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Sivanesan S, Howell MD, DiDonato CJ, Singh RN. Antisense oligonucleotide mediated therapy of spinal muscular atrophy. Transl Neurosci 2013; 4:10.2478/s13380-013-0109-2. [PMID: 24265944 PMCID: PMC3832262 DOI: 10.2478/s13380-013-0109-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality. SMA results from deletions or mutations of survival motor neuron 1 (SMN1), an essential gene. SMN2, a nearly identical copy, can compensate for SMN1 loss if SMN2 exon 7 skipping is prevented. Among the many cis-elements involved in the splicing regulation of SMN exon 7, intronic splicing silencer N1 (ISS-N1) has emerged as the most effective target for an antisense oligonucleotide (ASO)-mediated splicing correction of SMN2 exon 7. Blocking of ISS-N1 by an ASO has been shown to fully restore SMN2 exon 7 inclusion in SMA patient cells as well as in vivo. Here we review how ISS-N1 targeting ASOs that use different chemistries respond differently in the various SMA mouse models. We also compare other ASO-based strategies for therapeutic splicing correction in SMA. Given that substantial progress on ASO-based strategies to promote SMN2 exon 7 inclusion in SMA has been made, and that similar approaches in a growing number of genetic diseases are possible, this report has wide implications.
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Affiliation(s)
- Senthilkumar Sivanesan
- Department of Biomedical Sciences, College of Veterinary Medicine (2034 Vet Med Bld.), Iowa State University, Ames, IA 50011
| | - Matthew D. Howell
- Department of Biomedical Sciences, College of Veterinary Medicine (2034 Vet Med Bld.), Iowa State University, Ames, IA 50011
| | - Christine J. DiDonato
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Human Molecular Genetics Program, Ann & Robert H. Lurie Children’s Hospital of Chicago, Research Center, Chicago, IL 60614
| | - Ravindra N. Singh
- Department of Biomedical Sciences, College of Veterinary Medicine (2034 Vet Med Bld.), Iowa State University, Ames, IA 50011
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102
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Therapeutic strategies for the treatment of spinal muscular atrophy. Future Med Chem 2013; 4:1733-50. [PMID: 22924510 DOI: 10.4155/fmc.12.107] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited neurodegenerative disease that results in progressive dysfunction of motor neurons of the anterior horn of the spinal cord. SMA is caused by the loss of full-length protein expression from the survival of motor neuron 1 (SMN1) gene. The disease has a unique genetic profile as it is autosomal recessive for the loss of SMN1, but a nearly identical homolog, SMN2, acts as a disease modifier whose expression is inversely correlated to clinical severity. Targeted therapeutic approaches primarily focus on increasing the levels of full-length SMN protein, through either gene replacement or regulation of SMN2 expression. There is currently no US FDA approved treatment for SMA. This is an exciting time as multiple efforts from academic and industrial laboratories are reaching the preclinical and clinical testing stages.
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103
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Poruk KE, Davis RH, Smart AL, Chisum BS, LaSalle BA, Chan GM, Gill G, Reyna SP, Swoboda KJ. Observational study of caloric and nutrient intake, bone density, and body composition in infants and children with spinal muscular atrophy type I. Neuromuscul Disord 2012; 22:966-73. [PMID: 22832342 PMCID: PMC3484247 DOI: 10.1016/j.nmd.2012.04.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 04/18/2012] [Accepted: 04/23/2012] [Indexed: 11/19/2022]
Abstract
Clinical experience supports a critical role for nutrition in patients with spinal muscular atrophy (SMA). Three-day dietary intake records were analyzed for 156 visits in 47 SMA type I patients, 25 males and 22 females, ages 1month to 13years (median 9.8months) and compared to dietary reference intakes for gender and age along with anthropometric measures and dual-energy X-ray absorptiometry (DEXA) data. Using standardized growth curves, twelve patients met criteria for failure to thrive (FTT) with weight for age <3rd percentile; eight met criteria based on weight for height. Percentage of body fat mass was not correlated with weight for height and weight for age across percentile categories. DEXA analysis further demonstrated that SMA type I children have higher fat mass and lower fat free mass than healthy peers (p<0.001). DEXA and dietary analysis indicates a strong correlation with magnesium intake and bone mineral density (r=0.65, p<0.001). Average caloric intake for 1-3years old was 68.8±15.8kcal/kg - 67% of peers' recommended intake. Children with SMA type I may have lower caloric requirements than healthy age-matched peers, increasing risk for over and undernourished states and deficiencies of critical nutrients. Standardized growth charts may overestimate FTT status in SMA type I.
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Affiliation(s)
- Katherine E Poruk
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Rebecca Hurst Davis
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Abby L Smart
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Benjamin S Chisum
- Department of Biomedical Informatics, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Bernie A LaSalle
- Department of Biomedical Informatics, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Gary M Chan
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Gurmail Gill
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Sandra P Reyna
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Kathryn J Swoboda
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, Utah, USA
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104
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Clinical and molecular cross-sectional study of a cohort of adult type III spinal muscular atrophy patients: clues from a biomarker study. Eur J Hum Genet 2012; 21:630-6. [PMID: 23073312 DOI: 10.1038/ejhg.2012.233] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by mutations of the SMN1 gene. Based on severity, three forms of SMA are recognized (types I-III). All patients usually have 2-4 copies of a highly homologous gene (SMN2), which produces insufficient levels of functional survival motor neuron (SMN) protein due to the alternative splicing of exon 7. The availability of potential candidates to the treatment of SMA has raised a number of issues, including the availability of biomarkers. This study was aimed at evaluating whether the quantification of SMN2 products in peripheral blood is a suitable biomarker for SMA. Forty-five adult type III patients were evaluated by Manual Muscle Testing, North Star Ambulatory Assessment scale, 6-min walk test, myometry, forced vital capacity, and dual X-ray absorptiometry. Molecular assessments included SMN2 copy number, levels of full-length SMN2 (SMN2-fl) transcripts and those lacking exon 7 and SMN protein. Clinical outcome measures strongly correlated to each other. Lean body mass correlated inversely with years from diagnosis and with several aspects of motor performance. SMN2 copy number and SMN protein levels were not associated with motor performance or transcript levels. SMN2-fl levels correlated with motor performance in ambulant patients. Our results indicate that SMN2-fl levels correlate with motor performance only in patients preserving higher levels of motor function, whereas motor performance was strongly influenced by disease duration and lean body mass. If not taken into account, the confounding effect of disease duration may impair the identification of potential SMA biomarkers.
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105
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Lorson MA, Lorson CL. SMN-inducing compounds for the treatment of spinal muscular atrophy. Future Med Chem 2012; 4:2067-84. [PMID: 23157239 PMCID: PMC3589915 DOI: 10.4155/fmc.12.131] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant mortality. A neurodegenerative disease, it is caused by loss of SMN1, although low, but essential, levels of SMN protein are produced by the nearly identical gene SMN2. While no effective treatment or therapy currently exists, a new wave of therapeutics has rapidly progressed from cell-based and preclinical animal models to the point where clinical trials have initiated for SMA-specific compounds. There are several reasons why SMA has moved relatively rapidly towards novel therapeutics, including: SMA is monogenic; the molecular understanding of SMN gene regulation has been building for nearly 20 years; and all SMA patients retain one or more copies of SMN2 that produces low levels of full-length, fully functional SMN protein. This review primarily focuses upon the biology behind the disease and examines SMN1- and SMN2-targeted therapeutics.
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Affiliation(s)
- Monique A Lorson
- Department of Veterinary Pathobiology, Bond Life Sciences Center, Room 440C, University of Missouri, MO 65211 USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, Bond Life Sciences Center, Room 471G, University of Missouri, Columbia, MO 65211, USA
- Department of Molecular Microbiology & Immunology, University of Missouri, MO, USA
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106
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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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107
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Zolkipli Z, Sherlock M, Biggar WD, Taylor G, Hutchison JS, Peliowski A, Alman BA, Ling SC, Tein I. Abnormal fatty acid metabolism in spinal muscular atrophy may predispose to perioperative risks. Eur J Paediatr Neurol 2012; 16:549-53. [PMID: 22264649 DOI: 10.1016/j.ejpn.2012.01.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Revised: 12/28/2011] [Accepted: 01/01/2012] [Indexed: 12/22/2022]
Abstract
A 15 year old boy with SMA type II underwent spinal fusion and suffered a mitochondrial Reye-like catabolic crisis 4 days postop with hypoketotic hypoglycemia, lactic acidaemia, hyperammonemia and liver failure, with 90% coagulative necrosis and diffuse macro- and microvesicular steatosis, requiring orthotopic liver transplantation. This crisis responded in part to mitochondrial therapy and anabolic rescue. He made a dramatic sustained neurological recovery, though his post-transplant liver biopsies revealed micro- and macrosteatosis. We hypothesize that a combination of surgical stress-catecholamine induced lipolysis, prolonged general anaesthesia with propofol and sevoflurane, and perioperative fasting on a background of decreased β-oxidation were potential risk factors for the mitochondrial decompensation.
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Affiliation(s)
- Zarazuela Zolkipli
- Division of Neurology, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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108
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Zabnenkova VV, Dadali EL, Spiridonova MG, Zinchenko RA, Polyakov AV. Heterozygous carrier rate for type I–IV proximal spinal muscular atrophy in Chuvashes, Udmurts, and residents of the Moscow region. RUSS J GENET+ 2012. [DOI: 10.1134/s1022795412080091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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109
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Parra J, Tizzano EF. Raising obstetricians' awareness of spinal muscular atrophy: towards early detection and reproductive planning. J Matern Fetal Neonatal Med 2012; 25:2555-8. [PMID: 22712688 DOI: 10.3109/14767058.2012.703720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder that is caused by degeneration of α motor neurons in the spinal cord anterior horns. This degeneration can lead to progressive atrophy of proximal muscles, weakness, respiratory failure and death in severe cases. SMA is the most common neuromuscular disease of childhood and one of the main causes of infant death, with no cure in sight. This review highlights the impact of the disease in families, summarizes genetics and ultrasound advances, discusses how obstetricians can work towards its early detection and explores the options for reproductive planning.
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Affiliation(s)
- Juan Parra
- Department of Obstetrics and Gynecology, Hospital Sant Pau, and Ciberer U-705(3), Barcelona, Spain
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110
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Bowerman M, Murray LM, Beauvais A, Pinheiro B, Kothary R. A critical smn threshold in mice dictates onset of an intermediate spinal muscular atrophy phenotype associated with a distinct neuromuscular junction pathology. Neuromuscul Disord 2012; 22:263-76. [DOI: 10.1016/j.nmd.2011.09.007] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 09/07/2011] [Accepted: 09/27/2011] [Indexed: 11/24/2022]
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111
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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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112
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Zhou J, Zheng X, Shen H. Targeting RNA-splicing for SMA treatment. Mol Cells 2012; 33:223-8. [PMID: 22382684 PMCID: PMC3887702 DOI: 10.1007/s10059-012-0005-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 02/15/2012] [Accepted: 02/15/2012] [Indexed: 10/28/2022] Open
Abstract
The central dogma of DNA-RNA-protein was established more than 40 years ago. However, important biological processes have been identified since the central dogma was developed. For example, methylation is important in the regulation of transcription. In contrast, proteins, are more complex due to modifications such as phosphorylation, glycosylation, ubiquitination, or cleavage. RNA is the mediator between DNA and protein, but it can also be modulated at several levels. Among the most profound discoveries of RNA regulation is RNA splicing. It has been estimated that 80% of pre-mRNA undergo alternative splicing, which exponentially increases biological information flow in cellular processes. However, an increased number of regulated steps inevitably accompanies an increased number of errors. Abnormal splicing is often found in cells, resulting in protein dysfunction that causes disease. Splicing of the survival motor neuron (SMN) gene has been extensively studied during the last two decades. Accumulating knowledge on SMN splicing has led to speculation and search for spinal muscular atrophy (SMA) treatment by stimulating the inclusion of exon 7 into SMN mRNA. This mini-review summaries the latest progress on SMN splicing research as a potential treatment for SMA disease.
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Affiliation(s)
| | - Xuexiu Zheng
- School of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
| | - Haihong Shen
- School of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
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113
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Abstract
Human embryonic stem cells (HESCs) are of great interest in biology and medicine due to their ability to grow indefinitely in culture while maintaining their ability to differentiate into all different cell types in the human body. In addition, HESCs can be used for better understanding the key developmental processes and can, therefore, serve for studying genetic disorders for which no good research model exists. Preimplantation genetic diagnosis of in vitro derived embryos results in affected-spare blastocysts with specific known inherited mutations.These affected blastocysts can be used for the derivation of disease-bearing HESCs, which would serve for studying the molecular and pathophysiological mechanisms underlying the genetic disease for which they were diagnosed. This chapter describes the methods to derive HESCs carrying mutations for inherited disorders.
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114
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Parra J, Alias L, Also-Rallo E, Martínez-Hernández R, Senosiain R, Medina C, Alejos O, Rams N, Amenedo M, Ormo F, Jesús Barceló M, Calaf J, Baiget M, Bernal S, Tizzano EF. Evaluation of fetal nuchal translucency in 98 pregnancies at risk for severe spinal muscular atrophy: possible relevance of the SMN2 copy number. J Matern Fetal Neonatal Med 2011; 25:1246-9. [PMID: 22082206 DOI: 10.3109/14767058.2011.636101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To study fetal nuchal translucency (NT) thickness as a possible early marker in fetuses at risk for severe spinal muscular atrophy (SMA). To investigate the significance of the survival motor neuron (SMN) 2 gene copy number in affected fetuses. METHODS We performed 2D-ultrasound in 98 pregnancies at risk for SMA, all of which underwent prenatal molecular testing of the SMN1 gene. Crown-rump length (CRL) and NT measurements were obtained in all cases before chorionic villus sampling. Fetuses were diagnosed as healthy, carriers or affected according to the SMN1 molecular testing results. SMN2 copies were also tested in all affected fetuses. RESULTS Nineteen fetuses were predicted to be affected due to the absence of the SMN1 gene, 18 of which had two SMN2 copies. Mean CRL and NT values did not differ between healthy, carrier and affected fetuses. In the remaining affected case who had only one SMN2 copy, the ultrasound examination showed a NT value of 4.98 mm and findings compatible with hypoplastic left heart. CONCLUSIONS Most affected SMA fetuses have normal NT values. Our findings support the idea that SMN2 copy number in SMA fetuses is relevant for the development of congenital heart defects and increased NT values.
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Affiliation(s)
- Juan Parra
- Department of Obstetrics and Gynecology, Hospital Sant Pau, Universitat Autonoma de Barcelona, Spain
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115
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Montes J, Kaufmann P. Spinal Muscular Atrophy. Neuromuscul Disord 2011. [DOI: 10.1002/9781119973331.ch30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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116
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Xiao J, Marugan JJ, Zheng W, Titus S, Southall N, Cherry JJ, Evans M, Androphy EJ, Austin CP. Discovery, synthesis, and biological evaluation of novel SMN protein modulators. J Med Chem 2011; 54:6215-33. [PMID: 21819082 PMCID: PMC3174349 DOI: 10.1021/jm200497t] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disorder affecting the expression or function of survival motor neuron protein (SMN) due to the homozygous deletion or rare point mutations in the survival motor neuron gene 1 (SMN1). The human genome includes a second nearly identical gene called SMN2 that is retained in SMA. SMN2 transcripts undergo alternative splicing with reduced levels of SMN. Up-regulation of SMN2 expression, modification of its splicing, or inhibition of proteolysis of the truncated protein derived from SMN2 have been discussed as potential therapeutic strategies for SMA. In this manuscript, we detail the discovery of a series of arylpiperidines as novel modulators of SMN protein. Systematic hit-to-lead efforts significantly improved potency and efficacy of the series in the primary and orthogonal assays. Structure-property relationships including microsomal stability, cell permeability, and in vivo pharmacokinetics (PK) studies were also investigated. We anticipate that a lead candidate chosen from this series may serve as a useful probe for exploring the therapeutic benefits of SMN protein up-regulation in SMA animal models and a starting point for clinical development.
