disease etiology, the present article discusses possible therapeutic strategies that may ameliorate symptoms in patients suffering from SPAST-based Hereditary Spastic Paraplegia, which is usually termed SPG4-HSP.
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Affiliation(s)
- Neha Mohan
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19422, USA; (N.M.); (L.Q.)
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19422, USA; (N.M.); (L.Q.)
| | - Gerardo Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA;
| | - Peter W. Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19422, USA; (N.M.); (L.Q.)
- Correspondence: ; Tel.: +1-215-991-8289; Fax: +1-215-843-9082
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19
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Ji ZS, Li JP, Fu CH, Luo JX, Yang H, Zhang GW, Wu W, Lin HS. Spastin interacts with collapsin response mediator protein 3 to regulate neurite growth and branching. Neural Regen Res 2021; 16:2549-2556. [PMID: 33907047 PMCID: PMC8374569 DOI: 10.4103/1673-5374.313052] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Cytoskeletal microtubule rearrangement and movement are crucial in the repair of spinal cord injury. Spastin plays an important role in the regulation of microtubule severing. Both spastin and collapsin response mediator proteins can regulate neurite growth and branching; however, whether spastin interacts with collapsin response mediator protein 3 (CRMP3) during this process remains unclear, as is the mechanism by which CRMP3 participates in the repair of spinal cord injury. In this study, we used a proteomics approach to identify key proteins associated with spinal cord injury repair. We then employed liquid chromatography-mass spectrometry to identify proteins that were able to interact with glutathione S-transferase-spastin. Then, co-immunoprecipitation and staining approaches were used to evaluate potential interactions between spastin and CRMP3. Finally, we co-transfected primary hippocampal neurons with CRMP3 and spastin to evaluate their role in neurite outgrowth. Mass spectrometry identified the role of CRMP3 in the spinal cord injury repair process. Liquid chromatography-mass spectrometry pulldown assays identified three CRMP3 peptides that were able to interact with spastin. CRMP3 and spastin were co-expressed in the spinal cord and were able to interact with one another in vitro and in vivo. Lastly, CRMP3 overexpression was able to enhance the ability of spastin to promote neurite growth and branching. Therefore, our results confirm that spastin and CRMP3 play roles in spinal cord injury repair by regulating neurite growth and branching. These proteins may therefore be novel targets for spinal cord injury repair. The Institutional Animal Care and Use Committee of Jinan University, China approved this study (approval No. IACUS-20181008-03) on October 8, 2018.
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Affiliation(s)
- Zhi-Sheng Ji
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
| | - Jian-Ping Li
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Chao-Hua Fu
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou; Department of Orthopedics, Jiangmen Hospital of Sun Yat-sen University, Jiangmen, Guangdong Province, China
| | - Jian-Xian Luo
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
| | - Hua Yang
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
| | - Guo-Wei Zhang
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
| | - Wutian Wu
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province; Re-Stem Biotechnology Co., Ltd., Suzhou, Jiangsu Province; Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Hong-Sheng Lin
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
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20
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Sardina F, Pisciottani A, Ferrara M, Valente D, Casella M, Crescenzi M, Peschiaroli A, Casali C, Soddu S, Grierson AJ, Rinaldo C. Spastin recovery in hereditary spastic paraplegia by preventing neddylation-dependent degradation. Life Sci Alliance 2020; 3:3/12/e202000799. [PMID: 33106322 PMCID: PMC7652396 DOI: 10.26508/lsa.202000799] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/14/2020] [Accepted: 10/14/2020] [Indexed: 01/11/2023] Open
Abstract
Hereditary Spastic Paraplegia (HSP) is a neurodegenerative disease most commonly caused by autosomal dominant mutations in the SPG4 gene encoding the microtubule-severing protein spastin. We hypothesise that SPG4-HSP is attributable to reduced spastin function because of haploinsufficiency; thus, therapeutic approaches which elevate levels of the wild-type spastin allele may be an effective therapy. However, until now, how spastin levels are regulated is largely unknown. Here, we show that the kinase HIPK2 regulates spastin protein levels in proliferating cells, in differentiated neurons and in vivo. Our work reveals that HIPK2-mediated phosphorylation of spastin at S268 inhibits spastin K48-poly-ubiquitination at K554 and prevents its neddylation-dependent proteasomal degradation. In a spastin RNAi neuronal cell model, overexpression of HIPK2, or inhibition of neddylation, restores spastin levels and rescues neurite defects. Notably, we demonstrate that spastin levels can be restored pharmacologically by inhibiting its neddylation-mediated degradation in neurons derived from a spastin mouse model of HSP and in patient-derived cells, thus revealing novel therapeutic targets for the treatment of SPG4-HSP.
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Affiliation(s)
- Francesca Sardina
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy
| | - Alessandra Pisciottani
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy
| | - Manuela Ferrara
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy
| | - Davide Valente
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy.,Unit of Cellular Networks and Molecular Therapeutic Targets, IRCCS-Regina Elena National Cancer Institute, Rome, Italy
| | | | - Marco Crescenzi
- Core Facilities, Italian National Institute of Health, Rome, Italy
| | | | - Carlo Casali
- Department of Medico-Surgical Sciences and Biotechnologies, University of Rome Sapienza, Latina, Italy
| | - Silvia Soddu
- Unit of Cellular Networks and Molecular Therapeutic Targets, IRCCS-Regina Elena National Cancer Institute, Rome, Italy
| | - Andrew J Grierson
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Cinzia Rinaldo
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy .,Unit of Cellular Networks and Molecular Therapeutic Targets, IRCCS-Regina Elena National Cancer Institute, Rome, Italy
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Yu W, Jin H, Deng J, Nan D, Huang Y. A novel SPAST gene mutation identified in a Chinese family with hereditary spastic paraplegia. BMC MEDICAL GENETICS 2020; 21:123. [PMID: 32493220 PMCID: PMC7268315 DOI: 10.1186/s12881-020-01053-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 05/19/2020] [Indexed: 11/19/2022]
Abstract
Background Hereditary spastic paraplegia is a heterogeneous group of clinically and genetically neurodegenerative diseases characterized by progressive gait disorder. Hereditary spastic paraplegia can be inherited in various ways, and all modes of inheritance are associated with multiple genes or loci. At present, more than 76 disease-causing loci have been identified in hereditary spastic paraplegia patients. Here, we report a novel mutation in SPAST gene associated with hereditary spastic paraplegia in a Chinese family, further enriching the hereditary spastic paraplegia spectrum. Methods Whole genomic DNA was extracted from peripheral blood of the 15 subjects from a Chinese family using DNA Isolation Kit. The Whole Exome Sequencing of the proband was analyzed and the result was identified in the rest individuals. RaptorX prediction tool and Protein Variation Effect Analyzer were used to predict the effects of the mutation on protein tertiary structure and function. Results Spastic paraplegia has been inherited across at least four generations in this family, during which only four HSP patients were alive. The results obtained by analyzing the Whole Exome Sequencing of the proband exhibited a novel disease-associated in-frame deletion in the SPAST gene, and this mutation also existed in the rest three HSP patients in this family. This in-frame deletion consists of three nucleotides deletion (c.1710_1712delGAA) within the exon 16, resulting in lysine deficiency at the position 570 of the protein (p.K570del). This novel mutation was also predicted to result in the synthesis of misfolded SPAST protein and have the deleterious effect on the function of SPAST protein. Conclusion In this case, we reported a novel mutation in the known SPAST gene that segregated with HSP disease, which can be inherited in each generation. Simultaneously, this novel discovery significantly enriches the mutation spectrum, which provides an opportunity for further investigation of genetic pathogenesis of HSP.
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Affiliation(s)
- Weiwei Yu
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China
| | - Haiqiang Jin
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China
| | - Jianwen Deng
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China
| | - Ding Nan
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China
| | - Yining Huang
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street Xicheng District, Beijing, 100034, China.
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22
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Spastin mutations impair coordination between lipid droplet dispersion and reticulum. PLoS Genet 2020; 16:e1008665. [PMID: 32315314 PMCID: PMC7173978 DOI: 10.1371/journal.pgen.1008665] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 02/12/2020] [Indexed: 12/22/2022] Open
Abstract
Lipid droplets (LD) are affected in multiple human disorders. These highly dynamic organelles are involved in many cellular roles. While their intracellular dispersion is crucial to ensure their function and other organelles-contact, underlying mechanisms are still unclear. Here we show that Spastin, one of the major proteins involved in Hereditary Spastic Paraplegia (HSP), controls LD dispersion. Spastin depletion in zebrafish affects metabolic properties and organelle dynamics. These functions are ensured by a conserved complex set of splice variants. M1 isoforms determine LD dispersion in the cell by orchestrating endoplasmic reticulum (ER) shape along microtubules (MTs). To further impact LD fate, Spastin modulates transcripts levels and subcellular location of other HSP key players, notably Seipin and REEP1. In pathological conditions, mutations in human Spastin M1 disrupt this mechanism and impacts LD network. Spastin depletion influences not only other key proteins but also modulates specific neutral lipids and phospholipids, revealing an impact on membrane and organelle components. Altogether our results show that Spastin and its partners converge in a common machinery that coordinates LD dispersion and ER shape along MTs. Any alteration of this system results in HSP clinical features and impacts lipids profile, thus opening new avenues for novel biomarkers of HSP.
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23
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Zhu Z, Zhang C, Zhao G, Liu Q, Zhong P, Zhang M, Tang W, Zhan F, Tian W, Wang Y, Yin K, Huang X, Jiang J, Liu X, Liu S, Zhou H, Luan X, Tang H, Wang Y, Chen S, Cao L. Novel mutations in the SPAST gene cause hereditary spastic paraplegia. Parkinsonism Relat Disord 2019; 69:125-133. [PMID: 31751864 DOI: 10.1016/j.parkreldis.2019.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 10/05/2019] [Accepted: 11/05/2019] [Indexed: 01/14/2023]
Abstract
BACKGROUND Mutations in the SPAST gene are the most frequent cause of hereditary spastic paraplegia (HSP). We aim to extend the mutation spectrum of spastic paraplegia 4 (SPG4) and carried out experiment in vitro to explore the influence of the SPAST gene mutation on the function of corresponding protein. METHODS Whole-exome sequencing (WES) combined with multiplex ligation-dependent probe amplification (MLPA) were performed in a cohort of 150 patients clinically diagnosed with HSP. We focus on screening for mutations in SPAST gene and carrying out functional experiments to assess the effects of the novel variants. RESULTS A total of 34 different mutations in the SPAST gene were identified, of which 10 were novel, including 1 missense (c.1479T > A), 1 nonsense (c.766G > T), 3 splicing (c.1413 + 1_1413+4delGTAA, c.1729-1G > A and c.1536+2T > G) and 5 frameshift mutations (c.1094delC, c.885dupA, c.517_518delAG, c.280delG and c.908dupC). For 7 novel non-splicing mutations, functional study showed that accumulated M1 spastin colcocalized with microtubules which was different from a uniformly diffused M87 spastin. While an impairment in severing activity was observed in both mutant M1 and mutant M87, except for c.280delG. All 3 novel splicing variants w ere predicted to affect splicing by using bioinformatic programs. However, only c.1536+2T > G had no influence on splice site in vitro, which conflicts with the in-silico analysis. CONCLUSION We genetically diagnosed 40 SPG4 patients. All the novel non-splicing mutations except for c.280delG were certified to exert an effect on the microtubule-severing and all the novel splicing mutations other than c.1536+2T > G would cause abnormal splicing of the spastin.
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Affiliation(s)
- Zeyu Zhu
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Chao Zhang
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Neurology, Suzhou Hospital Affiliated to Anhui Medical University, Suzhou, China.
| | - Guohua Zhao
- Department of Neurology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Department of Neurology, The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China.
| | - Qing Liu
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
| | - Ping Zhong
- Department of Neurology, Suzhou Hospital Affiliated to Anhui Medical University, Suzhou, China.
| | - Mei Zhang
- Department of Neurology, Huainan First People's Hospital Affiliated to Bengbu Medical College, Huainan, Anhui Province, China.
| | - Weiguo Tang
- Department of Neurology, Zhoushan Hospital, Zhoushan, Zhejiang Province, China.
| | - Feixia Zhan
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Wotu Tian
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Yan Wang
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Neurology, Huainan First People's Hospital Affiliated to Bengbu Medical College, Huainan, Anhui Province, China.
| | - Kaili Yin
- McKusick-Zhang Center for Genetic Medicine and State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC), Beijing, China.
| | - Xiaojun Huang
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Jingwen Jiang
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Xiaoli Liu
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Neurology, Shanghai Fengxian District Central Hospital, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shangha, China.
| | - Shihua Liu
- Department of Neurology, Suzhou Hospital Affiliated to Anhui Medical University, Suzhou, China.
| | - Haiyan Zhou
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Xinghua Luan
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Huidong Tang
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Ying Wang
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Shengdi Chen
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Li Cao
- Department of Neurology and Institute of Neurology, Rui Jin Hospital & Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Fowler PC, Garcia-Pardo ME, Simpson JC, O'Sullivan NC. NeurodegenERation: The Central Role for ER Contacts in Neuronal Function and Axonopathy, Lessons From Hereditary Spastic Paraplegias and Related Diseases. Front Neurosci 2019; 13:1051. [PMID: 31680803 PMCID: PMC6801308 DOI: 10.3389/fnins.2019.01051] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/19/2019] [Indexed: 12/17/2022] Open
Abstract
The hereditary spastic paraplegias (HSPs) are a group of inherited neurodegenerative conditions whose characteristic feature is degeneration of the longest axons within the corticospinal tract which leads to progressive spasticity and weakness of the lower limbs. Though highly genetically heterogeneous, the majority of HSP cases are caused by mutations in genes encoding proteins that are responsible for generating and organizing the tubular endoplasmic reticulum (ER). Despite this, the role of the ER within neurons, particularly the long axons affected in HSP, is not well understood. Throughout axons, ER tubules make extensive contacts with other organelles, the cytoskeleton and the plasma membrane. At these ER contacts, protein complexes work in concert to perform specialized functions including organelle shaping, calcium homeostasis and lipid biogenesis, all of which are vital for neuronal survival and may be disrupted by HSP-causing mutations. In this article we summarize the proteins which mediate ER contacts, review the functions these contacts are known to carry out within neurons, and discuss the potential contribution of disruption of ER contacts to axonopathy in HSP.
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Affiliation(s)
- Philippa C Fowler
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - M Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Jeremy C Simpson
- UCD School of Biology and Environmental Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
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25
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Sandate CR, Szyk A, Zehr EA, Lander GC, Roll-Mecak A. An allosteric network in spastin couples multiple activities required for microtubule severing. Nat Struct Mol Biol 2019; 26:671-678. [PMID: 31285604 PMCID: PMC6761829 DOI: 10.1038/s41594-019-0257-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/24/2019] [Indexed: 12/30/2022]
Abstract
The AAA+ ATPase spastin remodels microtubule arrays through severing and its mutation is the most common cause of hereditary spastic paraplegias (HSP). Polyglutamylation of the tubulin C-terminal tail recruits spastin to microtubules and modulates severing activity. Here, we present a ~3.2 Å resolution cryo-EM structure of the Drosophila melanogaster spastin hexamer with a polyglutamate peptide bound in its central pore. Two electropositive loops arranged in a double-helical staircase coordinate the substrate sidechains. The structure reveals how concurrent nucleotide and substrate binding organizes the conserved spastin pore loops into an ordered network that is allosterically coupled to oligomerization, and suggests how tubulin tail engagement activates spastin for microtubule disassembly. This allosteric coupling may apply generally in organizing AAA+ protein translocases into their active conformations. We show that this allosteric network is essential for severing and is a hotspot for HSP mutations.
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Affiliation(s)
| | - Agnieszka Szyk
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Elena A Zehr
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | | | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA.
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26
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Qiang L, Piermarini E, Baas PW. New hypothesis for the etiology of SPAST-based hereditary spastic paraplegia. Cytoskeleton (Hoboken) 2019; 76:289-297. [PMID: 31108029 DOI: 10.1002/cm.21528] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 01/26/2023]
Abstract
Mutations of the SPAST gene are the chief cause of hereditary spastic paraplegia. Controversy exists in the medical community as to whether the etiology of the disease is haploinsufficiency or toxic gain-of-function properties of the mutant spastin proteins. In recognition of strong reasons that support each possible mechanism, here we present a novel perspective, based in part on new studies with mouse models and in part on the largest study to date on patients with the disease. We posit that haploinsufficiency does not cause the disease but makes the corticospinal tracts vulnerable to a second hit, which is usually the mutant spastin proteins but could also be proteins generated by mutations of other genes that may or may not cause the disease on their own.
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Affiliation(s)
- Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, Pennsylvania
| | - Emanuela Piermarini
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, Pennsylvania
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, Pennsylvania
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27
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Qiang L, Piermarini E, Muralidharan H, Yu W, Leo L, Hennessy LE, Fernandes S, Connors T, Yates PL, Swift M, Zholudeva LV, Lane MA, Morfini G, Alexander GM, Heiman-Patterson TD, Baas PW. Hereditary spastic paraplegia: gain-of-function mechanisms revealed by new transgenic mouse. Hum Mol Genet 2019; 28:1136-1152. [PMID: 30520996 DOI: 10.1093/hmg/ddy419] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 10/31/2018] [Accepted: 12/02/2018] [Indexed: 12/17/2022] Open
Abstract
Mutations of the SPAST gene, which encodes the microtubule-severing protein spastin, are the most common cause of hereditary spastic paraplegia (HSP). Haploinsufficiency is the prevalent opinion as to the mechanism of the disease, but gain-of-function toxicity of the mutant proteins is another possibility. Here, we report a new transgenic mouse (termed SPASTC448Y mouse) that is not haploinsufficient but expresses human spastin bearing the HSP pathogenic C448Y mutation. Expression of the mutant spastin was documented from fetus to adult, but gait defects reminiscent of HSP (not observed in spastin knockout mice) were adult onset, as is typical of human patients. Results of histological and tracer studies on the mouse are consistent with progressive dying back of corticospinal axons, which is characteristic of the disease. The C448Y-mutated spastin alters microtubule stability in a manner that is opposite to the expectations of haploinsufficiency. Neurons cultured from the mouse display deficits in organelle transport typical of axonal degenerative diseases, and these deficits were worsened by depletion of endogenous mouse spastin. These results on the SPASTC448Y mouse are consistent with a gain-of-function mechanism underlying HSP, with spastin haploinsufficiency exacerbating the toxicity of the mutant spastin proteins. These findings reveal the need for a different therapeutic approach than indicated by haploinsufficiency alone.
