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Choi K, Yang A, Baek J, Jeong H, Kang Y, Baek W, Kim JC, Kang M, Choi M, Ham Y, Son MJ, Han SB, Kim J, Jang JH, Ahn JS, Shen H, Woo SH, Kim JH, Cho S. Regulation of Survival Motor Neuron Gene Expression by Calcium Signaling. Int J Mol Sci 2021; 22:ijms221910234. [PMID: 34638572 PMCID: PMC8508836 DOI: 10.3390/ijms221910234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/07/2021] [Accepted: 09/16/2021] [Indexed: 11/21/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous survival of motor neurons 1 (SMN1) gene deletion, leaving a duplicate gene, SMN2, as the sole source of SMN protein. However, a defect in SMN2 splicing, involving exon 7 skipping, results in a low level of functional SMN protein. Therefore, the upregulation of SMN protein expression from the SMN2 gene is generally considered to be one of the best therapeutic strategies to treat SMA. Most of the SMA drug discovery is based on synthetic compounds, and very few natural compounds have been explored thus far. Here, we performed an unbiased mechanism-independent and image-based screen of a library of microbial metabolites in SMA fibroblasts using an SMN-specific immunoassay. In doing so, we identified brefeldin A (BFA), a well-known inhibitor of ER-Golgi protein trafficking, as a strong inducer of SMN protein. The profound increase in SMN protein was attributed to, in part, the rescue of the SMN2 pre-mRNA splicing defect. Intriguingly, BFA increased the intracellular calcium concentration, and the BFA-induced exon 7 inclusion of SMN2 splicing, was abrogated by the depletion of intracellular calcium and by the pharmacological inhibition of calcium/calmodulin-dependent kinases (CaMKs). Moreover, BFA considerably reduced the expression of Tra2-β and SRSF9 proteins in SMA fibroblasts and enhanced the binding of PSF and hnRNP M to an exonic splicing enhancer (ESE) of exon 7. Together, our results demonstrate a significant role for calcium and its signaling on the regulation of SMN splicing, probably through modulating the expression/activity of splicing factors.
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Affiliation(s)
- Kwangman Choi
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Medical Biotechnology, SoonChunHyang University, Asan 31538, Korea
| | - Ansook Yang
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Jiyeon Baek
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Hyejeong Jeong
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Yura Kang
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
| | - Woosun Baek
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
| | - Joon-Chul Kim
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
| | - Mingu Kang
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Miri Choi
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Youngwook Ham
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
| | - Min-Jeong Son
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
| | - Sang-Bae Han
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Janghwan Kim
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea;
| | - Jae-Hyuk Jang
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea
| | - Jong Seog Ahn
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea
| | - Haihong Shen
- Gwangju Institute of Science and Technology, School of life Sciences, Gwangju 61005, Korea;
| | - Sun-Hee Woo
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
| | - Jong Heon Kim
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
| | - Sungchan Cho
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
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Zappa G, LoMauro A, Baranello G, Cavallo E, Corti P, Mastella C, Costantino MA. Intellectual abilities, language comprehension, speech, and motor function in children with spinal muscular atrophy type 1. J Neurodev Disord 2021; 13:9. [PMID: 33530934 PMCID: PMC7856807 DOI: 10.1186/s11689-021-09355-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/19/2021] [Indexed: 11/18/2022] Open
Abstract
Background Spinal muscular atrophy (SMA) is a chronic, neuromuscular disease characterized by degeneration of spinal cord motor neurons, resulting in progressive muscular atrophy and weakness. SMA1 is the most severe form characterized by significant bulbar, respiratory, and motor dysfunction. SMA1 prevents children from speaking a clearly understandable and fluent language, with their communication being mainly characterized by eye movements, guttural sounds, and anarthria (type 1a); severe dysarthria (type 1b); and nasal voice and dyslalia (type 1c). The aim of this study was to analyze for the first time cognitive functions, language comprehension, and speech in natural history SMA1 children according to age and subtypes, to develop cognitive and language benchmarks that provide outcomes for the clinical medication trials that are changing SMA1 