Heidelberg scientists examine key function in the process of regeneration
Unlike what is possible with the human eye, fish are able to regenerate injuries to the retina at the cellular level. Scientists at Heidelberg University's Centre for Organismal Studies (COS) have now decoded how this regeneration starts, using studies of the model organism of the Medaka fish.
Confocal microscopy image of a section through the medaka fish retina. Single Müller glia and photoreceptor cells are labelled in different colours by a genetic system (red, green, yellow). Atoh7 expression in Müller glia cells leads a regeneration response in the absence of injury, including expansion of the cell soma and neurogenic cluster formation.
Image credit: Katharina Lust und Joachim Wittbrodt
Surprisingly, a single genetic factor triggers two central steps in the process of regeneration – cell division and the differentiation of progenitors into the different retinal cell types. These research results are of great biomedical relevance, according to Prof. Dr Joachim Wittbrodt. They were published in the journal “Development”.
Stem cells in the body can be stimulated in such a way that they start to correct faults autonomously – so far this has merely been science fiction. And yet scientists hope that it will one day be possible to target and replace lost cells in the body.
They focus on the retina of fish, since – unlike humans – fish are able to completely regenerate all retinal nerve cells upon injury. Special glia cells take on the function of stem cells. Why do fish have this ability but not humans, although the human eye also contains these retinal glia cells, also known as Müller cells?
Can the potential of these cells be activated and what factors ultimately stimulate this regenerative reaction? These questions are explored by Prof. Wittbrodt and his team at COS. The Heidelberg scientists have come up with a surprising reply.
Apparently the short pulse of a single genetic factor suffices to stimulate regeneration. The significant factor for cell differentiation is the Atoh7 gene. “We did not think that this key function could be triggered by a single factor,” says Lázaro Centanin, who carried out the study with Prof. Wittbrodt.
Lázaro Centanin explains that the complete regeneration response in the fish eye comprises several steps. First the Müller cells near the injury start to proliferate. The resultant neuronal clusters contain the progenitor cells for the cell types of the retina. In the last step, these progenitors differentiate and turn into the neuronal retinal cells to be restored.
Prof. Wittbrodt adds: “We used the potential of the Müller cells in the Medaka fish in order to test for factors that can evoke exactly this regenerative reaction without any kind of injury.” The different genetic factors employed are relevant either for the increase and growth of cells or play a part in cell differentiation. Joachim Wittbrodt’s research group has established a biological test system enabling the testing of the activity of arbitrary genes specifically in the Müller cells with respect to their regenerative potential.
“We were completely surprised that, with the Atoh7 gene, a single cell differentiation factor fulfils two functions and triggers not only proliferation but also differentiation into different retinal cell types,” says Katharina Lust, the first author of the study that has just been published. To underline the biomedical significance of these research findings, Prof. Wittbrodt points to degenerative retinal diseases that accompany the loss of neuronal cells and lead to blindness in humans.
The factor Atoh7 could either be used to generate retinal progenitor cells for transplantation to the degenerating eye, or also to stimulate the Müller cells directly endogenously. “We still have a long way to go before we can regenerate the human retina by endogenous stimulation of Müller cells. But it is a goal to work towards – and is not mere science fiction,” says the Heidelberg scientist.
Prof. Dr. Joachim Wittbrodt
Centre for Organismal Studies
Phone +49 6221 54-6499
Communications and Marketing
Phone +49 6221 54-2311
Marietta Fuhrmann-Koch | idw - Informationsdienst Wissenschaft
How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH
A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology