Sea anemones study identifies potentially regenerative stem cells linked to conserved genes

The sea anemone Nematostella vectensis is potentially immortal. Using molecular genetic methods, developmental biologists led by Ulrich Technau of the University of Vienna have identified for the first time potential candidates for multipotent stem cells in the sea anemone.

These stem cells are regulated by evolutionarily highly conserved genes, which in humans are usually active only in the formation of eggs and sperm, but confer on ancient animal phyla such as cnidarians a high degree of regenerative capacity that even allows them to escape aging. The results are published in Scientific progress and could also provide insights into the human aging process in the future.

“We live as long as our stem cells” is a somewhat bold but essentially correct statement. Stem cells contribute to the constant renewal of various cells and tissues in humans, for example blood cells, skin or hair. If stem cells lose this ability or if their number decreases over the course of life, the body ages or develops diseases. Stem cells are therefore of great interest for biomedical research.

While humans and most vertebrates can only regenerate parts of certain organs or limbs, other groups of animals have much more powerful regenerative mechanisms. This ability is made possible by pluripotent or multipotent stem cells, which can form (differentiate) almost all cell types in the body.

The sea anemone Nematostella vectensis is also highly regenerative: it can reproduce asexually by budding and shows no signs of aging, making it an interesting subject for stem cell research. However, researchers have not yet been able to identify stem cells in this animal.

Using the new “Single Cell Genomics” method, Technau and his team were able to identify cells of a complex organism based on their specific transcriptome profiles and determine from which stem cells they developed.

“By combining single-cell gene expression analyses and transgenesis, we were able to identify a large population of cells in the sea anemone that form differentiated cells such as nerve cells and gland cells and are therefore candidates to become multipotent stem cells,” says first author Andreas Denner from the University of Vienna. They had previously remained unknown due to their small size.

These potential stem cells express the nanos and piwi genes, which are highly conserved in evolution and enable the development of germ cells (sperm and eggs) in all animals, including humans. By specifically mutating the nanos2 gene using CRISPR genetic scissors, the scientists were also able to prove that this gene is necessary for the formation of germ cells in sea anemones. This gene has also been shown in other animals to be essential for the production of gametes.

This proves that this genetic function emerged around 600 million years ago and has been preserved to this day. Ulrich Technau and his team now want to investigate which special properties of the sea anemone’s stem cells are responsible for its potential immortality.