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Affiliation(s)
- Jingbo Xiao
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850
| | - Juan J. Marugan
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850
| | - Wei Zheng
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850
| | - Steve Titus
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850
| | - Noel Southall
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850
| | - Jonathan J. Cherry
- Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, LRB 328, Worcester, Massachusetts 01605
| | - Matthew Evans
- Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, LRB 328, Worcester, Massachusetts 01605
| | - Elliot J. Androphy
- Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, LRB 328, Worcester, Massachusetts 01605
| | - Christopher P. Austin
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850
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117
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Nölle A, Zeug A, van Bergeijk J, Tönges L, Gerhard R, Brinkmann H, Al Rayes S, Hensel N, Schill Y, Apkhazava D, Jablonka S, O'mer J, Srivastav RK, Baasner A, Lingor P, Wirth B, Ponimaskin E, Niedenthal R, Grothe C, Claus P. The spinal muscular atrophy disease protein SMN is linked to the Rho-kinase pathway via profilin. Hum Mol Genet 2011; 20:4865-78. [PMID: 21920940 DOI: 10.1093/hmg/ddr425] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spinal muscular atrophy (SMA), a frequent neurodegenerative disease, is caused by reduced levels of functional survival of motoneuron (SMN) protein. SMN is involved in multiple pathways, including RNA metabolism and splicing as well as motoneuron development and function. Here we provide evidence for a major contribution of the Rho-kinase (ROCK) pathway in SMA pathogenesis. Using an in vivo protein interaction system based on SUMOylation of proteins, we found that SMN is directly interacting with profilin2a. Profilin2a binds to a stretch of proline residues in SMN, which is heavily impaired by a novel SMN2 missense mutation (S230L) derived from a SMA patient. In different SMA models, we identified differential phosphorylation of the ROCK-downstream targets cofilin, myosin-light chain phosphatase and profilin2a. We suggest that hyper-phosphorylation of profilin2a is the molecular link between SMN and the ROCK pathway repressing neurite outgrowth in neuronal cells. Finally, we found a neuron-specific increase in the F-/G-actin ratio that further support the role of actin dynamics in SMA pathogenesis.
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Affiliation(s)
- Anna Nölle
- Institute for Neuroanatomy, Hannover Medical School, Hannover 30623, Germany
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Utility of survival motor neuron ELISA for spinal muscular atrophy clinical and preclinical analyses. PLoS One 2011; 6:e24269. [PMID: 21904622 PMCID: PMC3164180 DOI: 10.1371/journal.pone.0024269] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 08/04/2011] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVES Genetic defects leading to the reduction of the survival motor neuron protein (SMN) are a causal factor for Spinal Muscular Atrophy (SMA). While there are a number of therapies under evaluation as potential treatments for SMA, there is a critical lack of a biomarker method for assessing efficacy of therapeutic interventions, particularly those targeting upregulation of SMN protein levels. Towards this end we have engaged in developing an immunoassay capable of accurately measuring SMN protein levels in blood, specifically in peripheral blood mononuclear cells (PBMCs), as a tool for validating SMN protein as a biomarker in SMA. METHODS A sandwich enzyme-linked immunosorbent assay (ELISA) was developed and validated for measuring SMN protein in human PBMCs and other cell lysates. Protocols for detection and extraction of SMN from transgenic SMA mouse tissues were also developed. RESULTS The assay sensitivity for human SMN is 50 pg/mL. Initial analysis reveals that PBMCs yield enough SMN to analyze from blood volumes of less than 1 mL, and SMA Type I patients' PBMCs show ∼90% reduction of SMN protein compared to normal adults. The ELISA can reliably quantify SMN protein in human and mouse PBMCs and muscle, as well as brain, and spinal cord from a mouse model of severe SMA. CONCLUSIONS This SMN ELISA assay enables the reliable, quantitative and rapid measurement of SMN in healthy human and SMA patient PBMCs, muscle and fibroblasts. SMN was also detected in several tissues in a mouse model of SMA, as well as in wildtype mouse tissues. This SMN ELISA has general translational applicability to both preclinical and clinical research efforts.
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Lutz CM, Kariya S, Patruni S, Osborne MA, Liu D, Henderson CE, Li DK, Pellizzoni L, Rojas J, Valenzuela DM, Murphy AJ, Winberg ML, Monani UR. Postsymptomatic restoration of SMN rescues the disease phenotype in a mouse model of severe spinal muscular atrophy. J Clin Invest 2011; 121:3029-41. [PMID: 21785219 DOI: 10.1172/jci57291] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 05/18/2011] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a common neuromuscular disorder in humans. In fact, it is the most frequently inherited cause of infant mortality, being the result of mutations in the survival of motor neuron 1 (SMN1) gene that reduce levels of SMN protein. Restoring levels of SMN protein in individuals with SMA is perceived to be a viable therapeutic option, but the efficacy of such a strategy once symptoms are apparent has not been determined. We have generated mice harboring an inducible Smn rescue allele and used them in a model of SMA to investigate the effects of turning on SMN expression at different time points during the course of the disease. Restoring SMN protein even after disease onset was sufficient to reverse neuromuscular pathology and effect robust rescue of the SMA phenotype. Importantly, our findings also indicated that there was a therapeutic window of opportunity from P4 through P8 defined by the extent of neuromuscular synapse pathology and the ability of motor neurons to respond to SMN induction, following which restoration of the protein to the organism failed to produce therapeutic benefit. Nevertheless, our results suggest that even in severe SMA, timely reinstatement of the SMN protein may halt the progression of the disease and serve as an effective postsymptomatic treatment.
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120
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AKBARI MOHAMMADTAGHI, NORUZINIA MEHRDAD, MOZDARANI HOSSEIN, HAMID MOHAMMAD. Determination of exon 7 SMN1 deletion in Iranian patients and heterozygous carriers by quantitative real-time PCR. J Genet 2011; 90:133-6. [DOI: 10.1007/s12041-011-0038-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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121
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Shawky RM, El-Sayed NS. Clinico-epidemiologic characteristics of spinal muscular atrophy among Egyptians. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2011. [DOI: 10.1016/j.ejmhg.2011.02.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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122
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Large-scale population screening for spinal muscular atrophy: clinical implications. Genet Med 2011; 13:110-4. [PMID: 21233719 DOI: 10.1097/gim.0b013e3182017c05] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To determine the frequency of SMN1 deletion carriers in the Israeli population and to assess the feasibility of population screening for spinal muscular atrophy. METHODS A total of 6394 individuals without family history of spinal muscular atrophy underwent genetic screening by multiplex ligation-dependent probe amplification, designed to detect SMN1 exon 7 and exon 8 copy number. RESULTS One hundred fifty-nine individuals carried an SMN1 heterozygous exon 7 deletion, yielding a carrier frequency of 1:40. About 10.8% of individuals were found to carry two or more SMN1 exon 7 copies on the same chromosome (cis configuration). This implies that some deletion carriers may not be detected by multiplex ligation-dependent probe amplification or similar quantitative methods. The acceptance of spinal muscular atrophy screening among women undergoing testing for fragile X syndrome and cystic fibrosis reached 93%. CONCLUSIONS Currently used molecular techniques cannot detect about 5% of spinal muscular atrophy carriers with a cis configuration or individuals with SMN1 sequence mutations and de novo deletions. Thus, it is estimated that the spinal muscular atrophy carrier detection rate is about 90%. Given the severity of spinal muscular atrophy, the relatively high carrier frequency, and the estimated detection rate, we conclude that population-based screening for spinal muscular atrophy is feasible and acceptable.
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Dayangac-Erden D, Bora-Tatar G, Dalkara S, Demir AS, Erdem-Yurter H. Carboxylic acid derivatives of histone deacetylase inhibitors induce full length SMN2 transcripts: a promising target for spinal muscular atrophy therapeutics. Arch Med Sci 2011; 7:230-4. [PMID: 22291761 PMCID: PMC3258711 DOI: 10.5114/aoms.2011.22072] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 09/15/2010] [Accepted: 10/14/2010] [Indexed: 01/29/2023] Open
Abstract
INTRODUCTION Proximal spinal muscular atrophy (SMA) is a common autosomal recessively inherited neuromuscular disorder. It is caused by homozygous absence of the survival motor neuron 1 (SMN1) gene. SMN2, which modulates the severity of the disease, represents a major target for therapy. The aim of this study was to investigate whether SMN2 expression can be increased by caffeic acid, chlorogenic acid and curcumin, which are designed by modifications of the carboxylic acid class of histone deacetylase (HDAC) inhibitors. MATERIAL AND METHODS Using quantitative real-time PCR, we analysed the levels of full-length SMN2 and Δ7SMN2 mRNA. We performed LDH cytotoxicity assay to analyse whether SMN2 activating concentrations of caffeic acid, chlorogenic acid and curcumin were cytotoxic to fibroblasts. RESULTS We found that caffeic acid and curcumin were more efficient than chlorogenic acid and increased full-length SMN2 mRNA levels 1.5 and 1.7-fold, respectively. Δ7SMN2 mRNA levels were measured to investigate alternative splicing of exon 7. We also found that cytotoxicity was not observed at SMN2 activating concentrations. CONCLUSIONS Our data suggest that carboxylic acid derivatives including phenolic structure and symmetry could be a good candidate for SMA treatment.
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Affiliation(s)
- Didem Dayangac-Erden
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Gamze Bora-Tatar
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Sevim Dalkara
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Hacettepe University, Ankara, Turkey
| | - Ayhan S. Demir
- Department of Chemistry, Middle East Technical University, Ankara, Turkey
| | - Hayat Erdem-Yurter
- Department of Medical Biology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
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124
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Wu CY, Whye D, Glazewski L, Choe L, Kerr D, Lee KH, Mason RW, Wang W. Proteomic assessment of a cell model of spinal muscular atrophy. BMC Neurosci 2011; 12:25. [PMID: 21385431 PMCID: PMC3063191 DOI: 10.1186/1471-2202-12-25] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 03/08/2011] [Indexed: 12/29/2022] Open
Abstract
Background Deletion or mutation(s) of the survival motor neuron 1 (SMN1) gene causes spinal muscular atrophy (SMA), a neuromuscular disease characterized by spinal motor neuron death and muscle paralysis. Complete loss of the SMN protein is embryonically lethal, yet reduced levels of this protein result in selective death of motor neurons. Why motor neurons are specifically targeted by SMN deficiency remains to be determined. In this study, embryonic stem (ES) cells derived from a severe SMA mouse model were differentiated into motor neurons in vitro by addition of retinoic acid and sonic hedgehog agonist. Proteomic and western blot analyses were used to probe protein expression alterations in this cell-culture model of SMA that could be relevant to the disease. Results When ES cells were primed with Noggin/fibroblast growth factors (bFGF and FGF-8) in a more robust neural differentiation medium for 2 days before differentiation induction, the efficiency of in vitro motor neuron differentiation was improved from ~25% to ~50%. The differentiated ES cells expressed a pan-neuronal marker (neurofilament) and motor neuron markers (Hb9, Islet-1, and ChAT). Even though SMN-deficient ES cells had marked reduced levels of SMN (~20% of that in control ES cells), the morphology and differentiation efficiency for these cells are comparable to those for control samples. However, proteomics in conjunction with western blot analyses revealed 6 down-regulated and 14 up-regulated proteins with most of them involved in energy metabolism, cell stress-response, protein degradation, and cytoskeleton stability. Some of these activated cellular pathways showed specificity for either undifferentiated or differentiated cells. Increased p21 protein expression indicated that SMA ES cells were responding to cellular stress. Up-regulation of p21 was confirmed in spinal cord tissues from the same SMA mouse model from which the ES cells were derived. Conclusion SMN-deficient ES cells provide a cell-culture model for SMA. SMN deficiency activates cellular stress pathways, causing a dysregulation of energy metabolism, protein degradation, and cytoskeleton stability.
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Affiliation(s)
- Chia-Yen Wu
- Department of Biological Science, University of Delaware, Newark, DE, USA
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125
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Carrier screening for spinal muscular atrophy (SMA) in 107,611 pregnant women during the period 2005-2009: a prospective population-based cohort study. PLoS One 2011; 6:e17067. [PMID: 21364876 PMCID: PMC3045421 DOI: 10.1371/journal.pone.0017067] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 01/14/2011] [Indexed: 11/20/2022] Open
Abstract
Background Spinal muscular atrophy (SMA) is the most common neuromuscular autosomal recessive disorder. The American College of Medical Genetics has recently recommended routine carrier screening for SMA because of the high carrier frequency (1 in 25–50) as well as the severity of that genetic disease. Large studies are needed to determine the feasibility, benefits, and costs of such a program. Methods and Findings This is a prospective population-based cohort study of 107,611 pregnant women from 25 counties in Taiwan conducted during the period January 2005 to June 2009. A three-stage screening program was used: (1) pregnant women were tested for SMA heterozygosity; (2) if the mother was determined to be heterozygous for SMA (carrier status), the paternal partner was then tested; (3) if both partners were SMA carriers, prenatal diagnostic testing was performed. During the study period, a total of 2,262 SMA carriers with one copy of the SMN1 gene were identified among the 107,611 pregnant women that were screened. The carrier rate was approximately 1 in 48 (2.10%). The negative predictive value of DHPLC coupled with MLPA was 99.87%. The combined method could detect approximately 94% of carriers because most of the cases resulted from a common single deletion event. In addition, 2,038 spouses were determined to be SMA carriers. Among those individuals, 47 couples were determined to be at high risk for having offspring with SMA. Prenatal diagnostic testing was performed in 43 pregnant women (91.49%) and SMA was diagnosed in 12 (27.91%) fetuses. The prevalence of SMA in our population was 1 in 8,968. Conclusion The main benefit of SMA carrier screening is to reduce the burden associated with giving birth to an affected child. In this study, we determined the carrier frequency and genetic risk and provided carrier couples with genetic services, knowledge, and genetic counseling.
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Bueno KC, Gouvea SP, Genari AB, Funayama CA, Zanette DL, Silva WA, Oliveira AB, Scola RH, Werneck LC, Marques W. Detection of spinal muscular atrophy carriers in a sample of the Brazilian population. Neuroepidemiology 2011; 36:105-8. [PMID: 21335981 DOI: 10.1159/000324156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 01/03/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Spinal muscular atrophy is a common autosomal recessive neuromuscular disorder caused by mutations in the SMN1 gene. Identification of spinal muscular atrophy carriers has important implications for individuals with a family history of the disorder and for genetic counseling. The aim of this study was to determine the frequency of carriers in a sample of the nonconsanguineous Brazilian population by denaturing high-performance liquid chromatography (DHPLC). METHODS To validate the method, we initially determined the relative quantification of DHPLC in 28 affected patients (DHPLC values: 0.00) and 65 parents (DHPLC values: 0.49-0.69). Following quantification, we studied 150 unrelated nonconsanguineous healthy individuals from the general population. RESULTS Four of the 150 healthy individuals tested (with no family history of a neuromuscular disorder) presented a DHPLC value in the range of heterozygous carriers (0.6-0.68). CONCLUSIONS Based on these results, we estimated there is a carrier frequency of 2.7% in the nonconsanguineous Brazilian population, which is very similar to other areas of the world where consanguineous marriage is not common. This should be considered in the process of genetic counseling and risk calculations.
