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Dosi C, Masson R. The impact of three SMN2 gene copies on clinical characteristics and effect of disease-modifying treatment in patients with spinal muscular atrophy: a systematic literature review. Front Neurol 2024; 15:1308296. [PMID: 38487326 PMCID: PMC10937544 DOI: 10.3389/fneur.2024.1308296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 02/12/2024] [Indexed: 03/17/2024] Open
Abstract
Objective To review the clinical characteristics and effect of treatment in patients with spinal muscular atrophy (SMA) and three copies of the SMN2 gene. Methods We conducted a literature search in October 2022 to identify English-language clinical research on SMA that included SMN2 copy number according to PRISMA guidelines. Results Our search identified 44 studies examining the impact of three SMN2 copies on clinical characteristics (21 on phenotype, 13 on natural history, and 15 on functional status and other signs/symptoms). In children with type I SMA or presymptomatic infants with an SMN1 deletion, three SMN2 copies was associated with later symptom onset, slower decline in motor function and longer survival compared with two SMN2 copies. In patients with SMA type II or III, three SMN2 copies is associated with earlier symptom onset, loss of ambulation, and ventilator dependence compared with four SMN2 copies. Eleven studies examined treatment effects with nusinersen (nine studies), onasemnogene abeparvovec (one study), and a range of treatments (one study) in patients with three SMN2 copies. In presymptomatic infants, early treatment delayed the onset of symptoms and maintained motor function in those with three SMN2 copies. The impact of copy number on treatment response in symptomatic patients is still unclear. Conclusion SMN2 copy number is strongly correlated with SMA phenotype in patients with SMN1 deletion, while no correlation was found in patients with an SMN1 mutation. Patients with three SMN2 copies show a highly variable clinical phenotype. Early initiation of treatment is highly effective in presymptomatic patients with three SMN2 copies.
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Affiliation(s)
| | - Riccardo Masson
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Developmental Neurology Unit, Milan, Italy
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2
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Reiner J, Rosenblum LS, Xin W, Zhou Z, Zhu H, Leach N. Incidental molecular diagnoses and heterozygous risk alleles in a carrier screening cohort. Genet Med 2023; 25:100317. [PMID: 36459106 DOI: 10.1016/j.gim.2022.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/30/2022] [Accepted: 10/02/2022] [Indexed: 12/05/2022] Open
Abstract
PURPOSE Expanded pan-ethnic carrier screening is an effective tool for the management of reproductive risk. However, growth in the number of conditions screened, in combination with increasingly more comprehensive test methodologies, can lead to the detection of genetic findings that may affect the health of the tested individual. The objective of this study was to investigate the frequency of pathogenic genotypes in a presumed healthy carrier screening cohort to facilitate broader discussions regarding disclosure of genetic information from carrier screening. METHODS A retrospective analysis of 73,755 targeted carrier screens was performed to identify individuals with pathogenic genotypes and heterozygous risk alleles. RESULTS In this study, we identified 79 individuals (0.11%) with pathogenic genotypes associated with moderate to profound autosomal recessive or X-linked conditions. In addition, 10 cases had chromosome X dosage abnormalities suggestive of a sex chromosome abnormality. Heterozygote risk alleles represented the majority of ancillary findings in this cohort, including 280 female carriers of FMR1 premutation alleles, 15 heterozygous females with pathogenic DMD variants, and 174 heterozygotes with pathogenic variants in genes that may confer increased risk for somatic malignancies in the heterozygous state. CONCLUSION These data suggest that nearly 1% of individuals undergoing carrier screening will have a finding that may require clinical evaluation or surveillance.
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Wohnrade C, Velling AK, Mix L, Wurster CD, Cordts I, Stolte B, Zeller D, Uzelac Z, Platen S, Hagenacker T, Deschauer M, Lingor P, Ludolph AC, Lulé D, Petri S, Osmanovic A, Schreiber-Katz O. Health-Related Quality of Life in Spinal Muscular Atrophy Patients and Their Caregivers-A Prospective, Cross-Sectional, Multi-Center Analysis. Brain Sci 2023; 13:brainsci13010110. [PMID: 36672091 PMCID: PMC9857112 DOI: 10.3390/brainsci13010110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/29/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a disabling disease that affects not only the patient’s health-related quality of life (HRQoL), but also causes a high caregiver burden (CGB). The aim of this study was to evaluate HRQoL, CGB, and their predictors in SMA. In two prospective, cross-sectional, and multi-center studies, SMA patients (n = 39) and SMA patient/caregiver couples (n = 49) filled in the EuroQoL Five Dimension Five Level Scale (EQ-5D-5L) and the Short Form Health Survey 36 (SF-36). Caregivers (CGs) additionally answered the Zarit Burden Interview (ZBI) and the Hospital Anxiety and Depression Scale (HADS). Patients were clustered into two groups with either low or high HRQoL (EQ-5D-5L index value <0.259 or >0.679). The latter group was mostly composed of ambulatory type III patients with higher motor/functional scores. More severely affected patients reported low physical functioning but good mental health and vitality. The CGB (mean ZBI = 22/88) correlated negatively with patients’ motor/functional scores and age. Higher CGB was associated with a lower HRQoL, higher depression and anxiety, and more health impairments of the CGs. We conclude that patient and CG well-being levels interact closely, which highlights the need to consider the health of both parties while evaluating novel treatments.
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Affiliation(s)
- Camilla Wohnrade
- Department of Neurology, Hannover Medical School, 30625 Hannover, Germany
| | | | - Lucas Mix
- Department of Neurology, University of Ulm, 89081 Ulm, Germany
| | | | - Isabell Cordts
- Department of Neurology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Benjamin Stolte
- Department of Neurology and Center for Translational Neuro- and Behavioral Science, University Medicine Essen, 45147 Essen, Germany
| | - Daniel Zeller
- Department of Neurology, University of Wuerzburg, 97080 Wuerzburg, Germany
| | - Zeljko Uzelac
- Department of Neurology, University of Ulm, 89081 Ulm, Germany
| | - Sophia Platen
- Department of Neurology, University of Ulm, 89081 Ulm, Germany
| | - Tim Hagenacker
- Department of Neurology and Center for Translational Neuro- and Behavioral Science, University Medicine Essen, 45147 Essen, Germany
| | - Marcus Deschauer
- Department of Neurology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Paul Lingor
- Department of Neurology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Albert C. Ludolph
- Department of Neurology, University of Ulm, 89081 Ulm, Germany
- German Center for Neurodegenerative Diseases, 89081 Ulm, Germany
| | - Dorothée Lulé
- Department of Neurology, University of Ulm, 89081 Ulm, Germany
| | - Susanne Petri
- Department of Neurology, Hannover Medical School, 30625 Hannover, Germany
| | - Alma Osmanovic
- Department of Neurology, Hannover Medical School, 30625 Hannover, Germany
- Essen Center for Rare Diseases (EZSE), University Hospital Essen, 45147 Essen, Germany
| | - Olivia Schreiber-Katz
- Department of Neurology, Hannover Medical School, 30625 Hannover, Germany
- Correspondence:
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4
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Singh J, Patten SA. Modeling neuromuscular diseases in zebrafish. Front Mol Neurosci 2022; 15:1054573. [PMID: 36583079 PMCID: PMC9794147 DOI: 10.3389/fnmol.2022.1054573] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022] Open
Abstract
Neuromuscular diseases are a diverse group of conditions that affect the motor system and present some overlapping as well as distinct clinical manifestations. Although individually rare, the combined prevalence of NMDs is similar to Parkinson's. Over the past decade, new genetic mutations have been discovered through whole exome/genome sequencing, but the pathogenesis of most NMDs remains largely unexplored. Little information on the molecular mechanism governing the progression and development of NMDs accounts for the continual failure of therapies in clinical trials. Different aspects of the diseases are typically investigated using different models from cells to animals. Zebrafish emerges as an excellent model for studying genetics and pathogenesis and for developing therapeutic interventions for most NMDs. In this review, we describe the generation of different zebrafish genetic models mimicking NMDs and how they are used for drug discovery and therapy development.
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Affiliation(s)
- Jaskaran Singh
- INRS – Centre Armand Frappier Santé Biotechnologie, Laval, QC, Canada
| | - Shunmoogum A. Patten
- INRS – Centre Armand Frappier Santé Biotechnologie, Laval, QC, Canada,Departement de Neurosciences, Université de Montréal, Montréal, QC, Canada,Centre d'Excellence en Recherche sur les Maladies Orphelines – Fondation Courtois (CERMO-FC), Université du Québec à Montréal (UQAM), Montréal, QC, Canada,*Correspondence: Shunmoogum A. Patten,
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5
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Butchbach MER. Genomic Variability in the Survival Motor Neuron Genes ( SMN1 and SMN2): Implications for Spinal Muscular Atrophy Phenotype and Therapeutics Development. Int J Mol Sci 2021; 22:ijms22157896. [PMID: 34360669 PMCID: PMC8348669 DOI: 10.3390/ijms22157896] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant death worldwide that is characterized by loss of spinal motor neurons leading to muscle weakness and atrophy. SMA results from the loss of survival motor neuron 1 (SMN1) gene but retention of its paralog SMN2. The copy numbers of SMN1 and SMN2 are variable within the human population with SMN2 copy number inversely correlating with SMA severity. Current therapeutic options for SMA focus on increasing SMN2 expression and alternative splicing so as to increase the amount of SMN protein. Recent work has demonstrated that not all SMN2, or SMN1, genes are equivalent and there is a high degree of genomic heterogeneity with respect to the SMN genes. Because SMA is now an actionable disease with SMN2 being the primary target, it is imperative to have a comprehensive understanding of this genomic heterogeneity with respect to hybrid SMN1–SMN2 genes generated by gene conversion events as well as partial deletions of the SMN genes. This review will describe this genetic heterogeneity in SMA and its impact on disease phenotype as well as therapeutic efficacy.
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Affiliation(s)
- Matthew E. R. Butchbach
- Center for Applied Clinical Genomics, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA;
- Center for Pediatric Research, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA 19107, USA
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6
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Becker LL, Weiß C, Tietze A, Martiny V, Kaindl AM. Lumbar Puncture Opening Pressure in Patients with Spinal Muscular Atrophy. Neuropediatrics 2021; 52:219-223. [PMID: 33578442 DOI: 10.1055/s-0040-1722687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The announcement of a hydrocephalus as a possible side effect in patients with spinal muscular atrophy (SMA) receiving the drug nusinersen, promoted major concern and warrants further evaluation. In this retrospective monocentric study, we analyzed clinical data, lumbar puncture opening pressure (LOP) measurement, and ophthalmologic and neuroimaging results in 34 patients with SMA types 1 to 3 undergoing treatment with nusinersen. None of the patients reported symptoms indicative of increased intracranial pressure. In our cohort, the LOP was >20 cm H2O in 25 patients (70.5%), and within this group ≥28 cm H2O in 12 patients (35.3%), in two patients, it was increased prior to treatment initiation. Signs of increased intracranial pressure in ophthalmological assessments or brain imaging were only seen in one patient. We did not identify a correlation between increased LOP and SMA type, scoliosis, or age of the patients; however, it was slightly higher in patients receiving sedation. Our results raise the question whether the LOP is generally increased in SMA as part of the underlying disease, if so, what the etiology is, and whether the increased LOP needs to be treated.
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Affiliation(s)
- Lena-Luise Becker
- Department of Pediatric Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Center for Chronically Sick Children, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Institute for Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Claudia Weiß
- Center for Chronically Sick Children, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Anna Tietze
- Institute for Neuroradiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Viktoria Martiny
- Department of Pediatric Pneumology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Angela M Kaindl
- Department of Pediatric Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Center for Chronically Sick Children, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Institute for Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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7
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Kekou K, Svingou M, Sofocleous C, Mourtzi N, Nitsa E, Konstantinidis G, Youroukos S, Skiadas K, Katsalouli M, Pons R, Papavasiliou A, Kotsalis C, Pavlou E, Evangeliou A, Katsarou E, Voudris K, Dinopoulos A, Vorgia P, Niotakis G, Diamantopoulos N, Nakou I, Koute V, Vartzelis G, Papadimas GK, Papadopoulos C, Tsivgoulis G, Traeger-Synodinos J. Evaluation of Genotypes and Epidemiology of Spinal Muscular Atrophy in Greece: A Nationwide Study Spanning 24 Years. J Neuromuscul Dis 2021; 7:247-256. [PMID: 32417790 PMCID: PMC7836056 DOI: 10.3233/jnd-190466] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Background: Promising genetic treatments targeting the molecular defect of severe early-onset genetic conditions are expected to dramatically improve patients’ quality of life and disease epidemiology. Spinal Muscular Atrophy (SMA), is one of these conditions and approved therapeutic approaches have recently become available to patients. Objective: Analysis of genetic and clinical data from SMA patients referred to the single public-sector provider of genetic services for the disease throughout Greece followed by a retrospective assessment in the context of epidemiology and genotype-phenotype associations. Methods: Molecular genetic analysis and retrospective evaluation of findings for 361 patients tested positive for SMA- and 862 apparently healthy subjects from the general population. Spearman rank test and generalized linear models were applied to evaluate secondary modifying factors with respect to their impact on clinical severity and age of onset. Results: Causative variations- including 5 novel variants- were detected indicating a minimal incidence of about 1/12,000, and a prevalence of at least 1.5/100,000. For prognosis a minimal model pertaining disease onset before 18 months was proposed to include copy numbers of NAIP (OR = 9.9;95% CI, 4.7 to 21) and SMN2 (OR = 6.2;95% CI, 2.5–15.2) genes as well as gender (OR = 2.2;95% CI, 1.04 to 4.6). Conclusions: This long-term survey shares valuable information on the current status and practices for SMA diagnosis on a population basis and provides an important reference point for the future assessment of strategic advances towards disease prevention and health care planning.
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Affiliation(s)
- Kyriaki Kekou
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, "Aghia Sophia" Children's Hospital, Athens
| | - Maria Svingou
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, "Aghia Sophia" Children's Hospital, Athens
| | - Christalena Sofocleous
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, "Aghia Sophia" Children's Hospital, Athens.,Research Institute for the Study of Genetic and Malignant Disorders in Childhood, "Aghia Sophia" Children's Hospital, Athens
| | - Niki Mourtzi
- First Department of Paediatrics, Medical School, National and Kapodistrian University of Athens, "Aghia Sophia" Children's Hospital, Athens
| | - Evangelia Nitsa
- Postgraduate Program in Biostatistics School Of Medicine, National and Kapodistrian University of Athens, Athens
| | - George Konstantinidis
- Laboratory of, Medical School, National and Kapodistrian University of Athens, "Aghia Sophia" Children's Hospital, Athens
| | - Sotiris Youroukos
- First Department of Paediatrics, Medical School, National and Kapodistrian University of Athens, "Aghia Sophia" Children's Hospital, Athens
| | | | | | - Roser Pons
- First Department of Paediatrics, Medical School, National and Kapodistrian University of Athens, "Aghia Sophia" Children's Hospital, Athens
| | | | | | - Evangelos Pavlou
- 2nd Department of Pediatrics, School of Medicine, Aristotle University of Thessaloniki, University General Hospital AHEPA, Thessaloniki
| | - Athanasios Evangeliou
- Department of Pediatrics, School of Medicine, Aristotle University of Thessaloniki, General Hospital Papageorgiou, Thessaloniki
| | | | | | - Argirios Dinopoulos
- Third Department of Pediatrics, National & Kapodistrian University of Athens, "Attikon" University Hospital, Athens
| | - Pelagia Vorgia
- Pediatric Department, University Hospital of Heraklion, Crete
| | - George Niotakis
- Pediatric Neurology Clinics, Venizeleion General Hospital, Heraklion, Crete
| | | | - Iliada Nakou
- Department of Pediatrics, University of Ioannina, Stavros Niarchos Avenue, Ioannina
| | - Vasiliki Koute
- Pediatric Department, University Hospital of Larissa, University of Thessaly, Larissa
| | - George Vartzelis
- Second Department of Pediatrics, National and Kapodistrian University of Athens, Medical School, "P. & A. Kyriakou" Children's Hospital, Athens, Greece
| | | | - Constantinos Papadopoulos
- Department of Neurology, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens
| | - Georgios Tsivgoulis
- Second Department of Neurology, National & Kapodistrian University of Athens, "Attikon" University Hospital, Athens
| | - Joanne Traeger-Synodinos
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, "Aghia Sophia" Children's Hospital, Athens
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8
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Niba ETE, Nishio H, Wijaya YOS, Lai PS, Tozawa T, Chiyonobu T, Yamadera M, Okamoto K, Awano H, Takeshima Y, Saito T, Shinohara M. Clinical phenotypes of spinal muscular atrophy patients with hybrid SMN gene. Brain Dev 2021; 43:294-302. [PMID: 33036822 DOI: 10.1016/j.braindev.2020.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/26/2020] [Accepted: 09/08/2020] [Indexed: 01/09/2023]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a neuromuscular disease caused by homozygous deletion of SMN1 exons 7 and 8. However, exon 8 is retained in some cases, where SMN2 exon 7 recombines with SMN1 exon 8, forming a hybrid SMN gene. It remains unknown how the hybrid SMN gene contribute to the SMA phenotype. METHOD We analyzed 515 patients with clinical suspicion for SMA. SMN1 exons 7 and 8 deletion was detected by PCR followed by enzyme digestion. Hybrid SMN genes were further analyzed by nucleotide sequencing. SMN2 copy number was determined by real-time PCR. RESULTS SMN1 exon 7 was deleted in 228 out of 515 patients, and SMN1 exon 8 was also deleted in 204 out of the 228 patients. The remaining 24 patients were judged to carry a hybrid SMN gene. In the patients with SMN1 exon 7 deletion, the frequency of the severe phenotype was significantly lower in the patients with hybrid SMN gene than in the patients without hybrid SMN gene. However, as for the distribution of SMN2 exon 7 copy number among the clinical phenotypes, there was no significant difference between both groups of SMA patients with or without hybrid SMN gene. CONCLUSION Hybrid SMN genes are not rare in Japanese SMA patients, and it appears to be associated with a less severe phenotype. The phenotype of patients with hybrid SMN gene was determined by the copy number of SMN2 exon 7, as similarly for the patients without hybrid SMN gene.
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Affiliation(s)
- Emma Tabe Eko Niba
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Hisahide Nishio
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan; Faculty of Medical Rehabilitation, Kobe Gakuin University, Kobe, Japan.
| | - Yogik Onky Silvana Wijaya
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Poh San Lai
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
| | - Takenori Tozawa
- Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Misaki Yamadera
- Department of Neurology, National Hospital Organization Osaka Toneyama Medical Center, Toyonaka, Japan.
| | - Kentaro Okamoto
- Department of Pediatrics, Ehime Prefectural Imabari Hospital, Ehime, Japan.
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Yasuhiro Takeshima
- Department of Pediatrics, Hyogo College of Medicine, Nishinomiya, Japan.
| | - Toshio Saito
- Department of Neurology, National Hospital Organization Osaka Toneyama Medical Center, Toyonaka, Japan.
| | - Masakazu Shinohara
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan.
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Smeriglio P, Langard P, Querin G, Biferi MG. The Identification of Novel Biomarkers Is Required to Improve Adult SMA Patient Stratification, Diagnosis and Treatment. J Pers Med 2020; 10:jpm10030075. [PMID: 32751151 PMCID: PMC7564782 DOI: 10.3390/jpm10030075] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/22/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is currently classified into five different subtypes, from the most severe (type 0) to the mildest (type 4) depending on age at onset, best motor function achieved, and copy number of the SMN2 gene. The two recent approved treatments for SMA patients revolutionized their life quality and perspectives. However, upon treatment with Nusinersen, the most widely administered therapy up to date, a high degree of variability in therapeutic response was observed in adult SMA patients. These data, together with the lack of natural history information and the wide spectrum of disease phenotypes, suggest that further efforts are needed to develop precision medicine approaches for all SMA patients. Here, we compile the current methods for functional evaluation of adult SMA patients treated with Nusinersen. We also present an overview of the known molecular changes underpinning disease heterogeneity. We finally highlight the need for novel techniques, i.e., -omics approaches, to capture phenotypic differences and to understand the biological signature in order to revise the disease classification and device personalized treatments.
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Affiliation(s)
- Piera Smeriglio
- Centre of Research in Myology, Institute of Myology, Sorbonne Université, INSERM, 75013 Paris, France; (P.L.); (G.Q.)
- Correspondence: (P.S.); (M.G.B.)
| | - Paul Langard
- Centre of Research in Myology, Institute of Myology, Sorbonne Université, INSERM, 75013 Paris, France; (P.L.); (G.Q.)
| | - Giorgia Querin
- Centre of Research in Myology, Institute of Myology, Sorbonne Université, INSERM, 75013 Paris, France; (P.L.); (G.Q.)
- Association Institut de Myologie, Plateforme Essais Cliniques Adultes, 75013 Paris, France
- APHP, Service de Neuromyologie, Hôpital Pitié-Salpêtrière, 75013 Paris, France
| | - Maria Grazia Biferi
- Centre of Research in Myology, Institute of Myology, Sorbonne Université, INSERM, 75013 Paris, France; (P.L.); (G.Q.)
- Correspondence: (P.S.); (M.G.B.)
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10
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Custer SK, Astroski JW, Li HX, Androphy EJ. Interaction between alpha-COP and SMN ameliorates disease phenotype in a mouse model of spinal muscular atrophy. Biochem Biophys Res Commun 2019; 514:530-537. [PMID: 31060774 DOI: 10.1016/j.bbrc.2019.04.176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 04/26/2019] [Indexed: 11/25/2022]
Abstract
We report that expression of the α-COP protein rescues disease phenotype in a severe mouse model of Spinal Muscular Atrophy (SMA). Lentiviral particles expressing α-COP were injected directly into the testes of genetically pure mouse strain of interest resulting in infection of the spermatagonial stem cells. α-COP was stably expressed in brain, skeletal muscle, and spinal cord without altering SMN protein levels. SMA mice transgenic for α-COP live significantly longer than their non-transgenic littermates, and showed increased body mass and normal muscle morphology at postnatal day 15. We previously reported that binding between SMN and α-COP is required for restoration of neurite outgrowth in cells lacking SMN, and we report similar finding here. Lentiviral-mediated transgenic expression of SMN where the dilysine domain in exon 2b was mutated was not able to rescue the SMA phenotype despite robust expression of the mutant SMN protein in brain, muscle and spinal cord. These results demonstrate that α-COP is a validated modifier of SMA disease phenotype in a mammalian, vertebrate model and is a potential target for development of future SMN-independent therapeutic interventions.
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Affiliation(s)
- Sara K Custer
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA.
| | - Jacob W Astroski
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA
| | - Hong Xia Li
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA
| | - Elliot J Androphy
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA
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11
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Goodkey K, Aslesh T, Maruyama R, Yokota T. Nusinersen in the Treatment of Spinal Muscular Atrophy. Methods Mol Biol 2019; 1828:69-76. [PMID: 30171535 DOI: 10.1007/978-1-4939-8651-4_4] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
Spinal muscular atrophy (SMA) is one of the most common genetic causes of infantile death arising due to mutations in the SMN1 gene and the subsequent loss of motor neurons. With the discovery of the intronic splicing silencer N1 (ISS-N1) as a potential target for antisense therapy, several antisense oligonucleotides (ASOs) are being developed to include exon 7 in the final mRNA transcript of the SMN2 gene and thereby increasing the production of spinal motor neuron (SMN) proteins. Nusinersen (spinraza), a modified 2'-O-methoxyethyl (MOE) antisense oligonucleotide is the first drug to be approved by Food and Drug Agency (FDA) in December of 2016. Here we briefly review the pharmacological relevance of the drug, clinical trials, toxicity, and future directions following the approval of nusinersen.
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Affiliation(s)
- Kara Goodkey
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Tejal Aslesh
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Rika Maruyama
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada. .,The Friends of Garrett Cumming Research and Muscular Dystrophy Canada HM Toupin Neurological Science Research Chair, Edmonton, AB, Canada.
