351
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Laustriat D, Gide J, Barrault L, Chautard E, Benoit C, Auboeuf D, Boland A, Battail C, Artiguenave F, Deleuze JF, Bénit P, Rustin P, Franc S, Charpentier G, Furling D, Bassez G, Nissan X, Martinat C, Peschanski M, Baghdoyan S. In Vitro and In Vivo Modulation of Alternative Splicing by the Biguanide Metformin. MOLECULAR THERAPY-NUCLEIC ACIDS 2015; 4:e262. [PMID: 26528939 PMCID: PMC4877444 DOI: 10.1038/mtna.2015.35] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 09/22/2015] [Indexed: 01/02/2023]
Abstract
Major physiological changes are governed by alternative splicing of RNA, and its misregulation may lead to specific diseases. With the use of a genome-wide approach, we show here that this splicing step can be modified by medication and demonstrate the effects of the biguanide metformin, on alternative splicing. The mechanism of action involves AMPK activation and downregulation of the RBM3 RNA-binding protein. The effects of metformin treatment were tested on myotonic dystrophy type I (DM1), a multisystemic disease considered to be a spliceopathy. We show that this drug promotes a corrective effect on several splicing defects associated with DM1 in derivatives of human embryonic stem cells carrying the causal mutation of DM1 as well as in primary myoblasts derived from patients. The biological effects of metformin were shown to be compatible with typical therapeutic dosages in a clinical investigation involving diabetic patients. The drug appears to act as a modifier of alternative splicing of a subset of genes and may therefore have novel therapeutic potential for many more diseases besides those directly linked to defective alternative splicing.
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Affiliation(s)
| | | | | | - Emilie Chautard
- Centre de Recherche en Cancérologie de Lyon, INSERM U1052, Centre Léon Bérard, Lyon, France.,Université Lyon 1, CNRS, UMR 5558, INRIA Bamboo, Villeurbanne, France
| | - Clara Benoit
- Centre de Recherche en Cancérologie de Lyon, INSERM U1052, Centre Léon Bérard, Lyon, France
| | - Didier Auboeuf
- Centre de Recherche en Cancérologie de Lyon, INSERM U1052, Centre Léon Bérard, Lyon, France
| | - Anne Boland
- Centre National de Génotypage, Institut de Génomique, CEA, Evry, France
| | | | | | | | - Paule Bénit
- INSERM UMR 1141, Hôpital Robert Debré, Paris, France.,Université Paris 7, Faculté de Médecine Denis Diderot, Paris, France
| | - Pierre Rustin
- INSERM UMR 1141, Hôpital Robert Debré, Paris, France.,Université Paris 7, Faculté de Médecine Denis Diderot, Paris, France
| | - Sylvia Franc
- Centre Hospitalier Sud Francilien and CERITD, Evry Cedex, France
| | | | - Denis Furling
- Sorbonne Universités, UPMC Université Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, Paris 75013, France
| | - Guillaume Bassez
- GH Henri Mondor, Inserm U955, Université Paris Est, Créteil, France
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352
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Lo Cicero A, Nissan X. Pluripotent stem cells to model Hutchinson-Gilford progeria syndrome (HGPS): Current trends and future perspectives for drug discovery. Ageing Res Rev 2015; 24:343-8. [PMID: 26474742 DOI: 10.1016/j.arr.2015.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/02/2015] [Accepted: 10/07/2015] [Indexed: 12/27/2022]
Abstract
Progeria, or Hutchinson-Gilford progeria syndrome (HGPS), is a rare, fatal genetic disease characterized by an appearance of accelerated aging in children. This syndrome is typically caused by mutations in codon 608 (p.G608G) of the LMNA, leading to the production of a mutated form of lamin A precursor called progerin. In HGPS, progerin accumulates in cells causing progressive molecular defects, including nuclear shape abnormalities, chromatin disorganization, damage to DNA and delays in cell proliferation. Here we report how, over the past five years, pluripotent stem cells have provided new insights into the study of HGPS and opened new original therapeutic perspectives to treat the disease.
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353
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Czech C, Tang W, Bugawan T, Mano C, Horn C, Iglesias VA, Fröhner S, Zaworski PG, Paushkin S, Chen K, Kremer T. Biomarker for Spinal Muscular Atrophy: Expression of SMN in Peripheral Blood of SMA Patients and Healthy Controls. PLoS One 2015; 10:e0139950. [PMID: 26468953 PMCID: PMC4607439 DOI: 10.1371/journal.pone.0139950] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/17/2015] [Indexed: 11/24/2022] Open
Abstract
Spinal muscular atrophy is caused by a functional deletion of SMN1 on Chromosome 5, which leads to a progressive loss of motor function in affected patients. SMA patients have at least one copy of a similar gene, SMN2, which produces functional SMN protein, although in reduced quantities. The severity of SMA is variable, partially due to differences in SMN2 copy numbers. Here, we report the results of a biomarker study characterizing SMA patients of varying disease severity. SMN copy number, mRNA and Protein levels in whole blood of patients were measured and compared against a cohort of healthy controls. The results show differential regulation of expression of SMN2 in peripheral blood between patients and healthy subjects.
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Affiliation(s)
- Christian Czech
- Roche Pharmaceutical Research & Early Development, Neuroscience, Roche Innovation Center Basel F. Hoffmann –La Roche, Basel
- * E-mail:
| | - Wakana Tang
- Research - Genomics & Oncology, Roche Molecular Systems, Inc., Pleasanton, CA, United States of America
| | - Teodorica Bugawan
- Research - Genomics & Oncology, Roche Molecular Systems, Inc., Pleasanton, CA, United States of America
| | - Calvin Mano
- Research - Genomics & Oncology, Roche Molecular Systems, Inc., Pleasanton, CA, United States of America
| | - Carsten Horn
- Roche Pharmaceutical Research & Early Development, Neuroscience, Roche Innovation Center Basel F. Hoffmann –La Roche, Basel
| | - Victor Alejandro Iglesias
- Roche Pharmaceutical Research & Early Development, Neuroscience, Roche Innovation Center Basel F. Hoffmann –La Roche, Basel
| | | | | | | | - Karen Chen
- SMA Foundation, New York, NY, United States of America
| | - Thomas Kremer
- Roche Pharmaceutical Research & Early Development, Neuroscience, Roche Innovation Center Basel F. Hoffmann –La Roche, Basel
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354
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Systemic, postsymptomatic antisense oligonucleotide rescues motor unit maturation delay in a new mouse model for type II/III spinal muscular atrophy. Proc Natl Acad Sci U S A 2015; 112:E5863-72. [PMID: 26460027 DOI: 10.1073/pnas.1509758112] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Clinical presentation of spinal muscular atrophy (SMA) ranges from a neonatal-onset, very severe disease to an adult-onset, milder form. SMA is caused by the mutation of the Survival Motor Neuron 1 (SMN1) gene, and prognosis inversely correlates with the number of copies of the SMN2 gene, a human-specific homolog of SMN1. Despite progress in identifying potential therapies for the treatment of SMA, many questions remain including how late after onset treatments can still be effective and what the target tissues should be. These questions can be addressed in part with preclinical animal models; however, modeling the array of SMA severities in the mouse, which lacks SMN2, has proven challenging. We created a new mouse model for the intermediate forms of SMA presenting with a delay in neuromuscular junction maturation and a decrease in the number of functional motor units, all relevant to the clinical presentation of the disease. Using this new model, in combination with clinical electrophysiology methods, we found that administering systemically SMN-restoring antisense oligonucleotides (ASOs) at the age of onset can extend survival and rescue the neurological phenotypes. Furthermore, these effects were also achieved by administration of the ASOs late after onset, independent of the restoration of SMN in the spinal cord. Thus, by adding to the limited repertoire of existing mouse models for type II/III SMA, we demonstrate that ASO therapy can be effective even when administered after onset of the neurological symptoms, in young adult mice, and without being delivered into the central nervous system.
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355
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Oltean S. Modulators of alternative splicing as novel therapeutics in cancer. World J Clin Oncol 2015; 6:92-95. [PMID: 26468443 PMCID: PMC4600196 DOI: 10.5306/wjco.v6.i5.92] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/08/2015] [Accepted: 08/03/2015] [Indexed: 02/06/2023] Open
Abstract
Alternative splicing (AS), the process of removing introns from pre-mRNA and re-arrangement of exons to give several types of mature transcripts, has been described more than 40 years ago. However, until recently, it has not been clear how extensive it is. Genome-wide studies have now conclusively shown that more than 90% of genes are alternatively spliced in humans. This makes AS one of the main drivers of proteomic diversity and, consequently, determinant of cellular function repertoire. Unsurprisingly, given its extent, numerous splice isoforms have been described to be associated with several diseases including cancer. Many of them have antagonistic functions, e.g., pro- and anti-angiogenic or pro- and anti-apoptotic. Additionally several splice factors have been recently described to have oncogene or tumour suppressors activities, like SF3B1 which is frequently mutated in myelodysplastic syndromes. Beside the implications for cancer pathogenesis, de-regulated AS is recognized as one of the novel areas of cell biology where therapeutic manipulations may be designed. This editorial discusses the possibilities of manipulation of AS for therapeutic benefit in cancer. Approaches involving the use of oligonucleotides as well as small molecule splicing modulators are presented as well as thoughts on how specificity might be accomplished in splicing therapeutics.
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356
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McGovern VL, Iyer CC, Arnold WD, Gombash SE, Zaworski PG, Blatnik AJ, Foust KD, Burghes AHM. SMN expression is required in motor neurons to rescue electrophysiological deficits in the SMNΔ7 mouse model of SMA. Hum Mol Genet 2015; 24:5524-41. [PMID: 26206889 PMCID: PMC4572068 DOI: 10.1093/hmg/ddv283] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/10/2015] [Accepted: 07/13/2015] [Indexed: 12/23/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA) is the most frequent cause of hereditary infant mortality. SMA is an autosomal recessive neuromuscular disorder that results from the loss of the Survival Motor Neuron 1 (SMN1) gene and retention of the SMN2 gene. The SMN2 gene produces an insufficient amount of full-length SMN protein that results in loss of motor neurons in the spinal cord and subsequent muscle paralysis. Previously we have shown that overexpression of human SMN in neurons in the SMA mouse ameliorates the SMA phenotype while overexpression of human SMN in skeletal muscle had no effect. Using Cre recombinase, here we show that either deletion or replacement of Smn in motor neurons (ChAT-Cre) significantly alters the functional output of the motor unit as measured with compound muscle action potential and motor unit number estimation. However ChAT-Cre alone did not alter the survival of SMA mice by replacement and did not appreciably affect survival when used to deplete SMN. However replacement of Smn in both neurons and glia in addition to the motor neuron (Nestin-Cre and ChAT-Cre) resulted in the greatest improvement in survival of the mouse and in some instances complete rescue was achieved. These findings demonstrate that high expression of SMN in the motor neuron is both necessary and sufficient for proper function of the motor unit. Furthermore, in the mouse high expression of SMN in neurons and glia, in addition to motor neurons, has a major impact on survival.
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Affiliation(s)
- Vicki L McGovern
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Chitra C Iyer
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - W David Arnold
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA Department of Physical Medicine and Rehabilitation, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA and
| | - Sara E Gombash
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA and
| | | | - Anton J Blatnik
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Kevin D Foust
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA and
| | - Arthur H M Burghes
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
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357
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Sakuma M, Iida K, Hagiwara M. Deciphering targeting rules of splicing modulator compounds: case of TG003. BMC Mol Biol 2015; 16:16. [PMID: 26400733 PMCID: PMC4580995 DOI: 10.1186/s12867-015-0044-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/11/2015] [Indexed: 11/10/2022] Open
Abstract
Background Recent advances in the development of small chemical compounds that can modulate RNA splicing brought excitement to the field of splicing-targeting therapy. Splicing-targeting therapy tries to ameliorate the disease by altering the exon combination of transcripts to reduce the undesired effect of genetic mutations. However, the knowledge and tools to understand factors contributing to splicing modulator compound sensitivity have been lacking. Our goal was to establish a method to characterize sequence features found in compound sensitive exons. Results Here we developed a comparative transcriptomic approach to explore features that make an exon sensitive to a chemical compound. In this study, we chose TG003, a potential drug for Duchenne muscular dystrophy, and performed RNA-sequencing on samples from human and mouse skeletal muscle cells, with and without TG003 treatments. We compared TG003 responsiveness between homologous exon pairs and identified 21 pairs in which human exons were skip-enhanced but not mouse exons. We compared the sequence features; splice site scores, number of splicing factor binding sites, and properties of branch sequence and polypyrimidine tracts, and found that polypyrimidine tracts were stronger (longer stretches and richer content of consecutive polypyrimidine) in the mouse TG003 insensitive exons. We also compared the features between TG003 skip-enhanced and insensitive exons within the species, and discovered that human TG003 skip-enhanced exons were shorter and had less splicing factor binding sites than the group of human TG003 insensitive exons. Mouse insensitive exons homologous to human TG003 skip-enhanced exons shared these properties. Our results suggested that these features are prerequisites for TG003 skip-enhanced exons and weak polypyrimidine tracts are defining features, which were supported by a decision tree analysis on all cassette exons in human. Conclusions In this study we established a comparative transcriptomic approach, which shed lights on how small chemical compounds modulate RNA splicing. The results described here was the first attempt to decipher the targeting rules of a splicing modulator compound. We expect that this approach would contribute to the precise understanding of the mechanism of TG003-induced splicing modulation, expand target diseases of splicing modulators in general, as well as the development of new splicing modulators. Electronic supplementary material The online version of this article (doi:10.1186/s12867-015-0044-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maki Sakuma
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Konoecho Yoshida Sakyo-ku, Kyoto, 606-8501, Japan.
| | - Kei Iida
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Konoecho Yoshida Sakyo-ku, Kyoto, 606-8501, Japan.
| | - Masatoshi Hagiwara
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Konoecho Yoshida Sakyo-ku, Kyoto, 606-8501, Japan. .,Medical Research Support Center, Kyoto University Graduate School of Medicine, Konoecho Yoshida Sakyo-ku, Kyoto, 606-8501, Japan.
