Heading for regeneration

July 24, 2013
Heading for regeneration
The planarian species Dendrocoeulum lacteum is incapable of regenerating a lost head. This sample however was genetically modified -- head regrowth was reactivated. Credit: MPI-CBG

The rabbit can't do it, neither can a frog, but zebrafish and axolotls can and flatworms are true masters of the craft: Regeneration. Why some animals can re-grow lost body parts or organs while others cannot remains a big mystery. And even more intriguing to us regeneration-challenged humans is the question whether one might be able to activate regenerative abilities in species that don't usually regenerate.

Researchers at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden are now one step further in understanding the factors that regulate regeneration. They discovered a crucial in the flatworm Dendrocoelum lacteum that decides whether a lost head can be regenerated or not. And what is even more spectacular: The scientists manipulated the genetic circuitry of the worm in such a way as to fully restore its regeneration potential.

In his lab, Jochen Rink, research group leader at the MPI-CBG, usually studies the flatworm species Schmidtea mediterranea. It is known for its excellent regenerative abilities and thus a popular model species in regeneration research: "We can cut the worm to 200 pieces, and 200 new worms will regenerate from each and every piece", Rink explains. Now, for a change, Rink and colleagues brought a different beast into the lab, the flatworm Dendrocoelum lacteum. Even though a close cousin of the regeneration master S. mediterranea, this species had been reported to be incapable of regenerating heads from its posterior body half. "What's the salient difference between the two cousins", the researcher asked?

Together with researchers from the Center for Regenerative Therapies Dresden Rink's team searched for an answer amongst the genes of the two species, focusing on the so-called Wnt-signaling pathway. Like a cable link between two computers, signalling pathways transmit information between cells. The Dresden researchers inhibited the signal transducer of the Wnt pathway with RNAi and thus made the cells of the worm believe that the signalling pathway had been switched to "off". Consequently, Dendrocoelum lacteum were able to grow a fully functional head everywhere, even when cut at the very tail.

Re-building a head complete with brain, eyes and all the wiring in between is evidently complicated business. However, as the study showed, regeneration defects are not necessarily irreversible. Jochen Rink is stunned: "We thought we would have to manipulate hundreds of different switches to repair a defect; now we learned that sometimes only a few nodes may do". Will this knowledge soon be applicable to more complex organisms – like humans, for example? "We showed that by comparisons amongst related species we can obtain insights into why some animals regenerate while others don't – that's an important first step".

Explore further: Scientists find protein critical for tissue regeneration

More information: DOI: 10.1038/nature12359
DOI: 10.1038/nature12414
DOI: 10.1038/nature12403

Related Stories

Scientists find protein critical for tissue regeneration

March 20, 2012

A flatworm known for its ability to regenerate cells is shedding more light on how cancer could be treated and how regenerative medicine could better target diseases, according to researchers at the University of California, ...

Do salamanders hold the solution to regeneration?

May 20, 2013

Salamanders' immune systems are key to their remarkable ability to regrow limbs, and could also underpin their ability to regenerate spinal cords, brain tissue and even parts of their hearts, scientists have found.

Fingernails reveal clues to limb regeneration

June 12, 2013

Mammals possess the remarkable ability to regenerate a lost fingertip, including the nail, nerves and even bone. In humans, an amputated fingertip can sprout back in as little as two months, a phenomenon that has remained ...

Recommended for you

Anti-tumor antibodies could counter atherosclerosis, study finds

July 20, 2016

Investigators at the Stanford University School of Medicine have learned the signal that tumor cells display on their surfaces to protect themselves from being devoured by the immune system also plays a role in enabling atherosclerosis, ...

A more powerful way to develop therapeutics?

July 21, 2016

A University of Toronto scientist has developed a new method for identifying the raw ingredients necessary to build 'biologics', a powerful class of medications that has revolutionized treatment of diseases like rheumatoid ...

Technique uses 3-D weaving to grow a living hip replacement

July 18, 2016

With a goal of treating worn, arthritic hips without extensive surgery to replace them, scientists have programmed stem cells to grow new cartilage on a 3-D template shaped like the ball of a hip joint. What's more, using ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.