Navigation Links
Tissue loss triggers regeneration in planarian flatworms

CAMBRIDGE, Mass. (September 3, 2013) Unlike humans, planarian flatworms have the remarkable ability to regrow any missing body part, making them an ideal model with which to study the molecular basis of regeneration.

Over the years scientists have learned that planarians mount recovery responses that differ depending on the severity of the injury they suffer. For example, a worm with a cut or a puncture wound reacts at the cellular and molecular levels quite differently from one that loses its head or tail. What has remained unclear, however, is just exactly how these responses are triggered.

Whitehead Institute Member Peter Reddien and two of his former graduate students, Michael Gavio and Danielle Wenemoser, address this longstanding question this week in the journal eLife, revealing a fascinating interplay of signals between two wound-induced genes.

According to the work of Gavino, Wenemoser, and Reddien, regeneration initiation in planarians is regulated by the expression of the genes Smed-follistatin (or fst) and Smed-activin-1 and -2 (or act-1 and act-2), that together act like a switch. After a planarian is wounded, the type of injury determines the level fst expressionthe more extreme the loss of tissue, the higher the level of fst expressed. At puncture wounds, fst expression is low, and regeneration is inhibited. However, following amputation, which results in major loss of tissue, fst levels rise and in turn inhibit Activin proteins, allowing regeneration to begin.

To the researchers' surprise, this interaction only affects regeneration and healing related to injury. Normal maintenance and cell turnover throughout the planarian body continue unaffected when fst is inhibited, even though these activities rely on the same neoblast cell population that creates new tissue during regeneration.

"It's a really great phenotype," says Reddien, who is also a Howard Hughes Medical Institute Early Career Scientist and an associate professor of biology at Massachusetts Institute of Technology. "It's one of the dream phenotypesto have a defect that's regeneration-specific, where the neoblasts are working. It's just regeneration that isn't working."

Such a phenotype could be a powerful tool in the further exploration of mechanisms that control regeneration. And many questions about these mechanisms remain.

"For example, the animals know how far to grow in regeneration, so they don't make tumorous outgrowths," says Wenemoser, who is now a postdoctoral researcher at Stanford University. "There's some kind of regulation on homeostatic size, so they're not growing out all wild and crazy. There's definitely more to investigate there."

Gavio agrees, and points out that the fst/act-1/2 switch may ultimately help scientists tease apart regeneration in other organisms, including humans.

"This regulation by activin and follistatin may be conserved in other systems," says Gavio, who is currently a postdoctoral researcher at Univeristy of California, San Francisco. "There are a lot of hints in the scientific literature that versions of activin or follistatin or both are activated by injury and may play a role in regeneration in other animals, but pinning the role of initiating regeneration to them hasn't happened yet."


Contact: Nicole Rura
Whitehead Institute for Biomedical Research

Related biology news :

1. Fetal tissue-derived stem cells may be ideal source for repairing tissues and organs
2. New protocol developed to decontaminate human fetal tissues used for cell transplantation
3. Ovarian cancer metastases influenced by factors in target tissues
4. Bacterial DNA may integrate into human genome more readily in tumor tissue
5. Improved material for laser welding of tissue in intestinal surgery
6. Building better blood vessels could advance tissue engineering
7. Even mild traumatic brain injuries can kill brain tissue
8. Molecular basis identified for tissue specific immune regulation in the eye and kidney
9. Stem cell-based bioartificial tissues and organs
10. UT Arlington bioengineer to use hybrid imaging system to see deep tissue
11. UT Arlington engineer wins NSF award to support microfluidic analyses of tissue, cell samples
Post Your Comments:
(Date:10/29/2015)... 2015 NXTD ) ("NXT-ID" ... on the growing mobile commerce market and creator ... a leading marketplace to discover and buy innovative ... wallet on StackSocial for this holiday season.   ... "Company"), a biometric authentication company focused on the ...
(Date:10/27/2015)... -- In the present market scenario, security is one ... verticals such as banking, healthcare, defense, electronic gadgets, and ... secure & simplified access control and growing rate of ... bank accounts, misuse of users, , and so on. ... and smartphones are expected to provide potential opportunities for ...
(Date:10/27/2015)... Oct. 27, 2015 Synaptics Inc. (NASDAQ: SYNA ... that Google has adopted the Synaptics ® ClearPad ... to power its newest flagship smartphones, the Nexus 5X ... --> --> Synaptics ... provide strategic collaboration in the joint development of next ...
Breaking Biology News(10 mins):
(Date:12/1/2015)... ... December 01, 2015 , ... ... relationship marketing company specializing in scientifically backed, age-defying products, is featured as ... which highlights the exponential success and unrivaled opportunities that Nerium provides. Success ...
(Date:12/1/2015)... Dallas, Texas (PRWEB) , ... December 01, 2015 ... ... its annual global meeting this month and Dr. J. Kyle Mathews ... worldwide.” This includes the new single site hysterectomy. , An experienced urogynecologist, founder ...
(Date:11/30/2015)... ... , ... Global Stem Cells Group announced that its scientific team ... isolating adipose-derived stem cells. The announcement starts a new phase toward launching the simple, ... component of the lipoaspirate obtained from liposuction of excess adipose tissue. , Lipoaspirate, ...
(Date:11/30/2015)... Dec. 1, 2015 /PRNewswire/ - BioAmber Inc. (NYSE: BIOA ), ... joined the American Business Act on Climate Pledge, alongside more ... standing with the Obama Administration to demonstrate an ongoing commitment ... outcome to the COP21 Paris climate ... Sarnia, Canada . --> BioAmber ...
Breaking Biology Technology: