How does Hydra regenerate? A type of freshwater organism, the Hydra appears to be completely ageless, with a remarkable ability to regenerate and renew after suffering injury. Researchers at the Friedrich Miescher Institute for Biomedical Research are using chemical screens to gain deeper insights into the underlying mechanisms behind this regenerative capacity, as Dr Charisios Tsiairis explains. Hydra is an
important model system in biology, with many researchers deeply interested in its remarkable ability to regenerate itself after suffering an injury. While the Hydra is a very good model system, it has one major shortcoming in comparison to others like Drosophila or C.elegans, which are also widely used in research. “It’s not practical to do genetic screens using Hydra. It’s not very easy to cross Hydra between themselves, to achieve reliable production of eggs and sperm,” explains Dr Charisios Tsiairis, a researcher in self-organising cellular systems at the FMI in Basel. Instead of doing a genetic screen, Dr Tsiairis is using chemical screens to gain deeper insights into the regenerative capacity of Hydra. “We know that many chemicals have specific functions in inhibiting certain kinases, transcription factors, or receptors, and so on. If we can get
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a big library of these chemicals, and expose Hydra to them separately, then we could identify the effect of disturbing the product of a certain gene,” he outlines.
Hydra regeneration This will help researchers identify the specific chemicals that disturb the proper regeneration of the Hydra, as well as those that enhance
or accelerate it. With the chemical screen, researchers first bisect the Hydra, then place them under different conditions. “We examine which conditions allow these Hydras to regenerate, and also how fast,” says Dr Tsiairis. Normally a Hydra takes four days to regenerate, and now Dr Tsiairis aims to identify which factors may slow this down or speed up regeneration, using large-scale chemical screens. “The big challenge with screens like this is doing it in a high-throughput manner. We plan to screen about 4,000 chemicals and for a lot of conditions, so we want to find ways to do this automatically,” he says. “It’s a high-throughput screen, so we don’t want to have to identify the ideal concentration for every single chemical, as that would be highly time-consuming. We have conducted a preliminary screen to pick out what would be a good concentration for the majority of chemicals, and we are using this concentration throughout.”
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