Can the aging of cells be controlled?

The biological clock is ticking. All living things age. From single-celled organisms to elephants - all living things are subject to this natural law. No one can influence the advance of the clock hands, neither stop nor accelerate it. Can they? Not quite. It's a different story for the smallest living creatures. Members of the microbiology and macromolecular chemistry departments are investigating factors that influence cell aging. They are conducting this research as part of the "Clocks" Research Training Group. Prof. Dr. Raffael Schaffrath and Dr. Roland Klassen from the Department of Microbiology explain how to turn the clock hands forward and backward. "We are investigating factors that have an influence on cell aging," Klassen says. "The average lifespan of a living being is genetically pre-programmed. Elephants, for example, live to a very old age, unlike rodents, which often live only a few years or months," the biologist says. "We wanted to know if that could be changed."

Doesn't just help bake bread

How do you do that? How do you look into the clockwork of the biological clock? First of all, you need a model on which to test theories - and anyone who has ever baked a loaf of bread  knows this. "We use baker's yeast as a model system for our research," Klassen says. Yeast is particularly well suited for aging research. For researchers studying how cells develop, it is the ideal model. One advantage is that it doesn't live too long. It has a lifespan of about one month. So you can study its complete life cycle in a short time.

"Baking yeast was the first eukaryote to be completely sequenced," Klassen explains. "So it has been completely captured and studied in all its individual parts." A eukaryote is a living thing with a nucleus, and includes single-celled organisms and plants, as well as humans. Aging researchers have already discovered other things about baker's yeast: "For example, that a reduced calorie intake prolongs life ," Schaffrath says. "The single-cell organisms represent valuable tools for researching mechanisms of cell aging," the biologist says.

Influencing cell death

"Memento mori, remember your death, was said in the Middle Ages. This rule still applies today. But our possibilities to influence death - at least the death of a cell - have increased . Take rapamycin, for example. The team applied this compound to yeast. "We have conducted experiments with different agents and specifically looked for factors that can accelerate or delay cell death. With rapamycin, we had success," Klassen said. The compound prolonged the life cycle of the yeast cells. What opportunities does this work offer? Where are the results leading? The scientists cannot commit themselves. Empirical research is not a search for the fountain of youth. "Our goal is not to directly look for ways to prolong human life," Klassen emphasizes. But her work could make for exciting research. "Potentially, our results could be used in cancer research, for example. If we learn how to effectively influence cell death, such as speeding it up, perhaps we could use this knowledge to fight proliferating tumors."

"Like a clock"

Dr. Thomas Fuhrmann-Lieker is a professor in the Department of Macromolecular Chemistry and Molecular Materials. His object of study is diatoms. These organisms form the typical brown coating we know from our aquariums and are the model system for the research of Fuhrmann-Lieker's team. The team studies the self-assembly of materials, that is, how different substances form solid structures. "We are investigating how materials can organize themselves on the nanometer scale in order to use these structures in potential applications, such as photovoltaics," Fuhrmann-Lieker says. "We want to know how so-called 'soft materials' - substances that are neither gaseous nor crystalline - organize into solid materials."

"According to one theory, the cell wall of diatoms, also called diatoms, develops with the occurrence of instabilities and periodic separations of water- and oil-containing components," the chemist said. This enables the algae to create regular pore patterns in their cell wall by using as little genetic control as possible, he said. Fuhrmann-Lieker takes this a step further: by selectively adding specially functionalized molecules during the breeding of the algae, these are incorporated into the shell, resulting in novel composite materials with self-organized nanostructures.

Cell division plays a special role in the breeding process. "Cell division in diatoms shares similarities with, but also differs from, other unicellular eukaryotes in terms of cell aging due to their unique reproductive cycle," Fuhrmann-Lieker said. "The cell cycle and generation cycle function nested within each other like the gears of a clock." The chemists irradiate the diatoms with blue light, light rays of a specific wavelength. This is how they get the cells to divide all at the same time. As if on command. "In this way, we can influence the time factor in cell development."

"An enrichment for our work"

Collaboration with colleagues in other disciplines is helpful. "At the beginning, I couldn't even imagine working with the microbiology department," says Fuhrmann-Lieker. "After all, we are relatively far removed from biology in terms of methods. But our colleagues' methods are also an enrichment for our work. The cooperation broadens our horizons."

The biological clock is ticking. It cannot be stopped. But through the research of the Kassel natural scientists, we may learn to slow down or speed up the clockwork.

The Research Training Group Clocks
The Research Training Group "Biological Clocks" (abbreviated to "Clocks") at the University of Kassel was launched in 2017. The overall consortium is made up of working groups from biology, chemistry, physics and electrical engineering and is coordinated by Prof. Dr. Monika Stengl (Department of Animal Physiology); she has long been researching how internal clocks control physiological processes. Divided into four projects, the researchers are collecting data on cellular clocks and the temporal control of biological processes at different levels of complexity, such as neuron-driven behavior, metabolism, development and cell reproduction. Most members of the graduate program are also members of the Center for Interdisciplinary Nanostructure Science and Technology (CINSaT).

Click here to visit the Biological Clocks Research Training Group website: www.uni-kassel.de/projekte/graduiertenkolleg-biologische-uhren/startseite.html

By David Wüstehube

This article appeared in Publik 02/2019. Click here to access the full issue.