“Sport for endothelial cells”

A Lab Visit to Prof. Hans-Joachim Schnittler / interview series by the Cells in Motion Cluster of Excellence
Prof. Hans-Joachim Schnittler, Managing Director of the Institute of Anatomy and Vascular Biology, and a member of the Cells in Motion Cluster of Excellence

Prof. Schnittler, what scientific topic are you working on right now?

I’m looking into cells that can be athletically trained. To be exact: endothelial cells. These are cells which provide a coating for blood vessels and thus form a barrier between blood and tissue. Blood flows constantly along the endothelial surface. As a result of this flow of blood, and of the blood pressure, there are mechanical tensions on endothelial cells which we call shear stress. These tensions vary greatly in the cardiovascular system, and if they exceed a certain threshold value, then endothelial cells constantly change their appearance, as well as their function. In a certain way we can describe this adaptation as training. One of the things we’re investigating is the extent to which cells become more resistant as a result of this training. This might, for example, be of considerable importance in inflammatory reactions through infections or allergies – and perhaps in the metastasis of tumours too.

What characterizes you personally as a scientist?

What I find exciting is creativity in science. In particular, I think the organization of cells is simply stunning. If I didn’t, I would undoubtedly not have remained faithful to research. I get a lot of pleasure from making science more accessible for young people. I like working with them and training them. At the same time it’s a great challenge too. I find it enormously stimulating to work together with scientists from different countries and cultures. You can see this in the internationality of our research group and in our international collaborations. In addition to the many German scientists at my Institute, we also have colleagues from China, Palestine, Belarus, Russia and Iran.

What’s your favourite “toy” for research – and what can it do?

Before I started to study medicine I completed an apprenticeship as a machine tool builder, and my technical understanding is something I can also use here at the University. Many years ago we developed our automated BTF Flow System here in Münster. Using this, we can produce defined blood flow profiles, for example, on cultivated endothelial cells and, at the same time, examine the barrier function of the cells. We combine the BTF System with techniques such as live cell fluorescence microscopy, super-resolution microscopy or – a very recent development – digital holography. I’ve also benefited from my technical training in equipping our magnificent PAN Centre. I’ve initiated and built up a system – the first of its kind in the world – for the conservation and storage of body donors. This was carried out in constant coordination with the partners from industry who built the system. The Deanery of the Medical Faculty had complete confidence in our project, which helped us greatly – as did the support given by Infrastructure Management at the University Hospital. When we conceived the system we took ethical aspects into account in order to handle the bodies donated in a respectful way, as well as taking into consideration workplace safety for our employees.

Can you remember your happiest moment as a scientist?

That was while I was working on my PhD in 1984. Together with my two laboratory heads I built up a shear stress system with which we were able to see, for the first time, how endothelial cells react under conditions similar to those in blood vessels. Under certain conditions they form actin and myosin cables, in other words stress fibres. They stabilize the cells, which are under mechanical stress. These fibres glowed back at me in the microscope, so to speak. That was great and it was probably the moment that sparked my lasting fascination with science.

Which scientific phenomenon still regularly fascinates you today?

The high dynamics of cells, how they form clusters and communicate with one another within these clusters. One of the ways this happens is via cell contacts which are built up from minute molecular complexes. With the aid of live-cell and super-resolution microscopy we can examine the dynamics of the molecular complexes in live cells. It is incredibly exciting to see how minute functional units are formed and how the proteins interact with one another – which in turn leads to changes in the form and function of cells. This is one of the major topics in our field of research, and we use these techniques to examine the regulation of cells during shear stress and infections.

How much artistry, creativity and craftsmanship is there in your research?

Researchers need a lot of empathy and imagination. They also have to develop fictions and hypotheses that they can then investigate. In my opinion, two important requirements for creative scientific work are fascination with your work and a certain ability to accept frustrations. Manual dexterity and a lot of discipline are also necessary to carry out the sometimes painstaking experiments.