A sea creature, part of the same family as jellyfish and corals, has the ability to transform its end-of-life cells into stem cells capable of regrowing part of its body.
- American and Irish researchers have discovered clues to healing and aging by studying Hydractinia symbiolongicarpus.
- It is a tube-shaped creature, which would be able to regenerate certain parts of its body using “aging” cells.
- She would eject these senescent cells from her mouth.
Researchers from the University of Galway (Ireland) recently turned their attention to a sea creature called “Hydractinia symbiolongicarpus”. This small, tube-shaped creature is in the same family as jellyfish and coral, but it has a unique ability to regenerate. The latter can regenerate an entire part of his body from a fragment of tissue and his mouth. This discovery has aroused the interest of the scientific community, as it raises important questions about the molecular mechanisms that underlie regeneration in living organisms.
A special group of stem cells for regeneration
As part of their research, published in the journal Cell Reports, the scientists carried out an RNA sequencing of the Hydractinia symbiolongicarpus. The authors discovered that this creature had a special group of stem cells for regeneration. The Hydractinia symbiolongicarpus stores its regenerative stem cells in the lower part of its body. However, when the researchers remove her mouth, which is a part away from where the stem cells reside, she grows new body parts. So the team hypothesized that this creature must be generating new stem cells and looked for molecular signals that could direct this process.
A molecular signature associated with the aging process
The researchers then identified a specific molecular signature associated with the biological process of aging, also known as “senescence”. “Most of the studies on senescence are related to chronic inflammation, cancer and age-related diseases. (…) Generally, in humans, senescent cells remain senescent, and these cells cause chronic inflammation and induce aging of adjacent cells. Through animals like Hydractinia, we can learn how senescence can be beneficial and expand our understanding of aging and healing.”explained Andy Baxevanis, doctor of science and one of the authors of the study, in a statement.
Aging: a gene linked to this biological process activated in stem cells
When RNA sequencing indicated senescence, scientists scanned the genome of Hydractinia symbiolongicarpus for sequences similar to those of genes linked to senescence in humans. Of the three genes they identified, one was “turned on” in cells near where the animal was cut. When the researchers deleted this gene, the animals’ ability to develop senescent cells was blocked, and without the senescent cells, the creatures did not develop new stem cells and could not regenerate.
Next, the team tracked “ageing” cells in Hydractinia symbiolongicarpus to find out how it circumvents the damaging effects of senescence. Unexpectedly, the creatures ejected the senescent cells from their mouths. Although humans cannot rid themselves of “aging” cells as easily, the role of senescence-related genes in Hydractinia symbiolongicarpus suggests how the aging process evolved. “We still don’t understand how senescent cells trigger regeneration or how widespread this process is in the animal kingdom,” said Andy Baxevanis.