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12
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Dabbous O, Maru B, Jansen JP, Lorenzi M, Cloutier M, Guérin A, Pivneva I, Wu EQ, Arjunji R, Feltner D, Sproule DM. Survival, Motor Function, and Motor Milestones: Comparison of AVXS-101 Relative to Nusinersen for the Treatment of Infants with Spinal Muscular Atrophy Type 1. Adv Ther 2019; 36:1164-1176. [PMID: 30879249 PMCID: PMC6824368 DOI: 10.1007/s12325-019-00923-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Indexed: 11/17/2022]
Abstract
Introduction Infants with spinal muscular atrophy (SMA) type 1 typically face a decline in motor function and a severely shortened life expectancy. Clinical trials for SMA type 1 therapies, onasemnogene abeparvovec (AVXS-101) and nusinersen, demonstrated meaningful improvements in efficacy (e.g., overall survival) but there were no head-to-head clinical trials assessing comparative efficacy. This study estimated the treatment effects of AVXS-101 relative to nusinersen for the treatment of SMA type 1. Methods Overall survival, event-free survival (no death or need to use permanent assisted ventilation), improvement in motor function [increase of ≥ 4 points in Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) score from baseline], and motor milestone achievements (head control, rolling over, and sitting unassisted) reported in the onasemnogene abeparvovec (AVXS-101-CL-101; NCT02122952) and nusinersen (ENDEAR; NCT02193074) clinical trials were indirectly compared using frequentist and Bayesian approaches. Results Among symptomatic infants with SMA type 1, the number needed to treat (NNT) to prevent one more death with AVXS-101 instead of nusinersen was 6.2 [95% confidence intervals (CI) = 4.1–12.2], and the probability of preventing death was 20% higher for patients treated with AVXS-101 than nusinersen [risk ratio (RR) = 1.2, 95% CI 1.1–1.3]. For event-free survival, the NNT to prevent one more event was 2.6 (95% CI 2.0–3.6) and RR was 1.6 (95% CI 1.4–1.9). For improvement in motor function, NNT was 3.5 (95% CI 2.6–5.3) and RR was 1.4 (95% CI 1.2–1.6). For milestone achievements, the NNTs were 1.4 (95% CI 1.1–1.9), 1.5 (95% CI 1.1–2.5), and 1.2 (95% CI 1.0–1.5); RRs 4.2 (95% CI 2.6–6.7), 7.8 (95% CI 3.6–17.0), and 11.2 (95% CI 5.1–24.5) for head control, rolling over, and sitting unassisted, respectively. Results were similar using the Bayesian approach. Conclusion This indirect comparison (AVXS-101-CL-101 vs. ENDEAR) among symptomatic SMA type 1 infants suggests that AVXS-101 may have an efficacy advantage relative to nusinersen for overall survival, independence from permanent assisted ventilation, motor function, and motor milestones. Funding AveXis.
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13
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Saffari A, Kölker S, Hoffmann GF, Weiler M, Ziegler A. Novel challenges in spinal muscular atrophy - How to screen and whom to treat? Ann Clin Transl Neurol 2018; 6:197-205. [PMID: 30656198 PMCID: PMC6331314 DOI: 10.1002/acn3.689] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 10/17/2018] [Accepted: 10/18/2018] [Indexed: 12/27/2022] Open
Abstract
In recent years, disease‐modifying and life‐prolonging therapies for spinal muscular atrophy (SMA) have been developed. However, patients are currently diagnosed with significant delay and therapies are often administered in advanced stages of motor neuron degeneration, showing limited effects. Methods to identify children in presymptomatic stages are currently evaluated in newborn screening programs. Yet, not all children develop symptoms shortly after birth raising the question whom to treat and when to initiate therapy. Finally, monitoring disease progression becomes essential to individualize management. Here, we review the literature on screening approaches, strategies to predict disease severity, and biomarkers to monitor therapy.
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Affiliation(s)
- Afshin Saffari
- Division of Child Neurology and Metabolic Medicine Center for Child and Adolescent Medicine University Hospital Heidelberg Heidelberg Germany
| | - Stefan Kölker
- Division of Child Neurology and Metabolic Medicine Center for Child and Adolescent Medicine University Hospital Heidelberg Heidelberg Germany
| | - Georg F Hoffmann
- Division of Child Neurology and Metabolic Medicine Center for Child and Adolescent Medicine University Hospital Heidelberg Heidelberg Germany
| | - Markus Weiler
- Department of Neurology University Hospital Heidelberg Heidelberg Germany
| | - Andreas Ziegler
- Division of Child Neurology and Metabolic Medicine Center for Child and Adolescent Medicine University Hospital Heidelberg Heidelberg Germany
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14
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Wu X, Wang SH, Sun J, Krainer AR, Hua Y, Prior TW. A-44G transition in SMN2 intron 6 protects patients with spinal muscular atrophy. Hum Mol Genet 2018; 26:2768-2780. [PMID: 28460014 DOI: 10.1093/hmg/ddx166] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 04/25/2017] [Indexed: 01/14/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by reduced expression of survival of motor neuron (SMN), a protein expressed in humans by two paralogous genes, SMN1 and SMN2. These genes are nearly identical, except for 10 single-nucleotide differences and a 5-nucleotide insertion in SMN2. SMA is subdivided into four main types, with type I being the most severe. SMN2 copy number is a key positive modifier of the disease, but it is not always inversely correlated with clinical severity. We previously reported the c.859G > C variant in SMN2 exon 7 as a positive modifier in several patients. We have now identified A-44G as an additional positive disease modifier, present in a group of patients carrying 3 SMN2 copies but displaying milder clinical phenotypes than other patients with the same SMN2 copy number. One of the three SMN2 copies appears to have been converted from SMN1, but except for the C6T transition, no other changes were detected. Analyzed with minigenes, SMN1C6T displayed a ∼20% increase in exon 7 inclusion, compared to SMN2. Through systematic mutagenesis, we found that the improvement in exon 7 splicing is mainly attributable to the A-44G transition in intron 6. Using RNA-affinity chromatography and mass spectrometry, we further uncovered binding of the RNA-binding protein HuR to the -44 region, where it acts as a splicing repressor. The A-44G change markedly decreases the binding affinity of HuR, resulting in a moderate increase in exon 7 inclusion.
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Affiliation(s)
- Xingxing Wu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, China
| | - Shu-Huei Wang
- Department of Pathology, Ohio State University, Columbus, OH 43210, USA
| | - Junjie Sun
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, China
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, NY 11724, USA
| | - Yimin Hua
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
| | - Thomas W Prior
- Department of Pathology, Ohio State University, Columbus, OH 43210, USA
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15
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Abstract
Neurodegeneration is a leading cause of death in the developed world and a natural, albeit unfortunate, consequence of longer-lived populations. Despite great demand for therapeutic intervention, it is often the case that these diseases are insufficiently understood at the basic molecular level. What little is known has prompted much hopeful speculation about a generalized mechanistic thread that ties these disparate conditions together at the subcellular level and can be exploited for broad curative benefit. In this review, we discuss a prominent theory supported by genetic and pathological changes in an array of neurodegenerative diseases: that neurons are particularly vulnerable to disruption of RNA-binding protein dosage and dynamics. Here we synthesize the progress made at the clinical, genetic, and biophysical levels and conclude that this perspective offers the most parsimonious explanation for these mysterious diseases. Where appropriate, we highlight the reciprocal benefits of cross-disciplinary collaboration between disease specialists and RNA biologists as we envision a future in which neurodegeneration declines and our understanding of the broad importance of RNA processing deepens.
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Affiliation(s)
- Erin G Conlon
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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16
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Nash LA, McFall ER, Perozzo AM, Turner M, Poulin KL, De Repentigny Y, Burns JK, McMillan HJ, Warman Chardon J, Burger D, Kothary R, Parks RJ. Survival Motor Neuron Protein is Released from Cells in Exosomes: A Potential Biomarker for Spinal Muscular Atrophy. Sci Rep 2017; 7:13859. [PMID: 29066780 PMCID: PMC5655039 DOI: 10.1038/s41598-017-14313-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 10/06/2017] [Indexed: 11/09/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous mutation of the survival motor neuron 1 (SMN1) gene. Disease severity inversely correlates to the amount of SMN protein produced from the homologous SMN2 gene. We show that SMN protein is naturally released in exosomes from all cell types examined. Fibroblasts from patients or a mouse model of SMA released exosomes containing reduced levels of SMN protein relative to normal controls. Cells overexpressing SMN protein released exosomes with dramatically elevated levels of SMN protein. We observed enhanced quantities of exosomes in the medium from SMN-depleted cells, and in serum from a mouse model of SMA and a patient with Type 3 SMA, suggesting that SMN-depletion causes a deregulation of exosome release or uptake. The quantity of SMN protein contained in the serum-derived exosomes correlated with the genotype of the animal, with progressively less protein in carrier and affected animals compared to wildtype mice. SMN protein was easily detectable in exosomes isolated from human serum, with a reduction in the amount of SMN protein in exosomes from a patient with Type 3 SMA compared to a normal control. Our results suggest that exosome-derived SMN protein may serve as an effective biomarker for SMA.
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Affiliation(s)
- Leslie A Nash
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Emily R McFall
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Amanda M Perozzo
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Maddison Turner
- Kidney Research Centre, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Kathy L Poulin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Joseph K Burns
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Hugh J McMillan
- University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, Canada.,Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Jodi Warman Chardon
- University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada.,Division of Neurogenetics, Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada.,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Dylan Burger
- Kidney Research Centre, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Robin J Parks
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada. .,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada. .,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada. .,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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17
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Ar Rochmah M, Harahap NIF, Niba ETE, Nakanishi K, Awano H, Morioka I, Iijima K, Saito T, Saito K, Lai PS, Takeshima Y, Takeuchi A, Bouike Y, Okamoto M, Nishio H, Shinohara M. Genetic screening of spinal muscular atrophy using a real-time modified COP-PCR technique with dried blood-spot DNA. Brain Dev 2017; 39:774-782. [PMID: 28522225 DOI: 10.1016/j.braindev.2017.04.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/19/2017] [Accepted: 04/22/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a common neuromuscular disorder caused by mutations in SMN1. More than 95% of SMA patients carry homozygous SMN1 deletion. SMA is the leading genetic cause of infant death, and has been considered an incurable disease. However, a recent clinical trial with an antisense oligonucleotide drug has shown encouraging clinical efficacy. Thus, early and accurate detection of SMN1 deletion may improve prognosis of many infantile SMA patients. METHODS A total of 88 DNA samples (37 SMA patients, 12 carriers and 39 controls) from dried blood spots (DBS) on filter paper were analyzed. All participants had previously been screened for SMN genes by PCR restriction fragment length polymorphism (PCR-RFLP) using DNA extracted from freshly collected blood. DNA was extracted from DBS that had been stored at room temperature (20-25°C) for 1week to 5years. To ensure sufficient quality and quantity of DNA samples, target sequences were pre-amplified by conventional PCR. Real-time modified competitive oligonucleotide priming-PCR (mCOP-PCR) with the pre-amplified PCR products was performed for the gene-specific amplification of SMN1 and SMN2 exon 7. RESULTS Compared with PCR-RFLP using DNA from freshly collected blood, results from real-time mCOP-PCR using DBS-DNA for detection of SMN1 exon 7 deletion showed a sensitivity of 1.00 (CI [0.87, 1.00])] and specificity of 1.00 (CI [0.90, 1.00]), respectively. CONCLUSION We combined DNA extraction from DBS on filter paper, pre-amplification of target DNA, and real-time mCOP-PCR to specifically detect SMN1 and SMN2 genes, thereby establishing a rapid, accurate, and high-throughput system for detecting SMN1-deletion with practical applications for newborn screening.
