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Biology subjects

Coles, C. A.

Publications and source records attributed to Coles, C. A..

3 recordsLinked to original sources

Targeted DUX4 base editing improves muscle function in an iPSC-derived model of childhood-onset FSHD

Facioscapulohumeral muscular dystrophy (FSHD) is one of the most common dominant muscular dystrophies and remains without an approved disease modifying therapy. Caused by the aberrant expression of the cytotoxic gene DUX4, FSHD is typically diagnosed in adulthood, however clinical onset in children (<18 years of age) is often associated with a more severe and rapid disease. While clinical trials are underway, a lack of human-specific pre-clinical models limit effective testing of potential therapies, particularly in children. To fill this gap, we describe here the development of induced pluripotent stem cell-derived 2-and 3-dimensional skeletal muscle models of children with clinically defined mild, moderate, and severe FSHD. These iPSC-derived muscle models replicate key features of FSHD, including aberrant DUX4 mRNA expression, muscle atrophy, and weakness, which correlate with the individuals specific disease severity. Next, we assessed the efficacy of adenine base editing (ABE) as a potential gene therapy approach to treat FSHD. DUX4-targeted ABE reduced DUX4 mRNA expression, improved muscle area and force generation in the most severe individual. Together this work supports the use of iPSC-derived skeletal muscle models as a less invasive method to study childhood-onset FSHD and establishes targeted DUX4 gene editing therapies as a potential treatment approach.

cell biology↗

Low dose resveratrol promotes hypertrophy in wildtype skeletal muscle and reduces damage in skeletal muscle of exercised mdx mice.

Duchenne muscular dystrophy (DMD) is a progressive and fatal neuromuscular disorder for which there is no treatment. Therapies to restore dystrophin deficiency are not ready for clinical use and long-term efficiency is yet to be established. Therefore, there is a need to develop alternative strategies to treat DMD. Resveratrol is a nutraceutical with anti-inflammatory properties and previous studies have shown that high doses can benefit mdx mice. We treated 4-week-old mdx and wildtype mice with low-dose resveratrol (5mg/kg bodyweight/day) for 15 weeks. A voluntary exercise protocol was added to test if low dose resveratrol could reduce exercise-induced damage. We showed that resveratrol promoted skeletal muscle hypertrophy in the wildtype mice. There was no change in markers of pathology in the mdx mice; however, the low-dose resveratrol reduced exercised induced damage. Gene expression of immune cell markers such as CD86, CD163 and PCNA was reduced; however signalling targets associated with resveratrols mechanism of action of action including SIRT1 and NF-{kappa}B were unchanged. In conclusion, low-dose resveratrol was not effective in reducing disease pathology; however, its ability to promote hypertrophy in wildtype skeletal muscle could have direct applications to the livestock industry or in sports medicine.

physiology↗

Benfotiamine reduces pathology and improves muscle function in mdx mice.

Duchenne Muscular Dystrophy (DMD) is a progressive and fatal neuromuscular disease which arises from mutations in the dystrophin gene (DMD) that result in the absence or severe reduction of the cytoskeletal protein dystrophin. In addition to the primary dystrophin defect, secondary processes such as inflammation, calcium influx, dysregulated autophagy and fibrosis exacerbate dystrophic pathology and thus increase disease progression. While therapies to restore dystrophin deficiency are being developed, strategies which target these secondary processes could be of benefit to patients. Benfotiamine is a lipid soluble precursor to thiamine that can reduce secondary processes such as inflammation and oxidative stress in diabetic patients. As such we tested it in the mdx mouse model of DMD and found that benfotiamine reduced multiple markers of dystrophic pathology and improved grip strength. In addition, members of the utrophin and dystrophin glycoprotein complexes were significantly increased at the sarcolemma which could improve cell adhesion. We also demonstrated that benfotiamine treatment lowered the expression of macrophage markers and pro-inflammatory cytokines suggesting that benfotiamine is reducing dystrophic pathology by acting on inflammatory processes.

physiology↗