Muscular dystrophy is a neuromuscular disease that takes on multiple forms. It is caused by a genetic mutation, which makes cells unable to produce the proteins necessary for muscular growth. In muscular dystrophy, the tissues eventually break down and cause progressive muscular weakness.
This neuromuscular disease is diagnosed at a young age and children can develop both respiratory and heart issues over time. Skeletal muscles can also experience weakness, which could mean a lifetime of disability, poor quality of life, and high cost of care.
Currently, there is no cure for muscular dystrophy, and there are only approved treatments that can slow down the disease's progression. However, researchers are considering different approaches to repair the muscles. From gene editing to developing drugs, researchers want to find a way to restore muscular growth in patients.
A study has found a new protein that signals muscle formation
Muscles are very dynamic in the way they grow and repair themselves. When you are exerting yourself, your muscular fibers are torn apart. However, our cells and tissues have the ability to repair and build muscular tissues throughout our lifetime.
The growth or repair of muscles starts from the multiplication of stem cells, which multiply and divide into myoblasts. Myoblasts are the building blocks of the muscles that are fused together to form muscular fibers.
Researchers at the University of Louisville studied the muscular cells of newborn children and adults, identifying them with a signaling protein, MyD88, which is required by the human body to fuse myoblasts together. They found that the participants did not have enough myoblasts and MyD88.
In one of the experiments, the MyD88 gene was deleted, and researchers found that although the myoblasts continued to multiply and differentiate, they failed to fuse together to form muscular fiber. On the other hand, over-expression of MyD88 promoted the fusion of myoblasts after an injury.
This concept of MyD88 and its role in the formation of muscular fibers were also tested in genetically modified mice. Researchers created a defect in the mice's MyD88 gene, and they saw that the mice failed to form muscular tissue even when the myoblasts were continuing to produce. However, they also saw that after they restored their ability to produce MyD88, the myoblasts fused together to form muscular tissues.
This discovery may be key to finding a standalone treatment for muscular dystrophy
Researchers believe that MyD88 can play an important role in muscular repair, it can be used as a standalone treatment or in combination with other therapies to aid damaged muscle cells. They also think that MyD88 can halt the damage and degeneration of muscle cells in muscular dystrophy, ultimately stopping the disease.
Currently, physical therapy is effective in slowing down muscular dystrophy symptoms. However, the exercise does not aid the myoblasts to stick together, so the muscles are not regaining any strength. If researchers found a safe way to bring up MyD88, then patients can benefit from physical therapy. MyD88 has the potential to be a powerful and effective compound to help patients gain muscular mass.
Stem cell therapy is becoming an emerging field in regenerative medicine. This class of technology is being replicated in multiple research labs across the nation. Soon, stem cells will be injected into weak or damaged muscular tissues to boost a patient's muscular strength and form myoblasts. However, in order for this therapy to work for muscular dystrophy patients, these myoblasts need an agent to help them fuse together. This is where MyD88 will come in.
This study shows that MyD88 is essential for the formation muscular tissues and strength. In the future, it could be used as a standalone therapy or together with a stem cell treatment. Either way, we need more research to understand the myoblasts' primary function and their role in forming muscular structures.
- Hindi SM, Shin J, Gallot YS, et al. MyD88 promotes myoblast fusion in a cell-autonomous manner. Nature Communications. 2017;8(1):1624. doi:10.1038/s41467-017-01866-w.
- Gilbert SF. Myogenesis: The Development of Muscle. 2000. https://www.ncbi.nlm.nih.gov/books/NBK10006/. Accessed December 17, 2017.
- UofL. UofL researchers discover key signaling protein for muscle growth — School of Medicine University of Louisville. http://louisville.edu/medicine/news/uofl-researchers-discover-key-signaling-protein-for-muscle-growth. Published November 20, 2017. Accessed December 17, 2017.