scholarly journals Straightjacket/α2δ3 deregulation is associated with cardiac conduction defects in Myotonic Dystrophy type 1

2018 ◽  
Author(s):  
Emilie Plantié ◽  
Masayuki Nakamori ◽  
Yoan Renaud ◽  
Aline Huguet ◽  
Caroline Choquet ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Rna Binding ◽  
Cardiac Cells ◽  
Cardiac Conduction ◽  
Regulatory Subunit ◽  
Conduction Delay ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Intraventricular Conduction

ABSTRACTCardiac conduction defects decrease life expectancy in myotonic dystrophy type 1 (DM1), a complex toxic CTG repeat disorder involving misbalance between two RNA- binding factors, MBNL1 and CELF1. How this pathogenic DM1 condition translates into cardiac conduction disorders remains poorly understood. Here, we simulated MBNL1 and CELF1 misbalance in the Drosophila heart and identified associated gene deregulations using TU-tagging based transcriptional profiling of cardiac cells. We detected deregulations of several genes controlling cellular calcium levels and among them increased expression of straightjacket/α2δ3 that encodes a regulatory subunit of a voltage-gated calcium channel. Straightjacket overexpression in the fly heart leads to asynchronous heart beating, a hallmark of affected conduction, whereas cardiac straightjacket knockdown improves these symptoms in DM1 fly models. We also show that ventricular α2δ3 expression is low in healthy mice and humans but significantly elevated in ventricular muscles from DM1 patients with conduction defects. Taken together, this suggests that reducing the straightjacket/α2δ3 transcript levels in ventricular cardiomyocytes could represent a strategy to prevent conduction defects and in particular intraventricular conduction delay associated with DM1 pathology.

scholarly journals Straightjacket/α2δ3 deregulation is associated with cardiac conduction defects in myotonic dystrophy type 1

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Emilie Auxerre-Plantié ◽  
Masayuki Nakamori ◽  
Yoan Renaud ◽  
Aline Huguet ◽  
Caroline Choquet ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Rna Binding ◽  
Cardiac Cells ◽  
Cardiac Conduction ◽  
Regulatory Subunit ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Conduction Disorders ◽  
Decrease Life Expectancy

Cardiac conduction defects decrease life expectancy in myotonic dystrophy type 1 (DM1), a CTG repeat disorder involving misbalance between two RNA binding factors, MBNL1 and CELF1. However, how DM1 condition translates into conduction disorders remains poorly understood. Here we simulated MBNL1 and CELF1 misbalance in the Drosophila heart and performed TU-tagging-based RNAseq of cardiac cells. We detected deregulations of several genes controlling cellular calcium levels, including increased expression of straightjacket/α2δ3, which encodes a regulatory subunit of a voltage-gated calcium channel. Straightjacket overexpression in the fly heart leads to asynchronous heartbeat, a hallmark of abnormal conduction, whereas cardiac straightjacket knockdown improves these symptoms in DM1 fly models. We also show that ventricular α2δ3 expression is low in healthy mice and humans, but significantly elevated in ventricular muscles from DM1 patients with conduction defects. These findings suggest that reducing ventricular straightjacket/α2δ3 levels could offer a strategy to prevent conduction defects in DM1.

scholarly journals Author response: Straightjacket/α2δ3 deregulation is associated with cardiac conduction defects in myotonic dystrophy type 1

2019 ◽  
Author(s):  
Emilie Auxerre-Plantié ◽  
Masayuki Nakamori ◽  
Yoan Renaud ◽  
Aline Huguet ◽  
Caroline Choquet ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Cardiac Conduction ◽  
Author Response ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type

scholarly journals Brain Pathogenesis and Potential Therapeutic Strategies in Myotonic Dystrophy Type 1

2021 ◽  
Vol 13 ◽  
Author(s):  
Jie Liu ◽  
Zhen-Ni Guo ◽  
Xiu-Li Yan ◽  
Yi Yang ◽  
Shuo Huang
Keyword(s):  
Myotonic Dystrophy ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Brain Diseases ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Multiple Systems ◽  
Intervention Measures ◽  
Therapeutic Tools

Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy that affects multiple systems including the muscle and heart. The mutant CTG expansion at the 3′-UTR of the DMPK gene causes the expression of toxic RNA that aggregate as nuclear foci. The foci then interfere with RNA-binding proteins, affecting hundreds of mis-spliced effector genes, leading to aberrant alternative splicing and loss of effector gene product functions, ultimately resulting in systemic disorders. In recent years, increasing clinical, imaging, and pathological evidence have indicated that DM1, though to a lesser extent, could also be recognized as true brain diseases, with more and more researchers dedicating to develop novel therapeutic tools dealing with it. In this review, we summarize the current advances in the pathogenesis and pathology of central nervous system (CNS) deficits in DM1, intervention measures currently being investigated are also highlighted, aiming to promote novel and cutting-edge therapeutic investigations.

scholarly journals Increased Muscleblind levels by chloroquine treatment improve myotonic dystrophy type 1 phenotypes in in vitro and in vivo models

2019 ◽  
Vol 116 (50) ◽  
pp. 25203-25213 ◽  
Author(s):  
Ariadna Bargiela ◽  
Maria Sabater-Arcis ◽  
Jorge Espinosa-Espinosa ◽  
Miren Zulaica ◽  
Adolfo Lopez de Munain ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Rna Binding ◽  
Trinucleotide Repeat ◽  
Rna Binding Proteins ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Muscle Area ◽  
In Vivo Models

Myotonic dystrophy type 1 (DM1) is a life-threatening and chronically debilitating neuromuscular disease caused by the expansion of a CTG trinucleotide repeat in the 3′ UTR of the DMPK gene. The mutant RNA forms insoluble structures capable of sequestering RNA binding proteins of the Muscleblind-like (MBNL) family, which ultimately leads to phenotypes. In this work, we demonstrate that treatment with the antiautophagic drug chloroquine was sufficient to up-regulate MBNL1 and 2 proteins in Drosophila and mouse (HSALR) models and patient-derived myoblasts. Extra Muscleblind was functional at the molecular level and improved splicing events regulated by MBNLs in all disease models. In vivo, chloroquine restored locomotion, rescued average cross-sectional muscle area, and extended median survival in DM1 flies. In HSALR mice, the drug restored muscular strength and histopathology signs and reduced the grade of myotonia. Taken together, these results offer a means to replenish critically low MBNL levels in DM1.

scholarly journals Mexiletine in myotonic dystrophy type-1

Neurology ◽  
2020 ◽  
pp. 10.1212/WNL.0000000000011002
Author(s):  
Chad Heatwole ◽  
Elizabeth Luebbe ◽  
Spencer Rosero ◽  
Katy Eichinger ◽  
William Martens ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Cardiac Conduction ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Walk Distance ◽  
Hand Grip ◽  
Minute Walk Distance ◽  
Minute Walk

ObjectiveTo assess mexiletine's long-term safety and effect on 6 minute walk distance in a well-defined cohort of myotonic dystrophy type-1 (DM1) patients.MethodsWe performed a randomized, double-blind, placebo-controlled trial of mexiletine (150 mg 3 times daily) to evaluate its efficacy and safety in a homogenous cohort of adult ambulatory DM1 patients. The primary outcome was change in 6-minute walk distance at 6 months. Secondary outcomes included changes in hand grip myotonia, strength, swallowing, forced vital capacity, lean muscle mass, Myotonic Dystrophy Health Index scores, and 24-hour Holter and EKG results at 3 and 6 months.ResultsForty-two participants were randomized and 40 completed the 6-month follow-up (n = 20 in both groups). No significant effects of mexiletine were observed on 6-minute walk distance, but hand grip myotonia was improved with mexiletine treatment. There were no differences between the mexiletine and placebo groups with respect to the frequency or type of adverse events. Changes in PR, QRS, and QTc intervals were similar in mexiletine and placebo-treated participants.ConclusionsThere was no benefit of mexiletine on six-minute walk distance at 6 months. Although mexiletine had a sustained positive effect on objectively measured hand grip myotonia, this was not seen in measures reflecting participants' perceptions of their myotonia. No effects of mexiletine on cardiac conduction parameters were seen over the 6-month follow-up period.Classification of evidenceThis study provides Class I evidence that for ambulatory patients with DM1 mexiletine does not significantly change six-minute walk distance at 6 months.

scholarly journals Cardiac Conduction Disorders as Markers of Cardiac Events in Myotonic Dystrophy Type 1

2020 ◽  
Vol 9 (17) ◽  
Author(s):  
Hideki Itoh ◽  
Takashi Hisamatsu ◽  
Takuhisa Tamura ◽  
Kazuhiko Segawa ◽  
Toshiaki Takahashi ◽  
...  
Keyword(s):  
Sudden Death ◽  
Myotonic Dystrophy ◽  
Cardiac Conduction ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Cardiac Events ◽  
Conduction Disorders ◽  
Qrs Duration

Background Myotonic dystrophy type 1 involves cardiac conduction disorders. Cardiac conduction disease can cause fatal arrhythmias or sudden death in patients with myotonic dystrophy type 1. Methods and Results This study enrolled 506 patients with myotonic dystrophy type 1 (aged ≥15 years; >50 cytosine‐thymine‐guanine repeats) and was treated in 9 Japanese hospitals for neuromuscular diseases from January 2006 to August 2016. We investigated genetic and clinical backgrounds including health care, activities of daily living, dietary intake, cardiac involvement, and respiratory involvement during follow‐up. The cause of death or the occurrence of composite cardiac events (ie, ventricular arrhythmias, advanced atrioventricular blocks, and device implantations) were evaluated as significant outcomes. During a median follow‐up period of 87 months (Q1–Q3, 37–138 months), 71 patients expired. In the univariate analysis, pacemaker implantations (hazard ratio [HR], 4.35; 95% CI, 1.22–15.50) were associated with sudden death. In contrast, PQ interval ≥240 ms, QRS duration ≥120 ms, nutrition, or respiratory failure were not associated with the incidence of sudden death. The multivariable analysis revealed that a PQ interval ≥240 ms (HR, 2.79; 95% CI, 1.9–7.19, P <0.05) or QRS duration ≥120 ms (HR, 9.41; 95% CI, 2.62–33.77, P < 0.01) were independent factors associated with a higher occurrence of cardiac events than those observed with a PQ interval <240 ms or QRS duration <120 ms; these cardiac conduction parameters were not related to sudden death. Conclusions Cardiac conduction disorders are independent markers associated with cardiac events. Further investigation on the prediction of occurrence of sudden death is warranted.

scholarly journals Cardiac Pathology in Myotonic Dystrophy Type 1

2021 ◽  
Vol 22 (21) ◽  
pp. 11874
Author(s):  
Mani S. Mahadevan ◽  
Ramesh S. Yadava ◽  
Mahua Mandal
Keyword(s):  
Myotonic Dystrophy ◽  
Smooth Muscles ◽  
Clinical Manifestations ◽  
Cardiac Conduction ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Cardiac Pathology ◽  
Systemic Disorder ◽  
Cardiac Manifestations

Myotonic dystrophy type 1 (DM1), the most common muscular dystrophy affecting adults and children, is a multi-systemic disorder affecting skeletal, cardiac, and smooth muscles as well as neurologic, endocrine and other systems. This review is on the cardiac pathology associated with DM1. The heart is one of the primary organs affected in DM1. Cardiac conduction defects are seen in up to 75% of adult DM1 cases and sudden death due to cardiac arrhythmias is one of the most common causes of death in DM1. Unfortunately, the pathogenesis of cardiac manifestations in DM1 is ill defined. In this review, we provide an overview of the history of cardiac studies in DM1, clinical manifestations, and pathology of the heart in DM1. This is followed by a discussion of emerging data about the utility of cardiac magnetic resonance imaging (CMR) as a biomarker for cardiac disease in DM1, and ends with a discussion on models of cardiac RNA toxicity in DM1 and recent clinical guidelines for cardiologic management of individuals with DM1.

scholarly journals High-throughput kinome-RNAi screen identifies protein kinase R activator (PACT) as a novel genetic modifier of CUG foci integrity in myotonic dystrophy type 1 (DM1)

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256276
Author(s):  
Nafisa Neault ◽  
Sean O’Reilly ◽  
Aiman Tariq Baig ◽  
Julio Plaza-Diaz ◽  
Mehrdad Azimi ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Myotonic Dystrophy ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Genetic Modifier ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Aberrant Expression ◽  
Significant Correction

Myotonic Dystrophy Type 1 (DM1) is the most common form of adult muscular dystrophy (~1:8000). In DM1, expansion of CTG trinucleotide repeats in the 3’ untranslated region of the dystrophia myotonica protein kinase (DMPK) gene results in DMPK mRNA hairpin structures which aggregate as insoluble ribonuclear foci and sequester several RNA-binding proteins. The resulting sequestration and misregulation of important splicing factors, such as muscleblind-like 1 (MBNL1), causes the aberrant expression of fetal transcripts for several genes that contribute to the disease phenotype. Previous work has shown that antisense oligonucleotide-mediated disaggregation of the intranuclear foci has the potential to reverse downstream anomalies. To explore whether the nuclear foci are, to some extent, controlled by cell signalling pathways, we have performed a screen using a small interfering RNA (siRNA) library targeting 518 protein kinases to look at kinomic modulation of foci integrity. RNA foci were visualized by in situ hybridization of a fluorescent-tagged (CAG)10 probe directed towards the expanded DMPK mRNA and the cross-sectional area and number of foci per nuclei were recorded. From our screen, we have identified PACT (protein kinase R (PKR) activator) as a novel modulator of foci integrity and have shown that PACT knockdown can both increase MBNL1 protein levels; however, these changes are not suffcient for significant correction of downstream spliceopathies.

scholarly journals A comprehensive atlas of fetal splicing patterns in the brain of adult myotonic dystrophy type 1 patients

2021 ◽  
Author(s):  
Max J. F. Degener ◽  
Remco T.P. van Cruchten ◽  
Brittney A. Otero ◽  
Eric T. Wang ◽  
Derick G. Wansink ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Healthy Individuals ◽  
Developmentally Regulated ◽  
The Central Nervous System ◽  
Splicing Patterns

ABSTRACTIn patients with myotonic dystrophy type 1 (DM1), dysregulation of RNA-binding proteins like MBNL and CELF1 leads to alternative splicing of exons and is thought to induce a return to fetal splicing patterns in adult tissues, including the central nervous system (CNS). To comprehensively evaluate this, we created an atlas of developmentally regulated splicing patterns in the frontal cortex of healthy individuals and DM1 patients by combining RNA-seq data from BrainSpan, GTEx and DM1 patients. Thirty four splice events displayed an inclusion pattern in DM1 patients that is typical for the fetal situation in healthy individuals. The regulation of DM1-relevant splicing patterns could partly be explained by changes in mRNA expression of the splice regulators MBNL1, MBNL2 and CELF1. On the contrary, interindividual differences in splicing patterns between healthy adults could not be explained by differential expression of these splice regulators. Our findings lend transcriptome-wide evidence to the previously noted shift to fetal splicing patterns in the adult DM1 brain as a consequence of an imbalance in antagonistic MBNL and CELF1 activities. Our atlas serves as a solid foundation for further study and understanding of the cognitive phenotype in patients.

Sign in / Sign up

Export Citation Format

Share Document