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Affiliation(s)
- Mawaddah Ar Rochmah
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nur Imma Fatimah Harahap
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Emma Tabe Eko Niba
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kenta Nakanishi
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ichiro Morioka
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Toshio Saito
- Division of Child Neurology, Department of Neurology, National Hospital Organization Toneyama National Hospital, Toyonaka, Japan
| | - Kayoko Saito
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Poh San Lai
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - Atsuko Takeuchi
- Analytical Laboratory, Kobe Pharmaceutical University, Kobe, Japan
| | | | - Maya Okamoto
- Center for Public Health, Pharmacological Evaluation Institute of Japan, Kawasaki, Japan
| | - Hisahide Nishio
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan; Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Masakazu Shinohara
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
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18
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Kaneko K, Arakawa R, Urano M, Aoki R, Saito K. Relationships between long-term observations of motor milestones and genotype analysis results in childhood-onset Japanese spinal muscular atrophy patients. Brain Dev 2017; 39:763-773. [PMID: 28601407 DOI: 10.1016/j.braindev.2017.04.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 04/28/2017] [Accepted: 04/28/2017] [Indexed: 12/11/2022]
Abstract
AIM To clarify the long-term natural history of SMA in Japanese patients by investigating the peak motor milestones of cases 7months through 57years of age, in efforts to contribute to evaluating outcomes of new therapeutic interventions. METHODS We sub-classified 112 SMA type I-III cases into type Ia, type Ib, type IIa, type IIb, type IIIa and type IIIb, according to peak motor milestone achieved, and analyzed the SMN1, SMN2 and NAIP genes in relation to clinical subtypes. RESULTS In type I cases, there was a significant difference (p<0.0001), depending on whether or not head control was obtained, in the time of ventilation support being required. In type II cases as well, the time at which the ability to maintain the sitting position independently was lost also differed significantly (p<0.01) between those acquiring the ability to sit unaided within eight months after birth and those acquiring this ability after eight months of age. In type III cases, being able versus unable to climb stairs was associated with a significant difference (p=0.02) in the median time until loss of walking independently. Positive correlations were also seen between copy numbers and the clinical severity of SMA. CONCLUSION Our long-term results show peak motor milestone evaluations distinguishing between subtypes to be useful not only as outcome measures for assessing treatment efficacy in clinical trials but also for predicting the clinical courses of Japanese SMA patients.
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Affiliation(s)
- Kaori Kaneko
- Affiliated Field of Medical Genetics, Division of Biomedical Engineering and Science, Graduate Course of Medicine, Graduate School of Tokyo Women's Medical University, Shinjuku, Tokyo, Japan
| | - Reiko Arakawa
- Institute of Medical Genetics, Tokyo Women's Medical University, Shinjuku, Tokyo, Japan
| | - Mari Urano
- Institute of Medical Genetics, Tokyo Women's Medical University, Shinjuku, Tokyo, Japan
| | - Ryoko Aoki
- Institute of Medical Genetics, Tokyo Women's Medical University, Shinjuku, Tokyo, Japan
| | - Kayoko Saito
- Affiliated Field of Medical Genetics, Division of Biomedical Engineering and Science, Graduate Course of Medicine, Graduate School of Tokyo Women's Medical University, Shinjuku, Tokyo, Japan; Institute of Medical Genetics, Tokyo Women's Medical University, Shinjuku, Tokyo, Japan.
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19
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Hensel N, Baskal S, Walter LM, Brinkmann H, Gernert M, Claus P. ERK and ROCK functionally interact in a signaling network that is compensationally upregulated in Spinal Muscular Atrophy. Neurobiol Dis 2017; 108:352-361. [PMID: 28916199 DOI: 10.1016/j.nbd.2017.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/22/2017] [Accepted: 09/11/2017] [Indexed: 01/08/2023] Open
Abstract
Spinal Muscular Atrophy (SMA) is a motoneuron disease caused by low levels of functional survival of motoneuron protein (SMN). Molecular disease mechanisms downstream of functional SMN loss are still largely unknown. Previous studies suggested an involvement of Rho kinase (ROCK) as well as the extracellular signal-regulated kinases (ERK) pathways in the pathomechanism. Both pathways are bi-directionally linked and inhibit each other. Thus, we hypothesize that both pathways regulate SMA pathophysiology in vivo in a combined manner rather than acting separately. Here, we applied the repurposed drugs, selumetinib, an ERK inhibitor, and the ROCK inhibitor fasudil to severe SMA mice. Thereby, separately applied inhibitors as well as a combination enabled us to explore the impact of the ROCK-ERK signaling network on SMA pathophysiology. ROCK inhibition specifically ameliorated the phenotype of selumetinib-treated SMA mice demonstrating an efficient ROCK to ERK crosstalk relevant for the SMA pathophysiology. However, ERK inhibition alone aggravated the condition of SMA mice and reduced the number of motoneurons indicating a compensatory hyper-activation of ERK in motoneurons. Taken together, we identified a regulatory network acting downstream of SMN depletion and upstream of the SMA pathophysiology thus being a future treatment target in combination with SMN dependent strategies.
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Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany
| | - Svetlana Baskal
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany
| | - Lisa Marie Walter
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany; Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Hella Brinkmann
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany
| | - Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany; Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany; Center for Systems Neuroscience (ZSN), Hannover, Germany.
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20
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Takarada T, Ar Rochmah M, Harahap NIF, Shinohara M, Saito T, Saito K, Lai PS, Bouike Y, Takeshima Y, Awano H, Morioka I, Iijima K, Nishio H, Takeuchi A. SMA mutations in SMN Tudor and C-terminal domains destabilize the protein. Brain Dev 2017; 39:606-612. [PMID: 28366534 DOI: 10.1016/j.braindev.2017.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 02/27/2017] [Accepted: 03/03/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND AND PURPOSE Most spinal muscular atrophy (SMA) patients are homozygous for survival of motor neuron 1 gene (SMN1) deletion. However, some SMA patients carry an intragenic SMN1 mutation. Such patients provide a clue to understanding the function of the SMN protein and the role of each domain of the protein. We previously identified mutations in the Tudor domain and C-terminal region of the SMN protein in three Japanese SMA patients. To clarify the effect of these mutations on protein stability, we conducted expression assays of SMN with mutated domains. PATIENTS AND METHODS Patients A and B carried a mutation in SMN1 exon 3, which encodes a Tudor domain, c.275G>C (p.Trp92Ser). Patient C carried a mutation in SMN1 exon 6, which encodes a YG-box; c.819_820insT (p.Thr274Tyrfs). We constructed plasmid expression vectors containing wild-type and mutant SMN1 cDNAs. After transfection of HeLa cells with the expression plasmids, RNA and protein were isolated and analyzed by reverse-transcription PCR and western blot analysis. RESULTS The abundance of wild-type and mutant SMN1 transcripts in HeLa cells was almost the same. However, western blot analysis showed lower levels of mutant SMN proteins compared with wild-type SMN. In mutant SMN proteins, it is noteworthy that the level of the p.Thr274Tyrfs mutant was much reduced compared with that of the p.Trp92Ser mutant. CONCLUSIONS SMN mutations may affect the stability and levels of the protein.
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Affiliation(s)
- Toru Takarada
- Analytical Laboratory, Kobe Pharmaceutical University, Kobe, Japan
| | - Mawaddah Ar Rochmah
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nur Imma Fatimah Harahap
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masakazu Shinohara
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Toshio Saito
- Department of Neurology, Toneyama National Hospital, Osaka, Japan
| | - Kayoko Saito
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Poh San Lai
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | | | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ichiro Morioka
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hisahide Nishio
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, Kobe, Japan; Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Atsuko Takeuchi
- Analytical Laboratory, Kobe Pharmaceutical University, Kobe, Japan
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21
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Boyd PJ, Tu WY, Shorrock HK, Groen EJN, Carter RN, Powis RA, Thomson SR, Thomson D, Graham LC, Motyl AAL, Wishart TM, Highley JR, Morton NM, Becker T, Becker CG, Heath PR, Gillingwater TH. Bioenergetic status modulates motor neuron vulnerability and pathogenesis in a zebrafish model of spinal muscular atrophy. PLoS Genet 2017; 13:e1006744. [PMID: 28426667 PMCID: PMC5417717 DOI: 10.1371/journal.pgen.1006744] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 05/04/2017] [Accepted: 04/05/2017] [Indexed: 11/18/2022] Open
Abstract
Degeneration and loss of lower motor neurons is the major pathological hallmark of spinal muscular atrophy (SMA), resulting from low levels of ubiquitously-expressed survival motor neuron (SMN) protein. One remarkable, yet unresolved, feature of SMA is that not all motor neurons are equally affected, with some populations displaying a robust resistance to the disease. Here, we demonstrate that selective vulnerability of distinct motor neuron pools arises from fundamental modifications to their basal molecular profiles. Comparative gene expression profiling of motor neurons innervating the extensor digitorum longus (disease-resistant), gastrocnemius (intermediate vulnerability), and tibialis anterior (vulnerable) muscles in mice revealed that disease susceptibility correlates strongly with a modified bioenergetic profile. Targeting of identified bioenergetic pathways by enhancing mitochondrial biogenesis rescued motor axon defects in SMA zebrafish. Moreover, targeting of a single bioenergetic protein, phosphoglycerate kinase 1 (Pgk1), was found to modulate motor neuron vulnerability in vivo. Knockdown of pgk1 alone was sufficient to partially mimic the SMA phenotype in wild-type zebrafish. Conversely, Pgk1 overexpression, or treatment with terazosin (an FDA-approved small molecule that binds and activates Pgk1), rescued motor axon phenotypes in SMA zebrafish. We conclude that global bioenergetics pathways can be therapeutically manipulated to ameliorate SMA motor neuron phenotypes in vivo.
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Affiliation(s)
- Penelope J. Boyd
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Wen-Yo Tu
- Sheffield Institute for Translation Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Hannah K. Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ewout J. N. Groen
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Roderick N. Carter
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Queens Medical Research Institute, Edinburgh, United Kingdom
| | - Rachael A. Powis
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Sophie R. Thomson
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Derek Thomson
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Laura C. Graham
- Division of Neurobiology, Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Anna A. L. Motyl
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas M. Wishart
- Division of Neurobiology, Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - J. Robin Highley
- Sheffield Institute for Translation Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Nicholas M. Morton
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Queens Medical Research Institute, Edinburgh, United Kingdom
| | - Thomas Becker
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Neuroregeneration, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Catherina G. Becker
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Neuroregeneration, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Paul R. Heath
- Sheffield Institute for Translation Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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22
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Sardone V, Zhou H, Muntoni F, Ferlini A, Falzarano MS. Antisense Oligonucleotide-Based Therapy for Neuromuscular Disease. Molecules 2017; 22:molecules22040563. [PMID: 28379182 PMCID: PMC6154734 DOI: 10.3390/molecules22040563] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/28/2017] [Accepted: 03/14/2017] [Indexed: 02/06/2023] Open
Abstract
Neuromuscular disorders such as Duchenne Muscular Dystrophy and Spinal Muscular Atrophy are neurodegenerative genetic diseases characterized primarily by muscle weakness and wasting. Until recently there were no effective therapies for these conditions, but antisense oligonucleotides, a new class of synthetic single stranded molecules of nucleic acids, have demonstrated promising experimental results and are at different stages of regulatory approval. The antisense oligonucleotides can modulate the protein expression via targeting hnRNAs or mRNAs and inducing interference with splicing, mRNA degradation, or arrest of translation, finally, resulting in rescue or reduction of the target protein expression. Different classes of antisense oligonucleotides are being tested in several clinical trials, and limitations of their clinical efficacy and toxicity have been reported for some of these compounds, while more encouraging results have supported the development of others. New generation antisense oligonucleotides are also being tested in preclinical models together with specific delivery systems that could allow some of the limitations of current antisense oligonucleotides to be overcome, to improve the cell penetration, to achieve more robust target engagement, and hopefully also be associated with acceptable toxicity. This review article describes the chemical properties and molecular mechanisms of action of the antisense oligonucleotides and the therapeutic implications these compounds have in neuromuscular diseases. Current strategies and carrier systems available for the oligonucleotides delivery will be also described to provide an overview on the past, present and future of these appealing molecules.
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Affiliation(s)
- Valentina Sardone
- Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, Developmental Neuroscience Programme, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.
| | - Haiyan Zhou
- Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, Developmental Neuroscience Programme, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, Developmental Neuroscience Programme, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London WC1N 3BG, UK.
| | - Alessandra Ferlini
- Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, Developmental Neuroscience Programme, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.
