Navigation Links
Moving toward regeneration
Date:8/30/2012

KANSAS CITY, MOThe skin, the blood, and the lining of the gutadult stem cells replenish them daily. But stem cells really show off their healing powers in planarians, humble flatworms fabled for their ability to rebuild any missing body part. Just how adult stem cells build the right tissues at the right times and places has remained largely unanswered.

Now, in a study published in an upcoming issue of Development, researchers at the Stowers Institute for Medical Research describe a novel system that allowed them to track stem cells in the flatworm Schmidtea mediterranea. The team found that the worms' stem cells, known as neoblasts, march out, multiply, and start rebuilding tissues lost to amputation.

"We were able to demonstrate that fully potent stem cells can mobilize when tissues undergo structural damage," says Howard Hughes Medical Institute and Stowers Investigator Alejandro Snchez Alvarado, Ph.D., who led the study. "And these processes are probably happening to both you and me as we speak, but are very difficult to visualize in organisms like us."

Stem cells hold the potential to provide an unlimited source of specialized cells for regenerative therapy of a wide variety of diseases but delivering human stem cell therapies to the right location in the body remains a major challenge. The ability to follow individual neoblasts opens the door to uncovering the molecular cues that help planarian stem cells navigate to the site of injury and ultimately may allow scientists to provide therapeutic stem cells with guideposts to their correct destination.

"Human counterparts exist for most of the genes that we have found to regulate the activities of planarian stem cells," says Snchez Alvarado. "But human beings have these confounding levels of complexity. Planarians are much simpler making them ideal model systems to study regeneration."

Scientists had first hypothesized in the late 1800s that planarian stem cells, which normally gather near the worms' midlines, can travel toward wounds. The past century produced evidence both for and against the idea. Snchez Alvarado, armed with modern tools, decided to revisit the question.

For the new study, first author Otto C. Guedelhoefer, IV, Ph.D., a former graduate student in Snchez Alvarado's lab, exposed S. mediterranea to radiation, which killed the worms' neoblasts while leaving other types of cells unharmed. The irradiated worms would wither and die within weeks unless Guedelhoefer transplanted some stem cells from another worm. The graft's stem cells sensed the presence of a woundthe transplant sitemigrated out of the graft, reproduced and rescued their host. Unlike adult stem cells in humans and other mammals, planarian stem cells remain pluripotent in fully mature animals and remain so even as they migrate.

But when Guedelhoefer irradiated only a part of the worm's body, the surviving stem cells could not sense the injury and did not mobilize to fix the damage, which showed that the stem cells normally stay in place. Only when a fair amount of irradiated tissue died did the stem cells migrate to the injured site and start to rebuild. Next, Guedelhoefer irradiated a worm's body part and cut it with a blade. The surviving stem cells arrived at the scene within days.

To perform the experiments, Guedelhoefer adapted worm surgery and x-ray methods created sixty to ninety years ago. "Going back to the old literature was essential and saved me tons of time," says Guedelhoefer, currently a postdoctoral fellow at the University of California, Santa Barbara. He was able to reproduce and quantify results obtained in 1949 by F. Dubois, a French scientist, who first developed the techniques for partially irradiating planarians with x-rays.

But Guedelhoefer went further. He pinpointed the locations of stem cells and studied how far they dispersed using RNA whole-mount in situ hybridization (WISH), specifically adapted to planarians in Snchez Alvarado's lab. Using WISH, he observed both original stem cells and their progeny by tagging specific pieces of mRNA . The technique allowed him to determine that pluripotent stem cells can travel and produce different types of progeny at the same time.

"In other systems, most migrating stem cell progeny are not pluripotent," says Guedelhoefer. "For the most part, blood stem cells in humans stay in the bone marrow but their progeny leave and turn into a few other cell types." But in planarians, it looks like those two things are completely separate. Stem cells can move and maintain the full potential to turn into other types of cells."

Next, Snchez Alvarado looks forward to implementing genetic screens and transplantation experiments to disrupt or enhance the cellular behaviors the team observed, to figure out the "rules of engagement" for stem cell migration, he says.

"Why can some animals regenerate whole body parts but you and I are not good at it?" says Snchez Alvarado. "Can we write an extra rule or erase one? Is it possible, for instance, to get rid of cancer while gaining regenerative properties? These are questions we'd love to have answers to."


'/>"/>
Contact: Kristin Kessler
krk@stowers.org
816-926-4136
Stowers Institute for Medical Research
Source:Eurekalert  

Related biology news :

1. Developing policy on moving threatened species called a grand challenge for conservation
2. Researchers moving towards ending threat of West Nile virus
3. Lets get moving: Unraveling how locomotion starts
4. Zebra fish point the way towards new therapies for amyotrophic lateral sclerosis
5. Chromosomal translocations point the way toward personalized cancer care
6. Toward an alternative for antibiotics to fight bacterial infections?
7. A step toward minute factories that produce medicine inside the body
8. Towards an agroforestry policy in Indonesia
9. Natural regeneration building urban forests, altering species composition
10. Mice with big brains provide insight into brain regeneration and developmental disorders
11. Beating famine: Sustainable food security through land regeneration in a changing climate
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Moving toward regeneration
(Date:5/16/2017)... TEANECK, N.J. , May 16, 2017  Veratad ... leading provider of online age and identity verification solutions, ... the K(NO)W Identity Conference 2017, May 15 thru May ... Ronald Regan Building and International Trade Center. ... across the globe and in today,s quickly evolving digital ...
(Date:4/18/2017)... -- Socionext Inc., a global expert in SoC-based imaging and computing solutions, ... which features the company,s hybrid codec technology. A demonstration utilizing TeraFaces ... will be showcased during the upcoming Medtec Japan at Tokyo Big ... Las Vegas Convention Center April 24-27. ... Click here for an image of ...
(Date:4/11/2017)... DUBLIN , Apr. 11, 2017 Research ... Tracking Market 2017-2021" report to their offering. ... The global eye tracking market to grow at ... The report, Global Eye Tracking Market 2017-2021, has been prepared based ... report covers the market landscape and its growth prospects over the ...
Breaking Biology News(10 mins):
(Date:6/23/2017)... and CARDIFF, UK (PRWEB) , ... June 23, 2017 , ... ... and Brian Lula, president of Physik Instrumente USA, have been selected as this year’s ... photonics . , The two have been invited along with other honorees to accept ...
(Date:6/23/2017)... ... 23, 2017 , ... The Academy of Model Aeronautics (AMA), ... Association (UAA), the unifying voice for collegiate aviation education, are launching a joint ... and success through a STEM-based education platform. , Much like the program currently ...
(Date:6/22/2017)... ... June 21, 2017 , ... RMC Pharmaceutical ... and engages Timothy Reinhardt to manage the new site. , Tim has 25 ... with his most recent role as the Director of Manufacturing and Supplier Quality ...
(Date:6/22/2017)... Wendelsheim, Germany (PRWEB) , ... June 22, 2017 ... ... , is taking over the allergy specialists DST Diagnostische Systeme & Technologien GmbH, ... We all know someone who suffers from hay fever, urticaria, asthma, atopic eczema ...
Breaking Biology Technology: