1
|
Roussel MP, Morin M, Girardin M, Fortin AM, Leone M, Mathieu J, Gagnon C, Duchesne E. Training program-induced skeletal muscle adaptations in two men with myotonic dystrophy type 1. BMC Res Notes 2019; 12:526. [PMID: 31429798 PMCID: PMC6700834 DOI: 10.1186/s13104-019-4554-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/10/2019] [Indexed: 01/03/2023] Open
Abstract
Objective The purpose of this side product of another unpublished research project, was to address the effects of a training program on skeletal muscle adaptations of people with myotonic dystrophy type 1 (DM1), under a multifaceted perspective. The objective of this study was to look at training induced muscular adaptations by evaluating changes in muscle strength, myofiber cross-sectional area (CSA), proportion of myofiber types and with indirect markers of muscle growth [proportion of centrally nucleated fibers (CNF) and density of neutrophils and macrophages]. Two men with DM1 underwent a 12-week strength/endurance training program (18 sessions). Two muscle biopsies were obtained pre- and post-training program. Results Muscular adaptations occurred only in Patient 1, who attended 72% of the training sessions compared to 39% for Patient 2. These adaptations included increase in the CSA of type I and II myofibers and changes in their proportion. No changes were observed in the percentage of CNF, infiltration of neutrophils and macrophages and muscle strength. These results illustrate the capacity of skeletal muscle cells to undergo adaptations linked to muscle growth in DM1 patients. Also, these adaptations seem to be dependent on the attendance. Trial registration Clinicaltrials.gov NCT04001920 retrospectively registered on June 26th, 2019
Collapse
Affiliation(s)
- Marie-Pier Roussel
- Département des sciences fondamentales, Université du Québec à Chicoutimi, Saguenay, QC, Canada.,Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, Installations de Jonquière, Saguenay, QC, Canada.,Centre de recherche-Hôpital Charles-Le Moyne - Saguenay-Lac-Saint-Jean sur les innovations en santé, Saguenay, QC, Canada
| | - Marika Morin
- Département des sciences de la santé, Université du Québec à Chicoutimi, Saguenay, QC, Canada
| | - Mélina Girardin
- Département des sciences de la santé, Université du Québec à Chicoutimi, Saguenay, QC, Canada
| | - Anne-Marie Fortin
- Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, Installations de Jonquière, Saguenay, QC, Canada
| | - Mario Leone
- Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, Installations de Jonquière, Saguenay, QC, Canada.,Département des sciences de la santé, Université du Québec à Chicoutimi, Saguenay, QC, Canada
| | - Jean Mathieu
- Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, Installations de Jonquière, Saguenay, QC, Canada.,Centre de recherche-Hôpital Charles-Le Moyne - Saguenay-Lac-Saint-Jean sur les innovations en santé, Saguenay, QC, Canada.,Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Cynthia Gagnon
- Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, Installations de Jonquière, Saguenay, QC, Canada.,Centre de recherche-Hôpital Charles-Le Moyne - Saguenay-Lac-Saint-Jean sur les innovations en santé, Saguenay, QC, Canada.,Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Elise Duchesne
- Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, Installations de Jonquière, Saguenay, QC, Canada. .,Centre de recherche-Hôpital Charles-Le Moyne - Saguenay-Lac-Saint-Jean sur les innovations en santé, Saguenay, QC, Canada. .,Département des sciences de la santé, Université du Québec à Chicoutimi, Saguenay, QC, Canada. .,Unité d'enseignement en physiothérapie, Département des sciences de la santé, Université du Québec à Chicoutimi, 555, boulevard de l'Université, Saguenay, G7H 2B1, Quebec, Canada.
| |
Collapse
|
2
|
Roussel MP, Morin M, Gagnon C, Duchesne E. What is known about the effects of exercise or training to reduce skeletal muscle impairments of patients with myotonic dystrophy type 1? A scoping review. BMC Musculoskelet Disord 2019; 20:101. [PMID: 30836978 PMCID: PMC6402179 DOI: 10.1186/s12891-019-2458-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 02/06/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Myotonic dystrophy type 1 (DM1) is a neuromuscular disease characterized by multisystemic involvements including a progressive loss of maximal muscle strength and muscle wasting. Poor lower-limb strength is an important factor explaining disrupted social participation of affected individuals. This review aims to map what is known about the effects of exercise and training programs undertaken to counteract skeletal muscle impairments in DM1 patients. METHODS Medline, CINAHL and EMBASE databases were searched. Regarding study eligibility, title and abstract of 704 studies followed by 45 full articles were reviewed according to the following eligibility criteria. Inclusion: (1) humans with DM1 and (2) experimental protocol relying on exercise or training. Exclusion: (1) studies that do not evaluate skeletal muscle responses or adaptations, (2) reviews covering articles already included and (3) pharmacological intervention at the same time of exercise or training program. RESULTS Twenty-one papers were selected for in-depth analysis. Different exercise or training protocols were found including: acute exercise, neuromuscular electric stimulation, strength training, aerobic training, balance training and multiple rehabilitation interventions. Seven studies reported clinical measurements only, five physiological parameters only and nine both types. CONCLUSION This scoping review offers a complete summary of the current scientific literature on the effect of exercise and training in DM1 and a framework for future studies based on the concomitant evaluation of the several outcomes in present literature. Although there were a good number of studies focusing on clinical measurements, heterogeneity between studies does not allow to identify what are the adequate training parameters to obtain exercise or training-induced positive impacts on muscle function. Scientific literature is even more scarce regarding physiological parameters, where much more research is needed to understand the underlying mechanisms of exercise response in DM1.
Collapse
Affiliation(s)
- Marie-Pier Roussel
- Département des sciences de la santé, physiothérapie, Université du Québec à Chicoutimi, 555, boulevard de l'Université, Chicoutimi, Quebec, G7H 2B1, Canada.,Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, 2230 rue de l'Hôpital, Saguenay, Québec, Canada.,Centre de recherche Charles-Le Moyne - Saguenay-Lac-Saint-Jean sur les innovations en santé, 2230 rue de l'Hôpital, Saguenay, Québec, Canada., Longueuil, Québec, Canada
| | - Marika Morin
- Département des sciences de la santé, physiothérapie, Université du Québec à Chicoutimi, 555, boulevard de l'Université, Chicoutimi, Quebec, G7H 2B1, Canada
| | - Cynthia Gagnon
- Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, 2230 rue de l'Hôpital, Saguenay, Québec, Canada.,Centre de recherche Charles-Le Moyne - Saguenay-Lac-Saint-Jean sur les innovations en santé, 2230 rue de l'Hôpital, Saguenay, Québec, Canada., Longueuil, Québec, Canada.,Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Québec, Canada
| | - Elise Duchesne
- Département des sciences de la santé, physiothérapie, Université du Québec à Chicoutimi, 555, boulevard de l'Université, Chicoutimi, Quebec, G7H 2B1, Canada. .,Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, 2230 rue de l'Hôpital, Saguenay, Québec, Canada. .,Centre de recherche Charles-Le Moyne - Saguenay-Lac-Saint-Jean sur les innovations en santé, 2230 rue de l'Hôpital, Saguenay, Québec, Canada., Longueuil, Québec, Canada.
| |
Collapse
|
3
|
Thomas JD, Oliveira R, Sznajder ŁJ, Swanson MS. Myotonic Dystrophy and Developmental Regulation of RNA Processing. Compr Physiol 2018; 8:509-553. [PMID: 29687899 DOI: 10.1002/cphy.c170002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Myotonic dystrophy (DM) is a multisystemic disorder caused by microsatellite expansion mutations in two unrelated genes leading to similar, yet distinct, diseases. DM disease presentation is highly variable and distinguished by differences in age-of-onset and symptom severity. In the most severe form, DM presents with congenital onset and profound developmental defects. At the molecular level, DM pathogenesis is characterized by a toxic RNA gain-of-function mechanism that involves the transcription of noncoding microsatellite expansions. These mutant RNAs disrupt key cellular pathways, including RNA processing, localization, and translation. In DM, these toxic RNA effects are predominantly mediated through the modulation of the muscleblind-like and CUGBP and ETR-3-like factor families of RNA binding proteins (RBPs). Dysfunction of these RBPs results in widespread RNA processing defects culminating in the expression of developmentally inappropriate protein isoforms in adult tissues. The tissue that is the focus of this review, skeletal muscle, is particularly sensitive to mutant RNA-responsive perturbations, as patients display a variety of developmental, structural, and functional defects in muscle. Here, we provide a comprehensive overview of DM1 and DM2 clinical presentation and pathology as well as the underlying cellular and molecular defects associated with DM disease onset and progression. Additionally, fundamental aspects of skeletal muscle development altered in DM are highlighted together with ongoing and potential therapeutic avenues to treat this muscular dystrophy. © 2018 American Physiological Society. Compr Physiol 8:509-553, 2018.
Collapse
Affiliation(s)
- James D Thomas
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| | - Ruan Oliveira
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| | - Łukasz J Sznajder
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| |
Collapse
|
4
|
Tan SV, Z'graggen WJ, Boërio D, Turner C, Hanna MG, Bostock H. In vivo assessment of muscle membrane properties in myotonic dystrophy. Muscle Nerve 2016; 54:249-57. [PMID: 26789642 DOI: 10.1002/mus.25025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 12/16/2015] [Accepted: 12/28/2015] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Myotonia in myotonic dystrophy types 1 (DM1) and 2 (DM2) is generally attributed to reduced chloride-channel conductance. We used muscle velocity recovery cycles (MVRCs) to investigate muscle membrane properties in DM1 and DM2, using comparisons with myotonia congenita (MC). METHODS MVRCs and responses to repetitive stimulation were compared between patients with DM1 (n = 18), DM2 (n = 5), MC (n = 18), and normal controls (n = 20). RESULTS Both DM1 and DM2 showed enhanced late supernormality after multiple conditioning stimuli, indicating delayed repolarization as in MC. Contrary to MC, however, DM1 showed reduced early supernormality after multiple conditioning stimuli, and weak DM1 patients also showed abnormally slow latency recovery after repetitive stimulation. CONCLUSIONS These findings support the presence of impaired chloride conductance in both DM1 and DM2. The early supernormality changes indicate that sodium currents were reduced in DM1, whereas the weakness-associated slow recovery after repetitive stimulation may provide an indication of reduced Na(+) /K(+) -ATPase activation. Muscle Nerve 54: 249-257, 2016.
Collapse
Affiliation(s)
- S Veronica Tan
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, The National, Queen Square, London, WC1N 3BG, UK.,Institute of Neurology, University College London, Queen Square, London, UK.,Department of Neurology and Neurophysiology, St Thomas' Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.,Department of Academic Neurosciences, Kings College, London, UK
| | - Werner J Z'graggen
- Department of Neurosurgery, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Delphine Boërio
- Department of Neurosurgery, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Christopher Turner
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, The National, Queen Square, London, WC1N 3BG, UK.,Institute of Neurology, University College London, Queen Square, London, UK
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, The National, Queen Square, London, WC1N 3BG, UK.,Institute of Neurology, University College London, Queen Square, London, UK
| | - Hugh Bostock
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, The National, Queen Square, London, WC1N 3BG, UK.,Institute of Neurology, University College London, Queen Square, London, UK.,Department of Neurosurgery, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| |
Collapse
|
5
|
Peng X, Shen X, Chen X, Liang R, Azares AR, Liu Y. Celf1 regulates cell cycle and is partially responsible for defective myoblast differentiation in myotonic dystrophy RNA toxicity. Biochim Biophys Acta Mol Basis Dis 2015; 1852:1490-7. [PMID: 25887157 DOI: 10.1016/j.bbadis.2015.04.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/14/2015] [Accepted: 04/08/2015] [Indexed: 11/25/2022]
Abstract
Myotonic dystrophy is a neuromuscular disease of RNA toxicity. The disease gene DMPK harbors expanded CTG trinucleotide repeats on its 3'-UTR. The transcripts of this mutant DMPK led to misregulation of RNA-binding proteins including MBNL1 and Celf1. In myoblasts, CUG-expansion impaired terminal differentiation. In this study, we formally tested how the abundance of Celf1 regulates normal myocyte differentiation, and how Celf1 expression level mediates CUG-expansion RNA toxicity-triggered impairment of myocyte differentiation. As the results, overexpression of Celf1 largely recapitulated the defects of myocytes with CUG-expansion, by increasing myocyte cycling. Knockdown of endogenous Celf1 level led to precocious myotube formation, supporting a negative connection between Celf1 abundance and myocyte terminal differentiation. Finally, knockdown of Celf1 in myocyte with CUG-expansion led to partial rescue, by promoting cell cycle exit. Our results suggest that Celf1 plays a distinctive and negative role in terminal myocyte differentiation, which partially contribute to DM1 RNA toxicity. Targeting Celf1 may be a valid strategy in correcting DM1 muscle phenotypes, especially for congenital cases.
