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Updated: Dec 12, 2025
Cell Membrane Repair Assay Using a Two-photon Laser Microscope
Published on: January 2, 2018
Membrane Repair Deficit in Facioscapulohumeral Muscular Dystrophy
Adam J Bittel1, Sen Chandra Sreetama1, Daniel C Bittel1
1Research Center for Genetic Medicine, Children's National Hospital, 111 Michigan Ave NW, Washington, DC 20010, USA.
Abstract:
Deficits in plasma membrane repair have been identified in dysferlinopathy and Duchenne Muscular Dystrophy, and contribute to progressive myopathy. Although Facioscapulohumeral Muscular Dystrophy (FSHD) shares clinicopathological features with these muscular dystrophies, it is unknown if FSHD is characterized by plasma membrane repair deficits. Therefore, we exposed immortalized human FSHD myoblasts, immortalized myoblasts from unaffected siblings, and myofibers from a murine model of FSHD (FLExDUX4) to focal, pulsed laser ablation of the sarcolemma. Repair kinetics and success were determined from the accumulation of intracellular FM1-43 dye post-injury. We subsequently treated FSHD myoblasts with a DUX4-targeting antisense oligonucleotide (AON) to reduce DUX4 expression, and with the antioxidant Trolox to determine the role of DUX4 expression and oxidative stress in membrane repair. Compared to unaffected myoblasts, FSHD myoblasts demonstrate poor repair and a greater percentage of cells that failed to repair, which was mitigated by AON and Trolox treatments. Similar repair deficits were identified in FLExDUX4 myofibers. This is the first study to identify plasma membrane repair deficits in myoblasts from individuals with FSHD, and in myofibers from a murine model of FSHD. Our results suggest that DUX4 expression and oxidative stress may be important targets for future membrane-repair therapies.
Insights
Facioscapulohumeral Muscular Dystrophy (FSHD) myoblasts show impaired plasma membrane repair. Treatments reducing DUX4 expression or oxidative stress improved repair, suggesting new therapeutic targets for FSHD.
Area of Science:
- Muscle biology
- Cellular repair mechanisms
- Genetic neuromuscular disorders
Background:
- Plasma membrane repair deficits are implicated in muscular dystrophies like dysferlinopathy and Duchenne Muscular Dystrophy.
- Facioscapulohumeral Muscular Dystrophy (FSHD) shares features with other muscular dystrophies, but its plasma membrane repair capacity is uncharacterized.
- The role of DUX4 expression and oxidative stress in FSHD pathophysiology is increasingly recognized.
Purpose of the Study:
- To investigate whether human FSHD myoblasts and a murine model of FSHD exhibit plasma membrane repair deficits.
- To determine the impact of DUX4 expression and oxidative stress on plasma membrane repair in FSHD.
- To explore potential therapeutic strategies targeting DUX4 and oxidative stress for FSHD.
Main Methods:
- Focal laser ablation of the sarcolemma was used to assess plasma membrane repair in immortalized human FSHD myoblasts and myofibers from a murine FSHD model (FLExDUX4).
- Repair kinetics and success were quantified by measuring intracellular FM1-43 dye accumulation post-injury.
- FSHD myoblasts were treated with a DUX4-targeting antisense oligonucleotide (AON) and the antioxidant Trolox to evaluate their effects on membrane repair.
Main Results:
- FSHD myoblasts exhibited significantly poorer plasma membrane repair compared to unaffected controls, with a higher percentage of cells failing to repair.
- Treatment with the DUX4-targeting AON and Trolox ameliorated the observed plasma membrane repair deficits in FSHD myoblasts.
- Similar plasma membrane repair deficits were observed in myofibers from the murine FLExDUX4 model of FSHD.
Conclusions:
- This study provides the first evidence of plasma membrane repair deficits in FSHD myoblasts and a murine FSHD model.
- DUX4 expression and associated oxidative stress appear to play a critical role in the impaired membrane repair observed in FSHD.
- Targeting DUX4 and oxidative stress presents a promising avenue for developing novel therapeutic interventions for FSHD.
