Human miRNA miR-675 inhibits DUX4 expression and may be exploited as a potential treatment for Facioscapulohumeral muscular dystrophy

AbstractFacioscapulohumeral muscular dystrophy (FSHD) is a potentially devastating myopathy caused by de-repression of the DUX4 gene in skeletal muscles. Effective therapies will likely involve DUX4 inhibition. RNA interference (RNAi) is one powerful approach to inhibit DUX4, and we previously described a RNAi gene therapy to achieve DUX4 silencing in FSHD cells and mice using engineered microRNAs. Here we report a strategy to direct RNAi against DUX4 using the natural microRNA miR-675, which is derived from the lncRNA H19. Human miR-675 inhibits DUX4 expression and associated outcomes in FSHD cell models. In addition, miR-675 delivery using gene therapy protects muscles from DUX4-associated death in mice. Finally, we show that three known miR-675-upregulating small molecules inhibit DUX4 and DUX4-activated FSHD biomarkers in FSHD patient-derived myotubes. To our knowledge, this is the first study demonstrating the use of small molecules to suppress a dominant disease gene using an RNAi mechanism.

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Homozygous nonsense variant in LRIF1 associated with facioscapulohumeral muscular dystrophy

Neurology ◽

10.1212/wnl.0000000000009617 ◽

2020 ◽

Vol 94 (23) ◽

pp. e2441-e2447 ◽

Cited By ~ 10

Author(s):

Kohei Hamanaka ◽

Darina Šikrová ◽

Satomi Mitsuhashi ◽

Hiroki Masuda ◽

Yukari Sekiguchi ◽

...

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Muscular Dystrophy ◽

Target Gene ◽

Disease Gene ◽

Facioscapulohumeral Muscular Dystrophy ◽

Target Gene Expression ◽

D4z4 Repeat ◽

Biopsy Examination ◽

Chromatin Relaxation

ObjectiveFacioscapulohumeral muscular dystrophy (FSHD) is a heterogenetic disorder predominantly characterized by progressive facial and scapular muscle weakness. Patients with FSHD either have a contraction of the D4Z4 repeat on chromosome 4q35 or mutations in D4Z4 chromatin modifiers SMCHD1 and DNMT3B, both causing D4Z4 chromatin relaxation and inappropriate expression of the D4Z4-encoded DUX4 gene in skeletal muscle. In this study, we tested the hypothesis whether LRIF1, a known SMCHD1 protein interactor, is a disease gene for idiopathic FSHD2.MethodsClinical examination of a patient with idiopathic FSHD2 was combined with pathologic muscle biopsy examination and with genetic, epigenetic, and molecular studies.ResultsA homozygous LRIF1 mutation was identified in a patient with a clinical phenotype consistent with FSHD. This mutation resulted in the absence of the long isoform of LRIF1 protein, D4Z4 chromatin relaxation, and DUX4 and DUX4 target gene expression in myonuclei, all molecular and epigenetic hallmarks of FSHD. In concordance, LRIF1 was shown to bind to the D4Z4 repeat, and knockdown of the LRIF1 long isoform in muscle cells results in DUX4 and DUX4 target gene expression.ConclusionLRIF1 is a bona fide disease gene for FSHD2. This study further reinforces the unifying genetic mechanism, which postulates that FSHD is caused by D4Z4 chromatin relaxation, resulting in inappropriate DUX4 expression in skeletal muscle.

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p53 convergently activates Dux/DUX4 in embryonic stem cells and in facioscapulohumeral muscular dystrophy cell models

Nature Genetics ◽

10.1038/s41588-021-00893-0 ◽

2021 ◽

Author(s):

Edward J. Grow ◽

Bradley D. Weaver ◽

Christina M. Smith ◽

Jingtao Guo ◽

Paula Stein ◽

...

Keyword(s):

Stem Cells ◽

Embryonic Stem Cells ◽

Muscular Dystrophy ◽

Embryonic Stem ◽

Facioscapulohumeral Muscular Dystrophy ◽

Cell Models

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Identification of candidate miRNA biomarkers for facioscapulohumeral muscular dystrophy using DUX4-based mouse models

Disease Models & Mechanisms ◽

10.1242/dmm.049016 ◽

2021 ◽

Author(s):

Andreia M. Nunes ◽

Monique Ramirez ◽

Takako I. Jones ◽

Peter L. Jones

Keyword(s):

Muscular Dystrophy ◽

Mouse Model ◽

Mouse Models ◽

Skeletal Muscles ◽

Facioscapulohumeral Muscular Dystrophy ◽

Muscle Pathology ◽

Aged Mouse ◽

Serum Samples ◽

Key Aspects ◽

Different Levels

Facioscapulohumeral muscular dystrophy (FSHD) is caused by misexpression of DUX4 in skeletal myocytes. As DUX4 is the key therapeutic target in FSHD, surrogate biomarkers of DUX4 expression in skeletal muscle are critically needed for clinical trials. While no natural animal models of FSHD exist, transgenic mice with inducible DUX4 expression in skeletal muscles rapidly develop myopathic phenotypes consistent with FSHD. Here, we establish a new, more accurate FSHD-like mouse model based on chronic DUX4 expression in a small fraction of skeletal myonuclei that develops pathology mimicking key aspects of FSHD across its lifespan. Utilizing this new aged mouse model and DUX4-inducible mouse models, we characterized the DUX4-related microRNA signatures in skeletal muscles, which represent potential biomarkers for FSHD. We found increased expression of miR-31-5p and miR-206 in muscles expressing different levels of DUX4 and displaying varying degrees of pathology. Importantly, miR-206 expression is significantly increased in serum samples from FSHD patients compared with healthy controls. Our data support miR-31-5p and miR-206 as new potential regulators of muscle pathology and miR-206 as a potential circulating biomarker for FSHD.

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