course/trajectory. Methods This is a retrospective study including 22 children with SMA1 (10 affected by subtype 1a-1b: AB and 12 by 1c: C) aged 3–11 years in clinical stable condition with a coded way to communicate “yes” and “no”. Data from the following assessments have been retrieved from patient charts: one-dimensional Raven test (RCPM), to evaluate cognitive development (IQ); ALS Severity Score (ALSSS) to evaluate speech disturbances; Brown Bellugy modified for Italian standards (TCGB) to evaluate language comprehension; and Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) to assess motor functioning. Results SMA 1AB and 1C children were similar in age, with the former characterized by lower CHOP-INTEND scores compared to the latter. All 22 children had collaborated to RCPM and their median IQ was 120 with no difference (p = 0.945) between AB and C. Global median score of the speech domain of the ALSSS was 5; however, it was 2 in AB children, being significantly lower than C (6.5, p < 0.001). TCGB test had been completed by 13 children, with morphosyntactic comprehension being in the normal range (50). Although ALSSS did not correlate with both IQ and TCGB, it had a strong (p < 0.001) correlation with CHOP-INTEND described by an exponential rise to maximum. Conclusions Although speech and motor function were severely compromised, children with SMA1 showed general intelligence and language comprehension in the normal range. Speech impairment was strictly related to global motor impairment.
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Affiliation(s)
- Grazia Zappa
- SAPRE, Child and Adolescent Neuropsychiatric Service, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Viale Ungheria 29, 20138, Milan, Italy.
| | - Antonella LoMauro
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo Da Vinci, Milan, Italy
| | - Giovanni Baranello
- Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, London, UK.,UO Neurologia dello Sviluppo, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Emilia Cavallo
- Child and Adolescent Neuropsychiatric Service, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Priscilla Corti
- SAPRE, Child and Adolescent Neuropsychiatric Service, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Viale Ungheria 29, 20138, Milan, Italy
| | - Chiara Mastella
- SAPRE, Child and Adolescent Neuropsychiatric Service, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Viale Ungheria 29, 20138, Milan, Italy
| | - Maria Antonella Costantino
- Child and Adolescent Neuropsychiatric Service, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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New and Developing Therapies in Spinal Muscular Atrophy: From Genotype to Phenotype to Treatment and Where Do We Stand? Int J Mol Sci 2020; 21:ijms21093297. [PMID: 32392694 PMCID: PMC7246502 DOI: 10.3390/ijms21093297] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/03/2020] [Accepted: 05/04/2020] [Indexed: 02/08/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a congenital neuromuscular disorder characterized by motor neuron loss, resulting in progressive weakness. SMA is notable in the health care community because it accounts for the most common cause of infant death resulting from a genetic defect. SMA is caused by low levels of the survival motor neuron protein (SMN) resulting from SMN1 gene mutations or deletions. However, patients always harbor various copies of SMN2, an almost identical but functionally deficient copy of the gene. A genotype–phenotype correlation suggests that SMN2 is a potent disease modifier for SMA, which also represents the primary target for potential therapies. Increasing comprehension of SMA pathophysiology, including the characterization of SMN1 and SMN2 genes and SMN protein functions, has led to the development of multiple therapeutic approaches. Until the end of 2016, no cure was available for SMA, and management consisted of supportive measures. Two breakthrough SMN-targeted treatments, either using antisense oligonucleotides (ASOs) or virus-mediated gene therapy, have recently been approved. These two novel therapeutics have a common objective: to increase the production of SMN protein in MNs and thereby improve motor function and survival. However, neither therapy currently provides a complete cure. Treating patients with SMA brings new responsibilities and unique dilemmas. As SMA is such a devastating disease, it is reasonable to assume that a unique therapeutic solution may not be sufficient. Current approaches under clinical investigation differ in administration routes, frequency of dosing, intrathecal versus systemic delivery, and mechanisms of action. Besides, emerging clinical trials evaluating the efficacy of either SMN-dependent or SMN-independent approaches are ongoing. This review aims to address the different knowledge gaps between genotype, phenotypes, and potential therapeutics.
