Tiny wonders of the aquarium world, zebrafish can regenerate organs and tissues, including hearts, eye parts and fins. When a fin is lost, the fish regenerates a perfect copy in two weeks by orchestrating the growth of many tissue types, including bone, nerves, blood vessels, connective tissue and skin.
Scientists hope that understanding how zebrafish repair themselves will lead to new treatments for human conditions caused by damaged tissue, such as heart failure, diabetes and spinal cord injuries.
The regeneration regulator is one of a group of recently discovered molecules called microRNAs: small pieces of ribonucleic acid (RNA) that each can potentially control the activity of dozens of different genes. In humans, microRNAs play important roles in cell growth and death, among other functions. There are hundreds of kinds of microRNAs, and scientists are constantly discovering new roles they play.
In zebrafish, one or more microRNAs appear to be important to keep regeneration on hold until the fish needs new tissue, the Duke researchers say. In response to an injury, the fish then damp down levels of these microRNAs to aid regrowth. The team discovered that the ability of zebrafish to replace amputated fins is particularly sensitive to levels of a particular microRNA called miR-133.
The discovery makes sense because any animal that can rapidly grow new tissue needs to keep the system in check, said senior author Kenneth Poss, Ph.D., assistant professor of cell biology. "They probably need to have mechanisms to reduce the potential for unwelcome growth. The implication is that in order to make human tissue regenerate more effectively, we might want to look at some of these microRNAs as potential targets."
The results appear in the March 15, 2008 issue of the journal Genes & Development. Postdoctoral scholar Viravuth Yin, Ph.D., a member of Poss' lab, is first author on the study. Funding was provided by the National Institutes of Health, the American Heart Association, the Whitehead Foundation and Pew Charitable Trusts.
Poss and many other cell biologists believe that mammals may have the same tissue regeneration capability as zebrafish, salamanders and newts, but that it is locked away somewhere in our genome, silenced in the course of evolution. "The key is finding a way to turn on this regenerative ability in humans," Poss said.
The Duke researchers began their study by ferreting out any microRNAs present in fins at different stages of regrowth, then measuring whether there was a lot or a little of each molecule.
Dr. Poss' team eventually zeroed in on some of the most important microRNAs for regrowth by studying genetically modified zebrafish. The modification allows a critical signaling pathway to be shut down during regeneration. The pathway sends biochemical cues called growth factors that stimulate cell division and organ growth.
Levels of one microRNA in particular, miR-133, dropped during normal regeneration. But when the scientists blocked the signaling pathway briefly during regeneration, the amount of miR-133 jumped back up to the level found in uninjured fins. Further experiments showed that tweaking the concentration of miR-133 affected fin growth. When levels were raised, fin regrowth slowed; when they were dropped, regeneration sped up.
"Our work shows microRNAs appear to have an important role in regenerating complex tissues. Further studies could help us discover potential ways to stimulate this ability in mammals," Poss said.
Debbe Geiger | EurekAlert!
First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife
Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Life Sciences
25.10.2016 | Earth Sciences