Meeting Abstract
Zebrafish (Danio rerio) and giant danio (Devario aequipinnatus) represent comparative growth models, providing valuable data for the understanding of adult growth potential. These species exhibit two muscle growth paradigms, determinate (zebrafish) and indeterminate (giant danio), allowing for an in-depth investigation into the pathways that regulate muscle growth. Recent studies have shown that myogenic precursor cells (MPCs, adult muscle cells) from these two species exhibit differential biomarkers and proliferation capacities. The present study utilized a primary myogenic cell culture system to test the hypothesis that MPCs exhibit specific phenotypes that are responsible for muscle growth potential in adult organisms. To test this, MPCs from each species were isolated and cultured under the same conditions. Proliferating myoblasts were treated with several molecules to assess growth hormone, transforming growth factor, insulin and insulin-like growth factor pathways for 4 days. The cellular phenotype was measured by analyzing cell proliferation, cell differentiation, and gene expression changes between growth paradigms. Giant danio MPCs exhibit greater proliferative capacity, in vitro, compared to zebrafish MPCs. Consistent with the proliferative data, zebrafish cells express higher levels of the myogenic lineage commitment marker myf5. Also, the expression of Pax-3 and -7 genes are differentially regulated between the growth paradigms and growth factor treatments, which likely modulates pathways responsible for establishing growth trajectories. These data suggest that giant danio and zebrafish can serve as excellent model organisms for studies investigating how myogenic precursor cell phenotypes likely can contribute to organismal growth potential.
