The slow myoblast cell culture as a model to understand the myogenesis and growth of slow-twitch muscle

Abstract

Skeletal muscle is the most abundant tissue in teleost fish, representing up to 65% of the total body mass. Skeletal muscle fibres are broadly classified as fast (fast-twitch muscle) and slow (slow-twitch muscle), which are found in separate compartments and have different contractile and metabolic properties. A class of small noncoding RNAs, known as microRNAs, plays an important post-transcriptional regulation of genes, controlling several aspects of muscle development. The in vitro fish myoblast cell culture has demonstrated a very useful tool to study muscle growth, development and regulation, since it recapitulates the steps of myogenesis: myoblast commitment, proliferation, fusion and myotube formation. In addition, the myoblast cell cultures can be manipulated to evaluate the role of different factors in the regulation of skeletal muscle myogenesis and growth. The compartmentalization of skeletal muscle in fish allows the establishment of individual myoblast cell cultures from fast and slow muscle, so that the physiological differences between these tissues could be better studied in such systems. However, the myoblast cell culture has been only developed for fast skeletal muscle, while a similar model for slow muscle remains to be established and explored. In this work we propose to develop a slow muscle cell culture in order to overcome the gap in knowledge about slow muscle development in comparison with fast skeletal muscle. The comparative study of slow and fast muscle cell culture, especially the role of muscle-specific microRNAs, will be useful to investigate differences between the molecular pathways that control the myogenic, metabolic, contractile and physiologic properties in the both muscle types. Our work will contribute to better understand the myogenesis regulation in fish, allowing the development of a theoretic framework that may help to improve muscle growth. (AU)