Champion of regeneration, the freshwater polyp Hydra is capable of reforming a complete individual from any fragment of its body. It is even able to remain alive when all its neurons have disappeared.
Researchers at the University of Geneva (UNIGE), Switzerland, have discovered how: cells of the epithelial type modify their genetic program by overexpressing a series of genes, among which some are involved in diverse nervous functions.
Studying Hydra cellular plasticity may thus influence research in the context of neurodegenerative diseases. The results are published in Philosophical Transactions, the journal of the Royal Society.
The freshwater Hydra is endowed with an extraordinary power of regeneration, discovered by the Swiss naturalist Abraham Trembley more than 250 years ago.
The group of Brigitte Galliot, professor at the Department of Genetics and Evolution of the Faculty of Science of UNIGE, has studied the stem cells functioning and cellular plasticity of the polyp: «its nervous system regulates in particular contraction bursts, feeding behavior, moving or swimming. If the stem cells responsible for its renewal are depleted, the Hydra can still develop, even when all its neurons have disappeared. We wanted to understand how this is possible.»
Enhancing other cells’ sensing ability
The researchers compared gene expression at various positions along the body axis in polyps devoid or not of their nervous stem cells. They observed a modification of the genetic program in animals depleted of these cells: «we identified 25 overexpressed genes in epithelial cells, the cells forming the Hydra’s coating tissues. Some of these genes are involved in diverse nervous functions, such as neurogenesis or neurotransmission», says Yvan Wenger, co-first author of the article.
«Epithelial cells do not possess typical neuronal functions. However, Hydra’s loss of neurogenesis induces epithelial cells to modify their genetic program accordingly, indicating that they are ready to assume some of these functions.
These “naturally” genetically modified epithelial cells are thus likely to enhance their sensitivity and response to environmental signals, to partially compensate for the lack of nervous system», explains Wanda Buzgariu, co-first author of the article. The detail of these new functions remains to be discovered, as well as how epithelial cells proceed to overexpress these genes and thus adapt their genetic program.
Cellular plasticity maintains youth
Studying Hydra’s cellular plasticity may be relevant in the context of neurodegenerative diseases. Indeed, some of the genes identified in this animal play an important role in cellular reprogramming or in neurogenesis in mammals. The researchers therefore wonder: would it be possible to restore sensing or secretion functions from other cell types, when some neurons degenerate?
This study also allows to go back to the origins of nervous systems. Epithelial cells most probably preceded nerve cells, performing some of their functions, although in a much slower way. «The loss of neurogenesis in Hydra may provide an opportunity to observe a reverse evolutive process, because it sheds light on a repressed ancestral genetic toolkit. An atavism of epithelial cells, when they most probably also possessed proto-neuronal functions», concludes Brigitte Galliot.
Phone: +41 22 379 77 96
Julie Michaud | newswise
Scientists discover new 'architecture' in corn
21.01.2019 | Louisiana State University
Nuclear actin filaments determine T helper cell function
21.01.2019 | Universitätsklinikum Heidelberg
The scientific and political community alike stress the importance of German Antarctic research
Joint Press Release from the BMBF and AWI
The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
21.01.2019 | Life Sciences
21.01.2019 | Physics and Astronomy
21.01.2019 | Life Sciences