Skeletal Muscle Development: From Stem Cells to Body Movement

Development is the story of how stem cells multiply and specialise to differentiate into specific cell types which will make the tissues, organs and systems of the adult organism. In this chapter, this concept is illustrated by the example of the development of one tissue, namely skeletal muscle. Skeletal muscles are a component of the musculo-skeletal system which also includes the bones, tendons, nerves and blood vessels. All muscle stem cells (except the ones forming the muscles of the head) arise from specific transient mesodermal structures of early embryos called dermomyotomes. Along embryonic, then foetal and post-natal development, these cells are specified by a combination of different signals. They respond to these combinatory signals by migrating to their final destination, where they align and differentiate in perfect synchrony with the developing nerves, bones, tendons and blood vessels. During this process, some muscle stem cells keep their stemness until adulthood and are set aside, forming a reservoir of quiescent muscle stem cells. These cells, called satellite cells, are activated upon exercise, injury or disease. Knowing the story of muscle stem cells during development not only shows us how muscles are constructed but also provides a better understanding of the mechanisms of muscle-related diseases.