Collapse
Affiliation(s)
- Xiaoping Peng
- The First Affiliated Hospital of Nanchang University, Nanchang 330006, China; Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Xiaopeng Shen
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Xuanying Chen
- The First Affiliated Hospital of Nanchang University, Nanchang 330006, China; Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Rui Liang
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Alon R Azares
- Stem Cell Engineering, Texas Heart Institute, Houston, TX 77030, USA
| | - Yu Liu
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA.
| |
Collapse
|
6
|
Todd PK, Ackall FY, Hur J, Sharma K, Paulson HL, Dowling JJ. Transcriptional changes and developmental abnormalities in a zebrafish model of myotonic dystrophy type 1. Dis Model Mech 2013; 7:143-55. [PMID: 24092878 PMCID: PMC3882056 DOI: 10.1242/dmm.012427] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myotonic dystrophy type I (DM1) is a multi-system, autosomal dominant disorder caused by expansion of a CTG repeat sequence in the 3′UTR of the DMPK gene. The size of the repeat sequence correlates with age at onset and disease severity, with large repeats leading to congenital forms of DM1 associated with hypotonia and intellectual disability. In models of adult DM1, expanded CUG repeats lead to an RNA toxic gain of function, mediated at least in part by sequestering specific RNA splicing proteins, most notably muscleblind-related (MBNL) proteins. However, the impact of CUG RNA repeat expression on early developmental processes is not well understood. To better understand early developmental processes in DM1, we utilized the zebrafish, Danio rerio, as a model system. Direct injection of (CUG)91 repeat-containing mRNA into single-cell embryos induces toxicity in the nervous system and muscle during early development. These effects manifest as abnormal morphology, behavioral abnormalities and broad transcriptional changes, as shown by cDNA microarray analysis. Co-injection of zebrafish mbnl2 RNA suppresses (CUG)91 RNA toxicity and reverses the associated behavioral and transcriptional abnormalities. Taken together, these findings suggest that early expression of exogenously transcribed CUG repeat RNA can disrupt normal muscle and nervous system development and provides a new model for DM1 research that is amenable to small-molecule therapeutic development.
Collapse
Affiliation(s)
- Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | | | | | | |
Collapse
|
7
|
Bolognani F, Gallani AI, Sokol L, Baskin DS, Meisner-Kober N. mRNA stability alterations mediated by HuR are necessary to sustain the fast growth of glioma cells. J Neurooncol 2011; 106:531-42. [PMID: 21935689 DOI: 10.1007/s11060-011-0707-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2010] [Accepted: 08/19/2011] [Indexed: 10/17/2022]
Abstract
Regulation of mRNA decay is an important mechanism controlling gene expression. Steady state levels of mRNAs can be markedly altered by changes in the decay rate. The control of mRNA stability depends on sequences in the transcript itself and on RNA-binding proteins that dynamically bind to these sequences. A well characterized sequence motif, which has been shown to be present in many short-lived mRNAs, is the de-stabilizing adenylate/uridylate-rich element (ARE) located at the 3' untranslated region (3'UTR) of mRNAs. HuR is an RNA-binding protein, which binds to AREs and in doing so, increases the half-life and steady state levels of the corresponding mRNA. Using tissue microarray technology, we found that HuR is over-expressed in human gliomas. We also found that there is a change in HuR localization from being solely in the nucleus to being expressed at high levels in the cytosol. Moreover, a positive correlation was found between total HuR levels, cytosolic localization and tumor grade. We also studied the decay rate of several HuR target mRNAs and found that these mRNAs have a slower rate of decay in glioma cell lines than in astrocytes. Finally, we have been able to decrease both the stability and steady state level of these transcripts in glioma cells using an RNA decoy. More importantly, the decoy transfected cells and cells exposed to a HuR inhibitor have reduced cell growth. In addition, pharmacological inhibition of HuR also resulted in glioma cell growth inhibition. In conclusion, our data suggest that post-transcriptional control abnormalities mediated by HuR are necessary to sustain the rapid growth of this devastating type of cancer.
Collapse
Affiliation(s)
- Federico Bolognani
- Department of Neurosurgery, The Methodist Hospital and The Methodist Hospital Research Institute, Houston, TX 77030, USA.
| | | | | | | | | |
Collapse
|
8
|
Normal myogenesis and increased apoptosis in myotonic dystrophy type-1 muscle cells. Cell Death Differ 2010; 17:1315-24. [PMID: 20431600 DOI: 10.1038/cdd.2010.33] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Myotonic dystrophy (DM) is caused by a (CTG)(n) expansion in the 3'-untranslated region of DMPK gene. Mutant transcripts are retained in nuclear RNA foci, which sequester RNA binding proteins thereby misregulating the alternative splicing. Controversy still surrounds the pathogenesis of the DM1 muscle distress, characterized by myotonia, weakness and wasting with distal muscle atrophy. Eight primary human cell lines from adult-onset (DM1) and congenital (cDM1) patients, (CTG)(n) range 90-1800, were successfully differentiated into aneural-immature and contracting-innervated-mature myotubes. Morphological, immunohistochemical, RT-PCR and western blotting analyses of several markers of myogenesis indicated that in vitro differentiation-maturation of DM1 myotubes was comparable to age-matched controls. In all pathological muscle cells, (CTG)(n) expansions were confirmed by long PCR and RNA fluorescence in situ hybridization. Moreover, the DM1 myotubes showed the splicing alteration of insulin receptor and muscleblind-like 1 (MBNL1) genes associated with the DM1 phenotype. Considerable myotube loss and atrophy of 15-day-differentiated DM1 myotubes indicated activated catabolic pathways, as confirmed by the presence of apoptotic (caspase-3 activation, cytochrome c release, chromatin fragmentation) and autophagic (P62/LC3) markers. Z-VAD treatment significantly reduced the decrease in myonuclei number and in average width in 15-day-differentiated DM1 myotubes. We thus propose that the muscle wasting typical in DM1 is due to impairment of muscle mass maintenance-regeneration, through premature apoptotic-autophagic activation, rather than altered myogenesis.
