Stem Cells Responsible for Flatworm’s Regenerative Capabilities

After sequencing the genome of flatworms (Macrostomum lignano), researchers from Cold Springs Harbor Laboratory (CSHL) have concluded that it can regenerate parts of its entire body ? with the exception of its brain. According to the scientists, this has potential applications in stem cell research.

“This and other regenerating flatworms have the same kind of pathway operating in stem cells that is responsible for their remarkable regenerative capabilities.” Gregory Hannon, a CSHL professor, said in a news release. “As we started to try to understand the biology of these stem cells, it very quickly became clear that we needed information about the genetic content of these organisms.”

As certain species grow, base cells called stem cells develop into many different cell types. They also act as an internal repair system, dividing and replenishing other cells as needed, similar to how flatworms regenerate body parts that are injured.

Hannon was studying an important pathway in mammalian reproductive tissues when M. lignano caught his eye. When his researchers took a closer look, they found that the flatworm had a very complex genome with repetitive elements, which made it hard to assemble. This required the use of long-read, or high-quality, sequencing technology.

“At the genomic level it has almost no relationship to anything else that’s ever been sequenced. It’s very strange and unique in that sense,” notes Michael Schatz, a CSHL associate professor.

“The worms are just like floating sacks full of stem cells, so they’re very easily accessible,” said Kaja Wasik, the study’s lead author who conducted the work as a Ph.D. student in Hannon’s lab. “From what we looked at, it looks like many of the developmental pathways that are present in humans are also present in the worms, and we can now study whether they potentially could be involved in regeneration.”

M. lignano aids in stem cell researcher because it is small, has simple tissues, is transparent and uses sexual reproduction, the researchers noted. Sequencing the flatworm’s genome is a stepping stone in understanding exactly how its cells are able to regenerate.

Their findings were recently published in the journal Proceedings of the National Academy of Sciences.