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Affiliation(s)
| | | | | | | | | | - Laura E Hennessy
- Department of Neurology, Drexel University College of Medicine, Queen Lane, Philadelphia, PA, USA
| | | | | | | | | | | | | | - Gerardo Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Guillermo M Alexander
- Department of Neurology, Drexel University College of Medicine, Queen Lane, Philadelphia, PA, USA
| | - Terry D Heiman-Patterson
- Department of Neurology, Drexel University College of Medicine, Queen Lane, Philadelphia, PA, USA
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28
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Ji Z, Zhang G, Chen L, Li J, Yang Y, Cha C, Zhang J, Lin H, Guo G. Spastin Interacts with CRMP5 to Promote Neurite Outgrowth by Controlling the Microtubule Dynamics. Dev Neurobiol 2018; 78:1191-1205. [PMID: 30257070 DOI: 10.1002/dneu.22640] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/27/2018] [Accepted: 09/07/2018] [Indexed: 12/14/2022]
Abstract
Changing the microtubule dynamics is sufficient to alter the axon and dendrite specification and development. Spastin participates in the growth and regeneration of neurites by severing microtubules into small segments, and collapsin response mediator protein 5 (CRMP5) provides structural support and serves as a track for cargo transport by promoting microtubule polymerization. Nevertheless, how spastin and CRMP5 cooperate to regulate neurite outgrowth by controlling the microtubule dynamics needs to be elucidated. In our present study, spastin interacted with CRMP5 in vitro and in vivo. The binding domains for the spastin and CRMP5 interaction were the N-terminal fragment of spastin (residues 270-328) and the C-terminal fragment of CRMP5 (residues 472-564). Spastin and its truncation mutants, including the microtubule-binding domain (MTBD) and ATPases associated with diverse cellular activities (AAA) domain, were necessary for the severing of microtubules. Furthermore, we demonstrated that microtubule polymerization of CRMP5 interfered with the microtubule-severing function of spastin. Knocking down either spastin or CRMP5 inhibited neurite outgrowth in hippocampal neurons. However, co-transfected spastin and CRMP5 promoted the outgrowth of neurites including dendrites and axons. Taken together, our data support a model in which the spastin interaction with CRMP5 promotes neurite outgrowth by controlling the microtubule dynamics.
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Affiliation(s)
- Zhisheng Ji
- Department of Orthopedics, the First Affiliated Hospital of Jinan University, Guangzhou, China.,Department of Anatomy, Medical College of Jinan University, Guangzhou, China
| | - Guowei Zhang
- Department of Orthopedics, the First Affiliated Hospital of Jinan University, Guangzhou, China.,Department of Anatomy, Medical College of Jinan University, Guangzhou, China
| | - Li Chen
- Department of Anatomy, Medical College of Jinan University, Guangzhou, China
| | - Jiong Li
- Department of Anatomy, Medical College of Jinan University, Guangzhou, China
| | - Yuhao Yang
- Department of Orthopedics, the First Affiliated Hospital of Jinan University, Guangzhou, China.,Department of Anatomy, Medical College of Jinan University, Guangzhou, China
| | - Caihui Cha
- Department of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Jifeng Zhang
- Department of Anatomy, Medical College of Jinan University, Guangzhou, China
| | - Hongsheng Lin
- Department of Orthopedics, the First Affiliated Hospital of Jinan University, Guangzhou, China.,Department of Anatomy, Medical College of Jinan University, Guangzhou, China
| | - Guoqing Guo
- Department of Anatomy, Medical College of Jinan University, Guangzhou, China
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29
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Jardin N, Giudicelli F, Ten Martín D, Vitrac A, De Gois S, Allison R, Houart C, Reid E, Hazan J, Fassier C. BMP- and neuropilin 1-mediated motor axon navigation relies on spastin alternative translation. Development 2018; 145:dev.162701. [PMID: 30082270 PMCID: PMC6141775 DOI: 10.1242/dev.162701] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 07/16/2018] [Indexed: 12/22/2022]
Abstract
Functional analyses of genes responsible for neurodegenerative disorders have unveiled crucial links between neurodegenerative processes and key developmental signalling pathways. Mutations in SPG4-encoding spastin cause hereditary spastic paraplegia (HSP). Spastin is involved in diverse cellular processes that couple microtubule severing to membrane remodelling. Two main spastin isoforms are synthesised from alternative translational start sites (M1 and M87). However, their specific roles in neuronal development and homeostasis remain largely unknown. To selectively unravel their neuronal function, we blocked spastin synthesis from each initiation codon during zebrafish development and performed rescue analyses. The knockdown of each isoform led to different motor neuron and locomotion defects, which were not rescued by the selective expression of the other isoform. Notably, both morphant neuronal phenotypes were observed in a CRISPR/Cas9 spastin mutant. We next showed that M1 spastin, together with HSP proteins atlastin 1 and NIPA1, drives motor axon targeting by repressing BMP signalling, whereas M87 spastin acts downstream of neuropilin 1 to control motor neuron migration. Our data therefore suggest that defective BMP and neuropilin 1 signalling may contribute to the motor phenotype in a vertebrate model of spastin depletion.
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Affiliation(s)
- Nicolas Jardin
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - François Giudicelli
- Sorbonne Universités, UPMC Université Paris 06, CNRS, INSERM, Biologie du Développement Paris Seine - Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Daniel Ten Martín
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - Anaïs Vitrac
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - Stéphanie De Gois
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - Rachel Allison
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, UK
| | - Corinne Houart
- Medical Research Council Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Evan Reid
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, UK
| | - Jamilé Hazan
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
| | - Coralie Fassier
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Neuroscience Paris Seine - Institut de Biologie Paris-Seine (NPS-IBPS), 75005 Paris, France
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30
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Plaud C, Joshi V, Kajevu N, Poüs C, Curmi PA, Burgo A. Functional differences of short and long isoforms of spastin harboring missense mutation. Dis Model Mech 2018; 11:11/9/dmm033704. [PMID: 30213879 PMCID: PMC6177001 DOI: 10.1242/dmm.033704] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 07/03/2018] [Indexed: 01/05/2023] Open
Abstract
Mutations of the SPG4 (SPAST) gene encoding for spastin protein are the main causes of hereditary spastic paraplegia. Spastin binds to microtubules and severs them through the enzymatic activity of its AAA domain. Several missense mutations located in this domain lead to stable, nonsevering spastins that decorate a subset of microtubules, suggesting a possible negative gain-of-function mechanism for these mutants. Of the two main isoforms of spastin, only mutations of the long isoform, M1, are supposed to be involved in the onset of the pathology, leaving the role of the ubiquitously expressed shorter one, M87, not fully investigated and understood. Here, we show that two isoforms of spastin harboring the same missense mutation bind and bundle different subsets of microtubules in HeLa cells, and likely stabilize them by increasing the level of acetylated tubulin. However, only mutated M1 has the ability to interact with wild-type M1, and decorates a subset of perinuclear microtubules associated with the endoplasmic reticulum that display higher resistance to microtubule depolymerization and increased intracellular ionic strength, compared with those decorated by mutated M87. We further show that only mutated M1 decorates microtubules of proximal axons and dendrites, and strongly impairs axonal transport in cortical neurons through a mechanism likely independent of the microtubule-severing activity of this protein. Summary: Long and short isoforms of spastin (SPG4) harboring the same missense mutation show different intracellular localization, resistance to pharmacological treatments and effects on axonal cargo transport.
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Affiliation(s)
- Clément Plaud
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
| | - Vandana Joshi
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
| | - Natallie Kajevu
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
| | - Christian Poüs
- INSERM UMR-S 1193, Faculty of Pharmacy, Univirsité Paris-Sud, Université Paris-Saclay, 92296 Châtenay-Malabry, France
| | - Patrick A Curmi
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
| | - Andrea Burgo
- Structure and Activity of Normal and Pathological Biomolecules, INSERM U1204, Université Paris Saclay, Université d'Evry, 91000 Evry, France
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31
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Rao AN, Patil A, Black MM, Craig EM, Myers KA, Yeung HT, Baas PW. Cytoplasmic Dynein Transports Axonal Microtubules in a Polarity-Sorting Manner. Cell Rep 2018; 19:2210-2219. [PMID: 28614709 DOI: 10.1016/j.celrep.2017.05.064] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 04/20/2017] [Accepted: 05/18/2017] [Indexed: 01/20/2023] Open
Abstract
Axonal microtubules are predominantly organized into a plus-end-out pattern. Here, we tested both experimentally and with computational modeling whether a motor-based polarity-sorting mechanism can explain this microtubule pattern. The posited mechanism centers on cytoplasmic dynein transporting plus-end-out and minus-end-out microtubules into and out of the axon, respectively. When cytoplasmic dynein was acutely inhibited, the bi-directional transport of microtubules in the axon was disrupted in both directions, after which minus-end-out microtubules accumulated in the axon over time. Computational modeling revealed that dynein-mediated transport of microtubules can establish and preserve a predominantly plus-end-out microtubule pattern as per the details of the experimental findings, but only if a kinesin motor and a static cross-linker protein are also at play. Consistent with the predictions of the model, partial depletion of TRIM46, a protein that cross-links axonal microtubules in a manner that influences their polarity orientation, leads to an increase in microtubule transport.
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Affiliation(s)
- Anand N Rao
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, USA
| | - Ankita Patil
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, USA
| | - Mark M Black
- Department of Anatomy and Cell Biology, Temple University, Philadelphia, PA 19140, USA
| | - Erin M Craig
- Department of Physics, Central Washington University, Ellensburg, WA 98926, USA
| | - Kenneth A Myers
- Department Biological Sciences, University of the Sciences, Philadelphia, PA 19104, USA
| | - Howard T Yeung
- Department of Physics, Central Washington University, Ellensburg, WA 98926, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, USA.
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Leo L, Weissmann C, Burns M, Kang M, Song Y, Qiang L, Brady ST, Baas PW, Morfini G. Mutant spastin proteins promote deficits in axonal transport through an isoform-specific mechanism involving casein kinase 2 activation. Hum Mol Genet 2017; 26:2321-2334. [PMID: 28398512 DOI: 10.1093/hmg/ddx125] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/24/2017] [Indexed: 01/19/2023] Open
Abstract
Mutations of various genes cause hereditary spastic paraplegia (HSP), a neurological disease involving dying-back degeneration of upper motor neurons. From these, mutations in the SPAST gene encoding the microtubule-severing protein spastin account for most HSP cases. Cumulative genetic and experimental evidence suggests that alterations in various intracellular trafficking events, including fast axonal transport (FAT), may contribute to HSP pathogenesis. However, the mechanisms linking SPAST mutations to such deficits remain largely unknown. Experiments presented here using isolated squid axoplasm reveal inhibition of FAT as a common toxic effect elicited by spastin proteins with different HSP mutations, independent of microtubule-binding or severing activity. Mutant spastin proteins produce this toxic effect only when presented as the tissue-specific M1 isoform, not when presented as the ubiquitously-expressed shorter M87 isoform. Biochemical and pharmacological experiments further indicate that the toxic effects of mutant M1 spastins on FAT involve casein kinase 2 (CK2) activation. In mammalian cells, expression of mutant M1 spastins, but not their mutant M87 counterparts, promotes abnormalities in the distribution of intracellular organelles that are correctable by pharmacological CK2 inhibition. Collectively, these results demonstrate isoform-specific toxic effects of mutant M1 spastin on FAT, and identify CK2 as a critical mediator of these effects.
