Zebrafish chemical compound screen uncovers inducers of skeletal muscle engraftment across species

Stem cell transplantation presents a potentially curative strategy for genetic disorders of skeletal muscle, but the application of this approach has been limited due to the deleterious effects of cell expansion in vitro and poor engraftment efficiency. In an effort to overcome this hurdle, we sought to identify molecular signals that enhance the myogenic activity of cultured muscle progenitors. Here, we report the development and application of a cross-species small molecule screening platform employing zebrafish and mouse, which enables rapid, direct evaluation of the effects of chemical compounds on the engraftment of transplanted muscle precursor cells. Using this system, we screened a library of bioactive lipids to identify those that could increase myogenic engraftment in zebrafish and mice. These efforts identified two lipids, lysophosphatidic acid (LPA) and niflumic acid (NFA), both linked to activation of intracellular calcium ion flux, which showed conserved, dose-dependent and synergistic effects in promoting muscle engraftment across these vertebrate species. Overall design: To analyze the effect of LPA and NFA on gene expression of mice and zebrafsh muscle cells, we treated freshly isolated mice muscle stem cells and cultured zebrafish myogenic progenitor cells and the with 5uM LPA and 10 uM NFA for 2 hrs. Control treatment was done with DMSO.