Collapse
|
9
|
Nykamp KR, Swanson MS. Toxic RNA in the nucleus: unstable microsatellite expression in neuromuscular disease. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2008; 35:57-77. [PMID: 15113079 DOI: 10.1007/978-3-540-74266-1_3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- Keith R Nykamp
- Department of Molecular Genetics and Microbiology, Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, Florida 32610-0266, USA
| | | |
Collapse
|
10
|
Abstract
PURPOSE OF REVIEW The aim of this review is to highlight recent progress in elucidating the disease mechanism in myotonic dystrophy type 1 and type 2. RECENT FINDINGS Research on myotonic dystrophy has led to the recognition of a novel RNA-mediated disease process. In myotonic dystrophy it is the RNA rather than protein product of a disease gene that has deleterious effects on muscle cells. These unusual RNAs, which contain a long expanse of CUG or CCUG repeats, have far reaching effects on cell function by influencing the biogenesis of other cellular RNAs. One aspect of RNA metabolism that is particularly affected is the regulation of alternative splicing. By this mechanism, effects of myotonic dystrophy repeat expansions impact many different pathways, triggering a complex set of signs and symptoms. SUMMARY The genetic lesion in myotonic dystrophy does not eliminate an essential muscle protein. Instead, it induces a defect of RNA processing that is potentially reversible. The nature of this disease process raises the possibility that myotonic dystrophy, among genetic disorders, may be unusually susceptible to treatment using non-gene-therapy approaches.
Collapse
Affiliation(s)
- Thurman M Wheeler
- Department of Neurology, University of Rochester, Rochester, New York, USA
| | | |
Collapse
|
11
|
Cho DH, Tapscott SJ. Myotonic dystrophy: Emerging mechanisms for DM1 and DM2. Biochim Biophys Acta Mol Basis Dis 2007; 1772:195-204. [PMID: 16876389 DOI: 10.1016/j.bbadis.2006.05.013] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 05/26/2006] [Accepted: 05/26/2006] [Indexed: 01/27/2023]
Abstract
Myotonic dystrophy (DM) is a complex multisystemic disorder linked to two different genetic loci. Myotonic dystrophy type 1 (DM1) is caused by an expansion of a CTG repeat located in the 3' untranslated region (UTR) of DMPK (myotonic dystrophy protein kinase) on chromosome 19q13.3. Myotonic dystrophy type 2 (DM2) is caused by an unstable CCTG repeat in intron 1 of ZNF9 (zinc finger protein 9) on chromosome 3q21. Therefore, both DM1 and DM2 are caused by a repeat expansion in a region transcribed into RNA but not translated into protein. The discovery that these two distinct mutations cause largely similar clinical syndromes put emphasis on the molecular properties they have in common, namely, RNA transcripts containing expanded, non-translated repeats. The mutant RNA transcripts of DM1 and DM2 aberrantly affect the splicing of the same target RNAs, such as chloride channel 1 (ClC-1) and insulin receptor (INSR), resulting in their shared myotonia and insulin resistance. Whether the entire disease pathology of DM1 and DM2 is caused by interference in RNA processing remains to be seen. This review focuses on the molecular significance of the similarities and differences between DM1 and DM2 in understanding the disease pathology of myotonic dystrophy.
Collapse
Affiliation(s)
- Diane H Cho
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | | |
Collapse
|
12
|
Kuyumcu-Martinez NM, Cooper TA. Misregulation of alternative splicing causes pathogenesis in myotonic dystrophy. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2006; 44:133-59. [PMID: 17076268 PMCID: PMC4127983 DOI: 10.1007/978-3-540-34449-0_7] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Myotonic dystrophy (DM), the most common form of adult onset muscular dystrophy, affects skeletal muscle, heart, and the central nervous system (CNS). Mortality results primarily from muscle wasting and cardiac arrhythmias. There are two forms of the disease: DM1 and DM2. DM1, which constitutes 98% of cases, is caused by a CTG expansion in the 3' untranslated region (UTR) of the DMPK gene. DM2 is caused by a CCTG expansion in the first intron of the ZNF9 gene. RNA containing CUG- or CCUG-expanded repeats are transcribed but are retained in the nucleus in foci. Disease pathogenesis results primarily from a gain of function of the expanded RNAs, which alter developmentally regulated alternative splicing as well as pathways of muscle differentiation. The toxic RNA has been implicated in sequestration of splicing regulators and transcription factors thereby causing specific symptoms of the disease. Here we review the proposed mechanisms for the toxic effects of the expanded repeats and discuss the molecular mechanisms of splicing misregulation and disease pathogenesis.
Collapse
|
13
|
O'Cochlain DF, Perez-Terzic C, Reyes S, Kane GC, Behfar A, Hodgson DM, Strommen JA, Liu XK, van den Broek W, Wansink DG, Wieringa B, Terzic A. Transgenic overexpression of human DMPK accumulates into hypertrophic cardiomyopathy, myotonic myopathy and hypotension traits of myotonic dystrophy. Hum Mol Genet 2004; 13:2505-18. [PMID: 15317754 DOI: 10.1093/hmg/ddh266] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abnormal expression of human myotonic dystrophy protein kinase (hDMPK) gene products has been implicated in myotonic dystrophy type 1 (DM1), yet the impact of distress accumulation produced by persistent overexpression of this poorly understood member of the Rho kinase-related protein kinase gene-family remains unknown. Here, in the aged transgenic murine line carrying approximately 25 extra copies of a complete hDMPK gene with all exons and an intact promoter region (Tg26-hDMPK), overexpression of mRNA and protein transgene products in cardiac, skeletal and smooth muscles resulted in deficient exercise endurance, an integrative index of muscle systems underperformance. In contrast to age-matched (11-15 months) wild-type controls, hearts from Tg26-hDMPK developed cardiomyopathic remodeling with myocardial hypertrophy, myocyte disarray and interstitial fibrosis. Hypertrophic cardiomyopathy was associated with a propensity for dysrhythmia and characterized by overt intracellular calcium overload promoting nuclear translocation of transcription factors responsible for maladaptive gene reprogramming. Skeletal muscles in distal limbs of Tg26-hDMPK showed myopathy with myotonic discharges coupled with deficit in sarcolemmal chloride channels, required regulators of hyperexcitability. Fiber degeneration in Tg26-hDMPK resulted in sarcomeric disorganization, centralization of nuclei and tubular aggregation. Moreover, the reduced blood pressure in Tg26-hDMPK indicated deficient arterial smooth muscle tone. Thus, the cumulative stress induced by permanent overexpression of hDMPK gene products translates into an increased risk for workload intolerance, hypertrophic cardiomyopathy with dysrhythmia, myotonic myopathy and hypotension, all distinctive muscle traits of DM1. Proper expression of hDMPK is, therefore, mandatory in supporting the integral balance among cytoarchitectural infrastructure, ion-homeostasis and viability control in various muscle cell types.