- UOL Medical Genetics, University of Ferrara, Ferrara 44121, Italy.
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23
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Gama-Carvalho M, L Garcia-Vaquero M, R Pinto F, Besse F, Weis J, Voigt A, Schulz JB, De Las Rivas J. Linking amyotrophic lateral sclerosis and spinal muscular atrophy through RNA-transcriptome homeostasis: a genomics perspective. J Neurochem 2017; 141:12-30. [PMID: 28054357 DOI: 10.1111/jnc.13945] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/02/2016] [Accepted: 12/24/2016] [Indexed: 12/11/2022]
Abstract
In this review, we present our most recent understanding of key biomolecular processes that underlie two motor neuron degenerative disorders, amyotrophic lateral sclerosis, and spinal muscular atrophy. We focus on the role of four multifunctional proteins involved in RNA metabolism (TDP-43, FUS, SMN, and Senataxin) that play a causal role in these diseases. Recent results have led to a novel scenario of intricate connections between these four proteins, bringing transcriptome homeostasis into the spotlight as a common theme in motor neuron degeneration. We review reported functional and physical interactions between these four proteins, highlighting their common association with nuclear bodies and small nuclear ribonucleoprotein particle biogenesis and function. We discuss how these interactions are turning out to be particularly relevant for the control of transcription and chromatin homeostasis, including the recent identification of an association between SMN and Senataxin required to ensure the resolution of DNA-RNA hybrid formation and proper termination by RNA polymerase II. These connections strongly support the existence of common pathways underlying the spinal muscular atrophy and amyotrophic lateral sclerosis phenotype. We also discuss the potential of genome-wide expression profiling, in particular RNA sequencing derived data, to contribute to unravelling the underlying mechanisms. We provide a review of publicly available datasets that have addressed both diseases using these approaches, and highlight the value of investing in cross-disease studies to promote our understanding of the pathways leading to neurodegeneration.
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Affiliation(s)
- Margarida Gama-Carvalho
- Universidade de Lisboa, Faculdade de Ciências, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal
| | - Marina L Garcia-Vaquero
- Universidade de Lisboa, Faculdade de Ciências, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal
| | - Francisco R Pinto
- Universidade de Lisboa, Faculdade de Ciências, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal
| | | | - Joachim Weis
- Institute of Neuropathology, RWTH Aachen University, Aachen, Germany
| | - Aaron Voigt
- Department of Neurology, University Hospital, RWTH Aachen University, Aachen, Germany.,JARA-Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Jörg B Schulz
- Department of Neurology, University Hospital, RWTH Aachen University, Aachen, Germany.,JARA-Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Javier De Las Rivas
- Cancer Research Center (CiC-IBMCC, CSIC/USAL/IBSAL), Consejo Superior de Investigaciones Científicas (CSIC) and Universidad de Salamanca (USAL), Salamanca, Spain
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24
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Imaging Flow Cytometry Analysis to Identify Differences of Survival Motor Neuron Protein Expression in Patients With Spinal Muscular Atrophy. Pediatr Neurol 2016; 61:70-5. [PMID: 27353697 DOI: 10.1016/j.pediatrneurol.2016.05.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/09/2016] [Accepted: 05/18/2016] [Indexed: 11/20/2022]
Abstract
BACKGROUND Spinal muscular atrophy is a neurodegenerative disorder caused by the deficient expression of survival motor neuron protein in motor neurons. A major goal of disease-modifying therapy is to increase survival motor neuron expression. Changes in survival motor neuron protein expression can be monitored via peripheral blood cells in patients; therefore we tested the sensitivity and utility of imaging flow cytometry for this purpose. METHODS After the immortalization of peripheral blood lymphocytes from a human healthy control subject and two patients with spinal muscular atrophy type 1 with two and three copies of SMN2 gene, respectively, we used imaging flow cytometry analysis to identify significant differences in survival motor neuron expression. A bright detail intensity analysis was used to investigate differences in the cellular localization of survival motor neuron protein. RESULTS Survival motor neuron expression was significantly decreased in cells derived from patients with spinal muscular atrophy relative to those derived from a healthy control subject. Moreover, survival motor neuron expression correlated with the clinical severity of spinal muscular atrophy according to SMN2 copy number. The cellular accumulation of survival motor neuron protein was also significantly decreased in cells derived from patients with spinal muscular atrophy relative to those derived from a healthy control subject. CONCLUSIONS The benefits of imaging flow cytometry for peripheral blood analysis include its capacities for analyzing heterogeneous cell populations; visualizing cell morphology; and evaluating the accumulation, localization, and expression of a target protein. Imaging flow cytometry analysis should be implemented in future studies to optimize its application as a tool for spinal muscular atrophy clinical trials.
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25
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Sintusek P, Catapano F, Angkathunkayul N, Marrosu E, Parson SH, Morgan JE, Muntoni F, Zhou H. Histopathological Defects in Intestine in Severe Spinal Muscular Atrophy Mice Are Improved by Systemic Antisense Oligonucleotide Treatment. PLoS One 2016; 11:e0155032. [PMID: 27163330 PMCID: PMC4862622 DOI: 10.1371/journal.pone.0155032] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 04/22/2016] [Indexed: 12/28/2022] Open
Abstract
Gastrointestinal (GI) defects, including gastroesophageal reflux, constipation and delayed gastric emptying, are common in patients with spinal muscular atrophy (SMA). Similar GI dysmotility has been identified in mouse models with survival of motor neuron (SMN) protein deficiency. We previously described vascular defects in skeletal muscle and spinal cord of SMA mice and we hypothesized that similar defects could be involved in the GI pathology observed in these mice. We therefore investigated the gross anatomical structure, enteric vasculature and neurons in the small intestine in a severe mouse model of SMA. We also assessed the therapeutic response of GI histopathology to systemic administration of morpholino antisense oligonucleotide (AON) designed to increase SMN protein expression. Significant anatomical and histopathological abnormalities, with striking reduction of vascular density, overabundance of enteric neurons and increased macrophage infiltration, were detected in the small intestine in SMA mice. After systemic AON treatment in neonatal mice, all the abnormalities observed were significantly restored to near-normal levels. We conclude that the observed GI histopathological phenotypes and functional defects observed in these SMA mice are strongly linked to SMN deficiency which can be rescued by systemic administration of AON. This study on the histopathological changes in the gastrointestinal system in severe SMA mice provides further indication of the complex role that SMN plays in multiple tissues and suggests that at least in SMA mice restoration of SMN production in peripheral tissues is essential for optimal outcome.
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MESH Headings
- Animals
- Animals, Newborn
- Disease Models, Animal
- Gene Expression
- Genetic Therapy/methods
- Heterozygote
- Homozygote
- Humans
- Injections, Subcutaneous
- Intestine, Small/blood supply
- Intestine, Small/drug effects
- Intestine, Small/innervation
- Intestine, Small/pathology
- Macrophages/drug effects
- Macrophages/metabolism
- Macrophages/pathology
- Mice
- Mice, Transgenic
- Morpholinos/administration & dosage
- Motor Neurons/drug effects
- Motor Neurons/metabolism
- Motor Neurons/pathology
- Muscular Atrophy, Spinal/genetics
- Muscular Atrophy, Spinal/metabolism
- Muscular Atrophy, Spinal/pathology
- Muscular Atrophy, Spinal/therapy
- Oligonucleotides, Antisense/administration & dosage
- Phenotype
- Spinal Cord/blood supply
- Spinal Cord/drug effects
- Spinal Cord/pathology
- Survival of Motor Neuron 1 Protein/agonists
- Survival of Motor Neuron 1 Protein/genetics
- Survival of Motor Neuron 1 Protein/metabolism
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Affiliation(s)
- Palittiya Sintusek
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
- Division of Gastroenterology and Hepatology, Department of Pediatrics, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, Bangkok, Thailand
| | - Francesco Catapano
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
| | - Napat Angkathunkayul
- Department of Pathology, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Elena Marrosu
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
| | - Simon H. Parson
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Euan MacDonald Center for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Jennifer E. Morgan
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
- * E-mail: (HZ); (FM)
| | - Haiyan Zhou
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
- * E-mail: (HZ); (FM)
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26
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Butchbach MER. Copy Number Variations in the Survival Motor Neuron Genes: Implications for Spinal Muscular Atrophy and Other Neurodegenerative Diseases. Front Mol Biosci 2016; 3:7. [PMID: 27014701 PMCID: PMC4785180 DOI: 10.3389/fmolb.2016.00007] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/25/2016] [Indexed: 12/11/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA), a leading genetic cause of infant death worldwide, is an early-onset, autosomal recessive neurodegenerative disease characterized by the loss of spinal α-motor neurons. This loss of α-motor neurons is associated with muscle weakness and atrophy. SMA can be classified into five clinical grades based on age of onset and severity of the disease. Regardless of clinical grade, proximal SMA results from the loss or mutation of SMN1 (survival motor neuron 1) on chromosome 5q13. In humans a large tandem chromosomal duplication has lead to a second copy of the SMN gene locus known as SMN2. SMN2 is distinguishable from SMN1 by a single nucleotide difference that disrupts an exonic splice enhancer in exon 7. As a result, most of SMN2 mRNAs lack exon 7 (SMNΔ7) and produce a protein that is both unstable and less than fully functional. Although only 10–20% of the SMN2 gene product is fully functional, increased genomic copies of SMN2 inversely correlates with disease severity among individuals with SMA. Because SMN2 copy number influences disease severity in SMA, there is prognostic value in accurate measurement of SMN2 copy number from patients being evaluated for SMA. This prognostic value is especially important given that SMN2 copy number is now being used as an inclusion criterion for SMA clinical trials. In addition to SMA, copy number variations (CNVs) in the SMN genes can affect the clinical severity of other neurological disorders including amyotrophic lateral sclerosis (ALS) and progressive muscular atrophy (PMA). This review will discuss how SMN1 and SMN2 CNVs are detected and why accurate measurement of SMN1 and SMN2 copy numbers is relevant for SMA and other neurodegenerative diseases.
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Affiliation(s)
- Matthew E R Butchbach
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, DE, USA; Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for ChildrenWilmington, DE, USA; Department of Biological Sciences, University of DelawareNewark, DE, USA; Department of Pediatrics, Thomas Jefferson UniversityPhiladelphia, PA, USA
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27
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Swiderski K, Lynch GS. Therapeutic potential of orphan drugs for the rare skeletal muscle diseases. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1085858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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28
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Zhou H, Meng J, Marrosu E, Janghra N, Morgan J, Muntoni F. Repeated low doses of morpholino antisense oligomer: an intermediate mouse model of spinal muscular atrophy to explore the window of therapeutic response. Hum Mol Genet 2015; 24:6265-77. [PMID: 26264577 DOI: 10.1093/hmg/ddv329] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 08/06/2015] [Indexed: 11/14/2022] Open
Abstract
The human SMN2 transgenic mice are well-established models of spinal muscular atrophy (SMA). While the severe type I mouse model has a rapidly progressive condition mimicking type I SMA in humans, the mild type III mice do not faithfully recapitulate chronic SMA variants affecting children. A SMA mouse model that clinically mimics the features of type II and III SMA in human is therefore needed. In this study, we generated intermediately affected SMA mice by delivering low-dose morpholino oligomer (PMO25) into the existing severe SMA mice. We show that a single low-dose administration of PMO25 moderately extended the survival of severe type I SMA mice. The neuromuscular pathology is also modestly but significantly improved in these mice. A second administration of PMO25 at postnatal day 5 (PND5) demonstrated an additive effect on survival. Additional systemic administration of low-dose PMO25 at 2-week intervals suppressed the occurrence of distal necrosis beyond postnatal day 100, and induced more complete phenotypic rescue than a single bolus high-dose injection at PND0. Our study demonstrates that survival of motor neuron (SMN) is required early at a critical threshold to prevent symptoms and suggests that subsequent systemic administration of low-dose PMO25 in SMA mice can provide therapeutic benefit and phenotypic rescue, presumably via peripheral SMN restoration. Our work also provides additional insight into the time window of response to administration of antisense oligonucleotides to SMA mice with an intermediate phenotype. This information is crucial at a time when a number of therapeutic interventions are in clinical trials in SMA patients.
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Affiliation(s)
- Haiyan Zhou
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Jinhong Meng
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Elena Marrosu
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Narinder Janghra
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Jennifer Morgan
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
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29
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Aartsma-Rus A, Ferlini A, Goemans N, Pasmooij AMG, Wells DJ, Bushby K, Vroom E, Balabanov P. Translational and regulatory challenges for exon skipping therapies. Hum Gene Ther 2015; 25:885-92. [PMID: 25184444 DOI: 10.1089/hum.2014.086] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Several translational challenges are currently impeding the therapeutic development of antisense-mediated exon skipping approaches for rare diseases. Some of these are inherent to developing therapies for rare diseases, such as small patient numbers and limited information on natural history and interpretation of appropriate clinical outcome measures. Others are inherent to the antisense oligonucleotide (AON)-mediated exon skipping approach, which employs small modified DNA or RNA molecules to manipulate the splicing process. This is a new approach and only limited information is available on long-term safety and toxicity for most AON chemistries. Furthermore, AONs often act in a mutation-specific manner, in which case multiple AONs have to be developed for a single disease. A workshop focusing on preclinical development, trial design, outcome measures, and different forms of marketing authorization was organized by the regulatory models and biochemical outcome measures working groups of Cooperation of Science and Technology Action: "Networking towards clinical application of antisense-mediated exon skipping for rare diseases." The workshop included participants from patient organizations, academia, and members of staff from the European Medicine Agency and Medicine Evaluation Board (the Netherlands). This statement article contains the key outcomes of this meeting.
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Affiliation(s)
- Annemieke Aartsma-Rus
- 1 Department of Human Genetics, Leiden University Medical Center , 2333 ZA Leiden, The Netherlands
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30
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Hensel N, Rademacher S, Claus P. Chatting with the neighbors: crosstalk between Rho-kinase (ROCK) and other signaling pathways for treatment of neurological disorders. Front Neurosci 2015; 9:198. [PMID: 26082680 PMCID: PMC4451340 DOI: 10.3389/fnins.2015.00198] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 05/18/2015] [Indexed: 12/11/2022] Open
Abstract
ROCK inhibition has been largely applied as a strategy to treat neurodegenerative diseases (NDDs) and promising results have been obtained in the recent years. However, the underlying molecular and cellular mechanisms are not fully understood and different models have been proposed for neurodegenerative disorders. Here, we aim to review the current knowledge obtained for NDDs identifying common mechanisms as well as disease-specific models. In addition to the role of ROCK in different cell types such as neurons and microglia, we focus on the molecular signaling-pathways which mediate the beneficial effects of ROCK. Besides canonical ROCK signaling, modulation of neighboring pathways by non-canonical ROCK-crosstalk is a recurrent pattern in many NDD-model systems and has been suggested to mediate beneficial effects of ROCK-inhibition.
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Affiliation(s)
- Niko Hensel
- Hannover Medical School, Institute of Neuroanatomy Hannover, Germany ; Niedersachsen Research Network on Neuroinfectiology Hannover, Germany
| | - Sebastian Rademacher
- Hannover Medical School, Institute of Neuroanatomy Hannover, Germany ; Center for Systems Neuroscience Hannover, Germany
| | - Peter Claus
- Hannover Medical School, Institute of Neuroanatomy Hannover, Germany ; Niedersachsen Research Network on Neuroinfectiology Hannover, Germany ; Center for Systems Neuroscience Hannover, Germany
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31
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Yamamoto T, Sato H, Lai PS, Nurputra DK, Harahap NIF, Morikawa S, Nishimura N, Kurashige T, Ohshita T, Nakajima H, Yamada H, Nishida Y, Toda S, Takanashi JI, Takeuchi A, Tohyama Y, Kubo Y, Saito K, Takeshima Y, Matsuo M, Nishio H. Intragenic mutations in SMN1 may contribute more significantly to clinical severity than SMN2 copy numbers in some spinal muscular atrophy (SMA) patients. Brain Dev 2014; 36:914-20. [PMID: 24359787 DOI: 10.1016/j.braindev.2013.11.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 11/20/2013] [Accepted: 11/25/2013] [Indexed: 11/18/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by deletion or intragenic mutation of SMN1. SMA is classified into several subtypes based on clinical severity. It has been reported that the copy number of SMN2, a highly homologous gene to SMN1, is associated with clinical severity among SMA patients with homozygous deletion of SMN1. The purpose of this study was to clarify the genotype-phenotype relationship among the patients without homozygous deletion of SMN1. METHODS We performed molecular genetic analyses of SMN1 and SMN2 in 112 Japanese patients diagnosed as having SMA based on the clinical findings. For the patients retaining SMN1, the PCR or RT-PCR products of SMN1 were sequenced to identify the mutation. RESULTS Out of the 112 patients, 106 patients were homozygous for deletion of SMN1, and six patients were compound heterozygous for deletion of one SMN1 allele and intragenic mutation in the retained SMN1 allele. Four intragenic mutations were identified in the six patients: p.Ala2Val, p.Trp92Ser, p.Thr274TyrfsX32 and p.Tyr277Cys. To the best of our knowledge, all mutations except p.Trp92Ser were novel mutations which had never been previously reported. According to our observation, clinical severity of the six patients was determined by the type and location of the mutation rather than SMN2 copy number. CONCLUSION SMN2 copy number is not always associated with clinical severity of SMA patients, especially SMA patients retaining one SMN1 allele.
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Affiliation(s)
- Tomoto Yamamoto
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan; Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hideyuki Sato
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Poh San Lai
- Department of Paediatrics, Yong Loo Lin School of Medicine, NUHS, National University of Singapore, Singapore
| | - Dian Kesumapramudya Nurputra
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nur Imma Fatimah Harahap
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Satoru Morikawa
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan; Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Noriyuki Nishimura
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan; Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takashi Kurashige
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Tomohiko Ohshita
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Hideki Nakajima
- Department of Clinical Neuroscience and Neurology, Nagasaki University Graduate School of Biomedical Science, Nagasaki, Japan
| | - Hiroyuki Yamada
- Department of Pediatrics, Hyogo Prefectural Tsukaguchi Hospital, Amagasaki, Hyogo, Japan
| | - Yoshinobu Nishida
- Department of Pediatrics, Hyogo Prefectural Tsukaguchi Hospital, Amagasaki, Hyogo, Japan
| | - Soichiro Toda
- Department of Pediatrics, Kameda Medical Center, Kamogawa, Chiba, Japan
| | | | | | - Yumi Tohyama
- Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Himeji, Japan
| | - Yuji Kubo
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Kayoko Saito
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Yasuhiro Takeshima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masafumi Matsuo
- Department of Medical Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - Hisahide Nishio
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan; Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.
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32
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Lohkamp LN, von Au K, Goebel HH, Kress W, Grieben U, Drossel K, Garbes L, Wirth B, Heppner FL, Stenzel W. A paucisymptomatic neuromuscular disease mimicking type III 5q-SMA with complex rearrangements in the SMN gene. J Child Neurol 2014; 29:254-9. [PMID: 24334346 DOI: 10.1177/0883073813511858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Spinal muscular atrophy is an autosomal-recessive neuromuscular disorder, causing progressive proximal weakness and atrophy of the voluntary muscles. More than 96% of the spinal muscular atrophy patients show a homozygous absence of exons 7 and 8, or exon 7 only, in SMN1, the telomeric copy of the SMN gene. We report a young male patient with neurogenic symptoms and sparse muscle fiber atrophy, suggestive of a mild form of type III spinal muscular atrophy. He was found to be a carrier of intragenic mutations in both copies of the SMN gene, exhibiting a homozygous duplication of exons 7 and 8 in SMN1 and a homozygous deletion of exon 8 as well as a heterozygous deletion of exon 7 in SMN2. However, an intact full-length SMN1 complementary deoxyribonucleic acid was identified, and SMN protein levels in a muscle specimen were identical to that of a healthy control, formally excluding the diagnosis of spinal muscular atrophy III.
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Affiliation(s)
- Laura Nanna Lohkamp
- 1Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Hensel N, Stockbrügger I, Rademacher S, Broughton N, Brinkmann H, Grothe C, Claus P. Bilateral crosstalk of rho- and extracellular-signal-regulated-kinase (ERK) pathways is confined to an unidirectional mode in spinal muscular atrophy (SMA). Cell Signal 2013; 26:540-8. [PMID: 24316236 DOI: 10.1016/j.cellsig.2013.11.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 11/15/2013] [Accepted: 11/26/2013] [Indexed: 10/26/2022]
Abstract
Rho-kinase (ROCK) as well as extracellular signal regulated kinase (ERK) control actin cytoskeletal organization thereby regulating dynamic changes of cellular morphology. In neurons, motility processes such as axonal guidance and neurite outgrowth demand a fine regulation of upstream pathways. Here we demonstrate a bilateral ROCK-ERK information flow in neurons. This process is shifted towards an unidirectional crosstalk in a model of the neurodegenerative disease Spinal Muscular Atrophy (SMA), ultimately leading to neurite outgrowth dysregulations. As both pathways are of therapeutic relevance for SMA, our results argue for a combinatorial ROCK/ERK-targeting as a future treatment strategy.
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Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
| | - Inga Stockbrügger
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany
| | - Sebastian Rademacher
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
| | - Natasha Broughton
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany
| | - Hella Brinkmann
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany
| | - Claudia Grothe
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany; Niedersachsen Research Network on Neuroinfection (N-RENNT), Germany.
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Nurputra DK, Lai PS, Harahap NIF, Morikawa S, Yamamoto T, Nishimura N, Kubo Y, Takeuchi A, Saito T, Takeshima Y, Tohyama Y, Tay SKH, Low PS, Saito K, Nishio H. Spinal muscular atrophy: from gene discovery to clinical trials. Ann Hum Genet 2013; 77:435-63. [PMID: 23879295 DOI: 10.1111/ahg.12031] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 04/26/2013] [Indexed: 12/25/2022]
Abstract
Spinal muscular atrophy (SMA) is a common neuromuscular disorder with autosomal recessive inheritance, resulting in the degeneration of motor neurons. The incidence of the disease has been estimated at 1 in 6000-10,000 newborns with a carrier frequency of 1 in 40-60. SMA is caused by mutations of the SMN1 gene, located on chromosome 5q13. The gene product, survival motor neuron (SMN) plays critical roles in a variety of cellular activities. SMN2, a homologue of SMN1, is retained in all SMA patients and generates low levels of SMN, but does not compensate for the mutated SMN1. Genetic analysis demonstrates the presence of homozygous deletion of SMN1 in most patients, and allows screening of heterozygous carriers in affected families. Considering high incidence of carrier frequency in SMA, population-wide newborn and carrier screening has been proposed. Although no effective treatment is currently available, some treatment strategies have already been developed based on the molecular pathophysiology of this disease. Current treatment strategies can be classified into three major groups: SMN2-targeting, SMN1-introduction, and non-SMN targeting. Here, we provide a comprehensive and up-to-date review integrating advances in molecular pathophysiology and diagnostic testing with therapeutic developments for this disease including promising candidates from recent clinical trials.
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Affiliation(s)
- Dian K Nurputra
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
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Sifi Y, Sifi K, Boulefkhad A, Abadi N, Bouderda Z, Cheriet R, Magen M, Bonnefont JP, Munnich A, Benlatreche C, Hamri A. Clinical and Genetic Study of Algerian Patients with Spinal Muscular Atrophy. JOURNAL OF NEURODEGENERATIVE DISEASES 2013; 2013:903875. [PMID: 26317002 PMCID: PMC4437343 DOI: 10.1155/2013/903875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/12/2013] [Accepted: 02/18/2013] [Indexed: 11/23/2022]
Abstract
Spinal muscular atrophy (SMA) is the second most common lethal autosomal recessive disorder. It is divided into the acute Werdnig-Hoffmann disease (type I), the intermediate form (type II), the Kugelberg-Welander disease (type III), and the adult form (type IV). The gene involved in all four forms of SMA, the so-called survival motor neuron (SMN) gene, is duplicated, with a telomeric (tel SMN or SMN1) and a centromeric copy (cent SMN or SMN2). SMN1 is homozygously deleted in over 95% of SMA patients. Another candidate gene in SMA is the neuronal apoptosis inhibitory protein (NAIP) gene; it shows homozygous deletions in 45-67% of type I and 20-42% of type II/type III patients. Here we studied the SMN and NAIP genes in 92 Algerian SMA patients (20 type I, 16 type II, 53 type III, and 3 type IV) from 57 unrelated families, using a semiquantitative PCR approach. Homozygous deletions of SMN1 exons 7 and/or 8 were found in 75% of the families. Deletions of exon 4 and/or 5 of the NAIP gene were found in around 25%. Conversely, the quantitative analysis of SMN2 copies showed a significant correlation between SMN2 copy number and the type of SMA.
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Affiliation(s)
- Y. Sifi
- Service of Neurology CHU of Constantine, Algeria
- Laboratory of Biology and Molecular Genetics CHU and University of Constantine, Algeria
| | - K. Sifi
- Laboratory of Biology and Molecular Genetics CHU and University of Constantine, Algeria
- Laboratory of Biochemistry CHU of Constantine, Algeria
| | - A. Boulefkhad
- Service of Neurology CHU of Constantine, Algeria
- Laboratory of Biology and Molecular Genetics CHU and University of Constantine, Algeria
| | - N. Abadi
- Laboratory of Biology and Molecular Genetics CHU and University of Constantine, Algeria
- Laboratory of Biochemistry CHU of Constantine, Algeria
| | - Z. Bouderda
- Service of Pediatrics CHU de Constantine, Algeria
| | - R. Cheriet
- Service of Pediatrics CHU de Constantine, Algeria
| | - M. Magen
- Genetic Department of the Necker Hospital and Paris Descartes University, Paris, France
| | - J. P. Bonnefont
- Genetic Department of the Necker Hospital and Paris Descartes University, Paris, France
| | - A. Munnich
- Genetic Department of the Necker Hospital and Paris Descartes University, Paris, France
| | - C. Benlatreche
- Laboratory of Biology and Molecular Genetics CHU and University of Constantine, Algeria
- Laboratory of Biochemistry CHU of Constantine, Algeria
| | - A. Hamri
- Service of Neurology CHU of Constantine, Algeria
- Laboratory of Biochemistry CHU of Constantine, Algeria
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Zhou H, Janghra N, Mitrpant C, Dickinson RL, Anthony K, Price L, Eperon IC, Wilton SD, Morgan J, Muntoni F. A novel morpholino oligomer targeting ISS-N1 improves rescue of severe spinal muscular atrophy transgenic mice. Hum Gene Ther 2013; 24:331-42. [PMID: 23339722 DOI: 10.1089/hum.2012.211] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In the search for the most efficacious antisense oligonucleotides (AOs) aimed at inducing SMN2 exon 7 inclusion, we systematically assessed three AOs, PMO25 (-10, -34), PMO18 (-10, -27), and PMO20 (-10, -29), complementary to the SMN2 intron 7 splicing silencer (ISS-N1). PMO25 was the most efficacious in augmenting exon 7 inclusion in vitro in spinal muscular atrophy (SMA) patient fibroblasts and in vitro splicing assays. PMO25 and PMO18 were compared further in a mouse model of severe SMA. After a single intracerebroventricular (ICV) injection in neonatal mice, PMO25 increased the life span of severe SMA mice up to 30-fold, with average survival greater by 3-fold compared with PMO18 at a dose of 20 μg/g and 2-fold at 40 μg/g. Exon 7 inclusion was increased in the CNS but not in peripheral tissues. Systemic delivery of PMO25 at birth achieved a similar outcome and produced increased exon 7 inclusion both in the CNS and peripherally. Systemic administration of a 10-μg/g concentration of PMO25 conjugated to an octaguanidine dendrimer (VMO25) increased the life span only 2-fold in neonatal type I SMA mice, although it prevented tail necrosis in mild SMA mice. Higher doses and ICV injection of VMO25 were associated with toxicity. We conclude that (1) the 25-mer AO is more efficient than the 18-mer and 20-mer in modifying SMN2 splicing in vitro; (2) it is more efficient in prolonging survival in SMA mice; and (3) naked Morpholino oligomers are more efficient and safer than the Vivo-Morpholino and have potential for future SMA clinical applications.
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Affiliation(s)
- Haiyan Zhou
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, United Kingdom.
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Ting CH, Wen HL, Liu HC, Hsieh-Li HM, Li H, Lin-Chao S. The spinal muscular atrophy disease protein SMN is linked to the Golgi network. PLoS One 2012; 7:e51826. [PMID: 23284781 PMCID: PMC3524123 DOI: 10.1371/journal.pone.0051826] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 11/06/2012] [Indexed: 11/25/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by deficiency of the ubiquitous Survival of Motor Neuron (SMN) protein. SMN has been shown to be transported in granules along the axon and moved through cytoskeletal elements. However, the role and nature of SMN granules are still not well characterized. Here, using immunocytochemical methods and time-lapse studies we show that SMN granules colocalize with the Golgi apparatus in motor neuron-like NSC34 cells. Electron microscopy clearly revealed that SMN granules are transported into the Golgi stack and aggregate in the trans-Golgi apparatus. SMN granules are characterized as either coated or un-coated and behave like regulated secretory granules. Treatment of cells with monensin to disrupt Golgi-mediated granule secretion decreased SMN expression in neurites and caused growth cone defects similar to those seen in SMN knockdown cells. Knockdown of Cop-α, the protein that coats vesicles transporting proteins between the Golgi compartments, caused SMN granule accumulation in the Golgi apparatus. In addition to the well-studied role of SMN in small nuclear ribonucleoprotein (SnRNP) assembly, this work links SMN granules with the Golgi network and thus sheds light on Golgi-mediated SMN granule transport.
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Affiliation(s)
- Chen-Hung Ting
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail: (SL-C); (C-HT)
| | - Hsin-Lan Wen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Hui-Chun Liu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Hsiu-Mei Hsieh-Li
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Hung Li
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Sue Lin-Chao
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail: (SL-C); (C-HT)
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Modification of phenotype by SMN2 copy numbers in two Chinese families with SMN1 deletion in two continuous generations. Clin Chim Acta 2012; 413:1855-60. [DOI: 10.1016/j.cca.2012.07.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Revised: 07/15/2012] [Accepted: 07/28/2012] [Indexed: 12/28/2022]
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Wieme MH, Monia Ben H, Yosr B, Sihem S, Nawel T, Ines MA, Wajdi B, Najla K, Houda N, Faycal H, Rim A. Confirmation of the spinal motor neuron gene 2 (SMN2) copy numbers by real-time PCR. DIAGNOSTIC MOLECULAR PATHOLOGY : THE AMERICAN JOURNAL OF SURGICAL PATHOLOGY, PART B 2012; 21:172-175. [PMID: 22847162 DOI: 10.1097/pdm.0b013e31824696b6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disease caused by mutation or deletion of the survival motor neuron gene 1 (SMN1). SMN2, a copy gene, influences the severity of SMA and may be used in somatic gene therapy of patients with SMA in the future. The SMA carrier analysis developed at the Institute of Medical Genetics, Catholic University (Rome), on the Applied Biosystems real-time PCR instruments by Dr Danilo Tiziano and his group, provides a robust workflow to evaluate SMA carrier status. In this study, the SMN2 copy number was confirmed on 22 patients by developing our own assay on the basis of a relative real-time PCR system using the 7500 Fast Real-Time PCR System.
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Affiliation(s)
- Maamouri-Hicheri Wieme
- Department of Molecular Neurobiology and Neuropathology, La Rabta, National Institute of Neurology, Tunis, Tunisia.
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Amara A, Adala L, Ben Charfeddine I, Mamaï O, Mili A, Lazreg TB, H'mida D, Amri F, Salem N, Boughammura L, Saad A, Gribaa M. Correlation of SMN2, NAIP, p44, H4F5 and Occludin genes copy number with spinal muscular atrophy phenotype in Tunisian patients. Eur J Paediatr Neurol 2012; 16:167-74. [PMID: 21821450 DOI: 10.1016/j.ejpn.2011.07.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 05/29/2011] [Accepted: 07/18/2011] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder which is characterized by a high clinical variability with severe, intermediate, mild and adult forms. These forms are caused, in 95% of cases, by a homozygous deletion of exon 7 of SMN1 gene. Our purpose was the determination of a possible genotype-phenotype correlation between the copy number of SMN2, NAIP, p44, H4F5 and occludin genes localized in the same SMN1 region (5q13) and the severity of the disease in SMA Tunisian patients. PATIENTS AND METHODS Twenty six patients affected by SMA were enrolled in our study. MLPA and QMPSF were used to measure copy numbers of these genes. RESULTS We found that 31.3% of type I patients carried one copy of SMN2, while all patients of other forms had at least 2 copies. NAIP was absent in 87.5% of type I patients. Furthermore, all SMA type I patients had one copy of H4F5. No correlation was found for p44 and occludin genes. CONCLUSION There is a close relationship between SMN2, NAIP and H4F5 gene copy number and SMA disease severity, which is compatible with the previous reports.
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Affiliation(s)
- Abdelbasset Amara
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Street Ibn ELJAZZAR, 4000 Sousse, Tunisia.
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41
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Hensel N, Ratzka A, Brinkmann H, Klimaschewski L, Grothe C, Claus P. Analysis of the fibroblast growth factor system reveals alterations in a mouse model of spinal muscular atrophy. PLoS One 2012; 7:e31202. [PMID: 22348054 PMCID: PMC3278439 DOI: 10.1371/journal.pone.0031202] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 01/04/2012] [Indexed: 12/02/2022] Open
Abstract
The monogenetic disease Spinal Muscular Atrophy (SMA) is characterized by a progressive loss of motoneurons leading to muscle weakness and atrophy due to severe reduction of the Survival of Motoneuron (SMN) protein. Several models of SMA show deficits in neurite outgrowth and maintenance of neuromuscular junction (NMJ) structure. Survival of motoneurons, axonal outgrowth and formation of NMJ is controlled by neurotrophic factors such as the Fibroblast Growth Factor (FGF) system. Besides their classical role as extracellular ligands, some FGFs exert also intracellular functions controlling neuronal differentiation. We have previously shown that intracellular FGF-2 binds to SMN and regulates the number of a subtype of nuclear bodies which are reduced in SMA patients. In the light of these findings, we systematically analyzed the FGF-system comprising five canonical receptors and 22 ligands in a severe mouse model of SMA. In this study, we demonstrate widespread alterations of the FGF-system in both muscle and spinal cord. Importantly, FGF-receptor 1 is upregulated in spinal cord at a pre-symptomatic stage as well as in a mouse motoneuron-like cell-line NSC34 based model of SMA. Consistent with that, phosphorylations of FGFR-downstream targets Akt and ERK are increased. Moreover, ERK hyper-phosphorylation is functionally linked to FGFR-1 as revealed by receptor inhibition experiments. Our study shows that the FGF system is dysregulated at an early stage in SMA and may contribute to the SMA pathogenesis.
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Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Andreas Ratzka
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Hella Brinkmann
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Lars Klimaschewski
- Division of Neuroanatomy, Innsbruck Medical University, Innsbruck, Austria
| | - Claudia Grothe
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
- * E-mail:
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Evans MC, Cherry JJ, Androphy EJ. Differential regulation of the SMN2 gene by individual HDAC proteins. Biochem Biophys Res Commun 2011; 414:25-30. [PMID: 21925145 DOI: 10.1016/j.bbrc.2011.09.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 09/01/2011] [Indexed: 12/11/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder that is the leading genetic cause of infantile death. SMA is caused by homozygous deletion or mutation of the survival of motor neuron 1 gene (SMN1). The SMN2 gene is nearly identical to SMN1, however is alternatively spliced. The close relationship to SMN1 results in SMN2 being a very power genetic modifier of SMA disease severity and a target for therapies. We sought to identify the regulatory role individual HDAC proteins use to control expression of full length protein from the SMN2 genes. We used quantitative PCR to determine the effects shRNA silencing of individual HDACs on the steady state levels of a SMN2-luciferase reporter transcripts. We determined that reduction of individual HDAC proteins was sufficient to increase SMN protein levels in a transgenic reporter system. Knockdown of class I HDAC proteins preferentially activated the reporter by increased promoter transcription. Silencing of class II HDAC proteins maintained transcriptional activity; however silencing of HDAC 5 and 6 also appeared to enhance inclusion of an alternatively spliced exon. This work highlights HDAC proteins 2 and 6 as excellent investigative targets. These data are important to the basic understanding of SMN expression regulation and the refinements of current therapeutic compounds as well as the development of novel SMA therapeutics.
