Researchers at the University of Vienna have discovered a key mechanism that enables sea anemones to regenerate into a fully developed organism from disorganised clusters of cells. The study, published in Nature Communications, shows that the so-called Notch signalling pathway controls tissue organisation and the formation of the body axis. The findings provide new insights into the fundamental rules of biological self-organisation and could help us better understand how tissues form, organise themselves and regenerate following disruption.
Animal development follows genetic programmes that control the formation of cells, tissues and body structures. At the same time, these processes are often remarkably robust: at least some organisms are able to restore their ordered body organisation even after significant disruptions. How this capacity for self-organisation is controlled at the molecular level is as yet only partially understood.
About the study
The research team led by Ulrich Technau, from the Faculty of Life Sciences at the University of Vienna, which is part of the Vienna BioCenter, investigated how cell aggregates of the sea anemone Nematostella vectensis regenerate into a complete organism after being separated. Despite their simple body structure, sea anemones possess numerous developmental genes and mechanisms that are also found in other animals. Among these evolutionarily conserved mechanisms is the Notch-Delta signalling pathway, a communication system between neighbouring cells that was the focus of the study.
A single signalling pathway coordinates the formation of tissues and the body axis
When sea anemone cells are separated from one another and subsequently brought back together, a fully formed organism re-emerges within a few days. In this process, the body axis and tissue layers are restored in their correct spatial arrangement – reproducibly and without the addition of any growth factors. Lead author Sanjay Narayanaswamy was able to demonstrate that the Notch signalling pathway is crucial to this process. It ensures that cells sort themselves correctly and that different tissue types are distinguished from one another. If the signalling pathway is experimentally blocked, this organisation no longer occurs. At the same time, Notch also controls the formation of the body axis.
Interaction between key developmental programmes
Further experiments showed that the Notch signalling pathway works closely with the Wnt signalling pathway, which also plays a central role in axis formation and body development. The interaction of such networks enables biological systems to re-establish ordered structures even after significant disruption.
Relevance beyond the sea anemone
The ability of cells to organise themselves is fundamental to the formation and regeneration of tissues. As Notch and Wnt signalling pathways are also present in many other animals and in humans, the findings extend beyond the biology of the sea anemone. "Our aim is to understand why cnidarians can use these molecular mechanisms to form complete organisms so efficiently through self-organisation," says Ulrich Technau. "We hope to be able to derive general principles of tissue organisation and regeneration from this."
Summary
- Sea anemones can form a complete organism again within a few days from randomly assembled clusters of cells.
- The Notch signalling pathway controls both the formation of the body axis and the organisation of various tissue layers.
- Notch acts in conjunction with the Wnt signalling pathway, another key communication system between cells.
- The findings provide new insights into the molecular basis of biological self-organisation, which also plays a role in humans.
- These findings contribute to our understanding of the processes by which cells organise tissues and build bodily structures.
About the University of Vienna:
At the University of Vienna, curiosity has been the core principle of academic life for more than 650 years. For over 650 years the University of Vienna has stood for education, research and innovation. Today, it is ranked among the top 100 and thus the top four per cent of all universities worldwide and is globally connected. With degree programmes covering over 180 disciplines, and more than 10,000 employees we are one of the largest academic institutions in Europe. Here, people from a broad spectrum of disciplines come together to carry out research at the highest level and develop solutions for current and future challenges. Its students and graduates develop reflected and sustainable solutions to complex challenges using innovative spirit and curiosity.
The Faculty of Life Sciences bridges fundamental biological research with pressing questions of our time. Significant parts of the faculty are located at the Vienna BioCenter in Vienna’s 3rd district, one of Europe's largest hubs for excellent biological research, with over 2,800 scientists. This collaborative environment fosters cutting-edge discoveries, attracting top talent from around the world.