Myotonic dystrophy type 1 (DM1) is a chronically debilitating, rare genetic disease that originates from an expansion of a noncoding CTG repeat in the dystrophia myotonica protein kinase (DMPK) gene. The expansion becomes pathogenic when DMPK transcripts contain 50 or more repetitions due to the sequestration of the muscleblind-like (MBNL) family of proteins. Depletion of MBNLs causes alterations in splicing patterns in transcripts that contribute to clinical symptoms such as myotonia and muscle weakness and wasting. We previously found that microRNA (miR)-23b directly regulates MBNL1 in DM1 myoblasts and mice and that antisense technology ("antagomiRs") blocking this microRNA (miRNA) boosts MBNL1 protein levels. Here, we show the therapeutic effect over time in response to administration of antagomiR-23b as a treatment in human skeletal actin long repeat (HSA) mice. Subcutaneous administration of antagomiR-23b upregulated the expression of MBNL1 protein and rescued splicing alterations, grip strength, and myotonia in a dose-dependent manner with long-lasting effects. Additionally, the effects of the treatment on grip strength and myotonia were still slightly notable after 45 days. The pharmacokinetic data obtained provide further evidence that miR-23b could be a valid therapeutic target for DM1.
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http://dx.doi.org/10.1016/j.omtn.2020.07.021 | DOI Listing |
JACC Clin Electrophysiol
January 2025
Section of Cardiac Electrophysiology, Cardiovascular Medicine Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Background: Literature on the prevalence and management of atrial arrhythmias in patients with myotonic muscular dystrophy type 1 (MMD1) or myotonic muscular dystrophy type 2 (MMD2) is limited.
Objectives: This study sought to describe incidence, prevalence, and predictors of atrial fibrillation (AF) and atrial flutter (AFL) in a contemporary cohort of patients with myotonic muscular dystrophy (MMD).
Methods: Associations between patient factors and incident AF/AFL were analyzed in patients with MMD referred for routine electrophysiology evaluation between January 2013 and September 2023.
J Clin Invest
January 2025
Center for Inherited Myology Research, Virginia Commonwealth University, Richmond, United States of America.
Background: Myotonic dystrophy type 1 (DM1) is a multisystemic, CTG repeat expansion disorder characterized by a slow, progressive decline in skeletal muscle function. A biomarker correlating RNA mis-splicing, the core pathogenic disease mechanism, and muscle performance is crucial for assessing response to disease-modifying interventions. We evaluated the Myotonic Dystrophy Splice Index (SI), a composite RNA splicing biomarker incorporating 22 disease-specific events, as a potential biomarker of DM1 muscle weakness.
View Article and Find Full Text PDFCommun Med (Lond)
January 2025
Dyne Therapeutics Inc, Waltham, MA, USA.
Background: We developed the FORCE platform to overcome limitations of oligonucleotide delivery to muscle and enable their applicability to neuromuscular disorders. The platform consists of an antigen-binding fragment, highly specific for the human transferrin receptor 1 (TfR1), conjugated to an oligonucleotide via a cleavable valine-citrulline linker. Myotonic dystrophy type 1 (DM1) is a neuromuscular disorder caused by expanded CUG triplets in the DMPK RNA, which sequester splicing proteins in the nucleus, lead to spliceopathy, and drive disease progression.
View Article and Find Full Text PDFGeroscience
January 2025
Department of Physical Medicine and Rehabilitation, University of Missouri, Columbia, MO, USA.
Sarcopenia, the pathological age-related loss of muscle mass and strength, contributes to physical decline, frailty, and diminished healthspan. The impact of sarcopenia is expected to rise as the aging population grows, and treatments remain limited. Therefore, novel approaches for enhancing physical function and strength in older adults are desperately needed.
View Article and Find Full Text PDFNat Med
January 2025
Huntington's Disease Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK.
Huntington's disease (HD) is an autosomal dominant neurodegenerative disease with the age at which characteristic symptoms manifest strongly influenced by inherited HTT CAG length. Somatic CAG expansion occurs throughout life and understanding the impact of somatic expansion on neurodegeneration is key to developing therapeutic targets. In 57 HD gene expanded (HDGE) individuals, ~23 years before their predicted clinical motor diagnosis, no significant decline in clinical, cognitive or neuropsychiatric function was observed over 4.
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