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Affiliation(s)
- Matthew C Evans
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
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Petit F, Cuisset JM, Rouaix-Emery N, Cancés C, Sablonnière B, Bieth E, Moerman A, Sukno S, Hardy N, Holder-Espinasse M, Manouvrier-Hanu S, Vallée L. Insights into genotype-phenotype correlations in spinal muscular atrophy: a retrospective study of 103 patients. Muscle Nerve 2011; 43:26-30. [PMID: 21171094 DOI: 10.1002/mus.21832] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disorder associated with homozygous deletion of the survival motor neuron 1 gene (SMN1). Its centromeric copy gene, SMN2, is the major modifying factor. However, the genotype-phenotype correlation is incomplete and is therefore not useful in clinical practice. We studied a cohort of 103 patients in order to refine this correlation. In addition to standard disease severity data, we collected three additional criteria: age at death; brainstem involvement; and loss of ambulation. Gene dosage analysis was conducted by multiplex ligation-dependent probe amplification (MLPA). SMN2 copynumber was highly correlated with survival duration in SMA type I and ambulation conservation or loss in type III. Among SMA severity groups, it was not significantly different in cases with brainstem involvement. Although the SMN2 copynumber could provide prognostic indications, clinical discrepancies still exist among patients, suggesting the existence of unidentified modifying factors.
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Affiliation(s)
- Florence Petit
- Service de Génétique Clinique, CHU Hôpital Jeanne de Flandre, Lille, France
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Abstract
AbstractProgress in understanding the genetic basis and pathophysiology of spinal muscular atrophy (SMA), along with continuous efforts in finding a way to increase survival motor neuron (SMN) protein levels have resulted in several strategies that have been proposed as potential directions for efficient drug development. Here we provide an overview on the current status of the following approaches: 1) activation of SMN2 gene and increasing full length SMN2 transcript level, 2) modulating SMN2 splicing, 3) stabilizing SMN mRNA and SMN protein, 4) development of neurotrophic, neuroprotective and anabolic compounds and 5) stem cell and gene therapy. The new preclinical advances warrant a cautious optimism for emergence of an effective treatment in the very near future.
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Watihayati MS, Fatemeh H, Marini M, Atif AB, Zahiruddin WM, Sasongko TH, Tang TH, Zabidi-Hussin ZAMH, Nishio H, Zilfalil BA. Combination of SMN2 copy number and NAIP deletion predicts disease severity in spinal muscular atrophy. Brain Dev 2009; 31:42-5. [PMID: 18842367 DOI: 10.1016/j.braindev.2008.08.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 08/04/2008] [Accepted: 08/22/2008] [Indexed: 11/19/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by mutations in the SMN1 gene. The SMN2 gene is highly homologous to SMN1 and has been reported to be correlated with severity of the disease. The clinical presentation of SMA varies from severe to mild, with three clinical subtypes (type I, type II, and type III) that are assigned according to age of onset and severity of the disease. Here, we aim to investigate the potential association between the number of copies of SMN2 and the deletion in the NAIP gene with the clinical severity of SMA in patients of Malaysian origin. Forty-two SMA patients (14 of type I, 20 type II, and 8 type III) carrying deletions of the SMN1 gene were enrolled in this study. SMN2 copy number was determined by fluorescence-based quantitative polymerase chain reaction assay. Twenty-nine percent of type I patients carried one copy of SMN2, while the remaining 71% carried two copies. Among the type II and type III SMA patients, 29% of cases carried two copies of the gene, while 71% carried three or four copies of SMN2. Deletion analysis of NAIP showed that 50% of type I SMA patients had a homozygous deletion of exon 5 of this gene and that only 10% of type II SMA cases carried a homozygous deletion, while all type III patients carried intact copies of the NAIP gene. We conclude that there exists a close relationship between SMN2 copy number and SMA disease severity, suggesting that the determination of SMN2 copy number may be a good predictor of SMA disease type. Furthermore, NAIP gene deletion was found to be associated with SMA severity. In conclusion, combining the analysis of deletion of NAIP with the assessment of SMN2 copy number increases the value of this tool in predicting the severity of SMA.
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Affiliation(s)
- Mohd Shamshudin Watihayati
- Human Genome Center, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kota Bharu, Kelantan, Malaysia
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A natural history study of late onset spinal muscular atrophy types 3b and 4. J Neurol 2008; 255:1400-4. [PMID: 18575920 DOI: 10.1007/s00415-008-0929-0] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 01/31/2008] [Accepted: 03/06/2008] [Indexed: 01/19/2023]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by a homozygous deletion of the survival motor neuron (SMN)1 gene. The nearly identical SMN2 gene plays a disease modifying role. SMA is classified into four different subtypes based on age of onset and clinical course (SMA types 1-4). The natural history of early onset SMA types 1-3a has been studied extensively. Late onset SMA is rare and disease course has not been studied in detail. OBJECTIVE To perform a prospective study on the clinical course and the correlation with SMN2 copy numbers of late onset SMA. METHODS Patients fulfilling the diagnostic criteria for late onset SMA (types 3b and 4) were included in the study. At inclusion and follow-up, muscle strength, respiratory function, functional status and quality of life were assessed. SMN2 copy number was determined in all patients. RESULTS Twelve patients were identified and included. Six patients were siblings from one family, two patients were brothers from a second family and four patients were sporadic cases. All patients carried four copies of the SMN2 gene. Median age of disease onset was 22.2 years (10-37). Age of disease onset in patients from family one was lower as compared to the other patients. None of the outcome measures changed after a follow-up of 2.5 years. Five patients reported an increase in fatigue and muscle weakness. None of the patients showed symptoms of respiratory insufficiency. CONCLUSIONS This study indicates that late onset SMA is not characterized by disease progression and that alternative or surrogate disease markers are required for the design of future trials. This study confirms the finding that SMN2 copy number is a SMA disease course modifier.
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Tran VK, Sasongko TH, Hong DD, Hoan NT, Dung VC, Lee MJ, Gunadi, Takeshima Y, Matsuo M, Nishio H. SMN2 and NAIP gene dosages in Vietnamese patients with spinal muscular atrophy. Pediatr Int 2008; 50:346-51. [PMID: 18533950 DOI: 10.1111/j.1442-200x.2008.02590.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The SMN1 gene is now recognized as a spinal muscular atrophy (SMA)-causing gene, while SMN2 and NAIP have been characterized as a modifying factor of the clinical severity of SMA. Gene dosage of SMN2 is associated with clinical severity of SMA. But the relationship between gene dosage of NAIP and clinical severity of SMA remains to be clarified, although complete deletion of NAIP is frequent in type I patients. METHODS To evaluate the contribution of the SMN2 and NAIP gene dosages to SMA, quantitative real-time polymerase chain reaction was used to measure copy numbers of SMN2 and NAIP in 34 Vietnamese SMA patients lacking SMN1 (13 type I, 11 type II and 10 type III patients). RESULTS The SMN2 copy number in type I patients was significantly lower than that in type II-III patients, which was compatible with the previous reports. In contrast, 25 out of 34 patients had only zero or one copy of NAIP, while 50 out of 52 controls had two or more copies. For NAIP (+) genotype, six out of 13 type I patients, eight out of 11 type II patients and six out of 10 type III patients carried one NAIP copy. CONCLUSIONS The SMN2 copy number was related to the clinical severity of SMA among Vietnamese patients. The presence of one NAIP copy, that is, heterozygous NAIP deletion, was common in Vietnamese SMA, regardless of clinical phenotype.
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Affiliation(s)
- Van Khanh Tran
- Department of Pediatrics, Graduate School of Medicine, Kobe University, Japan
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48
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Labrum R, Rodda J, Krause A. The molecular basis of spinal muscular atrophy (SMA) in South African black patients. Neuromuscul Disord 2007; 17:684-92. [PMID: 17627822 DOI: 10.1016/j.nmd.2007.05.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 05/08/2007] [Accepted: 05/16/2007] [Indexed: 11/21/2022]
Abstract
SMA is an autosomal recessive disorder that results in symmetrical muscle weakness and wasting due to degeneration of the anterior horns of the spinal cord. The gene for SMA, the survival motor neuron (SMN) gene is found on chromosome 5q13, in a region harbouring a 500kb duplication, resulting in two copies (a telomeric and a centromeric) of each of the genes found within the duplication. SMN1 is homozygously deleted in approximately 95% of patients worldwide. Results of the current study show that only 51% (42/92) of South African black SMA patients have homozygous deletions of the SMN1 gene. This frequency is significantly lower than observed in the South African white patient group and in other international populations. The pattern of deletions in the South African black patients is also significantly different. In order to elucidate the molecular basis of SMA in the black population, a dosage assay enabling the detection of SMN1 deletion heterozygotes was independently developed. This assay confirmed SMN1 heterozygosity in at least 70% of black non-deletion SMA patients. However, no second disease-causing mutation or a common chromosomal background for this mutation could be identified in these patients. The frequency of SMA in both the black and white population was also determined using the SMN1 gene dosage assay. Results showed that SMA is more common than previously thought with carrier rates of 1 in 50 and 1 in 23 and a predicted birth incidence of 1 in 3574 and 1 in 1945 in the black population and the white population, respectively. Development and incorporation of the SMN1 dosage assay into the molecular diagnostic service will increase the percentage of cases in which the diagnosis of SMA can be confirmed and allow preclinical and prenatal diagnosis. Further gene characterisation and functional studies would need to be performed in order to further define the molecular basis of SMA in the South African black population.
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Affiliation(s)
- R Labrum
- Division of Human Genetics, School of Pathology, National Health Laboratory Service and University of the Witwatersrand, P.O. Box 1038, Johannesburg 2000, South Africa
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Abstract
The importance of alternative splicing in the regulation of diverse biological processes is reflected in the growing list of human diseases associated with known or suspected splicing defects. It is becoming evident that alternative splicing plays a particularly important role in neurologic disease, which is perhaps not surprising given the important role splicing plays in generating complexity and function in the brain. This review considers the evidence that defects in regulation of splicing may underlie many types of human neurologic diseases.
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Affiliation(s)
- Donny D Licatalosi
- Howard Hughes Medical Institute, Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, New York 10021, USA
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Kesari A, Misra UK, Kalita J, Mishra VN, Pradhan S, Patil SJ, Phadke SR, Mittal B. Study of survival of motor neuron (SMN) and neuronal apoptosis inhibitory protein (NAIP) gene deletions in SMA patients. J Neurol 2005; 252:667-71. [PMID: 15772743 DOI: 10.1007/s00415-005-0714-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Revised: 10/14/2004] [Accepted: 10/26/2004] [Indexed: 12/22/2022]
Abstract
In view of the paucity of deletion studies of survival of motor neuron (SMN) and neuronal apoptosis inhibitor protein (NAIP) genes in Indian SMA patients, this study has been undertaken to determine the status of SMN1, SMN2 and NAIP gene deletions in Indian SMA patients. Clinically and neurophysiologically diagnosed SMA patients were included in the study. A gene deletion study was carried out in 45 proximal SMA patients and 50 controls of the same ethnic group. Both SMN1 and NAIP genes showed homozygous absence in 76% and 31% respectively in proximal SMA patients. It is proposed that the lower deletion frequency of SMN1 gene in Indian patients may be due to mutations present in other genes or population variation, which need further study.
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Affiliation(s)
- Akanchha Kesari
- Dept. of Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareli Road, Lucknow-226014, India
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