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Kevadiya BD, Ottemann BM, Thomas MB, Mukadam I, Nigam S, McMillan J, Gorantla S, Bronich TK, Edagwa B, Gendelman HE. Neurotheranostics as personalized medicines. Adv Drug Deliv Rev 2019; 148:252-289. [PMID: 30421721 PMCID: PMC6486471 DOI: 10.1016/j.addr.2018.10.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 12/16/2022]
Abstract
The discipline of neurotheranostics was forged to improve diagnostic and therapeutic clinical outcomes for neurological disorders. Research was facilitated, in largest measure, by the creation of pharmacologically effective multimodal pharmaceutical formulations. Deployment of neurotheranostic agents could revolutionize staging and improve nervous system disease therapeutic outcomes. However, obstacles in formulation design, drug loading and payload delivery still remain. These will certainly be aided by multidisciplinary basic research and clinical teams with pharmacology, nanotechnology, neuroscience and pharmaceutic expertise. When successful the end results will provide "optimal" therapeutic delivery platforms. The current report reviews an extensive body of knowledge of the natural history, epidemiology, pathogenesis and therapeutics of neurologic disease with an eye on how, when and under what circumstances neurotheranostics will soon be used as personalized medicines for a broad range of neurodegenerative, neuroinflammatory and neuroinfectious diseases.
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Affiliation(s)
- Bhavesh D Kevadiya
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Brendan M Ottemann
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Midhun Ben Thomas
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Insiya Mukadam
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Saumya Nigam
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - JoEllyn McMillan
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Santhi Gorantla
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Tatiana K Bronich
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Benson Edagwa
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Howard E Gendelman
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA; Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA.
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Abera MB, Xiao J, Nofziger J, Titus S, Southall N, Zheng W, Moritz KE, Ferrer M, Cherry JJ, Androphy EJ, Wang A, Xu X, Austin C, Fischbeck KH, Marugan JJ, Burnett BG. ML372 blocks SMN ubiquitination and improves spinal muscular atrophy pathology in mice. JCI Insight 2016; 1:e88427. [PMID: 27882347 DOI: 10.1172/jci.insight.88427] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease and one of the leading inherited causes of infant mortality. SMA results from insufficient levels of the survival motor neuron (SMN) protein, and studies in animal models of the disease have shown that increasing SMN protein levels ameliorates the disease phenotype. Our group previously identified and optimized a new series of small molecules, with good potency and toxicity profiles and reasonable pharmacokinetics, that were able to increase SMN protein levels in SMA patient-derived cells. We show here that ML372, a representative of this series, almost doubles the half-life of residual SMN protein expressed from the SMN2 locus by blocking its ubiquitination and subsequent degradation by the proteasome. ML372 increased SMN protein levels in muscle, spinal cord, and brain tissue of SMA mice. Importantly, ML372 treatment improved the righting reflex and extended survival of a severe mouse model of SMA. These results demonstrate that slowing SMN degradation by selectively inhibiting its ubiquitination can improve the motor phenotype and lifespan of SMA model mice.
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Affiliation(s)
- Mahlet B Abera
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland, USA
| | - Jingbo Xiao
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Jonathan Nofziger
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Steve Titus
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Noel Southall
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Wei Zheng
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Kasey E Moritz
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland, USA
| | - Marc Ferrer
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Jonathan J Cherry
- Department of Dermatology,, School of Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Elliot J Androphy
- Department of Dermatology,, School of Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Amy Wang
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Xin Xu
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Christopher Austin
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Juan J Marugan
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA
| | - Barrington G Burnett
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland, USA
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Chen TH, Yang YH, Mai HH, Liang WC, Wu YC, Wang HY, Jong YJ. Reliability and validity of outcome measures of in-hospital and at-home visits in a randomized, double-blind, placebo-controlled trial for spinal muscular atrophy. J Child Neurol 2014; 29:1680-4. [PMID: 24163397 DOI: 10.1177/0883073813506935] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We used at-home assessments in a clinical trial to relieve the visit burden for participants. A total of 57 patients with type II or III spinal muscular atrophy were enrolled and 10 of them (7 type II and 3 type III) received at-home assessments. The primary end points were Gross Motor Function Measure, Manual Muscle Test, and serum biomarker. The secondary endpoints were Modified Hammersmith Functional Motor Scale and forced vital capacity. The correlation coefficients and analysis of covariance showed good reliability and validity of all outcome measures. Except for Gross Motor Function Measure and Modified Hammersmith Functional Motor Scale, there were no significant differences in measures between in-hospital and at-home groups (intersubject) or among 3 patients who received both at-home and in-hospital visits (intrasubject). We concluded that at-home assessments could provide sufficient reliability in a controlled trial. This modification could help design a successful clinical trial for spinal muscular atrophy.
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Affiliation(s)
- Tai-Heng Chen
- Division of Pediatric Emergency, Department of Emergency, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Hsin Yang
- Statistical Analysis Laboratory, Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Hui-Hsia Mai
- Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wen-Chen Liang
- Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Ching Wu
- Department of Physical Therapy, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Hui-Yi Wang
- Department of Physical Therapy, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yuh-Jyh Jong
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
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7
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Kariya S, Obis T, Garone C, Akay T, Sera F, Iwata S, Homma S, Monani UR. Requirement of enhanced Survival Motoneuron protein imposed during neuromuscular junction maturation. J Clin Invest 2014; 124:785-800. [PMID: 24463453 DOI: 10.1172/jci72017] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 10/31/2013] [Indexed: 02/03/2023] Open
Abstract
Spinal muscular atrophy is a common motor neuron disease caused by low survival motoneuron (SMN), a key protein in the proper splicing of genes. Restoring the protein is therefore a promising therapeutic strategy. Implementation of this strategy, however, depends on defining the temporal requirements for SMN. Here, we used controlled knockdown of SMN in transgenic mice to determine the precise postnatal stage requirements for this protein. Reducing SMN in neonatal mice resulted in a classic SMA-like phenotype. Unexpectedly, depletion of SMN in adults had relatively little effect. Insensitivity to low SMN emerged abruptly at postnatal day 17, which coincided with establishment of the fully mature neuromuscular junction (NMJ). Mature animals depleted of SMN eventually exhibited evidence of selective neuromuscular pathology that was made worse by traumatic injury. The ability to regenerate the mature NMJ in aged or injured SMN-depleted mice was grossly impaired, a likely consequence of the inability to meet the surge in demand for motoneuronal SMN that was seen in controls. Our results demonstrate that relative maturity of the NMJ determines the temporal requirement for the SMN protein. These observations suggest that the use of potent but potentially deleterious SMN-enhancing agents could be tapered in human patients once the neuromuscular system matures and reintroduced as needed to enhance SMN for remodeling aged or injured NMJs.
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8
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Shababi M, Lorson CL, Rudnik-Schöneborn SS. Spinal muscular atrophy: a motor neuron disorder or a multi-organ disease? J Anat 2013; 224:15-28. [PMID: 23876144 DOI: 10.1111/joa.12083] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2013] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disorder that is the leading genetic cause of infantile death. SMA is characterized by loss of motor neurons in the ventral horn of the spinal cord, leading to weakness and muscle atrophy. SMA occurs as a result of homozygous deletion or mutations in Survival Motor Neuron-1 (SMN1). Loss of SMN1 leads to a dramatic reduction in SMN protein, which is essential for motor neuron survival. SMA disease severity ranges from extremely severe to a relatively mild adult onset form of proximal muscle atrophy. Severe SMA patients typically die mostly within months or a few years as a consequence of respiratory insufficiency and bulbar paralysis. SMA is widely known as a motor neuron disease; however, there are numerous clinical reports indicating the involvement of additional peripheral organs contributing to the complete picture of the disease in severe cases. In this review, we have compiled clinical and experimental reports that demonstrate the association between the loss of SMN and peripheral organ deficiency and malfunction. Whether defective peripheral organs are a consequence of neuronal damage/muscle atrophy or a direct result of SMN loss will be discussed.
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Affiliation(s)
- Monir Shababi
- Department of Veterinary Pathobiology, Life Sciences Center, University of Missouri, Columbia, MO, USA; Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, USA
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Schreml J, Riessland M, Paterno M, Garbes L, Roßbach K, Ackermann B, Krämer J, Somers E, Parson SH, Heller R, Berkessel A, Sterner-Kock A, Wirth B. Severe SMA mice show organ impairment that cannot be rescued by therapy with the HDACi JNJ-26481585. Eur J Hum Genet 2012; 21:643-52. [PMID: 23073311 DOI: 10.1038/ejhg.2012.222] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the leading genetic cause of early childhood death worldwide and no therapy is available today. Many drugs, especially histone deacetylase inhibitors (HDACi), increase SMN levels. As all HDACi tested so far only mildly ameliorate the SMA phenotype or are unsuitable for use in humans, there is still need to identify more potent drugs. Here, we assessed the therapeutic power of the pan-HDACi JNJ-26481585 for SMA, which is currently used in various clinical cancer trials. When administered for 64 h at 100 nM, JNJ-26481585 upregulated SMN levels in SMA fibroblast cell lines, including those from non-responders to valproic acid. Oral treatment of Taiwanese SMA mice and control littermates starting at P0 showed no overt extension of lifespan, despite mild improvements in motor abilities and weight progression. Many treated and untreated animals showed a very rapid decline or unexpected sudden death. We performed exploratory autopsy and histological assessment at different disease stages and found consistent abnormalities in the intestine, heart and lung and skeletal muscle vasculature of SMA animals, which were not prevented by JNJ-26481585 treatment. Interestingly, some of these features may be only indirectly caused by α-motoneuron function loss but may be major life-limiting factors in the course of disease. A better understanding of - primary or secondary - non-neuromuscular organ involvement in SMA patients may improve standard of care and may lead to reassessment of how to investigate SMA patients clinically.
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Affiliation(s)
- Julia Schreml
- Institute of Human Genetics, University of Cologne, Cologne, Germany
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Lee AJH, Awano T, Park GH, Monani UR. Limited phenotypic effects of selectively augmenting the SMN protein in the neurons of a mouse model of severe spinal muscular atrophy. PLoS One 2012; 7:e46353. [PMID: 23029491 PMCID: PMC3459898 DOI: 10.1371/journal.pone.0046353] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 08/29/2012] [Indexed: 11/19/2022] Open
Abstract
The selective vulnerability of motor neurons to paucity of Survival Motor Neuron (SMN) protein is a defining feature of human spinal muscular atrophy (SMA) and indicative of a unique requirement for adequate levels of the protein in these cells. However, the relative contribution of SMN-depleted motor neurons to the disease process is uncertain and it is possible that their characteristic loss and the overall SMA phenotype is a consequence of low protein in multiple cell types including neighboring spinal neurons and non-neuronal tissue. To explore the tissue-specific requirements for SMN and, especially, the salutary effects of restoring normal levels of the protein to neuronal tissue of affected individuals, we have selectively expressed the protein in neurons of mice that model severe SMA. Expressing SMN pan-neuronally in mutant mice mitigated specific aspects of the disease phenotype. Motor performance of the mice improved and the loss of spinal motor neurons that characterizes the disease was arrested. Proprioceptive synapses on the motor neurons were restored and defects of the neuromuscular junctions mitigated. The improvements at the cellular level were reflected in a four-fold increase in survival. Nevertheless, mutants expressing neuronal SMN did not live beyond three weeks of birth, a relatively poor outcome compared to the effects of ubiquitously restoring SMN. This suggests that although neurons and, in particular, spinal motor neurons constitute critical cellular sites of action of the SMN protein, a truly effective treatment of severe SMA will require restoring the protein to multiple cell types including non-neuronal tissue.
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Affiliation(s)
- Andrew J-H. Lee
- Department of Pathology and Cell Biology, Columbia University, New York, New York, United States of America
- Center for Motor Neuron Biology and Disease, Columbia University, New York, New York, United States of America
| | - Tomoyuki Awano
- Department of Pathology and Cell Biology, Columbia University, New York, New York, United States of America
- Center for Motor Neuron Biology and Disease, Columbia University, New York, New York, United States of America
| | - Gyu-Hwan Park
- Department of Neuropharmacology, Kyungpook National University, Daegu, South Korea
| | - Umrao R. Monani
- Department of Pathology and Cell Biology, Columbia University, New York, New York, United States of America
- Department of Neurology, Columbia University, New York, New York, United States of America
- Center for Motor Neuron Biology and Disease, Columbia University, New York, New York, United States of America
- * E-mail:
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Wakeling EN, Joussemet B, Costiou P, Fanuel D, Moullier P, Barkats M, Fyfe JC. Failure of lower motor neuron radial outgrowth precedes retrograde degeneration in a feline model of spinal muscular atrophy. J Comp Neurol 2012; 520:1737-50. [PMID: 22120001 DOI: 10.1002/cne.23010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Feline spinal muscular atrophy (SMA) is a fully penetrant, autosomal recessive lower motor neuron disease in domestic cats that clinically resembles human SMA Type III. A whole genome linkage scan identified a ∼140-kb deletion that abrogates expression of LIX1, a novel SMA candidate gene of unknown function. To characterize the progression of feline SMA, we assessed pathological changes in muscle and spinal cord from 3 days of age to beyond onset of clinical signs. Electromyographic (EMG) analysis indicating denervation occurred between 10 and 12 weeks, with the first neurological signs occurring at the same time. Compound motor action potential (CMAP) amplitudes were significantly reduced in the soleus and extensor carpi radialis muscles at 8-11 weeks. Quadriceps femoris muscle fibers from affected cats appeared smaller at 10 weeks; by 12 weeks atrophic fibers were more prevalent than in age-matched controls. In affected cats, significant loss of L5 ventral root axons was observed at 12 weeks. By 21 weeks of age, affected cats had 40% fewer L5 motor axons than normal. There was no significant difference in total L5 soma number, even at 21 weeks; thus degeneration begins distal to the cell body and proceeds retrogradely. Morphometric analysis of L5 ventral roots and horns revealed that 4 weeks prior to axon loss, motor axons in affected cats failed to undergo radial enlargement, suggesting a role for the putative disease gene LIX1 in radial growth of axons.
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Affiliation(s)
- Erin N Wakeling
- Genetics Program, Michigan State University East Lansing, Michigan 48824, USA.
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Bebee TW, Dominguez CE, Samadzadeh-Tarighat S, Akehurst KL, Chandler DS. Hypoxia is a modifier of SMN2 splicing and disease severity in a severe SMA mouse model. Hum Mol Genet 2012; 21:4301-13. [PMID: 22763238 DOI: 10.1093/hmg/dds263] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a progressive neurodegenerative disease associated with low levels of the essential survival motor neuron (SMN) protein. Reduced levels of SMN is due to the loss of the SMN1 gene and inefficient splicing of the SMN2 gene caused by a C>T mutation in exon 7. Global analysis of the severe SMNΔ7 SMA mouse model revealed altered splicing and increased levels of the hypoxia-inducible transcript, Hif3alpha, at late stages of disease progression. Severe SMA patients also develop respiratory deficiency during disease progression. We sought to evaluate whether hypoxia was capable of altering SMN2 exon 7 splicing and whether increased oxygenation could modulate disease in a severe SMA mouse model. Hypoxia treatment in cell culture increased SMN2 exon 7 skipping and reduced SMN protein levels. Concordantly, the treatment of SMNΔ7 mice with hyperoxia treatment increased the inclusion of SMN2 exon 7 in skeletal muscles and resulted in improved motor function. Transfection splicing assays of SMN minigenes under hypoxia revealed that hypoxia-induced skipping is dependent on poor exon definition due to the SMN2 C>T mutation and suboptimal 5' splice site. Hypoxia treatment in cell culture led to increased hnRNP A1 and Sam68 levels. Mutation of hnRNP A1-binding sites prevented hypoxia-induced skipping of SMN exon 7 and was found to bind both hnRNP A1 and Sam68. These results implicate hypoxic stress as a modulator of SMN2 exon 7 splicing in disease progression and a coordinated regulation by hnRNP A1 and Sam68 as modifiers of hypoxia-induced skipping of SMN exon 7.
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Affiliation(s)
- Thomas W Bebee
- The Center for Childhood Cancer at the Research Institute at Nationwide Children’s Hospital, Columbus, OH, USA
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Current research on SMN protein and treatment strategies for spinal muscular atrophy. Neuromuscul Disord 2011; 22:193-7. [PMID: 21820901 DOI: 10.1016/j.nmd.2011.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 04/20/2011] [Accepted: 06/06/2011] [Indexed: 02/04/2023]
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Growing rods for scoliosis in spinal muscular atrophy: structural effects, complications, and hospital stays. Spine (Phila Pa 1976) 2011; 36:1305-11. [PMID: 21730818 DOI: 10.1097/brs.0b013e3182194937] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Retrospective analysis of patients with spinal muscular atrophy (SMA) treated with growing rod (GR) instrumentation for scoliosis. OBJECTIVE To evaluate structural effectiveness, complications, and length of hospital stay associated with GRs for scoliosis in SMA and to compare values with those of infantile and juvenile idiopathic scoliosis (IIS/JIS). SUMMARY OF BACKGROUND DATA Most studies evaluate GR effectiveness in all patients. We specifically examined SMA and IIS/JIS. METHODS We searched a multicenter database and found 15 patients with SMA and scoliosis treated with GRs for 54 ± 33 months. Radiographic measurements, complications, and hospital stay durations were compared with those of 80 GR patients with IIS/JIS observed for 43 ± 31 months. Measures of rib collapse, including T6:T10 mean rib-vertebral angle and T6:T12 thoracic width, were compared. Student t test was used to compare SMA and IIS/JIS values (significance level, P = 0.05). RESULTS Primary radiographic measurements in patients with SMA improved from preoperative to latest follow-up as follows: curve, 89° ± 19° to 55° ± 17°; pelvic obliquity, 31° ± 14° to 11° ± 10°; space-available-for-lung ratio, 0.86 ± 0.15 to 0.94 ± 0.21; and T1-S1 length grew 8.7 ± 3.2 cm. Rib collapse continued despite GR treatment in SMA but not in IIS/JIS. Hospital stays were longer for SMA than for IIS/JIS for lengthening procedures (P = 0.01) and trended to be longer for initial surgery (P = 0.08) and final fusion (P = 0.06). Patients with SMA and IIS/JIS experienced, respectively, 0.5 and 1.1 major complications per patient (P = 0.02). CONCLUSION GRs improve trunk height and the space-available-for-lung ratio while controlling curve and pelvic obliquity in young patients with SMA with severe scoliosis, but they do not halt rib collapse. For patients with SMA, hospital stays were longer than those for patients with IIS/JIS, whereas the rate of major complications was lower.
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Passini MA, Cheng SH. Prospects for the gene therapy of spinal muscular atrophy. Trends Mol Med 2011; 17:259-65. [DOI: 10.1016/j.molmed.2011.01.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/03/2011] [Accepted: 01/04/2011] [Indexed: 10/18/2022]
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Shababi M, Habibi J, Yang HT, Vale SM, Sewell WA, Lorson CL. Cardiac defects contribute to the pathology of spinal muscular atrophy models. Hum Mol Genet 2010; 19:4059-71. [DOI: 10.1093/hmg/ddq329] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
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Cho S, Dreyfuss G. A degron created by SMN2 exon 7 skipping is a principal contributor to spinal muscular atrophy severity. Genes Dev 2010; 24:438-42. [PMID: 20194437 DOI: 10.1101/gad.1884910] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous survival of motor neurons 1 (SMN1) gene deletions, leaving a duplicate gene, SMN2, as the sole source of SMN protein. However, most of the mRNA produced from SMN2 pre-mRNA is exon 7-skipped ( approximately 80%), resulting in a highly unstable and almost undetectable protein (SMNDelta7). We show that this splicing defect creates a potent degradation signal (degron; SMNDelta7-DEG) at SMNDelta7's C-terminal 15 amino acids. The S270A mutation inactivates SMNDelta7-DEG, generating a stable SMNDelta7 that rescues viability of SMN-deleted cells. These findings explain a key aspect of the SMA disease mechanism, and suggest new treatment approaches based on interference with SMNDelta7-DEG activity.
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Affiliation(s)
- Sungchan Cho
- Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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