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Affiliation(s)
- K C Bueno
- Departments of Neurosciences and Behavior Sciences, University of São Paulo, Ribeirão Preto, Brazil
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127
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Coady TH, Lorson CL. SMN in spinal muscular atrophy and snRNP biogenesis. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:546-64. [PMID: 21957043 DOI: 10.1002/wrna.76] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ribonucleoprotein (RNP) complexes function in nearly every facet of cellular activity. The spliceosome is an essential RNP that accurately identifies introns and catalytically removes the intervening sequences, providing exquisite control of spatial, temporal, and developmental gene expressions. U-snRNPs are the building blocks for the spliceosome. A significant amount of insight into the molecular assembly of these essential particles has recently come from a seemingly unexpected area of research: neurodegeneration. Survival motor neuron (SMN) performs an essential role in the maturation of snRNPs, while the homozygous loss of SMN1 results in the development of spinal muscular atrophy (SMA), a devastating neurodegenerative disease. In this review, the function of SMN is examined within the context of snRNP biogenesis and evidence is examined which suggests that the SMN functional defects in snRNP biogenesis may account for the motor neuron pathology observed in SMA.
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Affiliation(s)
- Tristan H Coady
- Department of Veterinary Pathobiology, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
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128
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Kaufmann P, McDermott MP, Darras BT, Finkel R, Kang P, Oskoui M, Constantinescu A, Sproule DM, Foley AR, Yang M, Tawil R, Chung W, Martens B, Montes J, O'Hagen J, Dunaway S, Flickinger JM, Quigley J, Riley S, Glanzman AM, Benton M, Ryan PA, Irvine C, Annis CL, Butler H, Caracciolo J, Montgomery M, Marra J, Koo B, De Vivo DC. Observational study of spinal muscular atrophy type 2 and 3: functional outcomes over 1 year. ACTA ACUST UNITED AC 2011; 68:779-86. [PMID: 21320981 DOI: 10.1001/archneurol.2010.373] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To characterize the short-term course of spinal muscular atrophy (SMA) in a genetically and clinically well-defined cohort of patients with SMA. DESIGN A comprehensive multicenter, longitudinal, observational study. SETTING The Pediatric Neuromuscular Clinical Research Network for SMA, a consortium of clinical investigators at 3 clinical sites. PARTICIPANTS Sixty-five participants with SMA types 2 and 3, aged 20 months to 45 years, were prospectively evaluated. INTERVENTION We collected demographic and medical history information and determined the SMN 2 copy number. MAIN OUTCOME MEASURES Clinical outcomes included measures of motor function (Gross Motor Function Measure and expanded Hammersmith Functional Motor Scale), pulmonary function (forced vital capacity), and muscle strength (myometry). Participants were evaluated every 2 months for the initial 6 months and every 3 months for the subsequent 6 months. We evaluated change over 12 months for all clinical outcomes and examined potential correlates of change over time including age, sex, SMA type, ambulatory status, SMN2 copy number, medication use, and baseline function. RESULTS There were no significant changes over 12 months in motor function, pulmonary function, and muscle strength measures. There was evidence of motor function gain in ambulatory patients, especially in those children younger than 5 years. Scoliosis surgery during the observation period led to a subsequent decline in motor function. CONCLUSIONS Our results confirm previous clinical reports suggesting that SMA types 2 and 3 represent chronic phenotypes that have relatively stable clinical courses. We did not detect any measurable clinical disease progression in SMA types 2 and 3 over 12 months, suggesting that clinical trials will have to be designed to measure improvement rather than stabilization of disease progression.
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Affiliation(s)
- Petra Kaufmann
- Department of Neurology, Columbia University, 710 W 168th St, 2nd Floor, New York, NY 10032, USA
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129
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Ultrasound evaluation of fetal movements in pregnancies at risk for severe spinal muscular atrophy. Neuromuscul Disord 2011; 21:97-101. [DOI: 10.1016/j.nmd.2010.09.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 08/06/2010] [Accepted: 09/21/2010] [Indexed: 11/20/2022]
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130
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Zou T, Yang X, Pan D, Huang J, Sahin M, Zhou J. SMN deficiency reduces cellular ability to form stress granules, sensitizing cells to stress. Cell Mol Neurobiol 2011; 31:541-50. [PMID: 21234798 DOI: 10.1007/s10571-011-9647-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 01/04/2011] [Indexed: 10/18/2022]
Abstract
Spinal Muscular Atrophy (SMA) is a neurodegenerative disease that is caused by deletion of the SMN (Survival of Motor Neuron) gene. The SMN protein is essential for cell survival and co-localized with TIA-1/R and G3BP, two characteristic markers of stress granules (SGs). To further study the SMN function in stress granules and in response to stress, we generated stable cell lines with SMN knockdown. Our data indicate that suppression of SMN drastically reduces cellular ability to form stress granules in response to stress treatment. In addition, we show that SMN deficiency sensitizes cells to sodium arsenite and H(2)O(2), two well-known stress inducers, leading to cell death at a much lower concentration of inducers in SMN knockdown cells than in control cells. Interestingly, the cell death is correlated with formation of stress granules, suggesting that involvement of SMN in formation of stress granules may play an important role in cell survival. Furthermore, rescue of SGs formation by overexpression of G3BP can reverse the defective formation of stress granules and results in partial abrogation of cell death against SMN deficiency. We deduce that modulation of stress response may be useful for potential SMN treatment.
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Affiliation(s)
- Tie Zou
- Department of Medicine, Program in Neuroscience, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
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131
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Pearn J. Differentiating diseases: the centrum of differential diagnosis in the evolution of Oslerian medicine. Fetal Pediatr Pathol 2011; 30:1-15. [PMID: 21204660 DOI: 10.3109/15513815.2011.520252] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Pivotal to best-practice medicine in the 21st century is the concept of differential diagnosis. What the classification of disease, nosology, is to pathology, so differential diagnosis is to the management of the individual patient. Doctor-patient interaction comprises a sequence that is a six-link chain comprising history-taking; examination; differential diagnosis; tests and investigations; provisional or definitive diagnosis; and finally, management. This chain, however abridged in detail, determines every medical encounter with every patient. This paradigm has gradually evolved since the time of recorded medical history. It had developed its present form, if not its name, in Western medicine and its derivatives, with the publication of Osler's The Principles and Practice of Medicine, in 1892. The term "differential diagnosis" first appeared in the first edition of Herbert French's book, An Index of Differential Diagnosis of Main Symptoms, published in 1913.
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Affiliation(s)
- John Pearn
- The School of Medicine, University of Queensland, Department of Paediatrics & Child Health, Royal Children's Hospital, Brisbane, Queensland, Australia.
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132
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Strategy for treating motor neuron diseases using a fusion protein of botulinum toxin binding domain and streptavidin for viral vector access: work in progress. Toxins (Basel) 2010; 2:2872-89. [PMID: 22069580 PMCID: PMC3153189 DOI: 10.3390/toxins2122872] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 12/16/2010] [Accepted: 12/17/2010] [Indexed: 12/12/2022] Open
Abstract
Although advances in understanding of the pathogenesis of amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) have suggested attractive treatment strategies, delivery of agents to motor neurons embedded within the spinal cord is problematic. We have designed a strategy based on the specificity of botulinum toxin, to direct entry of viral vectors carrying candidate therapeutic genes into motor neurons. We have engineered and expressed fusion proteins consisting of the binding domain of botulinum toxin type A fused to streptavidin (SAv). This fusion protein will direct biotinylated viral vectors carrying therapeutic genes into motor nerve terminals where they can enter the acidified endosomal compartments, be released and undergo retrograde transport, to deliver the genes to motor neurons. Both ends of the fusion proteins are shown to be functionally intact. The binding domain end binds to mammalian nerve terminals at neuromuscular junctions, ganglioside GT1b (a target of botulinum toxin), and a variety of neuronal cells including primary chick embryo motor neurons, N2A neuroblastoma cells, NG108-15 cells, but not to NG CR72 cells, which lack complex gangliosides. The streptavidin end binds to biotin, and to a biotinylated Alexa 488 fluorescent tag. Further studies are in progress to evaluate the delivery of genes to motor neurons in vivo, by the use of biotinylated viral vectors.
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133
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Kim SJ, Kim EJ, Min BW, Ban JS, Lee SG, Lee JH. Epidural anesthesia for the patient with type IV spinal muscular atrophy -A case report-. Korean J Anesthesiol 2010; 59 Suppl:S65-8. [PMID: 21286464 PMCID: PMC3030060 DOI: 10.4097/kjae.2010.59.s.s65] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 06/06/2010] [Accepted: 07/01/2010] [Indexed: 11/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a rare lower motor neurone disease in which anesthetic management is often difficult as a result of muscle weakness, hypersensitivity to non-depolarizing neuromuscular blocking agent, and succinylcholine induced hyperkalemia. We describe a 50-year-old patient with type IV SMA for synovectomy. We decided to use an epidural technique to avoid muscle relaxants and tracheal intubation. After operation, there was no exacerbation of neurologic signs and symptoms.
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Affiliation(s)
- Seon Jin Kim
- Department of Anesthesiology and Pain Medicine, Daegu Fatima Hospital, Daegu, Korea
| | - Eun Ju Kim
- Department of Anesthesiology and Pain Medicine, Daegu Fatima Hospital, Daegu, Korea
| | - Byung Woo Min
- Department of Anesthesiology and Pain Medicine, Daegu Fatima Hospital, Daegu, Korea
| | - Jong Seouk Ban
- Department of Anesthesiology and Pain Medicine, Daegu Fatima Hospital, Daegu, Korea
| | - Sang Gon Lee
- Department of Anesthesiology and Pain Medicine, Daegu Fatima Hospital, Daegu, Korea
| | - Ji Hyang Lee
- Department of Anesthesiology and Pain Medicine, Daegu Fatima Hospital, Daegu, Korea
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134
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Boyer JG, Bowerman M, Kothary R. The many faces of SMN: deciphering the function critical to spinal muscular atrophy pathogenesis. FUTURE NEUROLOGY 2010. [DOI: 10.2217/fnl.10.57] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Spinal muscular atrophy (SMA) is the leading genetic cause of infant death, affecting 1 in 6000–10,000 live births. SMA is an autosomal recessive disorder characterized by the degeneration of α-motor neurons, and lower limb and proximal muscle weakness and wasting. SMA is the result of the deletion of or mutations in the survival motor neuron (SMN)1 gene. Currently, our understanding of how loss of the widely expressed SMN leads to the selective pathogenesis observed in SMA is limited. Here, we discuss the known nuclear and cytoplasmic functions of the SMN protein and how they relate to the SMA pathology reported in motor neurons, striated muscle and at neuromuscular junctions. While a vast amount of work in various cell and animal models has increased our knowledge of the many functions of the SMN protein, we have yet to come to a full understanding of which role(s) are central to SMA pathogenesis.
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Affiliation(s)
- Justin G Boyer
- Ottawa Hospital Research Institute, Regenerative Medicine Program, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, ON, Canada
| | - Mélissa Bowerman
- Ottawa Hospital Research Institute, Regenerative Medicine Program, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, ON, Canada
| | - Rashmi Kothary
- Department of Medicine, University of Ottawa, ON, Canada
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135
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Conserved genes act as modifiers of invertebrate SMN loss of function defects. PLoS Genet 2010; 6:e1001172. [PMID: 21124729 PMCID: PMC2965752 DOI: 10.1371/journal.pgen.1001172] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 09/21/2010] [Indexed: 01/27/2023] Open
Abstract
Spinal Muscular Atrophy (SMA) is caused by diminished function of the Survival of Motor Neuron (SMN) protein, but the molecular pathways critical for SMA pathology remain elusive. We have used genetic approaches in invertebrate models to identify conserved SMN loss of function modifier genes. Drosophila melanogaster and Caenorhabditis elegans each have a single gene encoding a protein orthologous to human SMN; diminished function of these invertebrate genes causes lethality and neuromuscular defects. To find genes that modulate SMN function defects across species, two approaches were used. First, a genome-wide RNAi screen for C. elegans SMN modifier genes was undertaken, yielding four genes. Second, we tested the conservation of modifier gene function across species; genes identified in one invertebrate model were tested for function in the other invertebrate model. Drosophila orthologs of two genes, which were identified originally in C. elegans, modified Drosophila SMN loss of function defects. C. elegans orthologs of twelve genes, which were originally identified in a previous Drosophila screen, modified C. elegans SMN loss of function defects. Bioinformatic analysis of the conserved, cross-species, modifier genes suggests that conserved cellular pathways, specifically endocytosis and mRNA regulation, act as critical genetic modifiers of SMN loss of function defects across species.
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136
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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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137
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Nlend Nlend R, Meyer K, Schümperli D. Repair of pre-mRNA splicing: prospects for a therapy for spinal muscular atrophy. RNA Biol 2010; 7:430-40. [PMID: 20523126 DOI: 10.4161/rna.7.4.12206] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Recent analyses of complete genomes have revealed that alternative splicing became more prevalent and important during eukaryotic evolution. Alternative splicing augments the protein repertoire--particularly that of the human genome--and plays an important role in the development and function of differentiated cell types. However, splicing is also extremely vulnerable, and defects in the proper recognition of splicing signals can give rise to a variety of diseases. In this review, we discuss splicing correction therapies, by using the inherited disease Spinal Muscular Atrophy (SMA) as an example. This lethal early childhood disorder is caused by deletions or other severe mutations of SMN1, a gene coding for the essential survival of motoneurons protein. A second gene copy present in humans and few non-human primates, SMN2, can only partly compensate for the defect because of a single nucleotide change in exon 7 that causes this exon to be skipped in the majority of mRNAs. Thus SMN2 is a prime therapeutic target for SMA. In recent years, several strategies based on small molecule drugs, antisense oligonucleotides or in vivo expressed RNAs have been developed that allow a correction of SMN2 splicing. For some of these, a therapeutic benefit has been demonstrated in mouse models for SMA. This means that clinical trials of such splicing therapies for SMA may become possible in the near future.
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138
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Sukenik-Halevy R, Pesso R, Garbian N, Magal N, Shohat M. Large-Scale Population Carrier Screening for Spinal Muscular Atrophy in Israel—Effect of Ethnicity on the False-Negative Rate. Genet Test Mol Biomarkers 2010; 14:319-24. [DOI: 10.1089/gtmb.2009.0089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Rivka Sukenik-Halevy
- Rabin Medical Center, Recanati Institute of Medical Genetics, Petach Tikva, Israel
| | - Rachel Pesso
- Genetic Institute of Maccabi Health Insurance, Mega-Lab, Rehovot, Israel
| | - Noa Garbian
- Genetic Institute of Maccabi Health Insurance, Mega-Lab, Rehovot, Israel
| | - Nurit Magal
- Rabin Medical Center, Recanati Institute of Medical Genetics, Petach Tikva, Israel
| | - Mordechai Shohat
- Rabin Medical Center, Recanati Institute of Medical Genetics, Petach Tikva, Israel
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139
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Burlet P, Gigarel N, Magen M, Drunat S, Benachi A, Hesters L, Munnich A, Bonnefont JP, Steffann J. Single-sperm analysis for recurrence risk assessment of spinal muscular atrophy. Eur J Hum Genet 2010; 18:505-8. [PMID: 19904299 PMCID: PMC2987255 DOI: 10.1038/ejhg.2009.198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 09/10/2009] [Accepted: 09/11/2009] [Indexed: 11/09/2022] Open
Abstract
With the detection of a homozygous deletion of the survival motor neuron 1 gene (SMN1), prenatal and preimplantation genetic diagnosis (PGD) for spinal muscular atrophy has become feasible and widely applied. The finding of a de novo rearrangement, resulting in the loss of the SMN1 gene, reduces the recurrence risk from 25% to a lower percentage, the residual risk arising from recurrent de novo mutation or germline mosaicism. In a couple referred to our PGD center because their first child was affected with SMA, the male partner was shown to carry two SMN1 copies. An analysis of the SMN1 gene and two flanking markers was performed on 12 single spermatozoa, to determine whether the father carried a CIS duplication of the SMN1 gene on one chromosome and was a carrier, or if the deletion has occurred de novo. We showed that all spermatozoa that were carriers of the 'at-risk haplotype' were deleted for the SMN1 gene, confirming the carrier status of the father. We provide an original application of single germ cell studies to recessive disorders using coamplification of the gene and its linked markers. This efficient and easy procedure might be useful to elucidate complex genetic situations when samples from other family members are not available.
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Affiliation(s)
- Philippe Burlet
- Unité INSERM U781 Institut de Recherche Necker-Enfants Malades, service de génétique médicale, Hôpital Necker-Enfants Malades (Assistance Publique-Hôpitaux de Paris), Université Paris-Descartes, 75743 Paris Cedex 15, France.
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140
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The splicing regulator Sam68 binds to a novel exonic splicing silencer and functions in SMN2 alternative splicing in spinal muscular atrophy. EMBO J 2010; 29:1235-47. [PMID: 20186123 DOI: 10.1038/emboj.2010.19] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 01/26/2010] [Indexed: 12/24/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by loss of motor neurons in patients with null mutations in the SMN1 gene. An almost identical SMN2 gene is unable to compensate for this deficiency because a single C-to-T transition at position +6 in exon-7 causes skipping of the exon by a mechanism not yet fully elucidated. We observed that the C-to-T transition in SMN2 creates a putative binding site for the RNA-binding protein Sam68. RNA pull-down assays and UV-crosslink experiments showed that Sam68 binds to this sequence. In vivo splicing assays showed that Sam68 triggers SMN2 exon-7 skipping. Moreover, mutations in the Sam68-binding site of SMN2 or in the RNA-binding domain of Sam68 completely abrogated its effect on exon-7 skipping. Retroviral infection of dominant-negative mutants of Sam68 that interfere with its RNA-binding activity, or with its binding to the splicing repressor hnRNP A1, enhanced exon-7 inclusion in endogenous SMN2 and rescued SMN protein expression in fibroblasts of SMA patients. Our results thus indicate that Sam68 is a novel crucial regulator of SMN2 splicing.
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141
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Wen HL, Lin YT, Ting CH, Lin-Chao S, Li H, Hsieh-Li HM. Stathmin, a microtubule-destabilizing protein, is dysregulated in spinal muscular atrophy. Hum Mol Genet 2010; 19:1766-78. [PMID: 20176735 DOI: 10.1093/hmg/ddq058] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spinal muscular atrophy (SMA), a motor neuron degeneration disorder, is caused by either mutations or deletions of survival motor neuron 1 (SMN1) gene which result in insufficient SMN protein. Here, we describe a potential link between stathmin and microtubule defects in SMA. Stathmin was identified by screening Smn-knockdown NSC34 cells through proteomics analysis. We found that stathmin was aberrantly upregulated in vitro and in vivo, leading to a decreased level of polymerized tubulin, which was correlated with disease severity. Reduced microtubule densities and beta(III)-tubulin levels in distal axons of affected SMA-like mice and an impaired microtubule network in Smn-deficient cells were observed, suggesting an involvement of stathmin in those microtubule defects. Furthermore, knockdown of stathmin restored the microtubule network defects of Smn-deficient cells, promoted axon outgrowth and reduced the defect in mitochondria transport in SMA-like motor neurons. We conclude that aberrant stathmin levels may play a detrimental role in SMA; this finding suggests a novel approach to treating SMA by enhancing microtubule stability.
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Affiliation(s)
- Hsin-Lan Wen
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
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142
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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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143
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Abstract
AbstractReduced levels of the survival of motor neurons protein (SMN), cause the inherited neuromuscular disorder, spinal muscular atrophy (SMA). The majority of therapeutic approaches to date have been focused on finding ways to increase expression of functional SMN protein, though stabilization of SMN protein may also be an important consideration. SMN interacts, directly or indirectly, stably or transiently, with a large number of other proteins, some of which contribute to SMN stability and may therefore be potential targets for SMA therapy. We recently characterized the nuclear SMN interactome using LC-MALDI-TOF/TOF analysis of anti-SMN pull-downs and identified myb-binding protein-1a (Mybbp1a) as a novel partner. In light of interest in cytoplasm-specific roles of the SMN complex, we have applied the same approach to characterise the cytoplasmic SMN interactome. We now show that SMN complexes from HeLa cytoplasmic extracts differ significantly from those found in nuclear extracts, with gemin5, importinbeta and annexin A2 easily detected only in the cytoplasmic extracts, whereas interaction of SMN with Mybbp1a appears to occur only in the nucleus. SMN is ubiquitinylated and we also found proteins of the ubiquitin-proteasome system associated with SMN in the cytoplasm.
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144
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Dickson A, Osman E, Lorson CL. A negatively acting bifunctional RNA increases survival motor neuron both in vitro and in vivo. Hum Gene Ther 2009. [PMID: 19848583 DOI: 10.1089/hgt.2008.067] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder and is the leading genetic cause of infant mortality. SMA is caused by the loss of survival motor neuron-1 (SMN1). In humans, a nearly identical copy gene is present called SMN2, but this gene cannot compensate for the loss of SMN1 because of a single silent nucleotide difference in SMN2 exon 7. This single-nucleotide difference attenuates an exonic splice enhancer, resulting in the production of an alternatively spliced isoform lacking exon 7, which is essential for protein function. SMN2, however, is a critical disease modifier and is an outstanding target for therapeutic intervention because all SMA patients retain SMN2 and SMN2 maintains the same coding sequence as SMN1. Therefore, compounds or molecules that increase SMN2 exon 7 inclusion hold great promise for SMA therapeutics. Bifunctional RNAs have been previously used to increase SMN protein levels and derive their name from the presence of two domains: an antisense RNA sequence specific to the target RNA and an untethered RNA segment that serves as a binding platform for splicing factors. This study was designed to develop negatively acting bifunctional RNAs that recruit hnRNPA1 to exon 8 and block the general splicing machinery from the exon 8. By blocking the downstream splice site, this could competitively favor the inclusion of SMN exon 7 and therefore increase full-length SMN production. Here we identify a bifunctional RNA that stimulated full-length SMN expression in a variety of cell-based assays including SMA patient fibroblasts. Importantly, this molecule was also able to induce SMN expression in a previously described mouse model of SMA and demonstrates a novel therapeutic approach for SMA as well as a variety of diseases caused by a defect in splicing.
