We have generated UQACi001-A, a new induced pluripotent stem cell (iPSC) line derived from skin fibroblasts of a male patient with the generalized severe epidermolysis bullosa simplex phenotype ...(EBS-gen sev) and carrying the keratin 14 (K14) R125S mutation. Fibroblasts were reprogrammed using non-integrating Sendai virus vectors. The iPSC line displayed normal molecular karyotype, expressed pluripotency markers, is capable of differentiating into three embryonic germ layers and is genetically identical to the originating parental fibroblasts. The established iPSC model provides a valuable resource for studying the rare disease of epidermolysis bullosa simplex and developing new therapies as DNA editing by CRISPR/Cas9 technology.
Myotonic Dystrophy is the most common form of muscular dystrophy in adults, affecting an estimated 10 per 100,000 people. It is a multisystemic disorder affecting multiple generations with increasing ...severity. There are currently no licenced therapies to reverse, slow down or cure its symptoms. In 2009 TREAT-NMD (a global alliance with the mission of improving trial readiness for neuromuscular diseases) and the Marigold Foundation held a workshop of key opinion leaders to agree a minimal dataset for patient registries in myotonic dystrophy. Eight years after this workshop, we surveyed 22 registries collecting information on myotonic dystrophy patients to assess the proliferation and utility the dataset agreed in 2009. These registries represent over 10,000 myotonic dystrophy patients worldwide (Europe, North America, Asia and Oceania).
The registries use a variety of data collection methods (e.g. online patient surveys or clinician led) and have a variety of budgets (from being run by volunteers to annual budgets over €200,000). All registries collect at least some of the originally agreed data items, and a number of additional items have been suggested in particular items on cognitive impact.
The community should consider how to maximise this collective resource in future therapeutic programmes.
Abstract Myotonic dystrophy type 1 (DM1) and type II (DM2) are dominantly inherited multisystemic disorders. DM1 is triggered by the pathological expansion of a (CTG)n triplet repeat in the DMPK ...gene, whereas a (CCTG)n tetranucleotide repeat expansion in the ZNF9 gene causes DM2. Both forms of the disease share several features, even though the causative mutations and the loci involved differ. Important distinctions exist, such as the lack of a congenital form of DM2. The reason for these disparities is unknown. In this study, we characterized skeletal muscle satellite cells from adult DM2 patients to provide an in vitro model for the disease. We used muscle cells from DM1 biopsies as a comparison tool. Our main finding is that DM2 satellite cells differentiate normally in vitro . Myotube formation was similar to unaffected controls. In contrast, fetal DM1 cells were deficient in that ability. Consistent with this observation, the myogenic program in DM2 was intact but is compromised in fetal DM1 cells. Although expression of the ZNF9 gene was enhanced in DM2 during differentiation, the levels of the ZNF9 protein were substantially reduced. This suggests that the presence of a large CCTG tract impairs the translation of the ZNF9 mRNA. Additionally, DM2 muscle biopsies displayed the altered splicing of the insulin receptor mRNA, correlating with insulin resistance in the patients. Finally, CUGBP1 steady-state protein levels were unchanged in DM2 cultured muscle cells and in DM2 muscle biopsies relative to controls, whereas they are increased in DM1 muscle cells. Our findings suggest that the myogenic program throughout muscle development and tissue regeneration is intact in DM2.
Abstract The congenital form of myotonic dystrophy type 1 (DM1) is the most severe type of the disease associated with CTG expansions over 1500 repeats and delayed muscle maturation. The mechanistic ...basis of the congenital form of DM1 is mostly unknown. Here, we show that muscle satellite cells bearing large CTG expansions (> 3000) secrete a soluble factor that inhibits the fusion of normal myoblasts in culture. We identified this factor as prostaglandin E2 (PGE2 ). In these DM1 cells, PGE2 production is increased through up-regulation of cyclooxygenase 2 (Cox-2), mPGES-1 and prostaglandin EP2/EP4 receptors. Elevated levels of PGE2 inhibit myogenic differentiation by decreasing the intracellular levels of calcium. Exogenous addition of acetylsalicylic acid, an inhibitor of Cox enzymes, abolishes PGE2 abnormal secretion and restores the differentiation of DM1 muscle cells. These data indicate that the delay in muscle maturation observed in congenital DM1 may result, at least in part, from an altered autocrine mechanism. Inhibitors of prostaglandin synthesis may thus offer a powerful method to restore the differentiation of DM1 muscle cells.
Abstract Background Despite the fact that excessive daytime sleepiness (EDS) is one of the most common manifestations in patients with myotonic dystrophy type 1 (DM1), no treatment is yet available. ...Methylphenidate is being studied for prospective use in the treatment of EDS. Objective The aim of this investigator-initiated study was to evaluate the efficacy and tolerability of a single 20-mg morning dose of methylphenidate for the treatment of EDS in adults with DM1. Methods This randomized, double-blind, placebo-controlled, 3-week crossover trial was conducted at 2 sites in Quebec. French-Canadian patients with DM1 with an Epworth Sleepiness Scale score ≥10 were invited to participate in this crossover trial of 20 mg/d of methylphenidate versus placebo, with 3 weeks in each arm of the study separated by a 2-week washout period. The primary efficacy end points were the Daytime Sleepiness Scale and the Epworth Sleepiness Scale at week 3. Secondary end points included the energy/vitality scale of the RAND 36-Item Health Survey, the Profile of Mood States questionnaire, and the mean sleep latency test. Assessment of tolerability profile included a physical examination, measurement of blood pressure, standard 12-lead ECG, and laboratory tests. Adverse event assessments were recorded based on patient reporting at each visit on clinical report forms. Results In a total of 24 patients (12 men, 12 women; mean SD age, 46 13 years), 17 completed the study. Treatment with methylphenidate showed a significant change in median scores on the Daytime Sleepiness Scale (–3.0 vs –0.5; P = 0.003) and the Epworth Sleepiness Scale (–3.0 vs –1.5; P = 0.039). The Profile of Mood States and the energy/vitality scale from the RAND 36-Item Health Survey showed no significant changes. Likewise, there was no significant change in mean sleep latency test results. One patient died during the trial, but the autopsy results eliminated methylphenidate as cause of death. Three patients discontinued methylphenidate due to treatment-emergent adverse events (1, diarrhea; 2, nervousness and irritability). Loss of appetite, nausea, and palpitations were the most common adverse events reported by more patients treated with methylphenidate than those receiving placebo. Conclusion A single 20-mg dose of methylphenidate significantly reduced daytime sleepiness in this small selected population of patients with DM1. ClinicalTrials.gov identifier: NCT01421992.
Small interfering RNA (siRNA) duplexes induce the specific cleavage of target RNAs in mammalian cells. Their involvement in down-regulation of gene expression is termed RNA interference (RNAi). It is ...widely believed that RNAi predominates in the cytoplasm. We report here the co-existence of cytoplasmic and nuclear RNAi phenomena in primary human myotonic dystrophy type 1 (DM1) cells by targeting myotonic dystrophy protein kinase (DMPK) mRNAs. Heterozygote DM1 myoblasts from a human DM1 fetus produce a nuclear retained mutant DMPK transcript with large CUG repeats (∼3,200) from one allele of the DMPK gene and a wild type transcript with 18 CUG repeats, thus providing for both a nuclear and cytoplasmic expression profile to be evaluated. We demonstrate here for the first time down-regulation of the endogenous nuclear retained mutant DMPK mRNAs targeted with lentivirus-delivered short hairpin RNAs (shRNAs). This nuclear RNAi(-like) phenomenon was not observed when synthetic siRNAs were delivered by cationic lipids, suggesting either a link between processing of the shRNA and nuclear import or a separate pathway for processing shRNAs in the nuclei. Our observation of simultaneous RNAi on both cytoplasmic and nuclear retained DMPK has important implications for post-transcriptional gene regulation in both compartments of mammalian cells.
The original version of this article 1 unfortunately included an error to an author's name. Author Jordi Díaz-Manera was erroneously presented as Jorge Alberto Diaz Manera. The correct author name ...has been included in the author list of this Correction article.
Myotonic dystrophy type 1 (DM1) is a multisystem disorder that demonstrates variable symptoms and rates of progression. Muscle weakness is considered one of the main problems with a clinical picture ...that is characterized by distal weakness of the limbs progressing to proximal weakness. The main objective of this study was to characterize the maximal strength of ankle eversion and dorsiflexion in DM1 patients. Manual and handheld dynamometer (HHD) muscle testing were also compared.
The maximal strength of 22 patients from Quebec (mean age = 41,1 +/- 13,8) and 24 from Lyon (mean age = 41,6 +/- 10,2) were compared to 16 matched controls.
With the use of HHD, an excellent reproducibility of the torque measurements was obtained for both centers in eversion (R2 = 0,94/Quebec; 0,89/Lyon) and dorsiflexion (R2 = 0,96/Quebec; 0,90/Lyon). The differences between 3 groups of DM1 (mild, moderate, severe) and between them and controls were all statistically significant (p < 0,001). No statistical differences between sites were observed (p > 0.05). The degree of muscle strength decline in dorsiflexion (eversion) were 60% (47%), 77% (71%), and 87% (83%) for DM1 with mild, moderate, and severe impairments, respectively. The smallest mean difference between all DM1 patients taking together was 2.3 Nm, a difference about twice than the standard error of measurement. There was a strong relationship between eversion and dorsiflexion strength profiles (R2 = 0,87;Quebec/0,80;Lyon). Using a 10-point scale, manual muscle testing could not discriminate between the 3 groups of DM1 patients.
The HHD protocol showed discriminative properties suitable for multicentre therapeutic trial. The present results confirmed the capacity of quantitative muscle testing to discriminate between healthy and DM1 patients with different levels of impairments. This study is a preliminary step for the implementation of a valid, reliable and responsive clinical outcome for the measurement of muscle impairments with this population.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract Thirty-three French-Canadian families with non-dystrophic myotonia were identified. Fifty subjects were recruited and submitted to a complete clinical, electrophysiologic and genetic ...evaluation. Thirteen mutations were identified in CLCN1 and five mutations were identified in SCN4A. Onset in the lower extremities, presence of tongue myotonia and transient weakness suggested recessive CLCN1 mutations. Lid myotonia, absence of hypertrophy and exacerbation with cold temperature suggested SCN4A mutations. Pain was not a feature of dominant CLCN1 mutations while it could be seen in the others, more frequently in SCN4A mutations. Warm up phenomenon, hand grip myotonia, percussion myotonia, lid lag and hormonal effects were not distinguishing features. Repetitive nerve stimulation and short exercise test showed either a large (>50%) or mild-moderate (10–50%) decrement with recessive CLCN1 mutations while they showed only mild or no decrement with dominant CLCN1 and SCN4A mutations. The French-Canadian population shows wide phenotypic and genotypic heterogeneity in non-dystrophic myotonias.
In myotonic dystrophy type 1, several studies have suggested causal relationships between CTG repeat length and the severity of symptoms, such as weakness or myotonia. We aimed to explore these ...relationships in a large population of 144 DM1 patients. All patients underwent clinical and functional assessments using a standardized test for grip strength and myotonia assessment. Myotonia was assessed using a fully automatic software based on mathematical modeling of relaxation force curve. CTG repeat length was statistically correlated with both myotonia and grip strength, which are two major primary neuromuscular symptoms of DM1 patients. However, these relationships are not clinically meaningful and not predictive at the individual level.
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