Browsing by Author "Ruel, Tyler David"

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    Characterization of Muscle-Associated Cells in Adult Zebrafish
    (2019-12-20) Ruel, Tyler David; Huang, Peng; Childs, Sarah J.; Biernaskie, Jeff A.
    Skeletal muscles make up 40% of body weight in humans. Any compromises in muscle function will cause major consequences to the quality of a person’s life. It is therefore extremely important that this tissue is maintained in a state of homeostasis. To do this, muscle fibres that become damaged must be repaired by tissue-resident muscle-stem cells throughout the life of an animal. Several different kinds of muscle-associated cells have been described, including the two main populations: satellite cells (a population of muscle stem cells) and fibro/adipogenic progenitors (FAPs) (a population of mesenchymal stem cells). Using zebrafish as a model, the importance of muscle-associated cells in maintaining muscle homeostasis is demonstrated. Our lab has previously generated a col1a2¬-based transgenic line that labels collagen-expressing cells in zebrafish. Using a combination of immunohistochemistry and confocal microscopy, I characterize the dynamics and function of col1a2+ muscle-associated cells. A developmental time course shows that col1a2+ intramuscular cells increase in numbers during juvenile stages. In response to muscle injury, col1a2+ muscle-associated cells are expanded and contribute to muscle regeneration. Genetic ablation of col1a2+ cells, results in a compromised regenerative response. Using Cre-mediated lineage tracing, the developmental origin of intramuscular cells is traced to the dermomyotome and sclerotome, two sub-compartments of the embryonic somite. Finally, characterization of a col1a2 mutant line of zebrafish suggests that Type-I collagen is important for maintaining muscle integrity. These observations suggest the importance of col1a2+ muscle-associated cells in maintaining muscle homeostasis and for producing the extracellular matrix (ECM) within the skeletal muscle tissue to prevent degeneration.