Scientists have managed to find a way to activate head regeneration in a species of flatworm that usually has no regenerative abilities.
For humans, losing a limb is a traumatizing and life-changing event. It can take years to come to terms with life without an arm or leg and for some, phantom pains will haunt them for years. For other animals though, it isn’t quite as dramatic to lose a body part, and many species, including flatworms, arachnids and zebrafish, are able to regrow their lost limbs. Scientists have often wondered why some species have this ability while others don’t, and of course, they’ve also asked themselves if the ability can be activated in species that don’t usually exhibit regeneration. Now, researchers may have made a breakthrough.
Scientists from the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden have discovered a molecular “switch” in the flatworm species Dendrocoelum lacteum. The switch, hidden in the worm’s DNA, determines whether or not it can regenerate a head that has been severed. The scientists were able to manipulate this switch in such a way that the worm, which usually has no regenerative abilities, was indeed able to regrow the lost body part.
Jochen Rink, lead researcher on the team, had been studying a flatworm called Schmidtea mediterranea. The species is often used in regeneration research for its very powerful regenerative abilities: “We can cut the worm to 200 pieces, and 200 new worms will regenerate from each and every piece,” says Rink. Dendrocoelum lacteum is a close cousin to S. mediterranea, however it lacks the ability to regenerate limbs. Rink wanted to know why one species possessed the ability while the other didn’t.
It’s a worm, regenerating its head. Amazing!
His team began looking at the DNA of the two species, comparing them side-by-side. They focused specifically on Wnt-signaling pathways, which transmit information between cells. When they inhibited these pathways, the head would automatically regenerate. Strangely, the worm grew a fully functioning head, even when cut on the tail or other part of the body. “We thought we would have to manipulate hundreds of different switches to repair a regeneration defect; now we learned that sometimes only a few nodes may do,” explains Rink. Is this a first step towards regeneration among humans?