Sara Wickström combines biophysics, next-generation sequencing, and basic cell biology to investigate how cellular forces regulate the fate and position of stem cells within epithelial tissues.
Recognizing the achievements of women in STEM (science, technology, engineering, and mathematics) contributes to establishing role models for new generations of girls who otherwise may grow up with the mistaken notion of “that career is not for me.” Sara Wickström felt this way in her teens. She dreamed of exploring the universe depicted in the tons of space books that she read while growing up in Espoo, a suburb of Helsinki, Finland. But, despite excelling in her class, she had little support from school to pursue a career in physics. Knowing her passion for science, her mother did a little research and found that the medical school at the University of Helsinki had just started an MD/PhD program where one could enter scientific research right from the start, so she encouraged Sara to try this path even though she didn’t show a genuine interest in medicine. Amid many doubts, Sara finally enrolled in both medicine and electrical engineering—the latter at the Helsinki University of Technology. It only took one summer rotation in a cell biology lab for her to realize that the universe she had longed for was under the microscope. Thus, she focused on medicine and got her MD with a license to practice in 2001 and her PhD a few years later, in 2004, working in the laboratory of Jorma Keski-Oja studying the extracellular matrix and cell adhesion in endothelial cells. After her PhD and having tested the waters of clinical practice—working as a general practitioner for 1 yr—Sara moved to Germany to do a postdoc in integrin signaling in the lab of Reinhard Fässler at the Max Planck Institute for Biochemistry in Munich. She started her own lab—focused on epithelial stem cells—in 2010 at the Max Planck Institute for the Biology of Ageing in Cologne, Germany. The Wickström lab then pivoted between Germany and Finland—they moved to the University of Helsinki in 2018 and finally relocated to Münster, where Sara took a leadership role at the Max Planck Institute for Molecular Biomedicine as full-time director in early 2022.
We contacted Sara to learn more about her scientific journey so far.
Coming from the integrin signaling field, what drove your interest toward skin stem cells?
The Fässler lab, where I did my postdoc, studies integrin adhesion in vivo in mice—I joined them to learn mouse work, although my projects there were still mainly cell biological as that was my core interest at that time. One of the tissue models the lab was frequently using to study integrins was the skin epidermis. I quickly realized that the epidermis is a pretty cool, dynamic tissue with a large number of open, fundamental cell biological questions—the first and foremost being how skin cells make a stratified epithelium and how they constantly coordinate their fate with their position during the dynamic turnover. As the tissue dynamics are driven by stem cells, I wanted to also enter that field, so I dedicated the focus of my own lab to these questions.
What are you currently working on?
There are two major focuses of my lab at the moment. The first one is trying to understand how tissue scale mechanics are communicated to single cells and how mechanical inputs across scales impact cell behavior. The second major focus is understanding how mechanical force, directly and indirectly, impacts chromatin and transcription and how this potentially regulates cell state.
It seems that you have unleashed your inner physicist-engineer from your teens in addressing how mechanical forces are sensed by single cells in the skin and how these inputs influence stem cell fate and behavior. Have you brought a special approach to the lab to integrate physics, engineering, and cell biology?
I have greatly enjoyed being able to bring back my early interests in physics and engineering into my research. I love interdisciplinary science and I love learning new things myself, but it is key to also rely on and work with experts in these fields to generate new rigorous ways to look at stem cell biology and tissue dynamics. When I hear talks or read papers from different fields, I immediately think how to transfer new cool concepts and tools from other fields into my own research.
What did you learn during your PhD and postdoc that helped prepare you for being a group leader? Is there anything you were unprepared for?
My PhD supervisor was totally hands-off, so I learned very early on how to conceive a project, write manuscripts, and correspond with journals. From my postdoc I learned the skill of doing meticulous science and using multiple different experimental approaches to study a biological phenomenon. What I wasn’t properly prepared for was the challenges of being a manager and mentor. I have had to learn a lot—sometimes the hard way—and feel that I’m still constantly learning.
Did you rely on other peers to navigate the ins and outs of academia and to approach new fields?
When I started my career as an independent principal investigator (PI), it was great meeting Carien Niessen in Cologne. She is such a generous scientist, always there to help others. She supported me enormously in the beginning; we had joint lab meetings and a lot of exciting discussions about science. These discussions have greatly shaped the research direction in my lab and continue to do so! I was also very lucky to meet Ana Pombo at the time when we had made our first observations on the effects of mechanical force on the nucleus and chromatin. I greatly admire her rigorous and thoughtful approach to science, and she has been extremely generous in helping me get into the chromatin field. There are also a lot of people in the skin stem cell and mechanobiology communities who are just fantastic, community-minded, and generous. I think it’s important to choose the field and the communities one wants to be involved in very carefully.
Carefully choosing the field and communities one wants to be involved in is unquestionably a great piece of advice. What is the best advice you have been given?
I have received a lot of great advice along the way. One that has stuck with me was a point made by Michael Sixt when I was discussing my faculty position applications way back as a postdoc. His advice was to think about the most fundamental open questions in your area and try to address them, instead of following trends or designing projects based on career strategy. I still think about this a lot, and being able to freely choose research interests and topics is for me my number one favorite thing in academia!
As you started your second decade of independent research, are there major accomplishments and challenges that you remember distinctly?
The biggest accomplishment is the successful careers the scientists that I have had the privilege to mentor over the years have gone on to have, both in academia and in the industry.
A major challenge has been moving countries with the lab; this has for me been harder than setting up the lab the first time around. It requires a lot of work to get things going in a new place with new people, getting used to different ways of doing things, especially all the administrative issues, as in many places there is not much support for that. Although I have to say that in the end it has also been rewarding, as changing location always forces change of perspective and brings new ideas.
The administrative tasks seem to be a burden for most scientists, irrespective of their career stages and institute affiliations. Is that what you would change in academia if you could?
Well… what I would really want is to reduce the competitive aspects of science, increasing collaboration, inclusiveness, and teamwork. I think the competitiveness often drives science onto sidetracks, away from addressing the most important questions and pursuing transformative ideas as people are forced or incentivized to go for low-hanging fruits and trends. This is of course a challenging issue to change and, when resources are limited, it is hard to come up with strategies to distribute the resources in a fair and balanced way.
And what would you do if resources were unlimited?
That’s easy to answer. I would surely use the money to pay competitive salaries to a group of interdisciplinary scientists with whom I would share all the administrative and office tasks so that we together would have more time just to do more exploratory, ambitious experimentation as a team.
I feel a certain nostalgia in your words; would you go back to the bench to do experiments if you could?
[Laughs] I miss doing experiments! But I’m not sure if I would go back to the bench for real. What I know is that, if I could rewind my trajectory as a PI, I would take time to just really enjoy the early days, working shoulder to shoulder at the bench with my first students.
Is there anything else you wish you had more time to enjoy?
In my youth I used to be a competitive alpine skier and later was a player and coach of Ultimate Frisbee on the national team. I continued doing that even when I was already a PI. These days I unfortunately do not have so much time for these hobbies, but I still enjoy doing sports such as hiking or tennis whenever I can. Once a year I try to find time to dust off my skis for some backcountry downhill skiing. I am lucky to have a partner who loves these things too, so we spend our summer and winter breaks in the mountains.