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358
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Mechanistic principles of antisense targets for the treatment of spinal muscular atrophy. Future Med Chem 2015; 7:1793-808. [PMID: 26381381 DOI: 10.4155/fmc.15.101] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a major neurodegenerative disorder of children and infants. SMA is primarily caused by low levels of SMN protein owing to deletions or mutations of the SMN1 gene. SMN2, a nearly identical copy of SMN1, fails to compensate for the loss of the production of the functional SMN protein due to predominant skipping of exon 7. Several compounds, including antisense oligonucleotides (ASOs) that elevate SMN protein from SMN2 hold the promise for treatment. An ASO-based drug currently under Phase III clinical trial employs intronic splicing silencer N1 (ISS-N1) as its target. Cumulative studies on ISS-N1 reveal a wealth of information with significance to the overall therapeutic development for SMA. Here, the authors summarize the mechanistic principles behind various antisense targets currently available for SMA therapy.
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359
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Swiderski K, Lynch GS. Therapeutic potential of orphan drugs for the rare skeletal muscle diseases. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1085858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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360
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Abstract
Motor neuron diseases are neurological disorders characterized primarily by the degeneration of spinal motor neurons, skeletal muscle atrophy, and debilitating and often fatal motor dysfunction. Spinal muscular atrophy (SMA) is an autosomal-recessive motor neuron disease of high incidence and severity and the most common genetic cause of infant mortality. SMA is caused by homozygous mutations in the survival motor neuron 1 (SMN1) gene and retention of at least one copy of the hypomorphic gene paralog SMN2. Early studies established a loss-of-function disease mechanism involving ubiquitous SMN deficiency and suggested SMN upregulation as a possible therapeutic approach. In recent years, greater knowledge of the central role of SMN in RNA processing combined with deep characterization of animal models of SMA has significantly advanced our understanding of the cellular and molecular basis of the disease. SMA is emerging as an RNA disease not limited to motor neurons, but one that involves dysfunction of motor circuits that comprise multiple neuronal subpopulations and possibly other cell types. Advances in SMA research have also led to the development of several potential therapeutics shown to be effective in animal models of SMA that are now in clinical trials. These agents offer unprecedented promise for the treatment of this still incurable neurodegenerative disease.
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361
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Iyer CC, McGovern VL, Murray JD, Gombash SE, Zaworski PG, Foust KD, Janssen PML, Burghes AHM. Low levels of Survival Motor Neuron protein are sufficient for normal muscle function in the SMNΔ7 mouse model of SMA. Hum Mol Genet 2015; 24:6160-73. [PMID: 26276812 DOI: 10.1093/hmg/ddv332] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 08/10/2015] [Indexed: 11/14/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is an autosomal recessive disorder characterized by loss of lower motor neurons. SMA is caused by deletion or mutation of the Survival Motor Neuron 1 (SMN1) gene and retention of the SMN2 gene. The loss of SMN1 results in reduced levels of the SMN protein. SMN levels appear to be particularly important in motor neurons; however SMN levels above that produced by two copies of SMN2 have been suggested to be important in muscle. Studying the spatial requirement of SMN is important in both understanding how SMN deficiency causes SMA and in the development of effective therapies. Using Myf5-Cre, a muscle-specific Cre driver, and the Cre-loxP recombination system, we deleted mouse Smn in the muscle of mice with SMN2 and SMNΔ7 transgenes in the background, thus providing low level of SMN in the muscle. As a reciprocal experiment, we restored normal levels of SMN in the muscle with low SMN levels in all other tissues. We observed that decreasing SMN in the muscle has no phenotypic effect. This was corroborated by muscle physiology studies with twitch force, tetanic and eccentric contraction all being normal. In addition, electrocardiogram and muscle fiber size distribution were also normal. Replacement of Smn in muscle did not rescue SMA mice. Thus the muscle does not appear to require high levels of SMN above what is produced by two copies of SMN2 (and SMNΔ7).
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Affiliation(s)
| | | | | | | | | | | | | | - Arthur H M Burghes
- Department of Molecular and Cellular Biochemistry, Department of Neurology, Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA and
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362
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Takata KI, Tomida J, Reh S, Swanhart LM, Takata M, Hukriede NA, Wood RD. Conserved overlapping gene arrangement, restricted expression, and biochemical activities of DNA polymerase ν (POLN). J Biol Chem 2015; 290:24278-93. [PMID: 26269593 PMCID: PMC4591814 DOI: 10.1074/jbc.m115.677419] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Indexed: 12/12/2022] Open
Abstract
DNA polymerase ν (POLN) is one of 16 DNA polymerases encoded in vertebrate genomes. It is important to determine its gene expression patterns, biological roles, and biochemical activities. By quantitative analysis of mRNA expression, we found that POLN from the zebrafish Danio rerio is expressed predominantly in testis. POLN is not detectably expressed in zebrafish embryos or in mouse embryonic stem cells. Consistent with this, injection of POLN-specific morpholino antisense oligonucleotides did not interfere with zebrafish embryonic development. Analysis of transcripts revealed that vertebrate POLN has an unusual gene expression arrangement, sharing a first exon with HAUS3, the gene encoding augmin-like complex subunit 3. HAUS3 is broadly expressed in embryonic and adult tissues, in contrast to POLN. Differential expression of POLN and HAUS3 appears to arise by alternate splicing of transcripts in mammalian cells and zebrafish. When POLN was ectopically overexpressed in human cells, it specifically coimmunoprecipitated with the homologous recombination factors BRCA1 and FANCJ, but not with previously suggested interaction partners (HELQ and members of the Fanconi anemia core complex). Purified zebrafish POLN protein is capable of thymine glycol bypass and strand displacement, with activity dependent on a basic amino acid residue known to stabilize the primer-template. These properties are conserved with the human enzyme. Although the physiological function of pol ν remains to be clarified, this study uncovers distinctive aspects of its expression control and evolutionarily conserved properties of this DNA polymerase.
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Affiliation(s)
- Kei-Ichi Takata
- From the Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas 78957, the University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030,
| | - Junya Tomida
- From the Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas 78957, the University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
| | - Shelley Reh
- From the Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas 78957, the University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
| | - Lisa M Swanhart
- the Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, and
| | - Minoru Takata
- the Laboratory of DNA Damage Signaling, Department of Late Effects Studies, Radiation Biology Center, Kyoto University, Kyoto 606-8501, Japan
| | - Neil A Hukriede
- the Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, and
| | - Richard D Wood
- From the Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas 78957, the University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
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363
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Farooq F, MacKenzie AE. Current and emerging treatment options for spinal muscular atrophy. Degener Neurol Neuromuscul Dis 2015; 5:75-81. [PMID: 32669914 PMCID: PMC7337203 DOI: 10.2147/dnnd.s48420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/23/2015] [Indexed: 11/23/2022] Open
Abstract
Spinal muscular atrophy is one of the most common inherited neuromuscular conditions; our understanding of the genetic pathology and translational research coming from this insight has made significant progress over the past decade. This short review provides the background of the disease along with the bench to bedside progress of some promising treatment options to develop better understanding of the present state of the disease.
