Certain cells of the animal change to overcome the loss of its nervous system
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. Researcher 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 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.
Brigitte Galliot | EurekAlert!
Cells communicate in a dynamic code
19.02.2018 | California Institute of Technology
Studying mitosis' structure to understand the inside of cancer cells
19.02.2018 | Biophysical Society
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
19.02.2018 | Materials Sciences
19.02.2018 | Materials Sciences
19.02.2018 | Life Sciences