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Affiliation(s)
- Alexa Dickson
- Department of Molecular Microbiology and Immunology, Life Sciences Center, University of Missouri-Columbia, Columbia, MO 65211, USA
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145
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Dickson A, Osman E, Lorson CL. A negatively acting bifunctional RNA increases survival motor neuron both in vitro and in vivo. Hum Gene Ther 2009; 19:1307-15. [PMID: 19848583 DOI: 10.1089/hum.2008.067] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder and is the leading genetic cause of infant mortality. SMA is caused by the loss of survival motor neuron-1 (SMN1). In humans, a nearly identical copy gene is present called SMN2, but this gene cannot compensate for the loss of SMN1 because of a single silent nucleotide difference in SMN2 exon 7. This single-nucleotide difference attenuates an exonic splice enhancer, resulting in the production of an alternatively spliced isoform lacking exon 7, which is essential for protein function. SMN2, however, is a critical disease modifier and is an outstanding target for therapeutic intervention because all SMA patients retain SMN2 and SMN2 maintains the same coding sequence as SMN1. Therefore, compounds or molecules that increase SMN2 exon 7 inclusion hold great promise for SMA therapeutics. Bifunctional RNAs have been previously used to increase SMN protein levels and derive their name from the presence of two domains: an antisense RNA sequence specific to the target RNA and an untethered RNA segment that serves as a binding platform for splicing factors. This study was designed to develop negatively acting bifunctional RNAs that recruit hnRNPA1 to exon 8 and block the general splicing machinery from the exon 8. By blocking the downstream splice site, this could competitively favor the inclusion of SMN exon 7 and therefore increase full-length SMN production. Here we identify a bifunctional RNA that stimulated full-length SMN expression in a variety of cell-based assays including SMA patient fibroblasts. Importantly, this molecule was also able to induce SMN expression in a previously described mouse model of SMA and demonstrates a novel therapeutic approach for SMA as well as a variety of diseases caused by a defect in splicing.
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Affiliation(s)
- Alexa Dickson
- Department of Molecular Microbiology and Immunology, Life Sciences Center, University of Missouri-Columbia, Columbia, MO 65211, USA
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146
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Bora-Tatar G, Dayangaç-Erden D, Demir AS, Dalkara S, Yelekçi K, Erdem-Yurter H. Molecular modifications on carboxylic acid derivatives as potent histone deacetylase inhibitors: Activity and docking studies. Bioorg Med Chem 2009; 17:5219-28. [PMID: 19520580 DOI: 10.1016/j.bmc.2009.05.042] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2008] [Revised: 04/01/2009] [Accepted: 05/17/2009] [Indexed: 11/26/2022]
Abstract
In the light of known HDAC inhibitors, 33 carboxylic acid derivatives were tested to understand the structural requirements for HDAC inhibition activity. Several modifications were applied to develop the structure-activity relationships of carboxylic acid HDAC inhibitors. HDAC inhibition activities were investigated in vitro by using HeLa nuclear extract in a fluorimetric assay. Molecular docking was also carried out for the human HDAC8 enzyme in order to predict inhibition activity and the 3D poses of inhibitor-enzyme complexes. Of these compounds, caffeic acid derivatives such as chlorogenic acid and curcumin were found to be highly potent compared to sodium butyrate, which is a well-known HDAC inhibitor.
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Affiliation(s)
- Gamze Bora-Tatar
- Hacettepe University, Faculty of Medicine, Department of Medical Biology, 06100 Sihhiye, Ankara, Turkey
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147
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Wu CY, Gómez-Curet I, Funanage VL, Scavina M, Wang W. Increased susceptibility of spinal muscular atrophy fibroblasts to camptothecin is p53-independent. BMC Cell Biol 2009; 10:40. [PMID: 19445707 PMCID: PMC2692972 DOI: 10.1186/1471-2121-10-40] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Accepted: 05/16/2009] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Deletion or mutation(s) of the survival motor neuron 1 (SMN1) gene causes spinal muscular atrophy (SMA). The SMN protein is known to play a role in RNA metabolism, neurite outgrowth, and cell survival. Yet, it remains unclear how SMN deficiency causes selective motor neuron death and muscle atrophy seen in SMA. Previously, we have shown that skin fibroblasts from SMA patients are more sensitive to the DNA topoisomerase I inhibitor camptothecin, supporting a role for SMN in cell survival. Here, we examine the potential mechanism of camptothecin sensitivity in SMA fibroblasts. RESULTS Camptothecin treatment reduced the DNA relaxation activity of DNA topoisomerase I in human fibroblasts. In contrast, kinase activity of DNA topoisomerase I was not affected by camptothecin, because levels of phosphorylated SR proteins were not decreased. Upon camptothecin treatment, levels of p53 were markedly increased. To determine if p53 plays a role in the increased sensitivity of SMA fibroblasts to camptothecin, we analyzed the sensitivity of SMA fibroblasts to another DNA topoisomerase I inhibitor, beta-lapachone. This compound is known to induce death via a p53-independent pathway in several cancer cell lines. We found that beta-lapachone did not induce p53 activation in human fibroblasts. In addition, SMA and control fibroblasts showed essentially identical sensitivity to this compound. By immunofluorescence staining, SMN and p53 co-localized in gems within the nucleus, and this co-localization was overall reduced in SMA fibroblasts. However, depletion of p53 by siRNA did not lessen the camptothecin sensitivity in SMA fibroblasts. CONCLUSION Even though p53 and SMN are associated, the increased sensitivity of SMA fibroblasts to camptothecin does not occur through a p53-dependent mechanism.
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Affiliation(s)
- Chia-Yen Wu
- Nemours Biomedical Research, Alfred I, duPont Hospital for Children, Wilmington, DE, USA.
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148
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Dayangaç-Erden D, Bora G, Ayhan P, Kocaefe Ç, Dalkara S, Yelekçi K, Demir AS, Erdem-Yurter H. Histone Deacetylase Inhibition Activity and Molecular Docking of (E )-Resveratrol: Its Therapeutic Potential in Spinal Muscular Atrophy. Chem Biol Drug Des 2009; 73:355-64. [DOI: 10.1111/j.1747-0285.2009.00781.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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149
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Delatycki MB. Population screening for reproductive risk for single gene disorders in Australia: now and the future. Twin Res Hum Genet 2009; 11:422-30. [PMID: 18637742 DOI: 10.1375/twin.11.4.422] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Abstract As the results of the Human Genome Project are realized, it has become technically possible to identify carriers of numerous autosomal and X-linked recessive disorders. Couples at risk of having a child with one of these conditions have a number of reproductive options to avoid having a child with the condition should they wish. In Australia the haemoglobinopathies are the only group of conditions for which population screening is widely offered and which is government funded. In some Australian states there are also population screening programs for cystic fibrosis and autosomal recessive conditions more common in Ashkenazi Jewish individuals which are generally offered on a user pays basis. It is predicted that as consumer demand increases and testing becomes cheaper, that many people planning or in the early stages of pregnancy will have carrier screening for multiple genetic conditions. This will have significant implications for genetic counseling, laboratory and prenatal testing resources. In addition such screening raises a number of ethical issues including the value of lives of those born with genetic conditions for which screening is available.
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Affiliation(s)
- Martin B Delatycki
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Australia.
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150
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Tazi J, Bakkour N, Stamm S. Alternative splicing and disease. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1792:14-26. [PMID: 18992329 PMCID: PMC5632948 DOI: 10.1016/j.bbadis.2008.09.017] [Citation(s) in RCA: 382] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 09/19/2008] [Accepted: 09/30/2008] [Indexed: 12/11/2022]
Abstract
Almost all protein-coding genes are spliced and their majority is alternatively spliced. Alternative splicing is a key element in eukaryotic gene expression that increases the coding capacity of the human genome and an increasing number of examples illustrates that the selection of wrong splice sites causes human disease. A fine-tuned balance of factors regulates splice site selection. Here, we discuss well-studied examples that show how a disturbance of this balance can cause human disease. The rapidly emerging knowledge of splicing regulation now allows the development of treatment options.
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Affiliation(s)
- Jamal Tazi
- University of Montpellier II, Institute of Molecular Genetics, Centre Nationale de Recherche Scientifique, 1919 Route de Mende, France
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