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Affiliation(s)
- Faraz Farooq
- Science Education Division, Emirates College for Advanced Education, Abu Dhabi, United Arab Emirates.,Children's Hospital of Eastern Ontario (CHEO) Research Institute, Ottawa, ON, Canada
| | - Alex E MacKenzie
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Ottawa, ON, Canada.,University of Ottawa, Ottawa, ON, Canada
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364
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Wertz MH, Sahin M. Developing therapies for spinal muscular atrophy. Ann N Y Acad Sci 2015; 1366:5-19. [PMID: 26173388 DOI: 10.1111/nyas.12813] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 05/05/2015] [Accepted: 05/18/2015] [Indexed: 12/17/2022]
Abstract
Spinal muscular atrophy is an autosomal-recessive pediatric neurodegenerative disease characterized by loss of spinal motor neurons. It is caused by mutation in the gene survival of motor neuron 1 (SMN1), leading to loss of function of the full-length SMN protein. SMN has a number of functions in neurons, including RNA splicing and snRNP biogenesis in the nucleus, and RNA trafficking in neurites. The expression level of full-length SMN protein from the SMN2 locus modifies disease severity. Increasing full-length SMN protein by a small amount can lead to significant improvements in the neurological phenotype. Currently available interventions for spinal muscular atrophy patients are physical therapy and orthopedic, nutritional, and pulmonary interventions; these are palliative or supportive measures and do not address the etiology of the disease. In the past decade, there has been a push for developing therapeutics to improve motor phenotypes and increase life span of spinal muscular atrophy patients. These therapies are aimed primarily at restoration of full-length SMN protein levels, but other neuroprotective treatments have been investigated as well. Here, we discuss recent advances in basic and clinical studies toward finding safe and effective treatments of spinal muscular atrophy using gene therapy, antisense oligonucleotides, and other small molecule modulators of SMN expression.
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Affiliation(s)
- Mary H Wertz
- The F.M. Kirby Neurobiology Center, Department of Neurology, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts
| | - Mustafa Sahin
- The F.M. Kirby Neurobiology Center, Department of Neurology, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts
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365
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Wirth B, Barkats M, Martinat C, Sendtner M, Gillingwater TH. Moving towards treatments for spinal muscular atrophy: hopes and limits. Expert Opin Emerg Drugs 2015; 20:353-6. [PMID: 25920617 DOI: 10.1517/14728214.2015.1041375] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Spinal muscular atrophy (SMA), one of the most frequent and devastating genetic disorders causing neuromuscular degeneration, has reached the forefront of clinical translation. The quite unique genetic situation of SMA patients, who lack functional SMN1 but carry the misspliced SMN2 copy gene, creates the possibility of correcting SMN2 splicing by antisense oligonucleotides or drugs. Both strategies showed impressive results in pre-clinical trials and are now in Phase II-III clinical trials. SMN gene therapy approaches using AAV9-SMN vectors are also highly promising and have entered a Phase I clinical trial. However, careful analysis of SMA animal models and patients has revealed some limitations that need to be taken very seriously, including: i) a limited time-window for successful therapy delivery, making neonatal screening of SMA mandatory; ii) multi-organ impairment, requiring systemic delivery of therapies; and iii) a potential need for combined therapies that both increase SMN levels and target pathways that preserve/rescue motor neuron function over the lifespan. Meeting these challenges will likely be crucial to cure SMA, instead of only ameliorating symptoms, particularly in its most severe form. This review discusses therapies currently in clinical trials, the hopes for SMA therapy, and the potential limitations of these new approaches.
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Affiliation(s)
- Brunhilde Wirth
- a 1 University of Cologne, Institute of Human Genetics, Institute for Genetics, Center for Molecular Medicine Cologne , Kerpener Street 34, 50931 Cologne, Germany +49 221 478 86464 ; +49 221 478 86465 ;
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Palacino J, Swalley SE, Song C, Cheung AK, Shu L, Zhang X, Van Hoosear M, Shin Y, Chin DN, Keller CG, Beibel M, Renaud NA, Smith TM, Salcius M, Shi X, Hild M, Servais R, Jain M, Deng L, Bullock C, McLellan M, Schuierer S, Murphy L, Blommers MJJ, Blaustein C, Berenshteyn F, Lacoste A, Thomas JR, Roma G, Michaud GA, Tseng BS, Porter JA, Myer VE, Tallarico JA, Hamann LG, Curtis D, Fishman MC, Dietrich WF, Dales NA, Sivasankaran R. SMN2 splice modulators enhance U1-pre-mRNA association and rescue SMA mice. Nat Chem Biol 2015; 11:511-7. [PMID: 26030728 DOI: 10.1038/nchembio.1837] [Citation(s) in RCA: 322] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 05/06/2015] [Indexed: 12/17/2022]
Abstract
Spinal muscular atrophy (SMA), which results from the loss of expression of the survival of motor neuron-1 (SMN1) gene, represents the most common genetic cause of pediatric mortality. A duplicate copy (SMN2) is inefficiently spliced, producing a truncated and unstable protein. We describe herein a potent, orally active, small-molecule enhancer of SMN2 splicing that elevates full-length SMN protein and extends survival in a severe SMA mouse model. We demonstrate that the molecular mechanism of action is via stabilization of the transient double-strand RNA structure formed by the SMN2 pre-mRNA and U1 small nuclear ribonucleic protein (snRNP) complex. The binding affinity of U1 snRNP to the 5' splice site is increased in a sequence-selective manner, discrete from constitutive recognition. This new mechanism demonstrates the feasibility of small molecule-mediated, sequence-selective splice modulation and the potential for leveraging this strategy in other splicing diseases.
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Affiliation(s)
- James Palacino
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Susanne E Swalley
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Cheng Song
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Atwood K Cheung
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Lei Shu
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Xiaolu Zhang
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Mailin Van Hoosear
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Youngah Shin
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Donovan N Chin
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | | | - Martin Beibel
- Novartis Institutes for Biomedical Research, Forum 1, Basel, Switzerland
| | - Nicole A Renaud
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Thomas M Smith
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Michael Salcius
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Xiaoying Shi
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Marc Hild
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Rebecca Servais
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Monish Jain
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Lin Deng
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Caroline Bullock
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Michael McLellan
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Sven Schuierer
- Novartis Institutes for Biomedical Research, Forum 1, Basel, Switzerland
| | - Leo Murphy
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | | | - Cecile Blaustein
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Frada Berenshteyn
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Arnaud Lacoste
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Jason R Thomas
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Guglielmo Roma
- Novartis Institutes for Biomedical Research, Forum 1, Basel, Switzerland
| | - Gregory A Michaud
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Brian S Tseng
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Jeffery A Porter
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Vic E Myer
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - John A Tallarico
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Lawrence G Hamann
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Daniel Curtis
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Mark C Fishman
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - William F Dietrich
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
| | - Natalie A Dales
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, USA
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368
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Harris AW, Butchbach MER. The effect of the DcpS inhibitor D156844 on the protective action of follistatin in mice with spinal muscular atrophy. Neuromuscul Disord 2015; 25:699-705. [PMID: 26055638 DOI: 10.1016/j.nmd.2015.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/11/2015] [Accepted: 05/20/2015] [Indexed: 01/27/2023]
Abstract
Spinal muscular atrophy (SMA), a leading genetic cause of pediatric death in the world, is an early-onset disease affecting the motor neurons in the anterior horn of the spinal cord. This degeneration of motor neurons leads to loss of muscle function. At the molecular level, SMA results from the loss of or mutation in the survival motor neuron 1 (SMN1) gene. The number of copies of the nearly duplicated gene SMN2 modulates the disease severity in humans as well as in transgenic mouse models for SMA. Most preclinical therapeutic trials focus on identifying ways to increase SMN2 expression and to alter its splicing. Other therapeutic strategies have investigated compounds which protect affected motor neurons and their target muscles in an SMN-independent manner. In the present study, the effect of a combination regimen of the SMN2 inducer D156844 and the protectant follistatin on the disease progression and survival was measured in the SMNΔ7 SMA mouse model. The D156844/follistatin combination treatment improved the survival of, delayed the end stage of disease in and ameliorated the growth rate of SMNΔ7 SMA mice better than follistatin treatment alone. The D156844/follistatin combination treatment, however, did not provide additional benefit over D156844 alone with respect to survival and disease end stage even though it provided some additional therapeutic benefit over D156844 alone with respect to motor phenotype.
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Affiliation(s)
- Ashlee W Harris
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA
| | - Matthew E R Butchbach
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA; Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA; Department of Pediatrics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Department of Molecular and Cellular Biochemistry, College of Medicine, The Ohio State University, Columbus, Ohio, USA.
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369
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Faravelli I, Nizzardo M, Comi GP, Corti S. Spinal muscular atrophy--recent therapeutic advances for an old challenge. Nat Rev Neurol 2015; 11:351-9. [PMID: 25986506 DOI: 10.1038/nrneurol.2015.77] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the past decade, improved understanding of spinal muscular atrophy (SMA) aetiopathogenesis has brought us to a historical turning point: we are at the verge of development of disease-modifying treatments for this hitherto incurable disease. The increasingly precise delineation of molecular targets within the survival of motor neuron (SMN) gene locus has led to the development of promising therapeutic strategies. These novel avenues in treatment for SMA include gene therapy, molecular therapy with antisense oligonucleotides, and small molecules that aim to increase expression of SMN protein. Stem cell studies of SMA have provided an in vitro model for SMA, and stem cell transplantation could be used as a complementary strategy with a potential to treat the symptomatic phases of the disease. Here, we provide an overview of established data and novel insights into SMA pathogenesis, including discussion of the crucial function of the SMN protein. Preclinical evidence and recent advances from ongoing clinical trials are thoroughly reviewed. The final remarks are dedicated to future clinical perspectives in this rapidly evolving field, with a broad discussion on the comparison between the outlined therapeutic approaches and the remaining open questions.
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Affiliation(s)
- Irene Faravelli
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, Neurology Unit, IRCCS Foundation Ca'Granda Ospedale Maggiore Policlinico, University of Milan, via Francesco Sforza 35, 20122 Milan, Italy
| | - Monica Nizzardo
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, Neurology Unit, IRCCS Foundation Ca'Granda Ospedale Maggiore Policlinico, University of Milan, via Francesco Sforza 35, 20122 Milan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, Neurology Unit, IRCCS Foundation Ca'Granda Ospedale Maggiore Policlinico, University of Milan, via Francesco Sforza 35, 20122 Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, Neurology Unit, IRCCS Foundation Ca'Granda Ospedale Maggiore Policlinico, University of Milan, via Francesco Sforza 35, 20122 Milan, Italy
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370
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Khurana V, Tardiff DF, Chung CY, Lindquist S. Toward stem cell-based phenotypic screens for neurodegenerative diseases. Nat Rev Neurol 2015; 11:339-50. [PMID: 25986505 DOI: 10.1038/nrneurol.2015.79] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In the absence of a single preventive or disease-modifying strategy, neurodegenerative diseases are becoming increasingly prevalent in our ageing population. The mechanisms underlying neurodegeneration are poorly understood, making the target-based drug screening strategies that are employed by the pharmaceutical industry fraught with difficulty. However, phenotypic screening in neurons and glia derived from patients is now conceivable through unprecedented developments in reprogramming, transdifferentiation, and genome editing. We outline progress in this nascent field, but also consider the formidable hurdles to identifying robust, disease-relevant and screenable cellular phenotypes in patient-derived cells. We illustrate how analysis in the simple baker's yeast cell Saccharaomyces cerevisiae is driving discovery in patient-derived neurons, and how approaches in this model organism can establish a paradigm to guide the development of stem cell-based phenotypic screens.
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Affiliation(s)
- Vikram Khurana
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, WACC-835, 15 Parkman Street, Boston, MA 02114, USA
| | - Daniel F Tardiff
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
| | - Chee Yeun Chung
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
| | - Susan Lindquist
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
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371
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Kaczmarek A, Schneider S, Wirth B, Riessland M. Investigational therapies for the treatment of spinal muscular atrophy. Expert Opin Investig Drugs 2015; 24:867-81. [DOI: 10.1517/13543784.2015.1038341] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Anna Kaczmarek
- 1University of Cologne, Institute of Human Genetics, Kerpener Str. 34, Cologne 50931, Germany ;
- 2University of Cologne, Institute for Genetics, Cologne, Germany
- 3University of Cologne, Center for Molecular Medicine Cologne, Cologne, Germany
| | - Svenja Schneider
- 1University of Cologne, Institute of Human Genetics, Kerpener Str. 34, Cologne 50931, Germany ;
- 2University of Cologne, Institute for Genetics, Cologne, Germany
- 3University of Cologne, Center for Molecular Medicine Cologne, Cologne, Germany
| | - Brunhilde Wirth
- 1University of Cologne, Institute of Human Genetics, Kerpener Str. 34, Cologne 50931, Germany ;
- 2University of Cologne, Institute for Genetics, Cologne, Germany
- 3University of Cologne, Center for Molecular Medicine Cologne, Cologne, Germany
| | - Markus Riessland
- 1University of Cologne, Institute of Human Genetics, Kerpener Str. 34, Cologne 50931, Germany ;
- 2University of Cologne, Institute for Genetics, Cologne, Germany
- 3University of Cologne, Center for Molecular Medicine Cologne, Cologne, Germany
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372
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Ohe K, Hagiwara M. Modulation of alternative splicing with chemical compounds in new therapeutics for human diseases. ACS Chem Biol 2015; 10:914-24. [PMID: 25560473 DOI: 10.1021/cb500697f] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alternative splicing is a critical step where a limited number of human genes generate a complex and diverse proteome. Various diseases, including inherited diseases with abnormalities in the "genome code," have been found to result in an aberrant mis-spliced "transcript code" with correlation to the resulting phenotype. Chemical compound-based and nucleic acid-based strategies are trying to target this mis-spliced "transcript code". We will briefly mention about how to obtain splicing-modifying-compounds by high-throughput screening and overview of what is known about compounds that modify splicing pathways. The main focus will be on RNA-binding protein kinase inhibitors. In the main text, we will refer to diseases where splicing-modifying-compounds have been intensively investigated, with comparison to nucleic acid-based strategies. The information on their involvement in mis-splicing as well as nonsplicing events will be helpful in finding better compounds with less off-target effects for future implications in mis-splicing therapy.
