Harvard researchers have used Zebrafish, a tropical freshwater fish, to develop a way to turn human stem cells into muscle tissue.

Led by Leonard I. Zon, a senior investigator and professor of stem cell and regenerative biology, the study developed a technique to screen for chemicals in the Zebrafish that could make tissues grow better in a dish. The researchers focused on muscle tissue, showing that certain chemicals can expand muscle cells in a dish.

“We were able to show that one of those chemicals would stimulate mouse adult muscle cells to divide, and that is very helpful for doing transplants,” Zon said. “And we were also able to find that in human muscle, we were able to take a human iPS cell, which is a stem cell line, and turn it into muscle with three other chemicals that we found in our Zebrafish screen.”

Co-author Amy Wagers, also a professor of stem cell and regenerative biology, said that one of the goals of the research is to work towards treating muscular disorders.

“The bottom line really is that we have new ways of boosting regenerative cells for muscles—of growing new cells in a culture dish so that we can study muscle disease and hopefully sometime soon use them to support muscle generation in patients who need support for muscle repair,” Wagers said.

Research fellow and co-author Salvatore Iovino said that the use of the Zebrafish was crucial in the experiment.

“Zebrafish is an amazing organism suitable to study development processes and perform drug screenings,” Iovino said. “This is mainly due to the fact that these fishes are very easy to keep and breed [and] they lay [approximately] 200 eggs every week, making them a very useful model for the study of the embryo development.”

Zon explained that the research is paving the way to create cells of any tissue in the body.

“We’re starting, with our Zebrafish system, to take apart every single type of tissue and develop a map of different chemicals that we can use to dial up a certain kind of tissue,” Zon said.

As for future studies, Wagers said that the lab is collaborating with other researchers “to use these new cells that we can isolate and do additional drug screening using diseased cells to see if we can get around the impairments in the cells that cause muscle disease.”