He axolotla mexican amphibianis known worldwide for its extraordinary ability to reshape legs, tail, parts of the heart and even portions of its brain.
A group of scientists led by the Harvard University in the USA revealed how that animal activates stem cells throughout its body to regrow complete limbs.
The discovery, which was published in the journal cellsurprises the scientific community and awakens hope for the medicine of the future.
“I am very excited to present the work of our laboratory and our collaborators, in which we discovered that axolotls use adrenaline signaling to regenerate their limbs,” said the regenerative biologist and leader of the study. Jessica Whited.
“We hope to translate our findings to mammals, including humans, in the future.” They now know that the loss of a limb triggers an activation response throughout the axolotl’s body that initiates regeneration.
whited worked with thirty researchers from the Department of Regenerative Biology and Stem Cells and colleagues from the Broad Institute, which depends on Harvard and the Massachusetts Institute of Technology (MIT).
He axolotl It has external gills, smooth skin and usually always appears “smiling”. Lives in fresh water and it rarely completes its larval stage, which allows it to retain its regenerative capabilities throughout life.
Unlike humans and almost all animals, the axolotl can reconstruct large portions of its body, such as legs, tail, part of the heart or even lost segments of the brain. This unique trait makes it a irreplaceable model to study regeneration.
Scientists were looking for clues to explain how it activates such complex cellular processes. The main objective of the Harvard researchers was “to describe the complete process of activation of stem and progenitor cells after injury, and how “They reprogram their genetic structure to initiate regeneration.”
In addition to its biological value, the axolotl faces risk of extinction in the wildwhich motivates research that helps protect it while potentially useful mechanisms for humans are discovered.
The researchers identified a mechanism coordinated by the sympathetic nervous systemresponsible for the so-called response “fight or flight.”
They demonstrated the importance of stress signaling hormoneadrenaline, to prepare cells for regeneration.
When an axolotl loses a limb, it generates a “blastema”, a mass formed by precursor cells capable of becoming any type of tissue necessary.
The group’s analyzes found that cellular activation occurs throughout the entire organism, even in areas that were not injured. The team highlighted that this systemic cellular activity prepares the other limbs to regenerate faster, a response that provides advantages to the axolotl in nature, where it faces predators and losing body parts is common.
“The animal seems to form a short term memory of the injury throughout the body,” he mentioned Duygu Payzin-Dogruco-author of the study, who is developing her postdoctoral degree on the subject.
Cells rearrange their DNA to make it easier to turn on regenerative genes when needed. This “state of preparation” only lasts a few cycles of cell division, since it involves a lot of energy expenditure. After a month, there is no longer a difference in the speed of regeneration.
The process involves two main routes: one alpha-adrenergic signaling that “prepares” distant cells, and a beta-adrenergic which promotes growth in the injured part. In parallel, the “mTOR” pathway, a protein that regulates tissue growth and repair, is activated at all times.
The experiment demonstrates that axolotl regeneration depends on the coordination of chemical and genetic signals, activated by acute stress and controlled by hormones present in many vertebrates, including people.
The researchers made it clear that currently “axolotls can regenerate complete limbs, but mammals cannot.” They also indicated that genetic and molecular controls in the mammalian organism “they restrict the natural regenerative capacity.”
But they highlighted: “This tells us that we could take advantage of some mechanisms found in the axolotl to improve regeneration in humans. “We have some of the same components and we just need to find the right way to implement them.”