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Affiliation(s)
- Kenji Ohe
- †Department of Anatomy and Developmental Biology and ‡Training Program of Leaders for Integrated Medical System for Fruitful Healthy-Longevity Society (LIMS), Kyoto University Graduate School of Medicine, Kyoto 606-8315, Japan
| | - Masatoshi Hagiwara
- †Department of Anatomy and Developmental Biology and ‡Training Program of Leaders for Integrated Medical System for Fruitful Healthy-Longevity Society (LIMS), Kyoto University Graduate School of Medicine, Kyoto 606-8315, Japan
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373
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Gombash SE, Cowley CJ, Fitzgerald JA, Iyer CC, Fried D, McGovern VL, Williams KC, Burghes AHM, Christofi FL, Gulbransen BD, Foust KD. SMN deficiency disrupts gastrointestinal and enteric nervous system function in mice. Hum Mol Genet 2015; 24:3847-60. [PMID: 25859009 DOI: 10.1093/hmg/ddv127] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/07/2015] [Indexed: 12/19/2022] Open
Abstract
The 2007 Consensus Statement for Standard of Care in Spinal Muscular Atrophy (SMA) notes that patients suffer from gastroesophageal reflux, constipation and delayed gastric emptying. We used two mouse models of SMA to determine whether functional GI complications are a direct consequence of or are secondary to survival motor neuron (Smn) deficiency. Our results show that despite normal activity levels and food and water intake, Smn deficiency caused constipation, delayed gastric emptying, slow intestinal transit and reduced colonic motility without gross anatomical or histopathological abnormalities. These changes indicate alterations to the intrinsic neural control of gut functions mediated by the enteric nervous system (ENS). Indeed, Smn deficiency led to disrupted ENS signaling to the smooth muscle of the colon but did not cause enteric neuron loss. High-frequency electrical field stimulation (EFS) of distal colon segments produced up to a 10-fold greater contractile response in Smn deficient tissues. EFS responses were not corrected by the addition of a neuronal nitric oxide synthase inhibitor indicating that the increased contractility was due to hyperexcitability and not disinhibition of the circuitry. The GI symptoms observed in mice are similar to those reported in SMA patients. Together these data suggest that ENS cells are susceptible to Smn deficiency and may underlie the patient GI symptoms.
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Affiliation(s)
| | | | | | - Chitra C Iyer
- Department of Molecular & Cellular Biochemistry, Wexner Medical Center and
| | - David Fried
- Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA and
| | - Vicki L McGovern
- Department of Molecular & Cellular Biochemistry, Wexner Medical Center and
| | - Kent C Williams
- Division of Pediatric Gastroenterology, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Arthur H M Burghes
- Department of Molecular & Cellular Biochemistry, Wexner Medical Center and
| | - Fedias L Christofi
- Department of Anesthesiology, The Ohio State University, Columbus, OH 43210, USA
| | - Brian D Gulbransen
- Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA and
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374
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Abstract
Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder pathologically characterized by the degeneration of motor neurons in the spinal cord and muscle atrophy. Motor neuron loss often results in severe muscle weakness causing affected infants to die before reaching 2 years of age. Patients with milder forms of SMA exhibit slowly progressive muscle weakness over many years. SMA is caused by the loss of SMN1 and the retention of at least 1 copy of a highly homologous SMN2. An alternative splicing event in the pre-mRNA arising from SMN2 results in the production of low levels of functional SMN protein. To date, there are no effective treatments available to treat patients with SMA. However, over the last 2 decades, the development of SMA mouse models and the identification of therapeutic targets have resulted in a promising drug pipeline for SMA. Here, we highlight some of the therapeutic strategies that have been developed to activate SMN2 expression, modulate splicing of the SMN2 pre-mRNA, or replace SMN1 by gene therapy. After 2 decades of translational research, we now stand within reach of a treatment for SMA.
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Affiliation(s)
- Constantin d’Ydewalle
- Department of Neurology, Johns Hopkins University School of Medicine, 855 North Wolfe St., Baltimore, MD 21205 USA
| | - Charlotte J. Sumner
- Department of Neurology, Johns Hopkins University School of Medicine, 855 North Wolfe St., Baltimore, MD 21205 USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe St., Baltimore, MD 21205 USA
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375
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Duque SI, Arnold WD, Odermatt P, Li X, Porensky PN, Schmelzer L, Meyer K, Kolb SJ, Schümperli D, Kaspar BK, Burghes AHM. A large animal model of spinal muscular atrophy and correction of phenotype. Ann Neurol 2015; 77:399-414. [PMID: 25516063 DOI: 10.1002/ana.24332] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/29/2014] [Accepted: 12/07/2014] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Spinal muscular atrophy (SMA) is caused by reduced levels of survival motor neuron (SMN) protein, which results in motoneuron loss. Therapeutic strategies to increase SMN levels including drug compounds, antisense oligonucleotides, and scAAV9 gene therapy have proved effective in mice. We wished to determine whether reduction of SMN in postnatal motoneurons resulted in SMA in a large animal model, whether SMA could be corrected after development of muscle weakness, and the response of clinically relevant biomarkers. METHODS Using intrathecal delivery of scAAV9 expressing an shRNA targeting pig SMN1, SMN was knocked down in motoneurons postnatally to SMA levels. This resulted in an SMA phenotype representing the first large animal model of SMA. Restoration of SMN was performed at different time points with scAAV9 expressing human SMN (scAAV9-SMN), and electrophysiology measurements and pathology were performed. RESULTS Knockdown of SMN in postnatal motoneurons results in overt proximal weakness, fibrillations on electromyography indicating active denervation, and reduced compound muscle action potential (CMAP) and motor unit number estimation (MUNE), as in human SMA. Neuropathology showed loss of motoneurons and motor axons. Presymptomatic delivery of scAAV9-SMN prevented SMA symptoms, indicating that all changes are SMN dependent. Delivery of scAAV9-SMN after symptom onset had a marked impact on phenotype, electrophysiological measures, and pathology. INTERPRETATION High SMN levels are critical in postnatal motoneurons, and reduction of SMN results in an SMA phenotype that is SMN dependent. Importantly, clinically relevant biomarkers including CMAP and MUNE are responsive to SMN restoration, and abrogation of phenotype can be achieved even after symptom onset.