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Affiliation(s)
- Lanfranco Leo
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Carina Weissmann
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Matthew Burns
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Minsu Kang
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA.,Marine Biological Laboratory, Woods Hole, MA, USA
| | - Yuyu Song
- Marine Biological Laboratory, Woods Hole, MA, USA.,Department of Genetics, School of Medicine, Yale University, New Haven, CT, USA
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Scott T Brady
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA.,Marine Biological Laboratory, Woods Hole, MA, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Gerardo Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA.,Marine Biological Laboratory, Woods Hole, MA, USA
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Kawarai T, Montecchiani C, Miyamoto R, Gaudiello F, Caltagirone C, Izumi Y, Kaji R, Orlacchio A. Spastic paraplegia type 4: A novel SPAST splice site donor mutation and expansion of the phenotype variability. J Neurol Sci 2017; 380:92-97. [PMID: 28870597 DOI: 10.1016/j.jns.2017.07.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 06/29/2017] [Accepted: 07/06/2017] [Indexed: 01/30/2023]
Abstract
Mutations in SPG4/SPAST are the most frequent molecular aetiology in the autosomal dominant form of hereditary spastic paraplegia (HSP). Loss-of-function and haploinsufficiency in SPAST have been demonstrated and the pure form of spastic paraplegia is a main clinical manifestation. This study is to explore the novel SPAST splice site donor variant, c.1004+3A>C, in seven patients from two families, one from Italy and the other from Japan. Exon 6 is skipped out by the variant, leading to a premature termination of translation, p.Gly290Trpfs*5. Measurement of SPAST transcripts in lymphocytes demonstrated a reduction through nonsense-mediated mRNA decay (NMD). Intra- and inter-familial phenotypic variations were observed, including age-at-onset, severity of spasticity, and scoliosis. Our study demonstrated further evidence of allelic heterogeneity in SPG4, dosage effects through NMD, and broad clinical features of the SPAST mutation.
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Affiliation(s)
- Toshitaka Kawarai
- Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-0042, Japan.
| | - Celeste Montecchiani
- Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC) - Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Santa Lucia, Rome, Italy; Dipartimento di Scienze Chirurgiche e Biomediche, Università di Perugia, Perugia, Italy
| | - Ryosuke Miyamoto
- Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-0042, Japan
| | - Fabrizio Gaudiello
- Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC) - Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Santa Lucia, Rome, Italy
| | - Carlo Caltagirone
- Laboratorio di Neurologia Clinica e Comportamentale, IRCCS Santa Lucia, Rome, Italy; Dipartimento di Medicina dei Sistemi, Università di Roma "Tor Vergata", Rome, Italy
| | - Yuishin Izumi
- Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-0042, Japan
| | - Ryuji Kaji
- Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-0042, Japan
| | - Antonio Orlacchio
- Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC) - Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Santa Lucia, Rome, Italy; Dipartimento di Scienze Chirurgiche e Biomediche, Università di Perugia, Perugia, Italy.
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Solowska JM, Rao AN, Baas PW. Truncating mutations of SPAST associated with hereditary spastic paraplegia indicate greater accumulation and toxicity of the M1 isoform of spastin. Mol Biol Cell 2017; 28:1728-1737. [PMID: 28495799 PMCID: PMC5491181 DOI: 10.1091/mbc.e17-01-0047] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/17/2017] [Accepted: 05/02/2017] [Indexed: 12/21/2022] Open
Abstract
The SPAST gene, which produces two isoforms of the microtubule-severing protein spastin, is the chief gene mutated in hereditary spastic paraplegia. Truncated M1 spastin proteins are toxic and have the potential to accumulate in these patients. The SPAST gene, which produces two isoforms (M1 and M87) of the microtubule-severing protein spastin, is the chief gene mutated in hereditary spastic paraplegia. Haploinsufficiency is a popular explanation for the disease, in part because most of the >200 pathogenic mutations of the gene are truncating and expected to produce only vanishingly small amounts of shortened proteins. Here we studied two such mutations, N184X and S245X, and our results suggest another possibility. We found that the truncated M1 proteins can accumulate to notably higher levels than their truncated M87 or wild-type counterparts. Reminiscent of our earlier studies on a pathogenic mutation that generates full-length M1 and M87 proteins, truncated M1 was notably more detrimental to neurite outgrowth than truncated M87, and this was true for both N184X and S245X. The greater toxicity and tendency to accumulate suggest that, over time, truncated M1 could damage the corticospinal tracts of human patients. Curiously, the N184X mutation triggers the reinitiation of translation at a third start codon in SPAST, resulting in synthesis of a novel M187 spastin isoform that is able to sever microtubules. Thus microtubule severing may not be as reduced as previously assumed in the case of that mutation.
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Affiliation(s)
- Joanna M Solowska
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
| | - Anand N Rao
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
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Baas PW, Rao AN, Matamoros AJ, Leo L. Stability properties of neuronal microtubules. Cytoskeleton (Hoboken) 2016; 73:442-60. [PMID: 26887570 PMCID: PMC5541393 DOI: 10.1002/cm.21286] [Citation(s) in RCA: 184] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/02/2016] [Accepted: 02/12/2016] [Indexed: 01/12/2023]
Abstract
Neurons are terminally differentiated cells that use their microtubule arrays not for cell division but rather as architectural elements required for the elaboration of elongated axons and dendrites. In addition to acting as compression-bearing struts that provide for the shape of the neuron, microtubules also act as directional railways for organelle transport. The stability properties of neuronal microtubules are commonly discussed in the biomedical literature as crucial to the development and maintenance of the nervous system, and have recently gained attention as central to the etiology of neurodegenerative diseases. Drugs that affect microtubule stability are currently under investigation as potential therapies for disease and injury of the nervous system. There is often a lack of consistency, however, in how the issue of microtubule stability is discussed in the literature, and this can affect the design and interpretation of experiments as well as potential therapeutic regimens. Neuronal microtubules are considered to be more stable than microtubules in dividing cells. On average, this is true, but in addition to an abundant stable microtubule fraction in neurons, there is also an abundant labile microtubule fraction. Both are functionally important. Individual microtubules consist of domains that differ in their stability properties, and these domains can also differ markedly in their composition as well as how they interact with various microtubule-related proteins in the neuron. Myriad proteins and pathways have been discussed as potential contributors to microtubule stability in neurons. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA.
| | - Anand N Rao
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Andrew J Matamoros
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Lanfranco Leo
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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36
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Microtubules in health and degenerative disease of the nervous system. Brain Res Bull 2016; 126:217-225. [PMID: 27365230 DOI: 10.1016/j.brainresbull.2016.06.016] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/22/2016] [Accepted: 06/27/2016] [Indexed: 01/04/2023]
Abstract
Microtubules are essential for the development and maintenance of axons and dendrites throughout the life of the neuron, and are vulnerable to degradation and disorganization in a variety of neurodegenerative diseases. Microtubules, polymers of tubulin heterodimers, are intrinsically polar structures with a plus end favored for assembly and disassembly and a minus end less favored for these dynamics. In the axon, microtubules are nearly uniformly oriented with plus ends out, whereas in dendrites, microtubules have mixed orientations. Microtubules in developing neurons typically have a stable domain toward the minus end and a labile domain toward the plus end. This domain structure becomes more complex during neuronal maturation when especially stable patches of polyaminated tubulin become more prominent within the microtubule. Microtubules are the substrates for molecular motor proteins that transport cargoes toward the plus or minus end of the microtubule, with motor-driven forces also responsible for organizing microtubules into their distinctive polarity patterns in axons and dendrites. A vast array of microtubule-regulatory proteins impart direct and indirect changes upon the microtubule arrays of the neuron, and these include microtubule-severing proteins as well as proteins responsible for the stability properties of the microtubules. During neurodegenerative diseases, microtubule mass is commonly diminished, and the potential exists for corruption of the microtubule polarity patterns and microtubule-mediated transport. These ill effects may be a primary causative factor in the disease or may be secondary effects, but regardless, therapeutics capable of correcting these microtubule abnormalities have great potential to improve the status of the degenerating nervous system.
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Zempel H, Mandelkow EM. Tau missorting and spastin-induced microtubule disruption in neurodegeneration: Alzheimer Disease and Hereditary Spastic Paraplegia. Mol Neurodegener 2015; 10:68. [PMID: 26691836 PMCID: PMC4687341 DOI: 10.1186/s13024-015-0064-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 12/08/2015] [Indexed: 12/16/2022] Open
Abstract
In Alzheimer Disease (AD), the mechanistic connection of the two major pathological hallmarks, namely deposition of Amyloid-beta (Aβ) in the form of extracellular plaques, and the pathological changes of the intracellular protein Tau (such as phosphorylation, missorting, aggregation), is not well understood. Genetic evidence from AD and Down Syndrome (Trisomy 21), and animal models thereof, suggests that aberrant production of Aβ is upstream of Tau aggregation, but also points to Tau as a critical effector in the pathological process. Yet, the cascade of events leading from increased levels of Aβ to Tau-dependent toxicity remains a matter of debate. Using primary neurons exposed to oligomeric forms of Aβ, we have found that Tau becomes mislocalized (missorted) into the somatodendritic compartment. Missorting of Tau correlates with loss of microtubules and downstream consequences such as loss of mature spines, loss of synaptic activity, and mislocalization of mitochondria. In this cascade, missorting of Tau induces mislocalization of TTLL6 (Tubulin-Tyrosine-Ligase-Like 6) into the dendrites. TTLL6 induces polyglutamylation of microtubules, which acts as a trigger for spastin mediated severing of dendritic microtubules. Loss of microtubules makes cells unable to maintain transport of mitochondria, which in turn results in synaptic dysfunction and loss of mature spines. These pathological changes are absent in TauKO derived primary neurons. Thus, Tau mediated mislocalization of TTLL6 and spastin activation reveals a pathological gain of function for Tau and spastin in this cellular model system of AD. In contrast, in hereditary spastic paraplegia (HSP) caused by mutations of the gene encoding spastin (spg4 alias SPAST), spastin function in terms of microtubule severing is decreased at least for the gene product of the mutated allele, resulting in overstable microtubules in disease model systems. Whether total spastin severing activity or microtubule stability in human disease is also affected is not yet clear. No human disease has been associated so far with the long-chain polyglutamylation enzyme TTLL6, or the other TTLLs (1,5,11) possibly involved. Here we review the findings supporting a role for Tau, spastin and TTLL6 in AD and other tauopathies, HSP and neurodegeneration, and summarize possible therapeutic approaches for AD and HSP.
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Affiliation(s)
- Hans Zempel
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany. .,MPI for Metabolism Research, Hamburg Outstation, c/o DESY, Hamburg, Germany.
| | - Eva-Maria Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany. .,CAESAR Research Center, Bonn, Germany. .,MPI for Metabolism Research, Hamburg Outstation, c/o DESY, Hamburg, Germany.
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Penazzi L, Bakota L, Brandt R. Microtubule Dynamics in Neuronal Development, Plasticity, and Neurodegeneration. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 321:89-169. [PMID: 26811287 DOI: 10.1016/bs.ircmb.2015.09.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Neurons are the basic information-processing units of the nervous system. In fulfilling their task, they establish a structural polarity with an axon that can be over a meter long and dendrites with a complex arbor, which can harbor ten-thousands of spines. Microtubules and their associated proteins play important roles during the development of neuronal morphology, the plasticity of neurons, and neurodegenerative processes. They are dynamic structures, which can quickly adapt to changes in the environment and establish a structural scaffold with high local variations in composition and stability. This review presents a comprehensive overview about the role of microtubules and their dynamic behavior during the formation and maturation of processes and spines in the healthy brain, during aging and under neurodegenerative conditions. The review ends with a discussion of microtubule-targeted therapies as a perspective for the supportive treatment of neurodegenerative disorders.
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Affiliation(s)
- Lorène Penazzi
- Department of Neurobiology, University of Osnabrück, Osnabrück, Germany
| | - Lidia Bakota
- Department of Neurobiology, University of Osnabrück, Osnabrück, Germany
| | - Roland Brandt
- Department of Neurobiology, University of Osnabrück, Osnabrück, Germany
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40
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Solowska JM, Baas PW. Hereditary spastic paraplegia SPG4: what is known and not known about the disease. Brain 2015; 138:2471-84. [PMID: 26094131 DOI: 10.1093/brain/awv178] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 05/02/2015] [Indexed: 01/11/2023] Open
Abstract
Mutations in more than 70 distinct loci and more than 50 mutated gene products have been identified in patients with hereditary spastic paraplegias, a diverse group of neurological disorders characterized predominantly, but not exclusively, by progressive lower limb spasticity and weakness resulting from distal degeneration of corticospinal tract axons. Mutations in the SPAST (previously known as SPG4) gene that encodes the microtubule-severing protein called spastin, are the most common cause of the disease. The aetiology of the disease is poorly understood, but partial loss of microtubule-severing activity resulting from inactivating mutations in one SPAST allele is the most postulated explanation. Microtubule severing is important for regulating various aspects of the microtubule array, including microtubule number, length, and mobility. In addition, higher numbers of dynamic plus-ends of microtubules, resulting from microtubule-severing events, may play a role in endosomal tubulation and fission. Even so, there is growing evidence that decreased severing of microtubules does not fully explain HSP-SPG4. The presence of two translation initiation codons in SPAST allows synthesis of two spastin isoforms: a full-length isoform called M1 and a slightly shorter isoform called M87. M87 is more abundant in both neuronal and non-neuronal tissues. Studies on rodents suggest that M1 is only readily detected in adult spinal cord, which is where nerve degeneration mainly occurs in humans with HSP-SPG4. M1, due to its hydrophobic N-terminal domain not shared by M87, may insert into endoplasmic reticulum membrane, and together with reticulons, atlastin and REEP1, may play a role in the morphogenesis of this organelle. Some mutated spastins may act in dominant-negative fashion to lower microtubule-severing activity, but others have detrimental effects on neurons without further lowering microtubule severing. The observed adverse effects on microtubule dynamics, axonal transport, endoplasmic reticulum, and endosomal trafficking are likely caused not only by diminished severing of microtubules, but also by neurotoxicity of mutant spastin proteins, chiefly M1. Some large deletions in SPAST might also affect the function of adjacent genes, further complicating the aetiology of the disease.
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Affiliation(s)
- Joanna M Solowska
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
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Katsetos CD, Reginato MJ, Baas PW, D'Agostino L, Legido A, Tuszyn Ski JA, Dráberová E, Dráber P. Emerging microtubule targets in glioma therapy. Semin Pediatr Neurol 2015; 22:49-72. [PMID: 25976261 DOI: 10.1016/j.spen.2015.03.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Major advances in the genomics and epigenomics of diffuse gliomas and glioblastoma to date have not been translated into effective therapy, necessitating pursuit of alternative treatment approaches for these therapeutically challenging tumors. Current knowledge of microtubules in cancer and the development of new microtubule-based treatment strategies for high-grade gliomas are the topic in this review article. Discussed are cellular, molecular, and pharmacologic aspects of the microtubule cytoskeleton underlying mitosis and interactions with other cellular partners involved in cell cycle progression, directional cell migration, and tumor invasion. Special focus is placed on (1) the aberrant overexpression of βIII-tubulin, a survival factor associated with hypoxic tumor microenvironment and dynamic instability of microtubules; (2) the ectopic overexpression of γ-tubulin, which in addition to its conventional role as a microtubule-nucleating protein has recently emerged as a transcription factor interacting with oncogenes and kinases; (3) the microtubule-severing ATPase spastin and its emerging role in cell motility of glioblastoma cells; and (4) the modulating role of posttranslational modifications of tubulin in the context of interaction of microtubules with motor proteins. Specific antineoplastic strategies discussed include downregulation of targeted molecules aimed at achieving a sensitization effect on currently used mainstay therapies. The potential role of new classes of tubulin-binding agents and ATPase inhibitors is also examined. Understanding the cellular and molecular mechanisms underpinning the distinct behaviors of microtubules in glioma tumorigenesis and drug resistance is key to the discovery of novel molecular targets that will fundamentally change the prognostic outlook of patients with diffuse high-grade gliomas.
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Affiliation(s)
- Christos D Katsetos
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA; Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Philadelphia, PA.
| | - Mauricio J Reginato
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA
| | - Luca D'Agostino
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA
| | - Agustin Legido
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA
| | - Jack A Tuszyn Ski
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta, Canada; Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Eduarda Dráberová
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Valakh V, Frey E, Babetto E, Walker LJ, DiAntonio A. Cytoskeletal disruption activates the DLK/JNK pathway, which promotes axonal regeneration and mimics a preconditioning injury. Neurobiol Dis 2015; 77:13-25. [PMID: 25726747 DOI: 10.1016/j.nbd.2015.02.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 01/12/2015] [Accepted: 02/15/2015] [Indexed: 10/23/2022] Open
Abstract
Nerve injury can lead to axonal regeneration, axonal degeneration, and/or neuronal cell death. Remarkably, the MAP3K dual leucine zipper kinase, DLK, promotes each of these responses, suggesting that DLK is a sensor of axon injury. In Drosophila, mutations in proteins that stabilize the actin and microtubule cytoskeletons activate the DLK pathway, suggesting that DLK may be activated by cytoskeletal disruption. Here we test this model in mammalian sensory neurons. We find that pharmacological agents designed to disrupt either the actin or microtubule cytoskeleton activate the DLK pathway, and that activation is independent of calcium influx or induction of the axon degeneration program. Moreover, activation of the DLK pathway by targeting the cytoskeleton induces a pro-regenerative state, enhancing axon regeneration in response to a subsequent injury in a process akin to preconditioning. This highlights the potential utility of activating the DLK pathway as a method to improve axon regeneration. Moreover, DLK is required for these responses to cytoskeletal perturbations, suggesting that DLK functions as a key neuronal sensor of cytoskeletal damage.
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Affiliation(s)
- Vera Valakh
- Department of Developmental Biology, Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Erin Frey
- Department of Developmental Biology, Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Elisabetta Babetto
- Department of Developmental Biology, Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Lauren J Walker
- Department of Developmental Biology, Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Aaron DiAntonio
- Department of Developmental Biology, Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, MO 63110, USA.
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