• genome organization
• muscle biopsy
• myotonic dystrophy type 1
• nuclear envelope
• nuclear envelope transmembrane proteins

• human primary muscle cell culture
• myotonic dystrophy type 1
• splicing
• transcriptomics

• Adult
• Cell Differentiation
• Cells, Cultured
• Humans
• Myoblasts/cytology
• Myoblasts/metabolism
• Myotonic Dystrophy/genetics
• Myotonic Dystrophy/metabolism
• RNA Splicing
• Transcriptome

Myotonic dystrophy type 1 (DM1) is an autosomal dominant multisystemic disorder caused by unstable CTG-repeat expansions in the DMPK gene. Tissue mosaicism has been described for the length of these repeat expansions. The most obvious affected tissue is skeletal muscle, making it the first target for therapy development. To date there is no approved therapy despite some existing approaches. Thus, there is the demand to further advance therapeutic developments, which will in return require several well-characterized preclinical tools and model systems. Here we describe a modified method to identify the CTG-repeat length in primary human myoblasts isolated from DM1 patients that requires less genomic DNA and avoids radioactive labeling. Using this method, we show that primary human DM1 myoblast cultures represent a population of cells with different CTG-repeat length. Comparing DNA from the identical muscle biopsy specimen, the range of CTG-repeat length in the myoblast culture is within the same range of the muscle biopsy specimen. In conclusion, primary human DM1 myoblast cultures are a well-suited model to investigate certain aspects of the DM1 pathology. They are a useful platform to perform first-line investigations of preclinical therapies.

• CTG-repeats
• DMPK
• myotonic dystrophy type 1
• primary human myoblast cultures
• repeat detection

Myotonic dystrophy type I (DM1) is the most common form of adult muscular dystrophy, caused by expansion of a CTG triplet repeat in the 3′ untranslated region (3′UTR) of the myotonic dystrophy protein kinase (DMPK) gene. The pathological CTG repeats result in protein trapping by expanded transcripts, a decreased DMPK translation and the disruption of the chromatin structure, affecting neighboring genes expression. The muscleblind-like (MBNL) and CUG-BP and ETR-3-like factors (CELF) are two families of tissue-specific regulators of developmentally programmed alternative splicing that act as antagonist regulators of several pre-mRNA targets, including troponin 2 (TNNT2), insulin receptor (INSR), chloride channel 1 (CLCN1) and MBNL2. Sequestration of MBNL proteins and up-regulation of CELF1 are key to DM1 pathology, inducing a spliceopathy that leads to a developmental remodelling of the transcriptome due to an adult-to-foetal splicing switch, which results in the loss of cell function and viability. Moreover, recent studies indicate that additional pathogenic mechanisms may also contribute to disease pathology, including a misregulation of cellular mRNA translation, localization and stability. This review focuses on the cause and effects of MBNL and CELF1 deregulation in DM1, describing the molecular mechanisms underlying alternative splicing misregulation for a deeper understanding of DM1 complexity. To contribute to this analysis, we have prepared a comprehensive list of transcript alterations involved in DM1 pathogenesis, as well as other deregulated mRNA processing pathways implications.

• CELF1
• DMPK
• MBNL
• myotonic dystrophy
• spliceopathy

• Alternative splicing
• Development
• Drosophila
• Muscle
• RNA-binding proteins

• Alternative splicing and polyadenylation
• Microsatellite repeat expansions
• Post-transcriptional gene regulation
• RNA toxicity
• RNA-binding proteins

• RNA binding proteins
• alternative splicing
• muscle development
• skeletal muscle
• type 1 diabetes

• Childhood myotonic dystrophy
• Clinical manifestations
• Congenital myotonic dystrophy
• Management
• Myotonic dystrophy type 1
• Natural history

To date, in Myotonic Dystrophy type 1 (DM1) the rehabilitative interventions have always been aimed at muscle strengthening, increasing of fatigue resistance and improving of aerobic metabolism efficiency whereas the electrical membrane fault has always been addressed pharmacologically. Neuromuscular electrical stimulation (NMES) is a useful therapeutic tool in sport medicine and in the rehabilitation of many clinical conditions characterized by motor impairment such as stroke, cerebral palsy and spinal cord injury.

The aim of our pilot study was to evaluate the effects of chronic electrical stimulation both on functional and electrical properties of muscle in a small group of DM1 patients.

Five DM1 patients and one patient with Congenital Myotonia (CM) performed a home electrical stimulation of the tibialis anterior muscle lasting 15 days with a frequency of two daily sessions of 60 minutes each. Muscle strength was assessed according to the MRC scale (Medical Research Council) and functional tests (10 Meter Walking Test, 6 Minutes Walking Test and Timed Up and Go Test) were performed. We analyzed the average rectified value of sEMG signal amplitude (ARV) to characterize the sarcolemmal excitability.

After the treatment an increase of muscle strength in those DM1 patients with a mild strength deficit was observed. In all subjects an improvement of 10MWT was recorded. Five patients improved their performance in the 6MWT. In TUG test 4 out of 6 patients showed a slight reduction in execution time. All patients reported a subjective improvement when walking. A complete recovery of the normal increasing ARV curve was observed in 4 out of 5 DM1 patients; the CM patient didn’t show modification of the ARV pattern.

NMES determined a clear-cut improvement of both the muscular weakness and the sarcolemmal excitability alteration in our small group of DM1 patients. Therefore this rehabilitative approach, if confirmed by further extensive studies, could be considered early in the management of muscular impairment in these patients. An attractive hypothesis to explain our encouraging result could be represented by a functional inhibition of SK3 channels expressed in muscle of DM1 subjects.