Collapse
Affiliation(s)
- D Fearghas O'Cochlain
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Watanabe T, Takagi A, Sasagawa N, Ishiura S, Nakase H. Altered expression of CUG binding protein 1 mRNA in myotonic dystrophy 1: possible RNA–RNA interaction. Neurosci Res 2004; 49:47-54. [PMID: 15099703 DOI: 10.1016/j.neures.2004.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Accepted: 01/20/2004] [Indexed: 11/16/2022]
Abstract
The triplet repeats mutation, which causes myotonic dystrophy 1 (DM1), is thought to have a dominant negative effect on RNA levels. In light of previous results using differential display analysis, the present study focused on the expression of CUG binding protein 1 (CUGBP1) mRNA. Northern blot analysis demonstrated that the quantity of CUGBP1 mRNA in three DM1 patients was approximately 70% of that observed in three normal controls (P < 0.05). In addition, a semi-quantitative RT-PCR assay showed that the relative amount of CUGBP1 mRNA was reduced in muscle biopsy samples from 10 DM1 patients compared to that from five normal individuals (P < 0.01) and 10 myopathic disease controls (P < 0.01). The amount of CUGBP1 mRNA was negatively correlated with the size of the CTG expansion (r = -0.85, P < 0.05). In vitro RNA-RNA binding experiments demonstrated that the incubation of expanded CUG repeats with CUGBP1 RNA generated a higher molecular weight band, which was digested by RNase III. The CUGBP1 mRNA was found to contain several CAG repeat sequences. These results suggest that the CUG expansion may bind to complementary sequences within the CUGBP1 mRNA and that this molecular interaction may affect CUGBP1 mRNA expression in DM1.
Collapse
Affiliation(s)
- Tomoji Watanabe
- Department of Neurology, Toranomon Hospital and Okinaka Memorial Institute for Medical Research, 222 Toranomon, Minato-ku, Tokyo 105-0001, Japan.
| | | | | | | | | |
Collapse
|
15
|
Abstract
Myogenesis is the developmental program that generates and regenerates skeletal muscle. This process is impaired in patients afflicted with myotonic dystrophy type 1 (DM1). Muscle development is disrupted in infants born with congenital DM1, and recent evidence suggests that defective regeneration may contribute to muscle weakness and wasting in affected adults. DM1 represents the first example of a human disease that is caused, at least in part, by pathogenic mRNA. Cell culture models have been used to demonstrate that mutant DM1 mRNA takes on a gain-of-function and inhibits myoblast differentiation. Although the molecular mechanism(s) by which this mutant mRNA disrupts myogenesis is not fully understood, recent findings suggest that anomalous RNA-protein interactions have downstream consequences that compromise key myogenic factors. In this review, we revisit morphological studies that revealed the nature of myogenic abnormalities seen in patients, describe cell culture systems that have been used to investigate this phenotype and discuss recent discoveries that for the first time have identified myogenic events that are disrupted in DM1.
Collapse
Affiliation(s)
- Jeffrey D Amack
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84108, USA
| | | |
Collapse
|
16
|
Iyer D, Belaguli N, Flück M, Rowan BG, Wei L, Weigel NL, Booth FW, Epstein HF, Schwartz RJ, Balasubramanyam A. Novel phosphorylation target in the serum response factor MADS box regulates alpha-actin transcription. Biochemistry 2003; 42:7477-86. [PMID: 12809504 DOI: 10.1021/bi030045n] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Serum response factor (SRF) is a phosphoprotein that regulates skeletal and cardiac alpha-actin gene transcription. Myotonic dystrophy protein kinase (DMPK), a muscle- and neuron-restricted kinase, enhanced SRF-mediated promoter activity of the skeletal and cardiac alpha-actin genes in C2C12 myoblasts as well as in nonmyogenic cells. DMPK phosphorylated SRF in vitro in the alphaI coil of the DNA-binding domain in the MADS box, a highly conserved region required for DNA binding, dimerization, and co-activator interaction in COS and CV1 cells. Threonine 159 in the MADS box alphaI coil was a specific phosphorylation target in vitro as well as in vivo of both DMPK and protein kinase C-alpha. Substitution of threonine 159 with the nonphosphorylatable residue alanine markedly diminished activation of the cardiac alpha-actin promoter in the presence of kinase, while its substitution with aspartic acid, to introduce a negative charge and mimic phosphorylation, restored activation completely. Phosphorylation of the MADS box may constitute a novel mechanism for regulation of SRF-dependent actin gene transcription.
Collapse
Affiliation(s)
- Dinakar Iyer
- Department of Medicine, Division of Endocrinology, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
DOI J, HARA T, OHTSUKA A, HAYASHI K. Role of Ca2+in corticosterone-induced muscle growth retardation. Anim Sci J 2002. [DOI: 10.1046/j.1344-3941.2002.00053.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
18
|
Quintero-Mora ML, Depardon F, Cisneros B. Expanded CTG repeats inhibit neuronal differentiation of the PC12 cell line. Biochem Biophys Res Commun 2002; 295:289-94. [PMID: 12150945 DOI: 10.1016/s0006-291x(02)00660-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Myotonic dystrophy (DM) is a dominant neuromuscular disorder caused by the expansion of trinucleotide CTG repeats in the 3-untranslated region (3'-UTR) of the MtPK gene. Although DM-associated mental retardation suggests that neuronal functions are disturbed by the expansion mutation, the effect of this alteration in neuronal cells has not been approached. In this study we established stable transfectans of PC12 neuronal cell line expressing the reporter gene CAT alone (empty-vector clone) or fused to the MtPK 3'-UTR with 5, 60, or 90 CTG repeats (CTG5, CTG60, and CTG90 clones, respectively). CTG90 cells exhibited a suppression of NGF-induced neuronal differentiation while empty-vector, CTG5 and CTG60 clones differentiated normally. CTG90 cells displayed normal activation of early differentiation markers, ERK1/2, but the up-regulation of the late marker MAP2 was dramatically reduced. Our neuronal cell system provides the first information of how the mutant MtPK 3'-UTR mRNA affects neuronal functions.
Collapse
Affiliation(s)
- María Leonor Quintero-Mora
- Departamento de Genética y Biología Molecular, Centro de Investigación y Estudios Avanzados del IPN, Avenida Instituto Politécnico Nacional 2508, Apartado Postal 14-740, C.P. 07000 Mexico D.F., Mexico
| | | | | |
Collapse
|
19
|
Abstract
K(+) channels play critical roles in a wide variety of physiological processes, including the regulation of heart rate, muscle contraction, neurotransmitter release, neuronal excitability, insulin secretion, epithelial electrolyte transport, cell volume regulation, and cell proliferation. As such, K(+) channels have been recognized as potential therapeutic drug targets for many years. Unfortunately, progress toward identifying selective K(+) channel modulators has been severely hampered by the need to use native currents and primary cells in the drug-screening process. Today, however, more than 80 K(+) channel and K(+) channel-related genes have been identified, and an understanding of the molecular composition of many important native K(+) currents has begun to emerge. The identification of these molecular K(+) channel drug targets should lead to the discovery of novel drug candidates. A summary of progress is presented.
Collapse
Affiliation(s)
- Alan Wickenden
- Icagen Inc., Suite 460, 4222 Emperor Boulevard, Durham, NC 27703, USA.
| |
Collapse
|
20
|
Timchenko NA, Iakova P, Cai ZJ, Smith JR, Timchenko LT. Molecular basis for impaired muscle differentiation in myotonic dystrophy. Mol Cell Biol 2001; 21:6927-38. [PMID: 11564876 PMCID: PMC99869 DOI: 10.1128/mcb.21.20.6927-6938.2001] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Differentiation of skeletal muscle is affected in myotonic dystrophy (DM) patients. Analysis of cultured myoblasts from DM patients shows that DM myoblasts lose the capability to withdraw from the cell cycle during differentiation. Our data demonstrate that the expression and activity of the proteins responsible for cell cycle withdrawal are altered in DM muscle cells. Skeletal muscle cells from DM patients fail to induce cytoplasmic levels of a CUG RNA binding protein, CUGBP1, while normal differentiated cells accumulate CUGBP1 in the cytoplasm. In cells from normal patients, CUGBP1 up-regulates p21 protein during differentiation. Several lines of evidence show that CUGBP1 induces the translation of p21 via binding to a GC-rich sequence located within the 5' region of p21 mRNA. Failure of DM cells to accumulate CUGBP1 in the cytoplasm leads to a significant reduction of p21 and to alterations of other proteins responsible for the cell cycle withdrawal. The activity of cdk4 declines during differentiation of cells from control patients, while in DM cells cdk4 is highly active during all stages of differentiation. In addition, DM cells do not form Rb/E2F repressor complexes that are abundant in differentiated cells from normal patients. Our data provide evidence for an impaired cell cycle withdrawal in DM muscle cells and suggest that alterations in the activity of CUGBP1 causes disruption of p21-dependent control of cell cycle arrest.
Collapse
Affiliation(s)
- N A Timchenko
- Huffington Center on Aging, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | | | |
Collapse
|
21
|
Ladd AN, Charlet N, Cooper TA. The CELF family of RNA binding proteins is implicated in cell-specific and developmentally regulated alternative splicing. Mol Cell Biol 2001; 21:1285-96. [PMID: 11158314 PMCID: PMC99581 DOI: 10.1128/mcb.21.4.1285-1296.2001] [Citation(s) in RCA: 321] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alternative splicing of cardiac troponin T (cTNT) exon 5 undergoes a developmentally regulated switch such that exon inclusion predominates in embryonic, but not adult, striated muscle. We previously described four muscle-specific splicing enhancers (MSEs) within introns flanking exon 5 in chicken cTNT that are both necessary and sufficient for exon inclusion in embryonic muscle. We also demonstrated that CUG-binding protein (CUG-BP) binds a conserved CUG motif within a human cTNT MSE and positively regulates MSE-dependent exon inclusion. Here we report that CUG-BP is one of a novel family of developmentally regulated RNA binding proteins that includes embryonically lethal abnormal vision-type RNA binding protein 3 (ETR-3). This family, which we call CELF proteins for CUG-BP- and ETR-3-like factors, specifically bound MSE-containing RNAs in vitro and activated MSE-dependent exon inclusion of cTNT minigenes in vivo. The expression of two CELF proteins is highly restricted to brain. CUG-BP, ETR-3, and CELF4 are more broadly expressed, and expression is developmentally regulated in striated muscle and brain. Changes in the level of expression and isoforms of ETR-3 in two different developmental systems correlated with regulated changes in cTNT splicing. A switch from cTNT exon skipping to inclusion tightly correlated with induction of ETR-3 protein expression during differentiation of C2C12 myoblasts. During heart development, the switch in cTNT splicing correlated with a transition in ETR-3 protein isoforms. We propose that ETR-3 is a major regulator of cTNT alternative splicing and that the CELF family plays an important regulatory role in cell-specific alternative splicing during normal development and disease.
Collapse
Affiliation(s)
- A N Ladd
- Department of Pathology, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | |
Collapse
|
22
|
Kimura T, Takahashi MP, Okuda Y, Kaido M, Fujimura H, Yanagihara T, Sakoda S. The expression of ion channel mRNAs in skeletal muscles from patients with myotonic muscular dystrophy. Neurosci Lett 2000; 295:93-6. [PMID: 11090982 DOI: 10.1016/s0304-3940(00)01598-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigated gene expression patterns of ion channels including the apamin-sensitive small-conductance Ca(2+)-activated K(+) (SK3) channel, the adult isoform of the skeletal muscle Na(+) channel (SkM1), the fetal isoform of skeletal muscle Na(+) channel (H1), and the Cl(-) channel (ClC-1) by using the semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) for muscle samples from patients with adult onset myotonic dystrophy (DM), amyotrophic lateral sclerosis, and polymyositis. Patients with DM showed a significant increase in SK3 mRNA but not in mRNAs for other ion channels. The increased expression of SK3 gene in DM did not correlate with H1, the marker of muscle denervation, or the percentage of type 2C fiber, the marker of muscle regeneration.