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Affiliation(s)
- Sandra I Duque
- Department of Molecular and Cellular Biochemistry, Ohio State University Wexner Medical Center, Columbus, OH
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376
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Taylor JL, Lee FK, Yazdanpanah GK, Staropoli JF, Liu M, Carulli JP, Sun C, Dobrowolski SF, Hannon WH, Vogt RF. Newborn blood spot screening test using multiplexed real-time PCR to simultaneously screen for spinal muscular atrophy and severe combined immunodeficiency. Clin Chem 2015; 61:412-9. [PMID: 25502182 PMCID: PMC7906865 DOI: 10.1373/clinchem.2014.231019] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a motor neuron disorder caused by the absence of a functional survival of motor neuron 1, telomeric (SMN1) gene. Type I SMA, a lethal disease of infancy, accounts for the majority of cases. Newborn blood spot screening (NBS) to detect severe combined immunodeficiency (SCID) has been implemented in public health laboratories in the last 5 years. SCID detection is based on real-time PCR assays to measure T-cell receptor excision circles (TREC), a byproduct of T-cell development. We modified a multiplexed real-time PCR TREC assay to simultaneously determine the presence or absence of the SMN1 gene from a dried blood spot (DBS) punch in a single reaction well. METHOD An SMN1 assay using a locked nucleic acid probe was initially developed with cell culture and umbilical cord blood (UCB) DNA extracts, and then integrated into the TREC assay. DBS punches were placed in 96-well arrays, washed, and amplified directly using reagents specific for TREC, a reference gene [ribonuclease P/MRP 30kDa subunit (RPP30)], and the SMN1 gene. The assay was tested on DBS made from UCB units and from peripheral blood samples of SMA-affected individuals and their family members. RESULTS DBS made from SMA-affected individuals showed no SMN1-specific amplification, whereas DBS made from all unaffected carriers and UCB showed SMN1 amplification above a well-defined threshold. TREC and RPP30 content in all DBS were within the age-adjusted expected range. CONCLUSIONS SMA caused by the absence of SMN1 can be detected from the same DBS punch used to screen newborns for SCID.
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Affiliation(s)
- Jennifer L Taylor
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, GA
| | - Francis K Lee
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, GA
| | | | | | - Mei Liu
- Genetics and Genomics, Biogen Idec, Cambridge, MA
| | | | - Chao Sun
- Genetics and Genomics, Biogen Idec, Cambridge, MA
| | - Steven F Dobrowolski
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - W Harry Hannon
- Newborn Screening Translation Research Initiative, CDC Foundation, Atlanta, GA
| | - Robert F Vogt
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, GA;
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377
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Ronchi D, Previtali SC, Sora MGN, Barera G, Del Menico B, Corti S, Bresolin N, Comi GP. Novel Splice-Site Mutation in SMN1 Associated with a very Severe SMA-I Phenotype. J Mol Neurosci 2015; 56:212-5. [DOI: 10.1007/s12031-014-0483-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 12/15/2014] [Indexed: 11/28/2022]
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378
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Dal Mas A, Rogalska M, Bussani E, Pagani F. Improvement of SMN2 pre-mRNA processing mediated by exon-specific U1 small nuclear RNA. Am J Hum Genet 2015; 96:93-103. [PMID: 25557785 PMCID: PMC4289686 DOI: 10.1016/j.ajhg.2014.12.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/05/2014] [Indexed: 12/20/2022] Open
Abstract
Exon-specific U1 snRNAs (ExSpe U1s) are modified U1 snRNAs that interact with intronic sequences downstream of the 5′ splice site (ss) by complementarity. This process restores exon skipping caused by different types of mutation. We have investigated the molecular mechanism and activity of these molecules in spinal muscular atrophy (SMA), a genetic neuromuscular disease where a silent exonic transition on the survival motor neuron 2 (SMN2) leads to exon 7 (E7) skipping. By using different cellular models, we show that a single chromosome-integrated copy of ExSpe U1 induced a significant correction of endogenous SMN2 E7 splicing and resulted in the restoration of the corresponding SMN protein levels. Interestingly, the analysis of pre-mRNA transcript abundance and decay showed that ExSpe U1s promote E7 inclusion and stabilizes the SMN pre-mRNA intermediate. This selective effect on pre-mRNA stability resulted in higher levels of SMN mRNAs in comparison with those after treatment with an antisense oligonucleotide (AON) that targets corresponding intronic sequences. In mice harboring the SMN2 transgene, AAV-mediated delivery of ExSpe U1 increased E7 inclusion in brain, heart, liver, kidney, and skeletal muscle. The positive effect of ExSpe U1s on SMN pre-mRNA processing highlights their therapeutic potential in SMA and in other pathologies caused by exon-skipping mutations.
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379
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Iascone DM, Henderson CE, Lee JC. Spinal muscular atrophy: from tissue specificity to therapeutic strategies. F1000PRIME REPORTS 2015; 7:04. [PMID: 25705387 PMCID: PMC4311279 DOI: 10.12703/p7-04] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is the most frequent genetic cause of death in infants and toddlers. All cases of spinal muscular atrophy result from reductions in levels of the survival motor neuron (SMN) protein, and so SMN upregulation is a focus of many preclinical and clinical studies. We examine four issues that may be important in planning for therapeutic success. First, neuromuscular phenotypes in the SMNΔ7 mouse model closely match those in human patients but peripheral disease manifestations differ, suggesting that endpoints other than mouse lifespan may be more useful in predicting clinical outcome. Second, SMN plays important roles in multiple central and peripheral cell types, not just motor neurons, and it remains unclear which of these cell types need to be targeted therapeutically. Third, should SMN-restoration therapy not be effective in all patients, blocking molecular changes downstream of SMN reduction may confer significant benefit, making it important to evaluate therapeutic targets other than SMN. Lastly, for patients whose disease progression is slowed, but who retain significant motor dysfunction, additional approaches used to enhance regeneration of the neuromuscular system may be of value.
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Affiliation(s)
- Daniel M Iascone
- Department of Rehabilitation and Regenerative Medicine, Center for Motor Neuron Biology and Disease, Columbia University Medical Center 630 West 168th Street, New York, NY 10032 USA ; Department of Neuroscience, Columbia Translational Neuroscience Initiative, Columbia University Medical Center 630 West 168th Street, New York, NY 10032 USA
| | - Christopher E Henderson
- Department of Rehabilitation and Regenerative Medicine, Center for Motor Neuron Biology and Disease, Columbia University Medical Center 630 West 168th Street, New York, NY 10032 USA ; Department of Neuroscience, Columbia Translational Neuroscience Initiative, Columbia University Medical Center 630 West 168th Street, New York, NY 10032 USA
| | - Justin C Lee
- Department of Rehabilitation and Regenerative Medicine, Center for Motor Neuron Biology and Disease, Columbia University Medical Center 630 West 168th Street, New York, NY 10032 USA ; Department of Neuroscience, Columbia Translational Neuroscience Initiative, Columbia University Medical Center 630 West 168th Street, New York, NY 10032 USA
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380
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Fratta P, Hanna MG. Neuromuscular diseases: progress in gene discovery drives diagnostics and therapeutics. Lancet Neurol 2015; 14:13-4. [DOI: 10.1016/s1474-4422(14)70239-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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381
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Pawellek A, McElroy S, Samatov T, Mitchell L, Woodland A, Ryder U, Gray D, Lührmann R, Lamond AI. Identification of small molecule inhibitors of pre-mRNA splicing. J Biol Chem 2014; 289:34683-98. [PMID: 25281741 PMCID: PMC4263873 DOI: 10.1074/jbc.m114.590976] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 10/02/2014] [Indexed: 11/06/2022] Open
Abstract
Eukaryotic pre-mRNA splicing is an essential step in gene expression for all genes that contain introns. In contrast to transcription and translation, few well characterized chemical inhibitors are available with which to dissect the splicing process, particularly in cells. Therefore, the identification of specific small molecules that either inhibit or modify pre-mRNA splicing would be valuable for research and potentially also for therapeutic applications. We have screened a highly curated library of 71,504 drug-like small molecules using a high throughput in vitro splicing assay. This identified 10 new compounds that both inhibit pre-mRNA splicing in vitro and modify splicing of endogenous pre-mRNA in cells. One of these splicing modulators, DDD00107587 (termed "madrasin," i.e. 2-((7methoxy-4-methylquinazolin-2-yl)amino)-5,6-dimethylpyrimidin-4(3H)-one RNAsplicing inhibitor), was studied in more detail. Madrasin interferes with the early stages of spliceosome assembly and stalls spliceosome assembly at the A complex. Madrasin is cytotoxic at higher concentrations, although at lower concentrations it induces cell cycle arrest, promotes a specific reorganization of subnuclear protein localization, and modulates splicing of multiple pre-mRNAs in both HeLa and HEK293 cells.
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Affiliation(s)
| | - Stuart McElroy
- the Drug Discovery Unit, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom and
| | - Timur Samatov
- the Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Lee Mitchell
- the Drug Discovery Unit, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom and
| | - Andrew Woodland
- the Drug Discovery Unit, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom and
| | - Ursula Ryder
- From the Centre of Gene Regulation and Expression and
| | - David Gray
- the Drug Discovery Unit, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom and
| | - Reinhard Lührmann
- the Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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382
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Transforming Our Approach to Translational Neuroscience: The Role and Impact of Charitable Nonprofits in Research. Neuron 2014; 84:526-32. [DOI: 10.1016/j.neuron.2014.10.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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383
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Abstract
Rare disease research has reached a tipping point, with the confluence of scientific and technologic developments that if appropriately harnessed, could lead to key breakthroughs and treatments for this set of devastating disorders. Industry-wide trends have revealed that the traditional drug discovery research and development (R&D) model is no longer viable, and drug companies are evolving their approach. Rather than only pursue blockbuster therapeutics for heterogeneous, common diseases, drug companies have increasingly begun to shift their focus to rare diseases. In academia, advances in genetics analyses and disease mechanisms have allowed scientific understanding to mature, but the lack of funding and translational capability severely limits the rare disease research that leads to clinical trials. Simultaneously, there is a movement towards increased research collaboration, more data sharing, and heightened engagement and active involvement by patients, advocates, and foundations. The growth in networks and social networking tools presents an opportunity to help reach other patients but also find researchers and build collaborations. The growth of collaborative software that can enable researchers to share their data could also enable rare disease patients and foundations to manage their portfolio of funded projects for developing new therapeutics and suggest drug repurposing opportunities. Still there are many thousands of diseases without treatments and with only fragmented research efforts. We will describe some recent progress in several rare diseases used as examples and propose how collaborations could be facilitated. We propose that the development of a center of excellence that integrates and shares informatics resources for rare diseases sponsored by all of the stakeholders would help foster these initiatives.
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Affiliation(s)
| | - Michele Rhee
- National Brain Tumor Society, Newton, MA, 02458, USA
| | - David C Swinney
- Institute for Rare and Neglected Diseases Drug Discovery (iRND3), Mountain View, CA, 94043, USA
| | - Sean Ekins
- Collaborative Drug Discovery, Inc., Burlingame, CA, 94010, USA ; Collaborations in Chemistry, Fuquay Varina, NC, 27526, USA ; Phoenix Nest Inc., Brooklyn, NY, 11215, USA ; Hereditary Neuropathy Foundation, New York, NY, 10016, USA ; Hannah's Hope Fund, Rexford, NY, NY 12148, USA
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384
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385
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Borg R, Cauchi RJ. GEMINs: potential therapeutic targets for spinal muscular atrophy? Front Neurosci 2014; 8:325. [PMID: 25360080 PMCID: PMC4197776 DOI: 10.3389/fnins.2014.00325] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/26/2014] [Indexed: 01/28/2023] Open
Abstract
The motor neuron degenerative disease spinal muscular atrophy (SMA) remains one of the most frequently inherited causes of infant mortality. Afflicted patients loose the survival motor neuron 1 (SMN1) gene but retain one or more copies of SMN2, a homolog that is incorrectly spliced. Primary treatment strategies for SMA aim at boosting SMN protein levels, which are insufficient in patients. SMN is known to partner with a set of diverse proteins collectively known as GEMINs to form a macromolecular complex. The SMN-GEMINs complex is indispensible for chaperoning the assembly of small nuclear ribonucleoproteins (snRNPs), which are key for pre-mRNA splicing. Pharmaceutics that alleviate the neuromuscular phenotype by restoring the fundamental function of SMN without augmenting its levels are also crucial in the development of an effective treatment. Their use as an adjunct therapy is predicted to enhance benefit to patients. Inspired by the surprising discovery revealing a premier role for GEMINs in snRNP biogenesis together with in vivo studies documenting their requirement for the correct function of the motor system, this review speculates on whether GEMINs constitute valid targets for SMA therapeutic development.
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Affiliation(s)
- Rebecca Borg
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta Msida, Malta
| | - Ruben J Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta Msida, Malta
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386
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Cully M. Beefing up the right splice variant to treat spinal muscular atrophy. Nat Rev Drug Discov 2014; 13:725. [DOI: 10.1038/nrd4445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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387
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Affiliation(s)
- Luisa Vigevani
- Centre de Regulació Genòmica, Dr. Aiguader 88, 08003 Barcelona, Spain. Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain.
| | - Juan Valcárcel
- Centre de Regulació Genòmica, Dr. Aiguader 88, 08003 Barcelona, Spain. Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain. Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg Lluis Companys 23, 08010, Barcelona, Spain.
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388
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Wyatt EJ, Sweeney HL, McNally EM. Meeting Report: New Directions in the Biology and Disease of Skeletal Muscle 2014. J Neuromuscul Dis 2014; 1:197-206. [PMID: 26207203 PMCID: PMC4508866 DOI: 10.3233/jnd-149003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The New Directions in the Biology and Disease of Skeletal Muscle is a scientific meeting, held every other year, with the stated purpose of bringing together scientists, clinicians, industry representatives and patient advocacy groups to disseminate new discovery useful for treatment inherited forms of neuromuscular disease, primarily the muscular dystrophies. This meeting originated as a response the Muscular Dystrophy Care Act in order to provide a venue for the free exchange of information, with the emphasis on unpublished or newly published data. Highlights of this years' meeting included results from early phase clinical trials for Duchenne Muscular Dystrophy, progress in understanding the epigenetic defects in Fascioscapulohumeral Muscular Dystrophy and new mechanisms of muscle membrane repair. The following is a brief report of the highlights from the conference.
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Affiliation(s)
- Eugene J Wyatt
- Department of Medicine, The University of Chicago, Chicago, IL USA
| | - H Lee Sweeney
- Department of Physiology, The University of Pennsylvania, Philadelphia, PA USA
| | - Elizabeth M McNally
- Department of Medicine, The University of Chicago, Chicago, IL USA ; Department of Human Genetics, The University of Chicago, Chicago, IL USA
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