• Follow-up
• In vivo
• Mouse
• Myotonic dystrophy type 1
• Skeletal muscle

Antisense therapy is an approach to fighting diseases using short DNA-like molecules called antisense oligonucleotides. Recently, antisense therapy has emerged as an exciting and promising strategy for the treatment of various neurodegenerative and neuromuscular disorders. Previous and ongoing pre-clinical and clinical trials have provided encouraging early results. Spinal muscular atrophy (SMA), Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS), Duchenne muscular dystrophy (DMD), Fukuyama congenital muscular dystrophy (FCMD), dysferlinopathy (including limb-girdle muscular dystrophy 2B; LGMD2B, Miyoshi myopathy; MM, and distal myopathy with anterior tibial onset; DMAT), and myotonic dystrophy (DM) are all reported to be promising targets for antisense therapy. This paper focuses on the current progress of antisense therapies in neurology.

Frontotemporal dementia (FTD) is a common dementia syndrome in patients under the age of 65 years with many features overlapping with amyotrophic lateral sclerosis (ALS). The link between FTD and ALS has been strengthened by the discovery that a hexanucleotide repeat expansion in a non-coding region of the C9ORF72 gene causes both familial and sporadic types of these two diseases. As we begin to understand the pathophysiological mechanisms by which this mutation leads to FTD and ALS (c9FTD/ALS), new targets for disease-modifying therapies will likely be unveiled. Putative C9ORF72 expansion pathogenic mechanisms include loss of C9ORF72 protein function, sequestration of nucleic acid binding proteins due to expanded hexanucleotide repeats, or a combination of the two. New animal models and other research tools informed by work in other repeat expansion neurodegenerative diseases such as the spinocerebellar ataxias will help to elucidate the mechanisms of C9ORF72-mediated disease. Similarly, re-examining previous studies of drugs developed to treat ALS in light of this new mutation may identify novel FTD treatments. Ultimately, research consortiums incorporating animal models and well-characterized clinical populations will be necessary to fully understand the natural history of the c9FTD/ALS clinical phenotypes and identify biomarkers and therapeutic agents that can cure the most common form of genetically determined FTD and ALS.

• 3' Untranslated Regions/genetics
• Computational Biology
• Evolution, Molecular
• Gene Expression Regulation
• Humans
• MicroRNAs/genetics
• MicroRNAs/metabolism
• Neurodegenerative Diseases/genetics
• Neurodegenerative Diseases/metabolism
• Proteins/genetics
• Proteins/metabolism
• Regression Analysis

The myotonic dystrophies (DM) are human diseases in which the accumulation of toxic RNA (CUG or CCUG) repeats in the cell causes sequestration of splicing factors, including MBNL1, leading to clinical symptoms such as muscle wasting and myotonia. We previously used Dynamic Combinatorial Chemistry to identify the first compounds known to inhibit (CUG)-MBNL1 binding in vitro. We now report transformation of those compounds into structures with activity in vivo. Introduction of a benzo[g]quinoline substructure previously unknown in the context of RNA recognition, as well as other modifications, provided several molecules with enhanced binding properties, including compounds with strong selectivity for CUG repeats over CAG repeats or CAG–CUG duplex RNA. Compounds readily penetrate cells, and improve luciferase activity in a mouse myoblast assay in which enzyme function is coupled to a release of nuclear CUG–RNA retention. Most importantly, two compounds are able to partially restore splicing in a mouse model of DM1.

• myotonic dystrophy
• facioscapulohumeral muscular dystrophy
• registry
• disease progression
• burdens of disease

• Adult
• Disease Progression
• Female
• Humans
• Male
• Muscular Dystrophy, Facioscapulohumeral/epidemiology
• Myotonic Dystrophy/epidemiology
• Patient Selection
• Rare Diseases
• Registries/standards
• Young Adult

• U54 NS048843-07 NINDS NIH HHS
• N01-AR-5-2274 NIAMS NIH HHS
• UL1 RR024160 NCRR NIH HHS
• U54 NS048843-09 NINDS NIH HHS
• U54-NS048843 NINDS NIH HHS
• N01-AR-0-2250 NIAMS NIH HHS
• U54 NS048843-08 NINDS NIH HHS
• U54 NS048843-06 NINDS NIH HHS
• N01AR02250 NIAMS NIH HHS
• N01AR52274 NIAMS NIH HHS
• U54 NS048843 NINDS NIH HHS

• repetitive dna
• epigenetics
• chromatin
• muscular dystrophy
• alternative splicing
• myotonic muscular dystrophy
• facioscapulohumeral muscular dystrophy

• Alternative Splicing
• Animals
• Humans
• Muscle, Skeletal/metabolism
• Muscular Dystrophies/genetics
• Muscular Dystrophies/metabolism
• RNA-Binding Proteins/metabolism

• 204279 European Research Council
• TCP05001 Telethon

• Aminoglycosides/chemistry
• Base Sequence
• Ligands
• Microarray Analysis
• Nucleic Acid Conformation
• Nucleic Acid Hybridization
• RNA/chemistry
• Structure-Activity Relationship

• R01 GM079235 NIGMS NIH HHS
• R01-GM079235 NIGMS NIH HHS

• Adolescent
• Adult
• Aged
• Bias
• Disability Evaluation
• Female
• Humans
• Male
• Middle Aged
• Models, Statistical
• Myotonic Dystrophy/diagnosis
• Myotonic Dystrophy/physiopathology
• Outcome Assessment, Health Care
• Reproducibility of Results
• Severity of Illness Index
• Surveys and Questionnaires
• Young Adult