Collapse
Affiliation(s)
- T Kimura
- Department of Neurology D-4, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, 565-0871, Osaka, Japan
| | | | | | | | | | | | | |
Collapse
|
23
|
Abstract
Tropomyosin is a component protein of the thin filament system in striated muscle, regulating the interaction between actin and myosin. The 3' untranslated region of the alpha-striated tropomyosin gene (TM UTR) induces muscle differentiation when expressed in primary fibroblasts, but the mechanism has not been defined. We hypothesize that fibroblasts utilize resident proteins to effect this response, perhaps by TM UTR binding to protein(s). In order to facilitate identification of protein(s) involved in mediating this differentiation response, we investigated the potential for this sequence to bind to cellular protein utilizing electrophoretic mobility gel shifting analysis (EMSA) with and without UV cross-linking. Under very specific conditions (including pH, KCl, and Mg concentration and extent of phosphorylation of protein), the TM UTR is able to bind protein in cells that differentiate upon TM UTR expression. Protein binding is significantly more extensive in cytoplasmic than nuclear protein preparations. Secondary structure of the RNA probe facilitates protein binding. The molecular masses of bound proteins are approximately 42 and 115 kDa under basal conditions. EMSA analysis of extract from cultured skeletal muscle confirms that protein binding by the TM UTR occurs in this cell type, and is more extensive in less differentiated cells. The demonstration of highly regulated protein binding by the TM UTR raises the possibility that this sequence may cause differentiation by binding to endogenous proteins, and further that this sequence may play a role in normal differentiation. Identification of proteins bound by the TM UTR will be necessary to completely define the mechanism by which it causes differentiation.
Collapse
Affiliation(s)
- H L Fang
- Department of Pediatrics, Cardiology Division, Wayne State University, Children's Hospital of Michigan, 3901 Beaubien Boulevard, Detroit, Michigan, 48201, USA
| | | |
Collapse
|
24
|
Eriksson M, Ansved T, Edstrom L, Wells DJ, Watt DJ, Anvret M, Carey N. Independent regulation of the myotonic dystrophy 1 locus genes postnatally and during adult skeletal muscle regeneration. J Biol Chem 2000; 275:19964-9. [PMID: 10748037 DOI: 10.1074/jbc.m001592200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Myotonic dystrophy is caused by a CTG(n) expansion in the 3'-untranslated region of a serine/threonine protein kinase gene (DMPK), which is flanked by two other genes, DMWD and SIX5. One hypothesis to explain the wide-ranging effects of this expansion is that, as the mutation expands, it alters the expression of one or more of these genes. The effects may vary in different tissues and developmental stages, but it has been difficult to develop these hypotheses as the normal postnatal developmental expression patterns of these genes have not been adequately investigated. We have developed accurate transcript quantification based on fluorescent real-time reverse transcription-polymerase chain reaction (TaqMan) to develop gene expression profiles during postnatal development in C57Bl/10 mice. Our results show extensive independent postnatal regulation of the myotonic dystrophy-locus genes in selected tissues and demonstrate which are the most highly expressed of the genes in each tissue. All three genes at the locus are expressed in the adult lens, questioning a previous model of cataractogenesis mediated solely by effects on Six5 expression. Additionally, using an in vivo model, we have shown that Dmpk levels decrease during the early stages of muscle regeneration. Our data provide a framework for investigation of tissue-specific pathological mechanisms in this disorder.
Collapse
Affiliation(s)
- M Eriksson
- Department of Molecular Medicine, Division of Neurology, and Division of Clinical Neurophysiology, Karolinska Hospital, Stockholm 171 76, Sweden.
| | | | | | | | | | | | | |
Collapse
|
25
|
Jin S, Shimizu M, Balasubramanyam A, Epstein HF. Myotonic dystrophy protein kinase (DMPK) induces actin cytoskeletal reorganization and apoptotic-like blebbing in lens cells. CELL MOTILITY AND THE CYTOSKELETON 2000; 45:133-48. [PMID: 10658209 DOI: 10.1002/(sici)1097-0169(200002)45:2<133::aid-cm5>3.0.co;2-s] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
DMPK, the product of the DM locus, is a member of the same family of serine-threonine protein kinases as the Rho-associated enzymes. In DM, membrane inclusions accumulate in lens fiber cells producing cataracts. Overexpression of DMPK in cultured lens epithelial cells led to apoptotic-like blebbing of the plasma membrane and reorganization of the actin cytoskeleton. Enzymatically active DMPK was necessary for both effects; inactive mutant DMPK protein did not produce either effect. Active RhoA but not constitutive GDP-state mutant protein produced similar effects as DMPK. The similar actions of DMPK and RhoA suggest that they may function in the same regulatory network. The observed effects of DMPK may be relevant to the removal of membrane organelles during normal lens differentiation and the retention of intracellular membranes in DM lenses.
Collapse
Affiliation(s)
- S Jin
- Departments of Neurology, the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | |
Collapse
|
26
|
Sasagawa N, Takahashi N, Suzuki K, Ishiura S. An expanded CTG trinucleotide repeat causes trans RNA interference: a new hypothesis for the pathogenesis of myotonic dystrophy. Biochem Biophys Res Commun 1999; 264:76-80. [PMID: 10527844 DOI: 10.1006/bbrc.1999.1435] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Here we report a novel mechanism for the pathogenesis of myotonic dystrophy (DM). The DMPK mRNA with expanded CTG trinucleotide repeats interacts with other transcripts having expanded CAG repeats. This "trans RNA interference" occurs in vitro only when the number of CTG repeats is over 140 and the number of target CAG repeats exceeds 35. The trans RNA interference can explain all the phenomena previously reported about DM.
