Harvard Stem Cell researchers have discovered that the same chemicals that stimulate muscle development in zebrafish can also be used to differentiate human stem cells into muscle cells in the laboratory, an historically challenging task that makes muscle cell therapy a more realistic clinical possibility.
The work, published in the journal Cell, began with a discovery by Boston Children's Hospital researchers, led by Leonard Zon, who tested 2,400 different chemicals in cultures of zebrafish embryo cells to determine if any could increase the numbers of muscle cells formed. Using fluorescent reporter fish in which muscle cells were visible during their creation, the researchers found six chemicals that were very effective at promoting muscle formation.
Zon shared his results with Amy Wagers at Harvard Department of Stem Cell and Regenerative Biology, who tested the six chemicals in mice. One of the six, called Forskolin, was found to increase the numbers of muscle stem cells from mice that could be obtained when these cells were grown in laboratory dishes. Moreover, the cultured cells successfully integrated into muscle when transplanted back into mice.
Inspired by the successful application of these chemicals in mice, Salvatore Iovino, in the Wagers lab and the lab of C. Ronald Kahn, at the Joslin Diabetes Center, investigated whether the chemicals would also affect human cells and found that a combination of three chemicals, including Forskolin, could induce differentiation of human induced pluripotent stem ( iPS ) cells, made by reprogramming skin cells. Exposure of iPS cells to these chemicals converted them into skeletal muscle, an outcome the Wagers and Kahn labs had been striving to achieve for years using conventional methods. When transplanted into a mouse, the human iPS-derived muscle cells also contributed to muscle repair, offering early promise that this protocol could provide a route to muscle stem cell therapy in humans. ( Xagena )
Source: Harvard University, 2013