Collapse
Affiliation(s)
- N Sasagawa
- Department of Life Sciences, Graduate School of Arts and Sciences, Tokyo, 153-8902, Japan
| | | | | | | |
Collapse
|
27
|
Watanabe T, Sasagawa N, Usuki F, Koike H, Saitoh N, Sorimachi H, Maruyama K, Nakase H, Takagi A, Ishiura S, Suzuki K. Overexpression of myotonic dystrophy protein kinase in C2C12 myogenic culture involved in the expression of ferritin heavy chain and interleukin-1alpha mRNAs. J Neurol Sci 1999; 167:26-33. [PMID: 10500258 DOI: 10.1016/s0022-510x(99)00133-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The specific function of myotonic dystrophy protein kinase (DMPK) is still not known. We found that overexpression of human DMPK in C2C12 myogenic culture induces the expression of ferritin heavy chain (FN-H) mRNA using differential display analysis. The quantity of FN-H mRNA was greater in the DMPK transfectant with five CTG triplet repeats in the 3'-untranslated region, while it was lower in the transfectant with 46 CTG repeats, over that of the control clone. We also investigated the quantity of interleukin 1-alpha (IL-1alpha) mRNA in each culture, due to the fact that this cytokine is able to induce FN-H expression, regardless of the concentration of free iron. Quantitative, competitive polymerase chain reaction (PCR) analysis revealed that the quantity of IL1-alpha mRNA is higher in the transfectant with five repeats, compared to the quantity of mRNA in the control clone; however, it is markedly lower in the clone with 46 repeats. These results suggest that overexpression of DMPK in C2C12 cultures may up-regulate IL-1alpha expression, resulting in the induction of FN-H expression. However, a large number of CTG repeats in the 3'-untranslated region of the DMPK gene may affect the pathway of IL-1alpha transcription, thereby resulting in decreased expression of FN-H.
Collapse
Affiliation(s)
- T Watanabe
- Department of Neurology, Toranomon Hospital and Okinaka Memorial Institute for Medical Research, 2-2-2 Toranomon, Minato-ku, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
L'ecuyer TJ, Schutte BC, Mendel KA, Morris E, Fulton AB. Muscle-specific transcription factors in fibroblasts expressing the alpha-striated tropomyosin 3' untranslated region. Mol Genet Metab 1999; 67:213-26. [PMID: 10381329 DOI: 10.1006/mgme.1999.2858] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The alpha-striated tropomyosin 3' untranslated region (TM UTR) promotes differentiation of fibroblasts into cells resembling skeletal muscle. To investigate the mechanism of this observation, RNA harvested from transfected primary fibroblasts was used for semiquantitative RT-PCR with primers specific for muscle transcription factors, showing that myoD and myogenin transcripts are detected in these cells, but that differentiation after TM UTR expression is independent of a detectable increase in these transcripts. Double immunofluorescent staining with antibodies to myoD family members and to titin confirms that muscle differentiation in TM UTR-transfected fibroblasts is independent of production of any transcription factor in this family. In contrast, the muscle transcription factor myocyte enhancer factor 2 (mef-2) is strongly expressed after transfection of fibroblasts with the TM UTR. The increase in mef-2 protein is due to an increase in the steady-state level of its mRNA, as shown by Northern analysis. The expression of p21 ordinarily observed in skeletal myogenesis before the expression of muscle-specific proteins is not seen in fibroblasts induced to differentiate by the TM UTR. These results demonstrate that post-transcriptional regulation of myoD family members is seen in fibroblasts, and that the TM UTR induces muscle differentiation independent of the myoD transcription factors and without expressing proteins characteristic of terminal withdrawal from the cell cycle. Finally, an increase in the steady-state level of mef-2 transcripts appears in the proximal pathway of myogenic activation in response to expression of the TM UTR. These results imply that fibroblasts can utilize an additional differentiation route upon TM UTR expression resulting in mature muscle other than that requiring myoD family members.
Collapse
Affiliation(s)
- T J L'ecuyer
- Department of Pediatrics, Wayne State University College of Medicine, Cardiology Division, 3901 Beaubien Boulevard, Detroit, Michigan, 48201, USA.
| | | | | | | | | |
Collapse
|
29
|
Bhagavati S, Bhagwati S, Shafiq SA, Xu W. (CTG)n repeats markedly inhibit differentiation of the C2C12 myoblast cell line: implications for congenital myotonic dystrophy. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1453:221-9. [PMID: 10036320 DOI: 10.1016/s0925-4439(98)00104-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Although the mutation for myotonic dystrophy has been identified as a (CTG)n repeat expansion located in the 3'-untranslated region of a gene located on chromosome 19, the mechanism of disease pathogenesis is not understood. The objective of this study was to assess the effect of (CTG)n repeats on the differentiation of myoblasts in cell culture. We report here that C2C12 myoblast cell lines permanently transfected with plasmid expressing 500 bases long CTG repeat sequences, exhibited a drastic reduction in their ability to fuse and differentiate into myotubes. The percentage of cells fused into myotubes in C2 C12 cells (53.4+/-4.4%) was strikingly different from those in the two CTG repeat carrying clones (1.8+/-0.4% and 3.3+/-0. 7%). Control C2C12 cells permanently transfected with vector alone did not show such an effect. This finding may have important implications in understanding the pathogenesis of congenital myotonic dystrophy.
Collapse
Affiliation(s)
- S Bhagavati
- Department of Neurology, State University of New York Health Sciences Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
| | | | | | | |
Collapse
|
30
|
Affiliation(s)
- L T Timchenko
- Department of Medicine, Section of Cardiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. . edu
| |
Collapse
|
31
|
Okoli G, Carey N, Johnson KJ, Watt DJ. Over expression of the murine myotonic dystrophy protein kinase in the mouse myogenic C2C12 cell line leads to inhibition of terminal differentiation. Biochem Biophys Res Commun 1998; 246:905-11. [PMID: 9618310 DOI: 10.1006/bbrc.1998.8723] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myotonic dystrophy (DM) is an autosomal dominant human disorder, caused by the abnormal expansion of a CTG trinucleotide repeat in the 3' untranslated region of a protein kinase gene (DMPK). Muscle symptoms are a common feature of the disorder and in the adult onset cases there are increased patterns of muscle fibre degeneration and regeneration. In the congenitally affected infants there is a failure of muscle maturation, with the histological presence of numerous immature fibres. However, the pathological mechanism in both forms of the disease is unclear. We report that over-expression of the murine dmpk gene, in a murine myogenic cell line, leads to markedly reduced levels of fusion to the terminally differentiated state. These findings complement recently published data using a heterologous expression/cell system and may have implications for the understanding of the disease process in this disorder.
Collapse
Affiliation(s)
- G Okoli
- Division of Neurosciences & Psychological Medicine, Imperial College School of Medicine, London
| | | | | | | |
Collapse
|